This semi-annual shareholder report contains important information about Morgan Stanley Long Duration Government Opportunities Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.morganstanley.com/im/shareholderreports. You can also request this information by contacting us at 1-800-869-6397.

Additional Information Phone Number

1-800-869-6397

Additional Information Website

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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
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$48	0.96%^{Footnote Reference1}

Footnote	Description
Footnote¹	Annualized

Expenses Paid, Amount

$ 48

Expense Ratio, Percent

0.96%

^[1]

AssetsNet

$ 207,354,228

Holdings Count | Holding

170

InvestmentCompanyPortfolioTurnover

133.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$207,354,228
# of Portfolio Holdings	170
Portfolio Turnover Rate	133%

Holdings [Text Block]

Credit Quality (% of net assets)^{Footnote Reference*}

Table Summary
Value	Value
Cash and Equivalents	-26.5%
Not Rated	3.5%
BB	0.4%
BBB	0.4%
A	0.3%
AA	120.3%
AAA	1.6%

Footnote	Description
Footnote^*	Security ratings disclosed with the exception for those labeled “not rated” is an aggregation of the highest security level rating amongst S&P Global Ratings, Moody’s Investors Services, Inc., and Fitch Ratings, each a Nationally Recognized Statistical Ratings Organization (“NRSRO”).

Credit Quality Explanation [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Agency Adjustable Rate Mortgages	0.1%
Commercial Mortgage-Backed Securities	0.3%
U.S. Agency Securities	2.7%
Mortgages - Other	4.4%
Agency Fixed Rate Mortgages	18.2%
Collateralized Mortgage Obligations - Agency Collateral Series	74.3%

Material Fund Change [Text Block]

Updated Prospectus Web Address

C000155939

Shareholder Report [Line Items]

Fund Name

Morgan Stanley Long Duration Government Opportunities Fund

Class Name

Class C

Trading Symbol

MSGVX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Morgan Stanley Long Duration Government Opportunities Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.morganstanley.com/im/shareholderreports. You can also request this information by contacting us at 1-800-869-6397.

Additional Information Phone Number

1-800-869-6397

Additional Information Website

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 C	$86	1.73%^{Footnote Reference1}

Footnote	Description
Footnote¹	Annualized

Expenses Paid, Amount

$ 86

Expense Ratio, Percent

1.73%

^[2]

AssetsNet

$ 207,354,228

Holdings Count | Holding

170

InvestmentCompanyPortfolioTurnover

133.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$207,354,228
# of Portfolio Holdings	170
Portfolio Turnover Rate	133%

Holdings [Text Block]

Credit Quality (% of net assets)^{Footnote Reference*}

Table Summary
Value	Value
Cash and Equivalents	-26.5%
Not Rated	3.5%
BB	0.4%
BBB	0.4%
A	0.3%
AA	120.3%
AAA	1.6%

Footnote	Description
Footnote^*	Security ratings disclosed with the exception for those labeled “not rated” is an aggregation of the highest security level rating amongst S&P Global Ratings, Moody’s Investors Services, Inc., and Fitch Ratings, each a Nationally Recognized Statistical Ratings Organization (“NRSRO”).

Credit Quality Explanation [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Agency Adjustable Rate Mortgages	0.1%
Commercial Mortgage-Backed Securities	0.3%
U.S. Agency Securities	2.7%
Mortgages - Other	4.4%
Agency Fixed Rate Mortgages	18.2%
Collateralized Mortgage Obligations - Agency Collateral Series	74.3%

Material Fund Change [Text Block]

Updated Prospectus Web Address

C000006470

Shareholder Report [Line Items]

Fund Name

Morgan Stanley Long Duration Government Opportunities Fund

Class Name

Class I

Trading Symbol

USGDX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Morgan Stanley Long Duration Government Opportunities Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.morganstanley.com/im/shareholderreports. You can also request this information by contacting us at 1-800-869-6397.

Additional Information Phone Number

1-800-869-6397

Additional Information Website

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	$30	0.61%^{Footnote Reference1}

Footnote	Description
Footnote¹	Annualized

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.61%

^[3]

AssetsNet

$ 207,354,228

Holdings Count | Holding

170

InvestmentCompanyPortfolioTurnover

133.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$207,354,228
# of Portfolio Holdings	170
Portfolio Turnover Rate	133%

Holdings [Text Block]

Credit Quality (% of net assets)^{Footnote Reference*}

Table Summary
Value	Value
Cash and Equivalents	-26.5%
Not Rated	3.5%
BB	0.4%
BBB	0.4%
A	0.3%
AA	120.3%
AAA	1.6%

Footnote	Description
Footnote^*	Security ratings disclosed with the exception for those labeled “not rated” is an aggregation of the highest security level rating amongst S&P Global Ratings, Moody’s Investors Services, Inc., and Fitch Ratings, each a Nationally Recognized Statistical Ratings Organization (“NRSRO”).

Credit Quality Explanation [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Agency Adjustable Rate Mortgages	0.1%
Commercial Mortgage-Backed Securities	0.3%
U.S. Agency Securities	2.7%
Mortgages - Other	4.4%
Agency Fixed Rate Mortgages	18.2%
Collateralized Mortgage Obligations - Agency Collateral Series	74.3%

Material Fund Change [Text Block]

Updated Prospectus Web Address

C000006469

Shareholder Report [Line Items]

Fund Name

Morgan Stanley Long Duration Government Opportunities Fund

Class Name

Class L

Trading Symbol

USGCX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about Morgan Stanley Long Duration Government Opportunities Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.morganstanley.com/im/shareholderreports. You can also request this information by contacting us at 1-800-869-6397.

Additional Information Phone Number

1-800-869-6397

Additional Information Website

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 L	$61	1.23%^{Footnote Reference1}

Footnote	Description
Footnote¹	Annualized

Expenses Paid, Amount

$ 61

Expense Ratio, Percent

1.23%

^[4]

AssetsNet

$ 207,354,228

Holdings Count | Holding

170

InvestmentCompanyPortfolioTurnover

133.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$207,354,228
# of Portfolio Holdings	170
Portfolio Turnover Rate	133%

Holdings [Text Block]

Credit Quality (% of net assets)^{Footnote Reference*}

Table Summary
Value	Value
Cash and Equivalents	-26.5%
Not Rated	3.5%
BB	0.4%
BBB	0.4%
A	0.3%
AA	120.3%
AAA	1.6%

Footnote	Description
Footnote^*	Security ratings disclosed with the exception for those labeled “not rated” is an aggregation of the highest security level rating amongst S&P Global Ratings, Moody’s Investors Services, Inc., and Fitch Ratings, each a Nationally Recognized Statistical Ratings Organization (“NRSRO”).

Credit Quality Explanation [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Agency Adjustable Rate Mortgages	0.1%
Commercial Mortgage-Backed Securities	0.3%
U.S. Agency Securities	2.7%
Mortgages - Other	4.4%
Agency Fixed Rate Mortgages	18.2%
Collateralized Mortgage Obligations - Agency Collateral Series	74.3%

Material Fund Change [Text Block]

Updated Prospectus Web Address

[1]	Annualized
[2]	Annualized
[3]	Annualized
[4]	Annualized

What were the Fund costs for the last six months?

Key Fund Statistics

Credit Quality (% of net assets)Footnote Reference*

Asset Allocation (% of total investments)

What were the Fund costs for the last six months?

Key Fund Statistics

Credit Quality (% of net assets)Footnote Reference*

Asset Allocation (% of total investments)

What were the Fund costs for the last six months?

Key Fund Statistics

Credit Quality (% of net assets)Footnote Reference*

Asset Allocation (% of total investments)

What were the Fund costs for the last six months?

Key Fund Statistics

Credit Quality (% of net assets)Footnote Reference*

Asset Allocation (% of total investments)

Credit Quality (% of net assets)^{Footnote Reference*}

Credit Quality (% of net assets)^{Footnote Reference*}

Credit Quality (% of net assets)^{Footnote Reference*}

Credit Quality (% of net assets)^{Footnote Reference*}