XML 76 R54.htm IDEA: XBRL DOCUMENT v3.20.2

SECURITIES - Additional Information (Details) - USD ($) $ in Billions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Residential Investment securities sold, carrying value	$ 5.5	$ 9.1	$ 47.4	$ 19.5

X

- Definition

Carrying value of mortgage backed securities sold during period.

+ References

No definition available.

+ Details

Name:	nly_MortgageBackedSecuritiesSoldCarryingValue
Namespace Prefix:	nly_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration