Mortgage Loans - Loan Restructuring - Summary of Loans Restructured (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 17,934	$ 27,527	$ 28,452	$ 46,491
Restructured loans, percent of total financing receivable		1.00%	1.00%	1.00%
Financing Receivable, Modified in Period, Loans Paid Off, Repurchased Or Sold During Period	200	$ 269	$ 604	$ 1,700
Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	9,004	12,099	11,837	15,803
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,851	5,638	6,582	12,552
Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,674	4,141	5,557	6,602
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,782	815	3,557	1,971
Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	623	4,834	919	9,563
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	16,986	$ 27,493	$ 27,134	$ 46,243
Restructured loans, percent of total financing receivable		1.00%	1.00%	1.00%
Single-family | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8,581	$ 12,076	$ 11,053	$ 15,566
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,851	5,638	6,582	12,552
Single-family | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,674	4,141	5,557	6,602
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,782	815	3,557	1,971
Single-family | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	98	4,823	385	9,552
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 16,066	$ 25,671	$ 25,644	$ 43,006
Restructured loans, percent of total financing receivable	1.00%	1.00%	1.00%	1.00%
Single-family | 20- and 30-year or more, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 8,107	$ 11,213	$ 10,410	$ 14,428
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,689	5,203	6,207	11,518
Single-family | 20- and 30-year or more, amortizing fixed-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,444	3,815	5,202	6,064
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	1,746	769	3,487	1,831
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	80	4,671	338	9,165
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	588	1,012	919	1,643
Single-family | 15-year or less, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	339	571	451	735
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	116	287	264	653
Single-family | 15-year or less, amortizing fixed-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	132	154	203	253
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	0	1	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	0	0	0	1
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	69	120	102	$ 226
Restructured loans, percent of total financing receivable				1.00%
Single-family | Adjustable-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	46	61	55	$ 84
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	10	27	27	77
Single-family | Adjustable-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	12	28	18	53
Single-family | Adjustable-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	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	1	4	2	12
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 263	$ 690	$ 469	$ 1,368
Restructured loans, percent of total financing receivable	1.00%	2.00%	2.00%	4.00%
Single-family | Other | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 89	$ 231	$ 137	$ 319
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	36	121	84	304
Single-family | Other | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	86	144	134	232
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	35	46	69	139
Single-family | Other | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	17	148	45	374
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	948	34	1,318	248
Multifamily | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	423	23	784	237
Multifamily | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 525	$ 11	$ 534	$ 11