XML 78 R58.htm IDEA: XBRL DOCUMENT
v3.19.3

LOANS - Fair Value and Unpaid Principal of Residential Mortgage Loan Portfolio (Details) - Residential mortgage loans - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Fair value | $ 3,596,133 | $ 2,454,637
Unpaid principal balance | $ 3,475,799 | $ 2,425,657

X
- Definition Mortgage loans fair value disclosure. + References No definition available. + Details
Name: | nly_MortgageLoansFairValueDisclosure
Namespace Prefix: | nly_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | srt_MortgageLoansOnRealEstateLineItems
Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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 -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719 + Details
Name: | us-gaap_PrincipalAmountOutstandingOfLoansHeldInPortfolio
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |