Mortgage Loans - Loan Restructuring - Subsequent Default (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	$ 2,761	$ 1,510	$ 2,814
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	1,799
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	269
Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	693
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	2,761	1,510	2,798
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	1,799
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	269
Single-family | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	693
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	2,601	1,302	2,578
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	1,695
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	258
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	648
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	56	37	10
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	56
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	10	5	2
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	7
Single-family | Adjustable-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0
Single-family | Adjustable-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	3
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	94	166	208
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	41
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	11
Single-family | Other | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	42
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0	$ 0	$ 16
Multifamily | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0
Multifamily | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	0
Multifamily | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, subsequent default	$ 0