SUBSEQUENT EVENTS (Details) - Subsequent Event $ in Millions	1 Months Ended
Jul. 31, 2025 USD ($) securitization
Subsequent Event [Line Items]
Number of closed securitizations \| securitization	2
Residential mortgage loans \| Line of Credit
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity, increase	$ 100.0
Residential Loan, OBX 2025-NQM12
Subsequent Event [Line Items]
Residential mortgage loan, face value	274.5
Residential Loan, OBX 2025-NQM13
Subsequent Event [Line Items]
Residential mortgage loan, face value	$ 662.7

Line of Credit Facility, Maximum Borrowing Capacity, Increase

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number Of Closed Securitizations

+ References

No definition available.

+ Details

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Namespace Prefix:	nly_
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Balance Type:	na
Period Type:	duration

- Definition

This is the result of the principal amount outstanding of total loans managed or securitized less securitized loans and loans that are in the process of being securitized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Subparagraph (a)
-Paragraph 4
-SubTopic 20
-Topic 860
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-4

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

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Period Type:	duration

- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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