Mortgage Loans - Credit Quality Indicators - SF (Details) - Single-family - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
2022	$ 420,513	$ 1,200,915
2021	1,205,201	1,082,870
2020	983,069	207,663
2019	175,989	100,239
2018	81,917	135,670
Prior	817,719	829,967
Total mortgage loans	3,684,408	3,557,324
Estimated mark-to-market loan-to-value ratio less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	292,970	1,001,159
2021	1,123,460	1,040,601
2020	976,947	204,398
2019	174,700	98,924
2018	81,237	134,953
Prior	815,893	826,785
Total mortgage loans	3,465,207	3,306,820
Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	69,898	132,354
2021	76,249	39,973
2020	4,741	2,712
2019	996	1,067
2018	586	632
Prior	1,231	1,972
Total mortgage loans	153,701	178,710
Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	57,604	67,381
2021	5,398	2,284
2020	1,353	544
2019	280	231
2018	81	60
Prior	289	597
Total mortgage loans	65,005	71,097
Estimated mark-to-market loan-to-value ratio greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	41	21
2021	94	12
2020	28	9
2019	13	17
2018	13	25
Prior	306	613
Total mortgage loans	495	697
20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Credit Quality Indicator [Line Items]
2022	378,824	994,858
2021	1,007,276	923,269
2020	842,459	181,151
2019	154,015	89,126
2018	73,041	111,760
Prior	671,518	668,941
Total mortgage loans	3,127,133	2,969,105
20- and 30-year or more, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	253,757	798,830
2021	926,196	881,290
2020	836,382	177,909
2019	152,731	87,825
2018	72,366	111,059
Prior	669,943	666,327
Total mortgage loans	2,911,375	2,723,240
20- and 30-year or more, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	68,200	129,340
2021	75,617	39,689
2020	4,698	2,689
2019	991	1,056
2018	583	622
Prior	1,100	1,687
Total mortgage loans	151,189	175,083
20- and 30-year or more, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	56,826	66,667
2021	5,369	2,278
2020	1,351	544
2019	280	229
2018	79	57
Prior	227	460
Total mortgage loans	64,132	70,235
20- and 30-year or more, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	41	21
2021	94	12
2020	28	9
2019	13	16
2018	13	22
Prior	248	467
Total mortgage loans	437	547
15-year or less, amortizing fixed-rate
Financing Receivable, Credit Quality Indicator [Line Items]
2022	37,556	199,318
2021	191,149	157,340
2020	138,675	25,406
2019	21,094	9,600
2018	7,699	20,720
Prior	111,049	121,043
Total mortgage loans	507,222	533,427
15-year or less, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	36,062	196,163
2021	190,699	157,076
2020	138,640	25,390
2019	21,091	9,595
2018	7,698	20,715
Prior	111,042	121,027
Total mortgage loans	505,232	529,966
15-year or less, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	1,054	2,576
2021	436	259
2020	34	16
2019	3	4
2018	1	2
Prior	2	7
Total mortgage loans	1,530	2,864
15-year or less, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	440	579
2021	14	5
2020	1	0
2019	0	1
2018	0	1
Prior	2	4
Total mortgage loans	457	590
15-year or less, amortizing fixed-rate | Estimated mark-to-market loan-to-value ratio greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	2
Prior	3	5
Total mortgage loans	3	7
Adjustable-rate
Financing Receivable, Credit Quality Indicator [Line Items]
2022	4,133	6,739
2021	6,776	2,261
2020	1,935	1,072
2019	850	1,240
2018	946	2,526
Prior	11,832	12,504
Total mortgage loans	26,472	26,342
Adjustable-rate | Estimated mark-to-market loan-to-value ratio less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	3,151	6,166
2021	6,565	2,235
2020	1,925	1,065
2019	848	1,236
2018	944	2,524
Prior	11,830	12,501
Total mortgage loans	25,263	25,727
Adjustable-rate | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	644	438
2021	196	25
2020	9	7
2019	2	4
2018	1	2
Prior	2	3
Total mortgage loans	854	479
Adjustable-rate | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	338	135
2021	15	1
2020	1	0
2019	0	0
2018	1	0
Prior	0	0
Total mortgage loans	355	136
Adjustable-rate | Estimated mark-to-market loan-to-value ratio greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior	0	0
Total mortgage loans	0	0
Other
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	34
2019	30	273
2018	231	664
Prior	23,320	27,479
Total mortgage loans	23,581	28,450
Other | Estimated mark-to-market loan-to-value ratio less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	34
2019	30	268
2018	229	655
Prior	23,078	26,930
Total mortgage loans	23,337	27,887
Other | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	3
2018	1	6
Prior	127	275
Total mortgage loans	128	284
Other | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	1
2018	1	2
Prior	60	133
Total mortgage loans	61	136
Other | Estimated mark-to-market loan-to-value ratio greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	1
2018	0	1
Prior	55	141
Total mortgage loans	55	143
U.S Government
Financing Receivable, Credit Quality Indicator [Line Items]
Total mortgage loans	$ 8,500	$ 9,500