Mortgage Loans - Loan Restructuring - Subsequent Default (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	$ 1,889	$ 1,403	$ 2,788	$ 2,220
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,228	859	1,806	1,355
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	633	334	936	457
Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	28	210	46	408
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,876	1,402	2,770	2,219
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,228	859	1,806	1,355
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	633	334	936	457
Single-family | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	15	209	28	407
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1,812	1,343	2,670	2,121
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	1,178	819	1,727	1,290
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	625	327	925	446
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	9	197	18	385
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	31	27	51	45
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	31	27	51	44
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	0	0
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0	1
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	4	4	7	5
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	3	2	5	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	0
Single-family | Adjustable-rate | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	1	2	2	2
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	29	28	42	48
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	16	11	23	18
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	8	7	11	11
Single-family | Other | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	5	10	8	19
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	13	1	18	1
Multifamily | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0	0
Multifamily | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	0	0	0	0
Multifamily | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost, subsequent default	$ 13	$ 1	$ 18	$ 1