Mortgage Loans - Loan Restructuring - Subsequent Default (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	$ 1,403	$ 2,220	$ 717
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	859	1,355	530
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	334	457	68
Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	210	408	119
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,402	2,219	717
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	859	1,355	530
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	334	457	68
Single-family | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	209	407	119
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,343	2,121	663
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	819	1,290	492
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	327	446	62
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, amortized cost, subsequent default	197	385	109
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	27	45	22
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	27	44	21
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	1
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, amortized cost, subsequent default	0	1	0
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	4	5	4
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	2	3	3
Single-family | Adjustable-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0
Single-family | Adjustable-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	2	2	1
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	28	48	28
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	11	18	14
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	7	11	5
Single-family | Other | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	10	19	9
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1	1	0
Multifamily | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0
Multifamily | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0
Multifamily | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	$ 1	$ 1	$ 0