Mortgage Loans - Credit Quality Indicators - SF (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	$ 16,693	$ 21,342	$ 34,274	$ 51,704
Restructured loans, percent of total financing receivable		1.00%	1.00%	1.00%
Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	8,055	$ 10,517	$ 12,548	$ 15,154
Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	2,559	4,122	8,788	15,935
Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	3,605	3,099	6,616	5,883
Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	1,850	1,170	5,304	2,943
Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	624	2,434	1,018	11,789
Single-family
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	213,882		213,882		$ 497,393
One fiscal year before	496,428		496,428		1,185,382
Two fiscal years before	1,121,901		1,121,901		963,992
Three fiscal years before	906,965		906,965		171,549
Four fiscal years before	158,837		158,837		79,469
Prior	787,043		787,043		790,243
Total mortgage loans	3,685,056		3,685,056		3,688,028
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff			0
One fiscal year, writeoff			24
Two fiscal years, writeoff			38
Three fiscal years, writeoff			39
Four fiscal years, writeoff			105
Prior			584
Total writeoff			790
Restructured loans, amortized cost	15,772	$ 21,318	$ 32,644	$ 51,499
Restructured loans, percent of total financing receivable		1.00%	1.00%	1.00%
Single-family | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	7,694	$ 10,511	$ 11,503	$ 14,967
Single-family | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	2,559	4,122	8,788	15,935
Single-family | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	3,605	3,099	6,616	5,883
Single-family | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	1,850	1,170	5,304	2,943
Single-family | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	64	2,416	433	11,771
Single-family | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	124,726		124,726		323,058
One fiscal year before	357,411		357,411		1,088,871
Two fiscal years before	1,079,130		1,079,130		956,653
Three fiscal years before	903,146		903,146		170,156
Four fiscal years before	157,914		157,914		78,758
Prior	785,300		785,300		788,467
Total mortgage loans	3,407,627		3,407,627		3,405,963
Single-family | Greater than 80% and less than or equal to 90%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	40,580		40,580		87,240
One fiscal year before	102,472		102,472		86,981
Two fiscal years before	39,265		39,265		5,949
Three fiscal years before	3,414		3,414		1,158
Four fiscal years before	831		831		620
Prior	1,267		1,267		1,196
Total mortgage loans	187,829		187,829		183,144
Single-family | Greater than 90% and less than or equal to 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	48,544		48,544		85,861
One fiscal year before	35,958		35,958		9,321
Two fiscal years before	3,382		3,382		1,334
Three fiscal years before	360		360		217
Four fiscal years before	75		75		79
Prior	257		257		281
Total mortgage loans	88,576		88,576		97,093
Single-family | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	32		32		1,234
One fiscal year before	587		587		209
Two fiscal years before	124		124		56
Three fiscal years before	45		45		18
Four fiscal years before	17		17		12
Prior	219		219		299
Total mortgage loans	1,024		1,024		1,828
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	205,363		205,363		452,015
One fiscal year before	453,466		453,466		992,804
Two fiscal years before	945,537		945,537		827,745
Three fiscal years before	783,649		783,649		150,454
Four fiscal years before	140,226		140,226		71,013
Prior	666,293		666,293		652,823
Total mortgage loans	3,194,534		3,194,534		3,146,854
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current fiscal year, writeoff			0
One fiscal year, writeoff			24
Two fiscal years, writeoff			37
Three fiscal years, writeoff			38
Four fiscal years, writeoff			104
Prior			533
Total writeoff			736
Restructured loans, amortized cost	14,978	$ 19,972	$ 30,942	$ 48,106
Restructured loans, percent of total financing receivable		1.00%	1.00%	2.00%
Single-family | 20- and 30-year or more, amortizing fixed-rate | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	7,287	$ 9,811	$ 10,851	$ 13,905
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	2,424	3,827	8,306	14,705
Single-family | 20- and 30-year or more, amortizing fixed-rate | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	3,407	2,869	6,216	5,417
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	1,819	1,144	5,209	2,832
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	41	2,321	360	11,247
Single-family | 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	117,474		117,474		281,257
One fiscal year before	316,653		316,653		896,977
Two fiscal years before	902,920		902,920		820,452
Three fiscal years before	779,843		779,843		149,067
Four fiscal years before	139,305		139,305		70,306
Prior	664,732		664,732		651,297
Total mortgage loans	2,920,927		2,920,927		2,869,356
Single-family | 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	39,749		39,749		84,864
One fiscal year before	100,635		100,635		86,335
Two fiscal years before	39,119		39,119		5,904
Three fiscal years before	3,402		3,402		1,152
Four fiscal years before	829		829		618
Prior	1,168		1,168		1,062
Total mortgage loans	184,902		184,902		179,935
Single-family | 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	48,108		48,108		84,664
One fiscal year before	35,593		35,593		9,284
Two fiscal years before	3,374		3,374		1,333
Three fiscal years before	359		359		217
Four fiscal years before	75		75		77
Prior	214		214		224
Total mortgage loans	87,723		87,723		95,799
Single-family | 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	32		32		1,230
One fiscal year before	585		585		208
Two fiscal years before	124		124		56
Three fiscal years before	45		45		18
Four fiscal years before	17		17		12
Prior	179		179		240
Total mortgage loans	982		982		1,764
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	6,620		6,620		39,748
One fiscal year before	36,996		36,996		185,938
Two fiscal years before	170,196		170,196		134,370
Three fiscal years before	121,612		121,612		20,242
Four fiscal years before	17,852		17,852		7,324
Prior	90,302		90,302		103,846
Total mortgage loans	443,578		443,578		491,468
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			1
Three fiscal years, writeoff			1
Four fiscal years, writeoff			0
Prior			4
Total writeoff			6
Restructured loans, amortized cost	538	805	1,051	1,739
Single-family | 15-year or less, amortizing fixed-rate | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	311	478	465	697
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	97	196	343	794
Single-family | 15-year or less, amortizing fixed-rate | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	130	129	241	245
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	1	1	2
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	1	1	1
Single-family | 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	5,995		5,995		37,830
One fiscal year before	36,184		36,184		185,511
Two fiscal years before	170,132		170,132		134,336
Three fiscal years before	121,606		121,606		20,239
Four fiscal years before	17,852		17,852		7,324
Prior	90,299		90,299		103,841
Total mortgage loans	442,068		442,068		489,081
Single-family | 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	416		416		1,363
One fiscal year before	758		758		410
Two fiscal years before	62		62		33
Three fiscal years before	6		6		3
Four fiscal years before	0		0		0
Prior	2		2		2
Total mortgage loans	1,244		1,244		1,811
Single-family | 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	209		209		552
One fiscal year before	54		54		16
Two fiscal years before	2		2		1
Three fiscal years before	0		0		0
Four fiscal years before	0		0		0
Prior	0		0		1
Total mortgage loans	265		265		570
Single-family | 15-year or less, amortizing fixed-rate | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0		0		3
One fiscal year before	0		0		1
Two fiscal years before	0		0		0
Three fiscal years before	0		0		0
Four fiscal years before	0		0		0
Prior	1		1		2
Total mortgage loans	1		1		6
Single-family | Adjustable-rate
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1,899		1,899		5,630
One fiscal year before	5,966		5,966		6,640
Two fiscal years before	6,168		6,168		1,877
Three fiscal years before	1,704		1,704		824
Four fiscal years before	732		732		908
Prior	10,236		10,236		11,229
Total mortgage loans	26,705		26,705		27,108
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			1
Prior			1
Total writeoff			2
Restructured loans, amortized cost	62	89	119	$ 224
Restructured loans, percent of total financing receivable				1.00%
Single-family | Adjustable-rate | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	42	49	59	$ 76
Single-family | Adjustable-rate | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	8	22	31	83
Single-family | Adjustable-rate | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	11	15	22	39
Single-family | Adjustable-rate | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	0	0	0
Single-family | Adjustable-rate | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	1	3	7	26
Single-family | Adjustable-rate | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	1,257		1,257		3,971
One fiscal year before	4,574		4,574		6,383
Two fiscal years before	6,078		6,078		1,865
Three fiscal years before	1,697		1,697		821
Four fiscal years before	730		730		906
Prior	10,231		10,231		11,226
Total mortgage loans	24,567		24,567		25,172
Single-family | 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	415		415		1,013
One fiscal year before	1,079		1,079		236
Two fiscal years before	84		84		12
Three fiscal years before	6		6		3
Four fiscal years before	2		2		1
Prior	4		4		3
Total mortgage loans	1,590		1,590		1,268
Single-family | 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	227		227		645
One fiscal year before	311		311		21
Two fiscal years before	6		6		0
Three fiscal years before	1		1		0
Four fiscal years before	0		0		1
Prior	1		1		0
Total mortgage loans	546		546		667
Single-family | Adjustable-rate | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0		0		1
One fiscal year before	2		2		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		0
Four fiscal years before	0		0		0
Prior	0		0		0
Total mortgage loans	2		2		1
Single-family | Other
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0		0		0
One fiscal year before	0		0		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		29
Four fiscal years before	27		27		224
Prior	20,212		20,212		22,345
Total mortgage loans	20,239		20,239		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			46
Total writeoff			46
Restructured loans, amortized cost	$ 194	$ 452	$ 532	$ 1,430
Restructured loans, percent of total financing receivable	1.00%	1.00%	2.00%	4.00%
Single-family | Other | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	$ 54	$ 173	$ 128	$ 289
Single-family | Other | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	30	77	108	353
Single-family | Other | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	57	86	137	182
Single-family | Other | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	31	25	94	109
Single-family | Other | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	22	91	65	497
Single-family | Other | Less than or equal to 80%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0		0		0
One fiscal year before	0		0		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		29
Four fiscal years before	27		27		222
Prior	20,038		20,038		22,103
Total mortgage loans	20,065		20,065		22,354
Single-family | 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		0
One fiscal year before	0		0		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		0
Four fiscal years before	0		0		1
Prior	93		93		129
Total mortgage loans	93		93		130
Single-family | 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		0
One fiscal year before	0		0		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		0
Four fiscal years before	0		0		1
Prior	42		42		56
Total mortgage loans	42		42		57
Single-family | Other | Greater than 100%
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Current fiscal year	0		0		0
One fiscal year before	0		0		0
Two fiscal years before	0		0		0
Three fiscal years before	0		0		0
Four fiscal years before	0		0		0
Prior	39		39		57
Total mortgage loans	39		39		57
Single-family | U.S Government
Financing Receivable, before Allowance for Credit Loss, by Origination Year [Abstract]
Total mortgage loans	6,200		6,200		$ 9,500
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total writeoff	4
Multifamily
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	921	24	1,630	205
Multifamily | Forbearance Plan
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	361	6	1,045	187
Multifamily | Payment Deferral
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Trial Modification and Repayment Plans
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Payment Delay and Term Extension
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	0	0	0	0
Multifamily | Payment Delay, Term Extension and Interest Rate Reduction
Financing Receivable, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Restructured loans, amortized cost	$ 560	$ 18	$ 585	$ 18