Mortgage Loans - Credit Quality Indicators - SF (Details) - Single-family - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 497,393	$ 1,200,915
One fiscal year before	1,185,382	1,082,870
Two fiscal years before	963,992	207,663
Three fiscal years before	171,549	100,239
Four fiscal years before	79,469	135,670
Prior	790,243	829,967
Total loans held for investment	3,688,028	3,557,324
Less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	323,058	1,001,159
One fiscal year before	1,088,871	1,040,601
Two fiscal years before	956,653	204,398
Three fiscal years before	170,156	98,924
Four fiscal years before	78,758	134,953
Prior	788,467	826,785
Total loans held for investment	3,405,963	3,306,820
Greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	87,240	132,354
One fiscal year before	86,981	39,973
Two fiscal years before	5,949	2,712
Three fiscal years before	1,158	1,067
Four fiscal years before	620	632
Prior	1,196	1,972
Total loans held for investment	183,144	178,710
Greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	85,861	67,381
One fiscal year before	9,321	2,284
Two fiscal years before	1,334	544
Three fiscal years before	217	231
Four fiscal years before	79	60
Prior	281	597
Total loans held for investment	97,093	71,097
Greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,234	21
One fiscal year before	209	12
Two fiscal years before	56	9
Three fiscal years before	18	17
Four fiscal years before	12	25
Prior	299	613
Total loans held for investment	1,828	697
20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	452,015	994,858
One fiscal year before	992,804	923,269
Two fiscal years before	827,745	181,151
Three fiscal years before	150,454	89,126
Four fiscal years before	71,013	111,760
Prior	652,823	668,941
Total loans held for investment	3,146,854	2,969,105
20- and 30-year or more, amortizing fixed-rate | Less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	281,257	798,830
One fiscal year before	896,977	881,290
Two fiscal years before	820,452	177,909
Three fiscal years before	149,067	87,825
Four fiscal years before	70,306	111,059
Prior	651,297	666,327
Total loans held for investment	2,869,356	2,723,240
20- and 30-year or more, amortizing fixed-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	84,864	129,340
One fiscal year before	86,335	39,689
Two fiscal years before	5,904	2,689
Three fiscal years before	1,152	1,056
Four fiscal years before	618	622
Prior	1,062	1,687
Total loans held for investment	179,935	175,083
20- and 30-year or more, amortizing fixed-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	84,664	66,667
One fiscal year before	9,284	2,278
Two fiscal years before	1,333	544
Three fiscal years before	217	229
Four fiscal years before	77	57
Prior	224	460
Total loans held for investment	95,799	70,235
20- and 30-year or more, amortizing fixed-rate | Greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,230	21
One fiscal year before	208	12
Two fiscal years before	56	9
Three fiscal years before	18	16
Four fiscal years before	12	22
Prior	240	467
Total loans held for investment	1,764	547
15-year or less, amortizing fixed-rate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	39,748	199,318
One fiscal year before	185,938	157,340
Two fiscal years before	134,370	25,406
Three fiscal years before	20,242	9,600
Four fiscal years before	7,324	20,720
Prior	103,846	121,043
Total loans held for investment	491,468	533,427
15-year or less, amortizing fixed-rate | Less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	37,830	196,163
One fiscal year before	185,511	157,076
Two fiscal years before	134,336	25,390
Three fiscal years before	20,239	9,595
Four fiscal years before	7,324	20,715
Prior	103,841	121,027
Total loans held for investment	489,081	529,966
15-year or less, amortizing fixed-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,363	2,576
One fiscal year before	410	259
Two fiscal years before	33	16
Three fiscal years before	3	4
Four fiscal years before	0	2
Prior	2	7
Total loans held for investment	1,811	2,864
15-year or less, amortizing fixed-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	552	579
One fiscal year before	16	5
Two fiscal years before	1	0
Three fiscal years before	0	1
Four fiscal years before	0	1
Prior	1	4
Total loans held for investment	570	590
15-year or less, amortizing fixed-rate | Greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3	0
One fiscal year before	1	0
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	0	2
Prior	2	5
Total loans held for investment	6	7
Adjustable-rate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	5,630	6,739
One fiscal year before	6,640	2,261
Two fiscal years before	1,877	1,072
Three fiscal years before	824	1,240
Four fiscal years before	908	2,526
Prior	11,229	12,504
Total loans held for investment	27,108	26,342
Adjustable-rate | Less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3,971	6,166
One fiscal year before	6,383	2,235
Two fiscal years before	1,865	1,065
Three fiscal years before	821	1,236
Four fiscal years before	906	2,524
Prior	11,226	12,501
Total loans held for investment	25,172	25,727
Adjustable-rate | Greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,013	438
One fiscal year before	236	25
Two fiscal years before	12	7
Three fiscal years before	3	4
Four fiscal years before	1	2
Prior	3	3
Total loans held for investment	1,268	479
Adjustable-rate | Greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	645	135
One fiscal year before	21	1
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	1	0
Prior	0	0
Total loans held for investment	667	136
Adjustable-rate | Greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1	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	0	0
Total loans held for investment	1	0
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	34
Three fiscal years before	29	273
Four fiscal years before	224	664
Prior	22,345	27,479
Total loans held for investment	22,598	28,450
Other | Less than or equal to 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	34
Three fiscal years before	29	268
Four fiscal years before	222	655
Prior	22,103	26,930
Total loans held for investment	22,354	27,887
Other | Greater than 80% and less than or equal to 90%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	3
Four fiscal years before	1	6
Prior	129	275
Total loans held for investment	130	284
Other | Greater than 90% and less than or equal to 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	1
Four fiscal years before	1	2
Prior	56	133
Total loans held for investment	57	136
Other | Greater than 100%
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	1
Four fiscal years before	0	1
Prior	57	141
Total loans held for investment	57	143
Government
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans held for investment	$ 9,500	$ 9,500