XML 74 R56.htm IDEA: XBRL DOCUMENT v3.24.0.1

SECURITIES - Component of Agency Mortgage-Backed Securities Portfolio by Issuing Agency Concentration (Details) - Agency Mortgage-Backed Securities - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Mortgage-Backed Securities Portfolio [Line Items]
Estimated fair value	$ 66,308,788	$ 62,274,895
Fannie Mae
Mortgage-Backed Securities Portfolio [Line Items]
Estimated fair value	60,477,303	54,043,015
Freddie Mac
Mortgage-Backed Securities Portfolio [Line Items]
Estimated fair value	5,778,809	8,174,080
Ginnie Mae
Mortgage-Backed Securities Portfolio [Line Items]
Estimated fair value	$ 52,676	$ 57,800

X

- Definition

Mortgage-Backed Securities Portfolio [Line Items]

+ References

No definition available.

+ Details

Name:	nly_MortgageBackedSecuritiesPortfolioLineItems
Namespace Prefix:	nly_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481961/940-320-45-2

+ Details

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

X

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=nly_AgencyMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: