Mortgage Loans - Loan Restructuring - Summary of Loans Restructured (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 42,625	$ 39,289	$ 57,198
Restructured loans, percent of total financing receivable (* less than)	1.00%	1.00%	1.00%
Restructured loans, paid off, repurchased or sold during period	$ 1,700	$ 1,800	$ 4,000
Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	12,297	12,154	17,160
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	11,288	11,246	18,195
Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8,880	7,588	5,737
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8,830	6,845	4,233
Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,330	1,456	11,873
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 41,355	$ 37,735	$ 56,875
Restructured loans, percent of total financing receivable (* less than)	1.00%	1.00%	2.00%
Single-family | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 12,146	$ 11,592	$ 16,877
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	11,288	11,246	18,195
Single-family | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8,880	7,588	5,737
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8,830	6,845	4,233
Single-family | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	211	464	11,833
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 39,719	$ 35,842	$ 53,310
Restructured loans, percent of total financing receivable (* less than)	1.00%	1.00%	2.00%
Single-family | 20- and 30-year or more, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 11,545	$ 10,935	$ 15,697
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	10,786	10,653	16,875
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	8,473	7,146	5,287
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	8,750	6,728	4,109
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	165	380	11,342
Single-family | 15-year or less, amortizing fixed-rate (less than)
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 1,099	$ 1,169	$ 1,907
Restructured loans, percent of total financing receivable (* less than)	0.50%	0.50%	0.50%
Single-family | 15-year or less, amortizing fixed-rate (less than) | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 476	$ 472	$ 794
Single-family | 15-year or less, amortizing fixed-rate (less than) | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	342	421	875
Single-family | 15-year or less, amortizing fixed-rate (less than) | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	276	273	233
Single-family | 15-year or less, amortizing fixed-rate (less than) | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	4	2	3
Single-family | 15-year or less, amortizing fixed-rate (less than) | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	1	2
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 133	$ 137	$ 241
Restructured loans, percent of total financing receivable (* less than)	1.00%	1.00%	1.00%
Single-family | Adjustable-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 58	$ 65	$ 90
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	38	36	76
Single-family | Adjustable-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	29	27	36
Single-family | Adjustable-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	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	8	9	39
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 404	$ 587	$ 1,417
Restructured loans, percent of total financing receivable (* less than)	2.00%	2.00%	4.00%
Single-family | Other | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 67	$ 120	$ 296
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	122	136	369
Single-family | Other | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	102	142	181
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	76	115	121
Single-family | Other | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	37	74	450
Multifamily (less than)
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 1,270	$ 1,554	323
Restructured loans, percent of total financing receivable (* less than)	0.50%	0.50%
Multifamily (less than) | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 151	$ 562	283
Multifamily (less than) | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0
Multifamily (less than) | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0
Multifamily (less than) | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0	0
Multifamily (less than) | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 1,119	$ 992	$ 40