Mortgage Loans - Credit Quality Indicators - SF (Details) - Single-family - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	$ 279,314	$ 497,393
One fiscal year before	489,031	1,185,382
Two fiscal years before	1,103,809	963,992
Three fiscal years before	890,887	171,549
Four fiscal years before	155,447	79,469
Prior	763,925	790,243
Total mortgage loans	3,682,413	3,688,028
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff	2
One fiscal year, writeoff	36
Two fiscal years, writeoff	54
Three fiscal years, writeoff	46
Four fiscal years, writeoff	109
Prior	619
Total writeoffs	866
Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	157,317	323,058
One fiscal year before	354,060	1,088,871
Two fiscal years before	1,060,673	956,653
Three fiscal years before	887,045	170,156
Four fiscal years before	154,553	78,758
Prior	762,320	788,467
Total mortgage loans	3,375,968	3,405,963
Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	58,766	87,240
One fiscal year before	97,186	86,981
Two fiscal years before	38,932	5,949
Three fiscal years before	3,432	1,158
Four fiscal years before	806	620
Prior	1,167	1,196
Total mortgage loans	200,289	183,144
Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	62,216	85,861
One fiscal year before	35,990	9,321
Two fiscal years before	4,014	1,334
Three fiscal years before	363	217
Four fiscal years before	71	79
Prior	230	281
Total mortgage loans	102,884	97,093
Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1,015	1,234
One fiscal year before	1,795	209
Two fiscal years before	190	56
Three fiscal years before	47	18
Four fiscal years before	17	12
Prior	208	299
Total mortgage loans	3,272	1,828
20- and 30-year or more, amortizing fixed-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	268,985	452,015
One fiscal year before	447,259	992,804
Two fiscal years before	932,415	827,745
Three fiscal years before	771,430	150,454
Four fiscal years before	137,546	71,013
Prior	650,407	652,823
Total mortgage loans	3,208,042	3,146,854
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff	2
One fiscal year, writeoff	35
Two fiscal years, writeoff	53
Three fiscal years, writeoff	45
Four fiscal years, writeoff	108
Prior	560
Total writeoffs	803
20- and 30-year or more, amortizing fixed-rate | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	148,641	281,257
One fiscal year before	314,384	896,977
Two fiscal years before	889,434	820,452
Three fiscal years before	767,596	149,067
Four fiscal years before	136,654	70,306
Prior	648,964	651,297
Total mortgage loans	2,905,673	2,869,356
20- and 30-year or more, amortizing fixed-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	57,686	84,864
One fiscal year before	95,509	86,335
Two fiscal years before	38,790	5,904
Three fiscal years before	3,424	1,152
Four fiscal years before	804	618
Prior	1,082	1,062
Total mortgage loans	197,295	179,935
20- and 30-year or more, amortizing fixed-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	61,658	84,664
One fiscal year before	35,602	9,284
Two fiscal years before	4,002	1,333
Three fiscal years before	363	217
Four fiscal years before	71	77
Prior	189	224
Total mortgage loans	101,885	95,799
20- and 30-year or more, amortizing fixed-rate | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1,000	1,230
One fiscal year before	1,764	208
Two fiscal years before	189	56
Three fiscal years before	47	18
Four fiscal years before	17	12
Prior	172	240
Total mortgage loans	3,189	1,764
15-year or less, amortizing fixed-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	7,951	3
One fiscal year before	35,931	1
Two fiscal years before	165,347	0
Three fiscal years before	117,797	0
Four fiscal years before	17,162	0
Prior	84,225	2
Total mortgage loans	428,413	6
15-year or less, amortizing fixed-rate | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	7,110
One fiscal year before	35,224
Two fiscal years before	165,294
Three fiscal years before	117,795
Four fiscal years before	17,162
Prior	84,222
Total mortgage loans	426,807
15-year or less, amortizing fixed-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	581	37,830
One fiscal year before	647	185,511
Two fiscal years before	52	134,336
Three fiscal years before	2	20,239
Four fiscal years before	0	7,324
Prior	1	103,841
Total mortgage loans	1,283	489,081
15-year or less, amortizing fixed-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	259	1,363
One fiscal year before	58	410
Two fiscal years before	1	33
Three fiscal years before	0	3
Four fiscal years before	0	0
Prior	1	2
Total mortgage loans	319	1,811
15-year or less, amortizing fixed-rate | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1	552
One fiscal year before	2	16
Two fiscal years before	0	1
Three fiscal years before	0	0
Four fiscal years before	0	0
Prior	1	1
Total mortgage loans	4	570
Adjustable-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	2,378	5,630
One fiscal year before	5,841	6,640
Two fiscal years before	6,047	1,877
Three fiscal years before	1,660	824
Four fiscal years before	712	908
Prior	9,720	11,229
Total mortgage loans	26,358	27,108
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff	0
One fiscal year, writeoff	1
Two fiscal years, writeoff	0
Three fiscal years, writeoff	0
Four fiscal years, writeoff	0
Prior	2
Total writeoffs	3
Adjustable-rate | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1,566	3,971
One fiscal year before	4,452	6,383
Two fiscal years before	5,945	1,865
Three fiscal years before	1,654	821
Four fiscal years before	710	906
Prior	9,716	11,226
Total mortgage loans	24,043	25,172
Adjustable-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	499	1,013
One fiscal year before	1,030	236
Two fiscal years before	90	12
Three fiscal years before	6	3
Four fiscal years before	2	1
Prior	3	3
Total mortgage loans	1,630	1,268
Adjustable-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	299	645
One fiscal year before	330	21
Two fiscal years before	11	0
Three fiscal years before	0	0
Four fiscal years before	0	1
Prior	1	0
Total mortgage loans	641	667
Adjustable-rate | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	14	1
One fiscal year before	29	0
Two fiscal years before	1	0
Three fiscal years before	0	0
Four fiscal years before	0	0
Prior	0	0
Total mortgage loans	44	1
Other
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	29
Four fiscal years before	27	224
Prior	19,573	22,345
Total mortgage loans	19,600	22,598
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff	0
One fiscal year, writeoff	0
Two fiscal years, writeoff	0
Three fiscal years, writeoff	0
Four fiscal years, writeoff	0
Prior	52
Total writeoffs	52
Other | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	29
Four fiscal years before	27	222
Prior	19,418	22,103
Total mortgage loans	19,445	22,354
Other | Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	0	1
Prior	81	129
Total mortgage loans	81	130
Other | Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	0	1
Prior	39	56
Total mortgage loans	39	57
Other | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	0	0
Prior	35	57
Total mortgage loans	35	57
Government
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Total mortgage loans	5,500	9,500
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total writeoffs	7
Fixed Rate Residential Mortgage 15 year Member
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff	0	39,748
One fiscal year, writeoff	0	185,938
Two fiscal years, writeoff	1	134,370
Three fiscal years, writeoff	1	20,242
Four fiscal years, writeoff	1	7,324
Prior	5	103,846
Total writeoffs	$ 8	$ 491,468