Shareholder Report
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6 Months Ended |
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Jun. 30, 2026
USD ($)
Holding
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| Shareholder Report [Line Items] |
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| Document Type |
N-CSRS
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| Amendment Flag |
false
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| Registrant Name |
State Street Navigator Securities Lending Trust
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| Entity Central Index Key |
0001011008
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| Entity Investment Company Type |
N-1A
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| Document Period End Date |
Jun. 30, 2026
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| Shareholder Report Annual or Semi-Annual |
Semi-Annual Shareholder Report
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| C000026831 |
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| Shareholder Report [Line Items] |
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| Fund Name |
State Street Navigator Securities Lending Government Money Market Portfolio
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| No Trading Symbol [Flag] |
true
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| Annual or Semi-Annual Statement [Text Block] |
This semi-annual shareholder report contains important information about the State Street Navigator Securities Lending Government Money Market Portfolio (the "Fund") for the period of January 1, 2026 through June 30, 2026.
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| Additional Information [Text Block] |
You can request additional information about the Fund by contacting us at 1-877-521-4083.
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| Additional Information Phone Number |
1-877-521-4083
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| 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 Navigator Securities Lending Government Money Market Portfolio |
$2 |
0.03%Footnote Reference* |
| Footnote |
Description |
Footnote* |
Annualized. | |
|
| Expenses Paid, Amount |
$ 2
|
|
| Expense Ratio, Percent |
0.03%
|
[1] |
| AssetsNet |
$ 8,148,503,930
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| Holdings Count | Holding |
173
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| Additional Fund Statistics [Text Block] |
Key Fund Statistics as of 6/30/2026- Total Net Assets$8,148,503,930
- Number of Portfolio Holdings173
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| Holdings [Text Block] |
Table Summary
Assets |
% |
Treasury Repurchase Agreements |
31.5% |
Government Agency Debt |
25.1% |
Treasury Debt |
20.3% |
Government Agency Repurchase Agreements |
16.2% | |
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| Largest Holdings [Text Block] |
Table Summary
Holdings |
% |
FICCRP Tri Party Repo A, 3.64%, due 07/01/26 |
9.2% |
Bank of America Tri Party A Repo, 3.64%, due 07/01/26 |
6.1% |
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26 |
6.0% |
RBC Capital Markets Tri Party D, 3.66%, due 07/01/26 |
3.7% |
Bank of America NA Tri Party D Repo, 3.65%, due 07/01/26 |
3.1% |
U.S. Treasury Notes, 3.75%, due 09/30/26 |
2.9% |
FICCNT Bi Party Repo, 3.64%, due 07/01/26 |
2.5% |
Wells Fargo Bank NA A, 3.64%, due 07/01/26 |
2.5% |
Federal Farm Credit Banks Funding Corp., 3.66%, due 04/07/27 |
1.6% |
Federal Home Loan Banks, 3.66%, due 02/04/27 |
1.6% | |
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| C000171428 |
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| Shareholder Report [Line Items] |
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| Fund Name |
State Street Navigator Securities Lending Portfolio I
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| No Trading Symbol [Flag] |
true
|
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| Annual or Semi-Annual Statement [Text Block] |
This semi-annual shareholder report contains important information about the State Street Navigator Securities Lending Portfolio I (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 by contacting us at 1-877-521-4083.
|
|
| Additional Information Phone Number |
1-877-521-4083
|
|
| 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 Navigator Securities Lending Portfolio I |
$2 |
0.04%Footnote Reference* |
| Footnote |
Description |
Footnote* |
Annualized. | |
|
| Expenses Paid, Amount |
$ 2
|
|
| Expense Ratio, Percent |
0.04%
|
[2] |
| AssetsNet |
$ 375,958,829
|
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| Holdings Count | Holding |
92
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| InvestmentCompanyPortfolioTurnover |
0.00%
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| Additional Fund Statistics [Text Block] |
Key Fund Statistics as of 6/30/2026- Total Net Assets$375,958,829
- Number of Portfolio Holdings92
- Portfolio Turnover Rate0%
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| Holdings [Text Block] |
Table Summary
Assets |
% |
Certificates Of Deposit |
32.0% |
Financial Company Commercial Paper |
27.1% |
Asset Backed Commercial Paper |
11.8% |
Other Notes |
10.1% |
Treasury Repurchase Agreements |
8.2% |
Other Repurchase Agreements |
6.5% |
Government Agency Repurchase Agreements |
2.7% | |
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| Largest Holdings [Text Block] |
Table Summary
Holdings |
% |
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26 |
2.9% |
Bank of Nova Scotia, 3.95%, due 08/07/26 |
2.7% |
Credit Industriel et Commercial, 3.74%, due 07/09/26 |
2.7% |
Commonwealth Bank of Australia, 3.81%, due 07/13/26 |
2.7% |
Nordea Bank Abp, 3.82%, due 07/07/26 |
2.7% |
Royal Bank of Canada, 3.67%, due 07/01/26 |
2.7% |
Mizuho Bank Ltd., 3.63%, due 07/01/26 |
2.7% |
Bank of America Tri Party A Repo, 3.64%, due 07/01/26 |
2.7% |
Anglesea Funding LLC, 3.80%, due 07/01/26 |
2.7% |
DNB Bank Asa, 4.11%, due 07/07/26 |
2.7% | |
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| C000206723 |
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| Shareholder Report [Line Items] |
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| Fund Name |
State Street Navigator Securities Lending Portfolio II
|
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| No Trading Symbol [Flag] |
true
|
|
| Annual or Semi-Annual Statement [Text Block] |
This semi-annual shareholder report contains important information about the State Street Navigator Securities Lending Portfolio II (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 by contacting us at 1-877-521-4083.
|
|
| Additional Information Phone Number |
1-877-521-4083
|
|
| 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 Navigator Securities Lending Portfolio II |
$2 |
0.04%Footnote Reference* |
| Footnote |
Description |
Footnote* |
Annualized. | |
|
| Expenses Paid, Amount |
$ 2
|
|
| Expense Ratio, Percent |
0.04%
|
[3] |
| AssetsNet |
$ 13,650,160,654
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|
| Holdings Count | Holding |
137
|
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| InvestmentCompanyPortfolioTurnover |
0.00%
|
|
| Additional Fund Statistics [Text Block] |
Key Fund Statistics as of 6/30/2026- Total Net Assets$13,650,160,654
- Number of Portfolio Holdings137
- Portfolio Turnover Rate0%
|
|
| Holdings [Text Block] |
Table Summary
Assets |
% |
Certificates Of Deposit |
28.3% |
Other Notes |
21.7% |
Financial Company Commercial Paper |
17.1% |
Asset Backed Commercial Paper |
12.3% |
Other Repurchase Agreements |
11.3% |
Treasury Repurchase Agreements |
6.2% |
Government Agency Repurchase Agreements |
1.8% | |
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| Largest Holdings [Text Block] |
Table Summary
Holdings |
% |
JP Morgan Sec LLC Tpr A, 3.64%, due 07/01/26 |
4.2% |
KBC Bank NV, 3.63%, due 07/01/26 |
3.7% |
Royal Bank of Canada, 3.67%, due 07/01/26 |
2.6% |
Mizuho Bank Ltd., 3.63%, due 07/01/26 |
1.9% |
Societe Generale Tri Party A, 3.70%, due 07/01/26 |
1.6% |
Svenska Handelsbanken AB, 3.61%, due 07/01/26 |
1.5% |
Canadian Imperial Bank of Commerce, 3.63%, due 07/01/26 |
1.5% |
ABN AMRO Bank NV, 3.63%, due 07/01/26 |
1.5% |
Landesbank Baden-Wuerttemberg, 3.64%, due 07/01/26 |
1.5% |
Societe Generale Tri Party A, 3.72%, due 07/07/26 |
1.4% | |
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