This semi-annual shareholder report contains important information about the State Street Aggregate Bond Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf. You can also request this information about the Fund by contacting us at 1-800-647-7327.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$23	0.46%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

^[1]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 3,376,762,098

Holdings Count | Holding

6,823

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,376,762,098
Number of Portfolio Holdings6,823
Portfolio Turnover Rate11%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
U.S. Treasury Obligations	45.7%
U.S. Government Agency Obligations	24.6%
Corporate Bonds & Notes	24.0%
Short-Term Investments	3.6%
Foreign Government Obligations	3.2%
Commercial Mortgage Backed Securities	0.4%
Mortgage-Backed Securities	0.4%
Asset-Backed Securities	0.3%
Municipal Bonds & Notes	0.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Notes, 4.13%, due 06/30/31	0.5%
U.S. Treasury Notes, 4.13%, due 02/15/36	0.4%
U.S. Treasury Notes, 3.38%, due 02/29/28	0.4%
U.S. Treasury Notes, 4.13%, due 06/15/29	0.4%
U.S. Treasury Notes, 4.25%, due 06/30/33	0.4%
U.S. Treasury Notes, 3.88%, due 03/31/28	0.4%
U.S. Treasury Notes, 4.25%, due 11/15/34	0.4%
U.S. Treasury Bonds, 5.00%, due 05/15/56	0.4%
U.S. Treasury Notes, 4.25%, due 08/15/35	0.4%
U.S. Treasury Notes, 4.00%, due 11/15/35	0.4%

C000136670

Shareholder Report [Line Items]

Fund Name

State Street Aggregate Bond Index Fund

Class Name

Class I

Trading Symbol

SSFDX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Aggregate Bond Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$0	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.01%

^[2]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 3,376,762,098

Holdings Count | Holding

6,823

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,376,762,098
Number of Portfolio Holdings6,823
Portfolio Turnover Rate11%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
U.S. Treasury Obligations	45.7%
U.S. Government Agency Obligations	24.6%
Corporate Bonds & Notes	24.0%
Short-Term Investments	3.6%
Foreign Government Obligations	3.2%
Commercial Mortgage Backed Securities	0.4%
Mortgage-Backed Securities	0.4%
Asset-Backed Securities	0.3%
Municipal Bonds & Notes	0.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Notes, 4.13%, due 06/30/31	0.5%
U.S. Treasury Notes, 4.13%, due 02/15/36	0.4%
U.S. Treasury Notes, 3.38%, due 02/29/28	0.4%
U.S. Treasury Notes, 4.13%, due 06/15/29	0.4%
U.S. Treasury Notes, 4.25%, due 06/30/33	0.4%
U.S. Treasury Notes, 3.88%, due 03/31/28	0.4%
U.S. Treasury Notes, 4.25%, due 11/15/34	0.4%
U.S. Treasury Bonds, 5.00%, due 05/15/56	0.4%
U.S. Treasury Notes, 4.25%, due 08/15/35	0.4%
U.S. Treasury Notes, 4.00%, due 11/15/35	0.4%

C000136669

Shareholder Report [Line Items]

Fund Name

State Street Aggregate Bond Index Fund

Class Name

Class K

Trading Symbol

SSFEX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Aggregate Bond Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$0	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.01%

^[3]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 3,376,762,098

Holdings Count | Holding

6,823

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,376,762,098
Number of Portfolio Holdings6,823
Portfolio Turnover Rate11%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
U.S. Treasury Obligations	45.7%
U.S. Government Agency Obligations	24.6%
Corporate Bonds & Notes	24.0%
Short-Term Investments	3.6%
Foreign Government Obligations	3.2%
Commercial Mortgage Backed Securities	0.4%
Mortgage-Backed Securities	0.4%
Asset-Backed Securities	0.3%
Municipal Bonds & Notes	0.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Notes, 4.13%, due 06/30/31	0.5%
U.S. Treasury Notes, 4.13%, due 02/15/36	0.4%
U.S. Treasury Notes, 3.38%, due 02/29/28	0.4%
U.S. Treasury Notes, 4.13%, due 06/15/29	0.4%
U.S. Treasury Notes, 4.25%, due 06/30/33	0.4%
U.S. Treasury Notes, 3.88%, due 03/31/28	0.4%
U.S. Treasury Notes, 4.25%, due 11/15/34	0.4%
U.S. Treasury Bonds, 5.00%, due 05/15/56	0.4%
U.S. Treasury Notes, 4.25%, due 08/15/35	0.4%
U.S. Treasury Notes, 4.00%, due 11/15/35	0.4%

C000143852

Shareholder Report [Line Items]

Fund Name

State Street Aggregate Bond Index Portfolio

Trading Symbol

SSAFX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Aggregate Bond Index Portfolio (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents. You can also request this information about the Fund by contacting us at 1-800-647-7327.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street Aggregate Bond Index Portfolio	$1	0.02%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.02%

^[4]

AssetsNet

$ 6,439,916,661

Holdings Count | Holding

6,823

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$6,439,916,661
Number of Portfolio Holdings6,823
Portfolio Turnover Rate11%

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
U.S. Treasury Obligations	45.7%
U.S. Government Agency Obligations	24.6%
Corporate Bonds & Notes	24.0%
Short-Term Investments	3.6%
Foreign Government Obligations	3.2%
Commercial Mortgage Backed Securities	0.4%
Mortgage-Backed Securities	0.4%
Asset-Backed Securities	0.3%
Municipal Bonds & Notes	0.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Notes, 4.13%, due 06/30/31	0.5%
U.S. Treasury Notes, 4.13%, due 02/15/36	0.4%
U.S. Treasury Notes, 3.38%, due 02/29/28	0.4%
U.S. Treasury Notes, 4.13%, due 06/15/29	0.4%
U.S. Treasury Notes, 4.25%, due 06/30/33	0.4%
U.S. Treasury Notes, 3.88%, due 03/31/28	0.4%
U.S. Treasury Notes, 4.25%, due 11/15/34	0.4%
U.S. Treasury Bonds, 5.00%, due 05/15/56	0.4%
U.S. Treasury Notes, 4.25%, due 08/15/35	0.4%
U.S. Treasury Notes, 4.00%, due 11/15/35	0.4%

C000246124

Shareholder Report [Line Items]

Fund Name

State Street Balanced Index Fund

Class Name

Class K

Trading Symbol

SSBIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Balanced Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$2	0.04%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 2

Expense Ratio, Percent

0.04%

^[5]

AssetsNet

$ 618,361,845

Holdings Count | Holding

2,494

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$618,361,845
Number of Portfolio Holdings2,494
Portfolio Turnover Rate7%

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Common Stocks	60.3%
Mutual Funds and Exchange Traded Products	39.2%
Short-Term Investments	0.9%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	39.2%
NVIDIA Corp.	4.0%
Apple, Inc.	3.5%
Microsoft Corp.	2.3%
Amazon.com, Inc.	1.9%
Alphabet, Inc., Class A	1.7%
Broadcom, Inc.	1.5%
Alphabet, Inc., Class C	1.4%
Micron Technology, Inc.	1.1%
Meta Platforms, Inc., Class A	1.0%

C000159454

Shareholder Report [Line Items]

Fund Name

State Street Emerging Markets Equity Index Fund

Class Name

Class K

Trading Symbol

SSKEX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Emerging Markets Equity Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$4	0.07%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 4

Expense Ratio, Percent

0.07%

^[6]

Material Change Date

Jun. 30, 2026

AssetsNet

$ 812,725,459

Holdings Count | Holding

1,102

InvestmentCompanyPortfolioTurnover

4.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$812,725,459
Number of Portfolio Holdings1,102
Portfolio Turnover Rate4%

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Taiwan	25.9%
South Korea	22.5%
China	14.7%
India	10.6%
Brazil	3.5%
Switzerland	2.9%
South Africa	2.4%
Saudi Arabia	2.3%
Mexico	1.7%
United Arab Emirates	1.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Taiwan Semiconductor Manufacturing Co. Ltd.	14.3%
Samsung Electronics Co. Ltd.	7.7%
SK Hynix, Inc.	7.2%
Tencent Holdings Ltd.	2.6%
Alibaba Group Holding Ltd.	1.5%
MediaTek, Inc.	1.5%
MSCI CHINA A INCLUSION Net Return USD Index, due 08/31/27	1.2%
UBS AG, due 06/04/27	0.9%
Delta Electronics, Inc.	0.9%
Samsung Electronics Co. Ltd.	0.8%

Material Fund Change [Text Block]

Material Fund Changes

This is a summary of certain changes of the Fund that occurred during the reporting period ended June 30, 2026. For more information contact 1-800-647-7327 (toll free) or refer to the Prospectus, which can be found on the Fund's website below.

Effective May 28, 2026, the Fund's principal investment strategy changed to reflect that although it is classified as “diversified” under the Investment Company Act of 1940, it may become “non‑diversified” solely as a result of tracking the Index, which may result in investing a relatively high percentage of its assets in a limited number of issuers.

Effective May 28, 2026, the Fund made changes to its principal strategy and added a corresponding risk, so that the Fund may become “non-diversified” solely as a result of tracking the MSCI Emerging Markets Index (e.g., changes in relative market capitalization or index weighting of one or more component securities). To the extent the Fund becomes non-diversified due solely to changes in the composition of its Index, it will not seek shareholder approval if and when the Fund shifts from diversified to non-diversified.

Material Fund Change Strategies [Text Block]

Material Fund Change Risks Change [Text Block]

Summary of Change Legend [Text Block]

C000029581

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Administrative Shares

Trading Symbol

STFAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Administrative Shares	$8	0.16%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 8

Expense Ratio, Percent

0.16%

^[7]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000136665

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Class A

Trading Symbol

SSSVX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$23	0.44%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.44%

^[8]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000136667

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Class I

Trading Symbol

SSSWX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$13	0.25%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 13

Expense Ratio, Percent

0.25%

^[9]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000136666

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Class K

Trading Symbol

SSSYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$1	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.01%

^[10]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000029583

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Class R Shares

Trading Symbol

SSFRX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R Shares	$32	0.61%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 32

Expense Ratio, Percent

0.61%

^[11]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000029582

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index Fund

Class Name

Service Shares

Trading Symbol

STBIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Service Shares	$14	0.26%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 14

Expense Ratio, Percent

0.26%

^[12]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 16,370,031,607

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$16,370,031,607
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000143850

Shareholder Report [Line Items]

Fund Name

State Street Equity 500 Index II Portfolio

Trading Symbol

SSEYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Equity 500 Index II Portfolio (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents. You can also request this information about the Fund by contacting us at 1-800-647-7327.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street Equity 500 Index II Portfolio	$1	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.01%

^[13]

AssetsNet

$ 24,967,693,908

Holdings Count | Holding

507

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$24,967,693,908
Number of Portfolio Holdings507
Portfolio Turnover Rate1%

Holdings [Text Block]

Top Ten Sectors

Table Summary
Sectors	%
Information Technology	37.3%
Financials	11.5%
Communication Services	9.5%
Consumer Discretionary	9.1%
Industrials	8.7%
Health Care	8.7%
Consumer Staples	4.5%
Energy	2.9%
Utilities	2.1%
Materials	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NVIDIA Corp.	7.4%
Apple, Inc.	6.5%
Microsoft Corp.	4.2%
Amazon.com, Inc.	3.5%
Alphabet, Inc., Class A	3.2%
Broadcom, Inc.	2.7%
Alphabet, Inc., Class C	2.5%
Micron Technology, Inc.	2.0%
Meta Platforms, Inc., Class A	1.9%
Tesla, Inc.	1.8%

C000251886

Shareholder Report [Line Items]

Fund Name

State Street Federal Government Money Market Fund

Class Name

Advantage Class

Trading Symbol

AGFXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Federal Government Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Advantage Class	$20	0.39%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 20

Expense Ratio, Percent

0.39%

^[14]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 191,471,683

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$191,471,683
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000251884

Shareholder Report [Line Items]

Fund Name

State Street Federal Treasury Money Market Fund

Class Name

Advantage Class

Trading Symbol

AFTXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Federal Treasury Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Advantage Class	$20	0.39%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 20

Expense Ratio, Percent

0.39%

^[15]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 143,263,438

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$143,263,438
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000251885

Shareholder Report [Line Items]

Fund Name

State Street Federal Treasury Plus Money Market Fund

Class Name

Advantage Class

Trading Symbol

ATPXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Federal Treasury Plus Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Advantage Class	$20	0.39%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 20

Expense Ratio, Percent

0.39%

^[16]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 107,652,690

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$107,652,690
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000136662

Shareholder Report [Line Items]

Fund Name

State Street Global All Cap Equity ex-U.S. Index Fund

Class Name

Class A

Trading Symbol

SSGHX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Global All Cap Equity ex-U.S. Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$26	0.49%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.49%

^[17]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 4,480,235,742

Holdings Count | Holding

5,631

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$4,480,235,742
Number of Portfolio Holdings5,631
Portfolio Turnover Rate6%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Japan	14.8%
Taiwan	8.9%
Canada	7.6%
South Korea	7.4%
United Kingdom	6.5%
China	6.0%
Germany	4.7%
Australia	4.6%
France	4.5%
India	4.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Taiwan Semiconductor Manufacturing Co. Ltd.	4.3%
Samsung Electronics Co. Ltd.	2.6%
SK Hynix, Inc.	2.2%
ASML Holding NV	1.8%
Tencent Holdings Ltd.	0.8%
HSBC Holdings PLC	0.8%
Novartis AG	0.7%
Roche Holding AG	0.7%
Royal Bank of Canada	0.7%
AstraZeneca PLC	0.7%

C000136664

Shareholder Report [Line Items]

Fund Name

State Street Global All Cap Equity ex-U.S. Index Fund

Class Name

Class I

Trading Symbol

SSGJX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$6	0.12%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 6

Expense Ratio, Percent

0.12%

^[18]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 4,480,235,742

Holdings Count | Holding

5,631

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$4,480,235,742
Number of Portfolio Holdings5,631
Portfolio Turnover Rate6%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Japan	14.8%
Taiwan	8.9%
Canada	7.6%
South Korea	7.4%
United Kingdom	6.5%
China	6.0%
Germany	4.7%
Australia	4.6%
France	4.5%
India	4.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Taiwan Semiconductor Manufacturing Co. Ltd.	4.3%
Samsung Electronics Co. Ltd.	2.6%
SK Hynix, Inc.	2.2%
ASML Holding NV	1.8%
Tencent Holdings Ltd.	0.8%
HSBC Holdings PLC	0.8%
Novartis AG	0.7%
Roche Holding AG	0.7%
Royal Bank of Canada	0.7%
AstraZeneca PLC	0.7%

C000136663

Shareholder Report [Line Items]

Fund Name

State Street Global All Cap Equity ex-U.S. Index Fund

Class Name

Class K

Trading Symbol

SSGLX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$2	0.03%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 2

Expense Ratio, Percent

0.03%

^[19]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 4,480,235,742

Holdings Count | Holding

5,631

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$4,480,235,742
Number of Portfolio Holdings5,631
Portfolio Turnover Rate6%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Japan	14.8%
Taiwan	8.9%
Canada	7.6%
South Korea	7.4%
United Kingdom	6.5%
China	6.0%
Germany	4.7%
Australia	4.6%
France	4.5%
India	4.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Taiwan Semiconductor Manufacturing Co. Ltd.	4.3%
Samsung Electronics Co. Ltd.	2.6%
SK Hynix, Inc.	2.2%
ASML Holding NV	1.8%
Tencent Holdings Ltd.	0.8%
HSBC Holdings PLC	0.8%
Novartis AG	0.7%
Roche Holding AG	0.7%
Royal Bank of Canada	0.7%
AstraZeneca PLC	0.7%

C000143853

Shareholder Report [Line Items]

Fund Name

State Street Global All Cap Equity ex-U.S. Index Portfolio

Trading Symbol

SSGVX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Global All Cap Equity ex-U.S. Index Portfolio (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents. You can also request this information about the Fund by contacting us at 1-800-647-7327.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street Global All Cap Equity ex-U.S. Index Portfolio	$2	0.03%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 2

Expense Ratio, Percent

0.03%

^[20]

AssetsNet

$ 12,141,019,088

Holdings Count | Holding

5,631

InvestmentCompanyPortfolioTurnover

4.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$12,141,019,088
Number of Portfolio Holdings5,631
Portfolio Turnover Rate4%

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Japan	14.8%
Taiwan	8.9%
Canada	7.6%
South Korea	7.4%
United Kingdom	6.5%
China	6.0%
Germany	4.7%
Australia	4.6%
France	4.5%
India	4.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Taiwan Semiconductor Manufacturing Co. Ltd.	4.3%
Samsung Electronics Co. Ltd.	2.6%
SK Hynix, Inc.	2.2%
ASML Holding NV	1.8%
Tencent Holdings Ltd.	0.8%
HSBC Holdings PLC	0.8%
Novartis AG	0.7%
Roche Holding AG	0.7%
Royal Bank of Canada	0.7%
AstraZeneca PLC	0.7%

C000155088

Shareholder Report [Line Items]

Fund Name

State Street Hedged International Developed Equity Index Fund

Class Name

Class K

Trading Symbol

SSHQX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Hedged International Developed Equity Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[21]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 4,700,201,015

Holdings Count | Holding

763

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$4,700,201,015
Number of Portfolio Holdings763
Portfolio Turnover Rate5%

Portfolio turnover rate is from the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Countries

Table Summary
Countries	%
Japan	21.7%
United Kingdom	10.2%
Germany	8.0%
France	7.6%
United States	6.8%
Australia	6.7%
Switzerland	5.8%
Netherlands	5.6%
Spain	3.5%
Italy	3.1%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
ASML Holding NV	3.3%
HSBC Holdings PLC	1.4%
Roche Holding AG	1.2%
Novartis AG	1.2%
AstraZeneca PLC	1.2%
Nestle SA	1.1%
Siemens AG	1.0%
Shell PLC	0.9%
Tokyo Electron Ltd.	0.9%
Mitsubishi UFJ Financial Group, Inc.	0.9%

C000143780

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Administration Class

Trading Symbol

SSKXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Institutional Treasury Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Administration Class	$18	0.36%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 18

Expense Ratio, Percent

0.36%

^[22]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000230479

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Bancroft Capital Class

Trading Symbol

VTTXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Bancroft Capital Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[23]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000231445

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Cabrera Capital Markets Class

Trading Symbol

CSJXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Cabrera Capital Markets Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[24]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000143781

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Institutional Class

Trading Symbol

SSJXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[25]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000052878

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Investment Class

Trading Symbol

TRVXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investment Class	$23	0.46%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

^[26]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000143782

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Investor Class

Trading Symbol

SSNXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$10	0.19%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.19%

^[27]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000231964

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Opportunity Class

Trading Symbol

OPRXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Opportunity Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[28]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000052877

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Money Market Fund

Class Name

Premier Class

Trading Symbol

TRIXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Premier Class	$6	0.11%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 6

Expense Ratio, Percent

0.11%

^[29]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 14,908,472,302

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$14,908,472,302
Number of Portfolio Holdings62

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Type

Table Summary
Asset	%
Treasury Debt	103.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
U.S. Treasury Bills, 3.58%, due 07/02/26	13.8%
U.S. Treasury Bills, 3.48%, due 07/09/26	8.6%
U.S. Treasury Bills, 3.61%, due 07/14/26	7.8%
U.S. Treasury Bills, 3.62%, due 07/07/26	5.8%
U.S. Treasury Floating Rate Notes, 3.96%, due 07/31/26	4.2%
U.S. Treasury Bills, 3.63%, due 08/18/26	3.8%
U.S. Treasury Bills, 3.64%, due 09/17/26	3.6%
U.S. Treasury Bills, 3.50%, due 08/13/26	3.6%
U.S. Treasury Bills, 3.61%, due 07/28/26	3.2%
U.S. Treasury Bills, 3.66%, due 08/25/26	3.2%

C000143785

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Administration Class

Trading Symbol

SSQXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Institutional Treasury Plus Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Administration Class	$18	0.36%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 18

Expense Ratio, Percent

0.36%

^[30]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000230480

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Bancroft Capital Class

Trading Symbol

VTLXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Bancroft Capital Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[31]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000231448

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Blaylock Van Class

Trading Symbol

BVYXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Blaylock Van Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[32]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000231447

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Cabrera Capital Markets Class

Trading Symbol

CAJXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Cabrera Capital Markets Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[33]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000143783

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Institutional Class

Trading Symbol

SAJXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[34]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000052879

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Investment Class

Trading Symbol

TPVXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investment Class	$23	0.46%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

^[35]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000143784

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Investor Class

Trading Symbol

SAEXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$10	0.19%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.19%

^[36]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000231965

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Opportunity Class

Trading Symbol

OPTXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Opportunity Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[37]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000052880

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Premier Class

Trading Symbol

TPIXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Premier Class	$6	0.11%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 6

Expense Ratio, Percent

0.11%

^[38]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000172254

Shareholder Report [Line Items]

Fund Name

State Street Institutional Treasury Plus Money Market Fund

Class Name

Trust Class

Trading Symbol

TPLXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Trust Class	$9	0.17%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 9

Expense Ratio, Percent

0.17%

^[39]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 80,785,024,474

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$80,785,024,474
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000143776

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Administration Class

Trading Symbol

SALXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Institutional U.S. Government Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Administration Class	$18	0.36%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 18

Expense Ratio, Percent

0.36%

^[40]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000230478

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Bancroft Capital Class

Trading Symbol

VTGXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Bancroft Capital Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[41]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000231443

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Blaylock Van Class

Trading Symbol

BUYXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Blaylock Van Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[42]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000231444

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Cabrera Capital Markets Class

Trading Symbol

CAHXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Cabrera Capital Markets Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[43]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000146109

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Class G

Trading Symbol

SSOXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can request additional information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class G	$4	0.07%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 4

Expense Ratio, Percent

0.07%

^[44]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000143775

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Institutional Class

Trading Symbol

SAHXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[45]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000052884

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Investment Class

Trading Symbol

GVVXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investment Class	$23	0.46%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

^[46]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000145476

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Investor Class

Trading Symbol

SAMXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$10	0.19%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.19%

^[47]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000276761

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Mercury Class

Trading Symbol

MRGXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Institutional U.S. Government Money Market Fund (the "Fund") for the period of June 24, 2026 (commencement of operations) through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Mercury Class	$0	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.06%

^[48]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Performance Inception Date

Jun. 24, 2026

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000231963

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Opportunity Class

Trading Symbol

OPGXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Opportunity Class	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[49]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000052883

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Premier Class

Trading Symbol

GVMXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Premier Class	$6	0.11%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 6

Expense Ratio, Percent

0.11%

^[50]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000069459

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Select Class

Trading Symbol

GVSXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Select Class	$4	0.08%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 4

Expense Ratio, Percent

0.08%

^[51]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000261738

Shareholder Report [Line Items]

Fund Name

State Street Institutional U.S. Government Money Market Fund

Class Name

Trust Class

Trading Symbol

GVBXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Trust Class	$9	0.17%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 9

Expense Ratio, Percent

0.17%

^[52]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 209,802,712,266

Holdings Count | Holding

241

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$209,802,712,266
Number of Portfolio Holdings241

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	32.8%
Treasury Debt	28.3%
Government Agency Repurchase Agreements	18.0%
Government Agency Debt	12.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	5.1%
FICCMS Tri Party Repo D, 3.65%, due 07/01/26	3.9%
FICCMS Tri Party Repo A, 3.64%, due 07/01/26	3.5%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	3.5%
Goldman Sacs Tri Party D, 3.65%, due 07/01/26	3.0%
FICCUB Bi Party Repo, 3.66%, due 07/01/26	2.6%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	2.6%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.5%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.4%
FICCNT Bi Party Repo, 3.65%, due 07/01/26	1.7%

C000158901

Shareholder Report [Line Items]

Fund Name

State Street Small/Mid Cap Equity Index Fund

Class Name

Class A

Trading Symbol

SSMJX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Small/Mid Cap Equity Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$26	0.48%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.48%

^[53]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 925,618,045

Holdings Count | Holding

2,473

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$925,618,045
Number of Portfolio Holdings2,473
Portfolio Turnover Rate5%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Industries

Table Summary
Industries	%
Biotechnology	7.1%
Banks	6.2%
Software	5.4%
Semiconductors & Semiconductor Equipment	5.3%
Aerospace & Defense	3.9%
IT Services	3.7%
Machinery	3.6%
Oil, Gas & Consumable Fuels	2.9%
Electronic Equipment, Instruments & Components	2.6%
Capital Markets	2.6%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Space Exploration Technologies Corp., Class A	1.0%
Snowflake, Inc.	1.0%
Bloom Energy Corp., Class A	0.9%
Cloudflare, Inc., Class A	0.9%
Astera Labs, Inc.	0.8%
Spotify Technology SA	0.8%
Rocket Lab Corp.	0.6%
Cheniere Energy, Inc.	0.6%
NU Holdings Ltd., Class A	0.5%
Ferguson Enterprises, Inc.	0.5%

C000158902

Shareholder Report [Line Items]

Fund Name

State Street Small/Mid Cap Equity Index Fund

Class Name

Class I

Trading Symbol

SSMLX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Small/Mid Cap Equity Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$15	0.27%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 15

Expense Ratio, Percent

0.27%

^[54]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 925,618,045

Holdings Count | Holding

2,473

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$925,618,045
Number of Portfolio Holdings2,473
Portfolio Turnover Rate5%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Industries

Table Summary
Industries	%
Biotechnology	7.1%
Banks	6.2%
Software	5.4%
Semiconductors & Semiconductor Equipment	5.3%
Aerospace & Defense	3.9%
IT Services	3.7%
Machinery	3.6%
Oil, Gas & Consumable Fuels	2.9%
Electronic Equipment, Instruments & Components	2.6%
Capital Markets	2.6%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Space Exploration Technologies Corp., Class A	1.0%
Snowflake, Inc.	1.0%
Bloom Energy Corp., Class A	0.9%
Cloudflare, Inc., Class A	0.9%
Astera Labs, Inc.	0.8%
Spotify Technology SA	0.8%
Rocket Lab Corp.	0.6%
Cheniere Energy, Inc.	0.6%
NU Holdings Ltd., Class A	0.5%
Ferguson Enterprises, Inc.	0.5%

C000158903

Shareholder Report [Line Items]

Fund Name

State Street Small/Mid Cap Equity Index Fund

Class Name

Class K

Trading Symbol

SSMKX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Small/Mid Cap Equity Index Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$2	0.03%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the corresponding portfolio in which the Fund invests.

Expenses Paid, Amount

$ 2

Expense Ratio, Percent

0.03%

^[55]

Expenses Represent Both Master and Feeder [Text]

Does not include expenses of the corresponding portfolio in which the Fund invests.

AssetsNet

$ 925,618,045

Holdings Count | Holding

2,473

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$925,618,045
Number of Portfolio Holdings2,473
Portfolio Turnover Rate5%

Portfolio turnover rate is from the corresponding Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Ten Industries

Table Summary
Industries	%
Biotechnology	7.1%
Banks	6.2%
Software	5.4%
Semiconductors & Semiconductor Equipment	5.3%
Aerospace & Defense	3.9%
IT Services	3.7%
Machinery	3.6%
Oil, Gas & Consumable Fuels	2.9%
Electronic Equipment, Instruments & Components	2.6%
Capital Markets	2.6%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Space Exploration Technologies Corp., Class A	1.0%
Snowflake, Inc.	1.0%
Bloom Energy Corp., Class A	0.9%
Cloudflare, Inc., Class A	0.9%
Astera Labs, Inc.	0.8%
Spotify Technology SA	0.8%
Rocket Lab Corp.	0.6%
Cheniere Energy, Inc.	0.6%
NU Holdings Ltd., Class A	0.5%
Ferguson Enterprises, Inc.	0.5%

C000158904

Shareholder Report [Line Items]

Fund Name

State Street Small/Mid Cap Equity Index Portfolio

Trading Symbol

SSMHX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Small/Mid Cap Equity Index Portfolio (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents. You can also request this information about the Fund by contacting us at 1-800-647-7327.

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/resources/master-portfolio-fund-documents

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street Small/Mid Cap Equity Index Portfolio	$1	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.01%

^[56]

AssetsNet

$ 2,967,156,008

Holdings Count | Holding

2,473

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$2,967,156,008
Number of Portfolio Holdings2,473
Portfolio Turnover Rate18%

Holdings [Text Block]

Top Ten Industries

Table Summary
Industries	%
Biotechnology	7.1%
Banks	6.2%
Software	5.4%
Semiconductors & Semiconductor Equipment	5.3%
Aerospace & Defense	3.9%
IT Services	3.7%
Machinery	3.6%
Oil, Gas & Consumable Fuels	2.9%
Electronic Equipment, Instruments & Components	2.6%
Capital Markets	2.6%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Space Exploration Technologies Corp., Class A	1.0%
Snowflake, Inc.	1.0%
Bloom Energy Corp., Class A	0.9%
Cloudflare, Inc., Class A	0.9%
Astera Labs, Inc.	0.8%
Spotify Technology SA	0.8%
Rocket Lab Corp.	0.6%
Cheniere Energy, Inc.	0.6%
NU Holdings Ltd., Class A	0.5%
Ferguson Enterprises, Inc.	0.5%

C000232295

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2025 Fund

Class Name

Class R3

Trading Symbol

SSAHX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2025 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$25	0.48%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.48%

^[57]

AssetsNet

$ 1,875,424,955

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,875,424,955
Number of Portfolio Holdings12
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	41.4%
Domestic Equity	22.0%
Inflation Linked	17.9%
International Equity	13.7%
Real Estate	4.9%
Short-Term Investments	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	21.1%
State Street Equity 500 Index II Portfolio	19.6%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	17.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	13.7%
State Street SPDR Portfolio Short Term Treasury ETF	7.8%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	2.5%
State Street SPDR Portfolio Short Term Corporate Bond ETF	2.0%

C000143868

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2025 Fund

Class Name

Class I

Trading Symbol

SSBRX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2025 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$6	0.11%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 6

Expense Ratio, Percent

0.11%

^[58]

AssetsNet

$ 1,875,424,955

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,875,424,955
Number of Portfolio Holdings12
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	41.4%
Domestic Equity	22.0%
Inflation Linked	17.9%
International Equity	13.7%
Real Estate	4.9%
Short-Term Investments	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	21.1%
State Street Equity 500 Index II Portfolio	19.6%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	17.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	13.7%
State Street SPDR Portfolio Short Term Treasury ETF	7.8%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	2.5%
State Street SPDR Portfolio Short Term Corporate Bond ETF	2.0%

C000143869

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2025 Fund

Class Name

Class K

Trading Symbol

SSBSX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2025 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$0	0.00%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Due to the Fund waiving acquired fund fees, the waiver exceeded total fund expenses. Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.00%

^[59]

AssetsNet

$ 1,875,424,955

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,875,424,955
Number of Portfolio Holdings12
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	41.4%
Domestic Equity	22.0%
Inflation Linked	17.9%
International Equity	13.7%
Real Estate	4.9%
Short-Term Investments	1.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	21.1%
State Street Equity 500 Index II Portfolio	19.6%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	17.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	13.7%
State Street SPDR Portfolio Short Term Treasury ETF	7.8%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	2.5%
State Street SPDR Portfolio Short Term Corporate Bond ETF	2.0%

C000232296

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2030 Fund

Class Name

Class R3

Trading Symbol

SSAJX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2030 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$26	0.51%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.51%

^[60]

AssetsNet

$ 3,476,848,136

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,476,848,136
Number of Portfolio Holdings13
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	32.2%
Domestic Equity	31.4%
International Equity	21.0%
Inflation Linked	12.1%
Real Estate	3.2%
Short-Term Investments	2.9%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	27.4%
State Street Global All Cap Equity ex-U.S. Index Portfolio	21.0%
State Street Aggregate Bond Index Portfolio	19.8%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	12.1%
State Street SPDR Bloomberg High Yield Bond ETF	6.5%
State Street Small/Mid Cap Equity Index Portfolio	4.1%
State Street SPDR Portfolio Long Term Treasury ETF	3.4%
State Street SPDR Dow Jones Global Real Estate ETF	3.2%
State Street SPDR Portfolio Short Term Treasury ETF	1.1%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	1.0%

C000143872

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2030 Fund

Class Name

Class I

Trading Symbol

SSBWX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2030 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$7	0.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.14%

^[61]

AssetsNet

$ 3,476,848,136

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,476,848,136
Number of Portfolio Holdings13
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	32.2%
Domestic Equity	31.4%
International Equity	21.0%
Inflation Linked	12.1%
Real Estate	3.2%
Short-Term Investments	2.9%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	27.4%
State Street Global All Cap Equity ex-U.S. Index Portfolio	21.0%
State Street Aggregate Bond Index Portfolio	19.8%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	12.1%
State Street SPDR Bloomberg High Yield Bond ETF	6.5%
State Street Small/Mid Cap Equity Index Portfolio	4.1%
State Street SPDR Portfolio Long Term Treasury ETF	3.4%
State Street SPDR Dow Jones Global Real Estate ETF	3.2%
State Street SPDR Portfolio Short Term Treasury ETF	1.1%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	1.0%

C000143873

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2030 Fund

Class Name

Class K

Trading Symbol

SSBYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2030 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$1	0.01%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.01%

^[62]

AssetsNet

$ 3,476,848,136

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,476,848,136
Number of Portfolio Holdings13
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	32.2%
Domestic Equity	31.4%
International Equity	21.0%
Inflation Linked	12.1%
Real Estate	3.2%
Short-Term Investments	2.9%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	27.4%
State Street Global All Cap Equity ex-U.S. Index Portfolio	21.0%
State Street Aggregate Bond Index Portfolio	19.8%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	12.1%
State Street SPDR Bloomberg High Yield Bond ETF	6.5%
State Street Small/Mid Cap Equity Index Portfolio	4.1%
State Street SPDR Portfolio Long Term Treasury ETF	3.4%
State Street SPDR Dow Jones Global Real Estate ETF	3.2%
State Street SPDR Portfolio Short Term Treasury ETF	1.1%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	1.0%

C000232297

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2035 Fund

Class Name

Class R3

Trading Symbol

SSAZX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2035 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$28	0.54%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 28

Expense Ratio, Percent

0.54%

^[63]

AssetsNet

$ 3,875,729,092

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,875,729,092
Number of Portfolio Holdings10
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	39.0%
Domestic Fixed Income	29.2%
International Equity	28.0%
Inflation Linked	2.9%
Short-Term Investments	1.2%
Real Estate	0.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	33.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	28.0%
State Street Aggregate Bond Index Portfolio	15.8%
State Street SPDR Portfolio Long Term Treasury ETF	8.1%
State Street Small/Mid Cap Equity Index Portfolio	5.8%
State Street SPDR Bloomberg High Yield Bond ETF	5.2%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	2.9%
State Street SPDR Dow Jones Global Real Estate ETF	0.7%

C000143876

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2035 Fund

Class Name

Class I

Trading Symbol

SSCJX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2035 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$9	0.17%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 9

Expense Ratio, Percent

0.17%

^[64]

AssetsNet

$ 3,875,729,092

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,875,729,092
Number of Portfolio Holdings10
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	39.0%
Domestic Fixed Income	29.2%
International Equity	28.0%
Inflation Linked	2.9%
Short-Term Investments	1.2%
Real Estate	0.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	33.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	28.0%
State Street Aggregate Bond Index Portfolio	15.8%
State Street SPDR Portfolio Long Term Treasury ETF	8.1%
State Street Small/Mid Cap Equity Index Portfolio	5.8%
State Street SPDR Bloomberg High Yield Bond ETF	5.2%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	2.9%
State Street SPDR Dow Jones Global Real Estate ETF	0.7%

C000143877

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2035 Fund

Class Name

Class K

Trading Symbol

SSCKX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2035 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$2	0.04%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 2

Expense Ratio, Percent

0.04%

^[65]

AssetsNet

$ 3,875,729,092

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,875,729,092
Number of Portfolio Holdings10
Portfolio Turnover Rate9%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	39.0%
Domestic Fixed Income	29.2%
International Equity	28.0%
Inflation Linked	2.9%
Short-Term Investments	1.2%
Real Estate	0.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	33.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	28.0%
State Street Aggregate Bond Index Portfolio	15.8%
State Street SPDR Portfolio Long Term Treasury ETF	8.1%
State Street Small/Mid Cap Equity Index Portfolio	5.8%
State Street SPDR Bloomberg High Yield Bond ETF	5.2%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	2.9%
State Street SPDR Dow Jones Global Real Estate ETF	0.7%

C000232298

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2040 Fund

Class Name

Class R3

Trading Symbol

SSAKX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2040 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[66]

AssetsNet

$ 3,659,144,589

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,659,144,589
Number of Portfolio Holdings8
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	43.4%
International Equity	31.7%
Domestic Fixed Income	24.7%
Short-Term Investments	1.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	35.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	31.8%
State Street Aggregate Bond Index Portfolio	12.2%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	7.5%
State Street SPDR Bloomberg High Yield Bond ETF	2.8%

C000143880

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2040 Fund

Class Name

Class I

Trading Symbol

SSCNX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2040 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$10	0.20%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.20%

^[67]

AssetsNet

$ 3,659,144,589

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,659,144,589
Number of Portfolio Holdings8
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	43.4%
International Equity	31.7%
Domestic Fixed Income	24.7%
Short-Term Investments	1.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	35.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	31.8%
State Street Aggregate Bond Index Portfolio	12.2%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	7.5%
State Street SPDR Bloomberg High Yield Bond ETF	2.8%

C000143881

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2040 Fund

Class Name

Class K

Trading Symbol

SSCQX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2040 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[68]

AssetsNet

$ 3,659,144,589

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,659,144,589
Number of Portfolio Holdings8
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	43.4%
International Equity	31.7%
Domestic Fixed Income	24.7%
Short-Term Investments	1.7%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	35.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	31.8%
State Street Aggregate Bond Index Portfolio	12.2%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	7.5%
State Street SPDR Bloomberg High Yield Bond ETF	2.8%

C000232299

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2045 Fund

Class Name

Class R3

Trading Symbol

SSAOX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2045 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[69]

AssetsNet

$ 3,496,455,714

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,496,455,714
Number of Portfolio Holdings7
Portfolio Turnover Rate7%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	47.2%
International Equity	34.6%
Domestic Fixed Income	18.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	37.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	34.6%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	9.4%
State Street Aggregate Bond Index Portfolio	8.4%

C000143884

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2045 Fund

Class Name

Class I

Trading Symbol

SSDDX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2045 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$12	0.23%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 12

Expense Ratio, Percent

0.23%

^[70]

AssetsNet

$ 3,496,455,714

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,496,455,714
Number of Portfolio Holdings7
Portfolio Turnover Rate7%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	47.2%
International Equity	34.6%
Domestic Fixed Income	18.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	37.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	34.6%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	9.4%
State Street Aggregate Bond Index Portfolio	8.4%

C000143885

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2045 Fund

Class Name

Class K

Trading Symbol

SSDEX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2045 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[71]

AssetsNet

$ 3,496,455,714

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,496,455,714
Number of Portfolio Holdings7
Portfolio Turnover Rate7%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	47.2%
International Equity	34.6%
Domestic Fixed Income	18.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	37.9%
State Street Global All Cap Equity ex-U.S. Index Portfolio	34.6%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Small/Mid Cap Equity Index Portfolio	9.4%
State Street Aggregate Bond Index Portfolio	8.4%

C000232290

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2050 Fund

Class Name

Class R3

Trading Symbol

SSAUX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2050 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[72]

AssetsNet

$ 3,063,838,130

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,063,838,130
Number of Portfolio Holdings6
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	50.1%
International Equity	36.7%
Domestic Fixed Income	13.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	38.7%
State Street Global All Cap Equity ex-U.S. Index Portfolio	36.7%
State Street Small/Mid Cap Equity Index Portfolio	11.4%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Aggregate Bond Index Portfolio	3.4%

C000143828

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2050 Fund

Class Name

Class I

Trading Symbol

SSDJX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2050 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$11	0.21%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 11

Expense Ratio, Percent

0.21%

^[73]

AssetsNet

$ 3,063,838,130

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,063,838,130
Number of Portfolio Holdings6
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	50.1%
International Equity	36.7%
Domestic Fixed Income	13.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	38.7%
State Street Global All Cap Equity ex-U.S. Index Portfolio	36.7%
State Street Small/Mid Cap Equity Index Portfolio	11.4%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Aggregate Bond Index Portfolio	3.4%

C000143829

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2050 Fund

Class Name

Class K

Trading Symbol

SSDLX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2050 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[74]

AssetsNet

$ 3,063,838,130

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$3,063,838,130
Number of Portfolio Holdings6
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	50.1%
International Equity	36.7%
Domestic Fixed Income	13.0%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	38.7%
State Street Global All Cap Equity ex-U.S. Index Portfolio	36.7%
State Street Small/Mid Cap Equity Index Portfolio	11.4%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%
State Street Aggregate Bond Index Portfolio	3.4%

C000232291

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2055 Fund

Class Name

Class R3

Trading Symbol

SSAWX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2055 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[75]

AssetsNet

$ 2,440,323,367

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$2,440,323,367
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000143832

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2055 Fund

Class Name

Class I

Trading Symbol

SSDOX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2055 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$10	0.20%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.20%

^[76]

AssetsNet

$ 2,440,323,367

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$2,440,323,367
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000143833

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2055 Fund

Class Name

Class K

Trading Symbol

SSDQX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2055 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[77]

AssetsNet

$ 2,440,323,367

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$2,440,323,367
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000232292

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2060 Fund

Class Name

Class R3

Trading Symbol

SSAYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2060 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[78]

AssetsNet

$ 1,816,038,285

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,816,038,285
Number of Portfolio Holdings5
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000143836

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2060 Fund

Class Name

Class I

Trading Symbol

SSDWX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2060 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$10	0.19%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.19%

^[79]

AssetsNet

$ 1,816,038,285

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,816,038,285
Number of Portfolio Holdings5
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000143837

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2060 Fund

Class Name

Class K

Trading Symbol

SSDYX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2060 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[80]

AssetsNet

$ 1,816,038,285

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,816,038,285
Number of Portfolio Holdings5
Portfolio Turnover Rate6%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.1%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.2%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.1%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000232300

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2065 Fund

Class Name

Class R3

Trading Symbol

SSFPX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2065 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$29	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.56%

^[81]

AssetsNet

$ 663,928,435

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

4.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$663,928,435
Number of Portfolio Holdings5
Portfolio Turnover Rate4%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.0%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000216582

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2065 Fund

Class Name

Class I

Trading Symbol

SSFJX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2065 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$16	0.30%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 16

Expense Ratio, Percent

0.30%

^[82]

AssetsNet

$ 663,928,435

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

4.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$663,928,435
Number of Portfolio Holdings5
Portfolio Turnover Rate4%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.0%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000216583

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2065 Fund

Class Name

Class K

Trading Symbol

SSFKX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2065 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[83]

AssetsNet

$ 663,928,435

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

4.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$663,928,435
Number of Portfolio Holdings5
Portfolio Turnover Rate4%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	52.0%
International Equity	38.1%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.1%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000253750

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2070 Fund

Class Name

Class I

Trading Symbol

SSGQX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2070 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[84]

AssetsNet

$ 94,789,074

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$94,789,074
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	51.9%
International Equity	38.2%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.2%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000253751

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2070 Fund

Class Name

Class K

Trading Symbol

SSGNX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2070 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[85]

AssetsNet

$ 94,789,074

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$94,789,074
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	51.9%
International Equity	38.2%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.2%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000253749

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement 2070 Fund

Class Name

Class R3

Trading Symbol

SSGUX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement 2070 Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$17	0.33%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 17

Expense Ratio, Percent

0.33%

^[86]

AssetsNet

$ 94,789,074

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

5.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$94,789,074
Number of Portfolio Holdings5
Portfolio Turnover Rate5%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Equity	51.9%
International Equity	38.2%
Domestic Fixed Income	9.6%
Short-Term Investments	0.3%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
State Street Equity 500 Index II Portfolio	39.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	38.2%
State Street Small/Mid Cap Equity Index Portfolio	13.0%
State Street SPDR Portfolio Long Term Treasury ETF	9.6%

C000232293

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement Fund

Class Name

Class R3

Trading Symbol

SSFQX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class R3	$23	0.46%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.46%

^[87]

AssetsNet

$ 1,395,140,994

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,395,140,994
Number of Portfolio Holdings12
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	50.1%
Inflation Linked	18.0%
Domestic Equity	16.7%
International Equity	10.2%
Real Estate	4.9%
Short-Term Investments	1.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	19.9%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	18.0%
State Street SPDR Portfolio Short Term Treasury ETF	15.8%
State Street Equity 500 Index II Portfolio	15.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	10.2%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Portfolio Short Term Corporate Bond ETF	4.0%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	1.7%

C000143856

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement Fund

Class Name

Class I

Trading Symbol

SSFNX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class I	$5	0.10%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 5

Expense Ratio, Percent

0.10%

^[88]

AssetsNet

$ 1,395,140,994

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,395,140,994
Number of Portfolio Holdings12
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	50.1%
Inflation Linked	18.0%
Domestic Equity	16.7%
International Equity	10.2%
Real Estate	4.9%
Short-Term Investments	1.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	19.9%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	18.0%
State Street SPDR Portfolio Short Term Treasury ETF	15.8%
State Street Equity 500 Index II Portfolio	15.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	10.2%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Portfolio Short Term Corporate Bond ETF	4.0%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	1.7%

C000143857

Shareholder Report [Line Items]

Fund Name

State Street Target Retirement Fund

Class Name

Class K

Trading Symbol

SSFOX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Target Retirement Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

Additional Information Phone Number

1-800-647-7327

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=mf

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class K	$0	0.00%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Due to the Fund waiving acquired fund fees, the waiver exceeded total fund expenses. Does not include expenses of the Underlying Funds in which the Fund invests.

Expenses Paid, Amount

$ 0

Expense Ratio, Percent

0.00%

^[89]

AssetsNet

$ 1,395,140,994

Holdings Count | Holding

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$1,395,140,994
Number of Portfolio Holdings12
Portfolio Turnover Rate8%

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Domestic Fixed Income	50.1%
Inflation Linked	18.0%
Domestic Equity	16.7%
International Equity	10.2%
Real Estate	4.9%
Short-Term Investments	1.5%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
State Street Aggregate Bond Index Portfolio	19.9%
State Street SPDR Bloomberg 1-10 Year TIPS ETF	18.0%
State Street SPDR Portfolio Short Term Treasury ETF	15.8%
State Street Equity 500 Index II Portfolio	15.0%
State Street Global All Cap Equity ex-U.S. Index Portfolio	10.2%
State Street SPDR Bloomberg High Yield Bond ETF	7.0%
State Street SPDR Dow Jones Global Real Estate ETF	4.9%
State Street SPDR Portfolio Short Term Corporate Bond ETF	4.0%
State Street SPDR Bloomberg Enhanced Roll Yield Commodity Strategy No. K-1 ETF	3.5%
State Street Small/Mid Cap Equity Index Portfolio	1.7%

C000192374

Shareholder Report [Line Items]

Fund Name

State Street Treasury Obligations Money Market Fund

Trading Symbol

TAQXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Treasury Obligations Money Market Fund (the "Fund") for the period of January 1, 2026 through June 30, 2026.

Additional Information [Text Block]

You can request additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information by contacting us at 1-866-392-0869.

Additional Information Phone Number

1-866-392-0869

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street Treasury Obligations Money Market Fund	$4	0.08%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

Expenses Paid, Amount

$ 4

Expense Ratio, Percent

0.08%

^[90]

Expenses Represent Both Master and Feeder [Text]

The expense table reflects the proportionate share of expenses allocated to the Fund by the affiliated Portfolio, in which the Fund invests.

AssetsNet

$ 4,721,462,836

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$4,721,462,836
Number of Portfolio Holdings96

Reflects holdings of the Portfolio, in which the Fund invests.

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Treasury Repurchase Agreements	57.9%
Treasury Debt	35.0%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	11.2%
FICCRP Tri Party Repo A, 3.64%, due 07/01/26	7.0%
FICCIN Tri Party Repo A, 3.64%, due 07/01/26	3.5%
BBVARP BBVARP Tri Party Repo A, 3.64%, due 07/01/26	3.0%
FICCBA Tri Party Repo A, 3.65%, due 07/01/26	2.9%
FICCWB Tri Party Repo A, 3.64%, due 07/01/26	2.8%
FICCNT Bi Party Repo, 3.64%, due 07/01/26	2.6%
U.S. Treasury Floating Rate Notes, 3.88%, due 01/31/28	2.6%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	2.5%
CIBC NY CORP Tri Party Repo A, 3.64%, due 07/01/26	2.3%

C000271009

Shareholder Report [Line Items]

Fund Name

State Street<sup style="inset: 1.5px 0px 4px; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 16px; font-weight: 700; grid-area: auto; line-height: 0px; margin: 0px; overflow: visible; position: relative; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">®</sup> Stablecoin Reserves Money Market Fund

Class Name

Capital Class

Trading Symbol

SSCXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street^® Stablecoin Reserves Money Market Fund (the "Fund") for the period of June 8, 2026 (commencement of operations) through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Capital Class	$1	0.18%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.18%

^[91]

Performance Inception Date

Jun. 08, 2026

AssetsNet

$ 121,044,641

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$121,044,641
Number of Portfolio Holdings10

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Treasury Repurchase Agreements	96.9%
Treasury Debt	4.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Deutsche Tri Party A, 3.64%, due 07/01/26	16.5%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	16.5%
Wells Fargo Bank NA A, 3.64%, due 07/01/26	16.5%
Bank of America Tri Party A Repo, 3.64%, due 07/01/26	12.6%
HSBC Tri Party A, 3.64%, due 07/01/26	12.4%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	12.4%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	9.9%
U.S. Treasury Bills, 3.64%, due 08/18/26	1.6%
U.S. Treasury Bills, 3.63%, due 09/17/26	1.6%
U.S. Treasury Bills, 3.66%, due 08/13/26	1.0%

C000271008

Shareholder Report [Line Items]

Fund Name

Class Name

Preferred Class

Trading Symbol

SSRXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Preferred Class	$1	0.12%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 1

Expense Ratio, Percent

0.12%

^[92]

Performance Inception Date

Jun. 08, 2026

AssetsNet

$ 121,044,641

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$121,044,641
Number of Portfolio Holdings10

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Treasury Repurchase Agreements	96.9%
Treasury Debt	4.3%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
Deutsche Tri Party A, 3.64%, due 07/01/26	16.5%
Goldman Sachs Tri Party A, 3.64%, due 07/01/26	16.5%
Wells Fargo Bank NA A, 3.64%, due 07/01/26	16.5%
Bank of America Tri Party A Repo, 3.64%, due 07/01/26	12.6%
HSBC Tri Party A, 3.64%, due 07/01/26	12.4%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	12.4%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26	9.9%
U.S. Treasury Bills, 3.64%, due 08/18/26	1.6%
U.S. Treasury Bills, 3.63%, due 09/17/26	1.6%
U.S. Treasury Bills, 3.66%, due 08/13/26	1.0%

C000271298

Shareholder Report [Line Items]

Fund Name

State Street Prime Retail Reserves Money Market Fund

Class Name

Advantage Class

Trading Symbol

PAVXX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street Prime Retail Reserves Money Market Fund (the "Fund") for the period of March 13, 2026 (commencement of operations) through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Advantage Class	$10	0.32%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 10

Expense Ratio, Percent

0.32%

^[93]

Performance Inception Date

Mar. 13, 2026

Material Change Date

Jun. 30, 2026

AssetsNet

$ 29,467,148

Holdings Count | Holding

102

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$29,467,148
Number of Portfolio Holdings102

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Financial Company Commercial Paper	19.1%
Certificates Of Deposit	19.0%
Government Agency Repurchase Agreements	18.7%
Treasury Repurchase Agreements	13.6%
Asset Backed Commercial Paper	12.4%
Other Repurchase Agreements	10.9%
Other Notes	5.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NatWest Markets Tri A, 3.64%, due 07/01/26	6.8%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/27/26	6.8%
Wells Fargo Bank NA D, 3.65%, due 07/01/26	6.8%
TD Securities USA Tri Party, 3.64%, due 07/01/26	6.8%
Goldman Sachs Tri Party D, 3.65%, due 07/01/26	6.8%
Bank of America Tri Party D Repo, 3.65%, due 07/01/26	5.1%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	3.4%
Abu Dhabi Islamic Bank, 3.62%, due 07/01/26	2.2%
Wells Fargo Bank NA, 3.89%, due 02/10/27	1.4%
BNG Bank NV, 3.64%, due 07/02/26	1.2%

Material Fund Change [Text Block]

Material Fund Changes

This is a summary of certain changes of the Fund that occurred during the reporting period ended June 30, 2026. For more information contact 1-866-392-0869 (toll free) or refer to the Prospectus, which can be found on the Fund's website below.

Effective May 19th, 2026, the Fund’s name changed from the State Street Federal Prime Retail Reserves Money Market Fund to the State Street Prime Retail Reserves Money Market Fund. This change did not result in any changes to the Fund’s Investment Objective, Principal Investment Strategies or Principal Risks of Investing in the Fund.

Material Fund Change Name [Text Block]

Summary of Change Legend [Text Block]

C000271297

Shareholder Report [Line Items]

Fund Name

State Street Prime Retail Reserves Money Market Fund

Class Name

Advisory Class

Trading Symbol

PRDXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Advisory Class	$11	0.35%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 11

Expense Ratio, Percent

0.35%

^[94]

Performance Inception Date

Mar. 13, 2026

Material Change Date

Jun. 30, 2026

AssetsNet

$ 29,467,148

Holdings Count | Holding

102

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$29,467,148
Number of Portfolio Holdings102

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Financial Company Commercial Paper	19.1%
Certificates Of Deposit	19.0%
Government Agency Repurchase Agreements	18.7%
Treasury Repurchase Agreements	13.6%
Asset Backed Commercial Paper	12.4%
Other Repurchase Agreements	10.9%
Other Notes	5.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NatWest Markets Tri A, 3.64%, due 07/01/26	6.8%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/27/26	6.8%
Wells Fargo Bank NA D, 3.65%, due 07/01/26	6.8%
TD Securities USA Tri Party, 3.64%, due 07/01/26	6.8%
Goldman Sachs Tri Party D, 3.65%, due 07/01/26	6.8%
Bank of America Tri Party D Repo, 3.65%, due 07/01/26	5.1%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	3.4%
Abu Dhabi Islamic Bank, 3.62%, due 07/01/26	2.2%
Wells Fargo Bank NA, 3.89%, due 02/10/27	1.4%
BNG Bank NV, 3.64%, due 07/02/26	1.2%

Material Fund Change [Text Block]

Material Fund Changes

Material Fund Change Name [Text Block]

Summary of Change Legend [Text Block]

C000271301

Shareholder Report [Line Items]

Fund Name

State Street Prime Retail Reserves Money Market Fund

Class Name

Agency Class

Trading Symbol

PRAXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Agency Class	$8	0.25%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 8

Expense Ratio, Percent

0.25%

^[95]

Material Change Date

Jun. 30, 2026

AssetsNet

$ 29,467,148

Holdings Count | Holding

102

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$29,467,148
Number of Portfolio Holdings102

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Financial Company Commercial Paper	19.1%
Certificates Of Deposit	19.0%
Government Agency Repurchase Agreements	18.7%
Treasury Repurchase Agreements	13.6%
Asset Backed Commercial Paper	12.4%
Other Repurchase Agreements	10.9%
Other Notes	5.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NatWest Markets Tri A, 3.64%, due 07/01/26	6.8%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/27/26	6.8%
Wells Fargo Bank NA D, 3.65%, due 07/01/26	6.8%
TD Securities USA Tri Party, 3.64%, due 07/01/26	6.8%
Goldman Sachs Tri Party D, 3.65%, due 07/01/26	6.8%
Bank of America Tri Party D Repo, 3.65%, due 07/01/26	5.1%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	3.4%
Abu Dhabi Islamic Bank, 3.62%, due 07/01/26	2.2%
Wells Fargo Bank NA, 3.89%, due 02/10/27	1.4%
BNG Bank NV, 3.64%, due 07/02/26	1.2%

Material Fund Change [Text Block]

Material Fund Changes

Material Fund Change Name [Text Block]

Summary of Change Legend [Text Block]

C000271300

Shareholder Report [Line Items]

Fund Name

State Street Prime Retail Reserves Money Market Fund

Class Name

Capital Class

Trading Symbol

PCPXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Capital Class	$5	0.18%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 5

Expense Ratio, Percent

0.18%

^[96]

Performance Inception Date

Mar. 13, 2026

Material Change Date

Jun. 30, 2026

AssetsNet

$ 29,467,148

Holdings Count | Holding

102

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$29,467,148
Number of Portfolio Holdings102

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Financial Company Commercial Paper	19.1%
Certificates Of Deposit	19.0%
Government Agency Repurchase Agreements	18.7%
Treasury Repurchase Agreements	13.6%
Asset Backed Commercial Paper	12.4%
Other Repurchase Agreements	10.9%
Other Notes	5.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NatWest Markets Tri A, 3.64%, due 07/01/26	6.8%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/27/26	6.8%
Wells Fargo Bank NA D, 3.65%, due 07/01/26	6.8%
TD Securities USA Tri Party, 3.64%, due 07/01/26	6.8%
Goldman Sachs Tri Party D, 3.65%, due 07/01/26	6.8%
Bank of America Tri Party D Repo, 3.65%, due 07/01/26	5.1%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	3.4%
Abu Dhabi Islamic Bank, 3.62%, due 07/01/26	2.2%
Wells Fargo Bank NA, 3.89%, due 02/10/27	1.4%
BNG Bank NV, 3.64%, due 07/02/26	1.2%

Material Fund Change [Text Block]

Material Fund Changes

Material Fund Change Name [Text Block]

Summary of Change Legend [Text Block]

C000271299

Shareholder Report [Line Items]

Fund Name

State Street Prime Retail Reserves Money Market Fund

Class Name

Cash Management Class

Trading Symbol

PCMXX

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash. You can also request this information about the Fund by contacting us at 1-866-392-0869 .

Material Fund Change Notice [Text Block]

This report describes changes to the Fund that occurred during the reporting period.

Additional Information Phone Number

1-866-392-0869

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=cash

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Cash Management Class	$5	0.15%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 5

Expense Ratio, Percent

0.15%

^[97]

Performance Inception Date

Mar. 13, 2026

Material Change Date

Jun. 30, 2026

AssetsNet

$ 29,467,148

Holdings Count | Holding

102

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$29,467,148
Number of Portfolio Holdings102

Holdings [Text Block]

Asset Allocation

Table Summary
Asset Types	%
Financial Company Commercial Paper	19.1%
Certificates Of Deposit	19.0%
Government Agency Repurchase Agreements	18.7%
Treasury Repurchase Agreements	13.6%
Asset Backed Commercial Paper	12.4%
Other Repurchase Agreements	10.9%
Other Notes	5.8%

Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holdings	%
NatWest Markets Tri A, 3.64%, due 07/01/26	6.8%
JP Morgan Sec LLC Tpr A, 3.64%, due 07/27/26	6.8%
Wells Fargo Bank NA D, 3.65%, due 07/01/26	6.8%
TD Securities USA Tri Party, 3.64%, due 07/01/26	6.8%
Goldman Sachs Tri Party D, 3.65%, due 07/01/26	6.8%
Bank of America Tri Party D Repo, 3.65%, due 07/01/26	5.1%
Credit Agricole Corporate Tri Party A Repo, 3.64%, due 07/01/26	3.4%
Abu Dhabi Islamic Bank, 3.62%, due 07/01/26	2.2%
Wells Fargo Bank NA, 3.89%, due 02/10/27	1.4%
BNG Bank NV, 3.64%, due 07/02/26	1.2%

Material Fund Change [Text Block]

Material Fund Changes

Material Fund Change Name [Text Block]

Summary of Change Legend [Text Block]

C000269915

Shareholder Report [Line Items]

Fund Name

Trading Symbol

MMK

Security Exchange Name

NYSEArca

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the State Street^® Prime Money Market ETF (the "Fund") for the period of February 12, 2026 (commencement of operations) through June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund, including the Prospectus, Statement of Additional Information, financial statements and other information at www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=etfs. You can also request this information about the Fund by contacting us at 1-866-787-2257.

Additional Information Phone Number

1-866-787-2257

Additional Information Website

www.ssga.com/us/en/institutional/fund-finder?tab=documents&type=etfs

Expenses [Text Block]

What were the Fund costs for the last six months? (based on a hypothetical $10,000 Investment)

Table Summary
Fund Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
State Street^® Prime Money Market ETF	$7	0.18%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

The dollar amount above reflects expenses paid since the commencement of operations. Expenses for the full reporting period would be higher.

Expenses Paid, Amount

$ 7

Expense Ratio, Percent

0.18%

^[98]

AssetsNet

$ 27,076,219

Holdings Count | Holding

Additional Fund Statistics [Text Block]

Key Fund Statistics as of 6/30/2026

Total Net Assets$27,076,219
Number of Portfolio Holdings69

Holdings [Text Block]

Top Security Types

Table Summary
Assets	%
Financial Company Commercial Paper	25.3%
Certificates Of Deposit	15.9%
Treasury Repurchase Agreements	14.8%
Asset Backed Commercial Paper	14.5%
Other Repurchase Agreements	10.5%
Government Agency Repurchase Agreements	7.9%
Treasury Debt	6.4%
Other Notes	4.6%

Largest Holdings [Text Block]

Top Holdings

Table Summary
Holdings	%
Bank of America Tri Party A Repo, 3.64%, due 07/01/26	7.4%
Goldman Sachs & Co. Tri Party D, 3.65%, due 07/01/26	4.1%
Mizuho Securities USA, 3.64%, due 07/01/26	3.7%
RBC Dominion Securities Tri Party, 3.65%, due 07/01/26	3.7%
NatWest Markets Securities, 3.64%, due 07/01/26	3.7%
Toronto Dominion Bank USA Tri Party B Repo, 3.72%, due 07/01/26	3.7%
Credit Agricole Corporate, 3.65%, due 07/01/26	3.7%
Verto Capital I Compartment D, 3.72%, due 07/02/26	1.8%
U.S. Treasury Bill, 3.70%, due 09/24/26	1.8%
Mackinac Funding Co LLC, 0.01%, due 09/01/26	1.5%

[1]	Annualized.
[2]	Annualized.
[3]	Annualized.
[4]	Annualized.
[5]	Annualized.
[6]	Annualized.
[7]	Annualized.
[8]	Annualized.
[9]	Annualized.
[10]	Annualized.
[11]	Annualized.
[12]	Annualized.
[13]	Annualized.
[14]	Annualized.
[15]	Annualized.
[16]	Annualized.
[17]	Annualized.
[18]	Annualized.
[19]	Annualized.
[20]	Annualized.
[21]	Annualized.
[22]	Annualized.
[23]	Annualized.
[24]	Annualized.
[25]	Annualized.
[26]	Annualized.
[27]	Annualized.
[28]	Annualized.
[29]	Annualized.
[30]	Annualized.
[31]	Annualized.
[32]	Annualized.
[33]	Annualized.
[34]	Annualized.
[35]	Annualized.
[36]	Annualized.
[37]	Annualized.
[38]	Annualized.
[39]	Annualized.
[40]	Annualized.
[41]	Annualized.
[42]	Annualized.
[43]	Annualized.
[44]	Annualized.
[45]	Annualized.
[46]	Annualized.
[47]	Annualized.
[48]	Annualized.
[49]	Annualized.
[50]	Annualized.
[51]	Annualized.
[52]	Annualized.
[53]	Annualized.
[54]	Annualized.
[55]	Annualized.
[56]	Annualized.
[57]	Annualized.
[58]	Annualized.
[59]	Annualized.
[60]	Annualized.
[61]	Annualized.
[62]	Annualized.
[63]	Annualized.
[64]	Annualized.
[65]	Annualized.
[66]	Annualized.
[67]	Annualized.
[68]	Annualized.
[69]	Annualized.
[70]	Annualized.
[71]	Annualized.
[72]	Annualized.
[73]	Annualized.
[74]	Annualized.
[75]	Annualized.
[76]	Annualized.
[77]	Annualized.
[78]	Annualized.
[79]	Annualized.
[80]	Annualized.
[81]	Annualized.
[82]	Annualized.
[83]	Annualized.
[84]	Annualized.
[85]	Annualized.
[86]	Annualized.
[87]	Annualized.
[88]	Annualized.
[89]	Annualized.
[90]	Annualized.
[91]	Annualized.
[92]	Annualized.
[93]	Annualized.
[94]	Annualized.
[95]	Annualized.
[96]	Annualized.
[97]	Annualized.
[98]	Annualized.