Mortgage Loans - Aging (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 4,129,325	$ 4,133,279
Loans 90 Days or More Delinquent and Accruing Interest	144	209
Nonaccrual Loans with No Allowance	$ 6,551	6,041
Table Footnote [Abstract]
Serious delinquency, days past due	90 days
Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 66,844	71,985
30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	32,269	36,206
60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	9,079	10,685
Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	25,496	25,094
Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	4,062,481	4,061,294
Single-family
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,597,612	3,609,326
Loans 90 Days or More Delinquent and Accruing Interest	137	191
Nonaccrual Loans with No Allowance	4,529	4,056
Table Footnote [Abstract]
Mortgage loans in process of foreclosure	$ 5,900	5,400
Single-family \| Minimum
Table Footnote [Abstract]
Serious delinquency, days past due	90 days
Single-family \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 63,037	68,226
Single-family \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	31,896	35,687
Single-family \| 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	9,079	10,685
Single-family \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	22,062	21,854
Single-family \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,534,575	3,541,100
Single-family \| 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,235,926	3,240,510
Loans 90 Days or More Delinquent and Accruing Interest	121	171
Nonaccrual Loans with No Allowance	4,150	3,713
Single-family \| 20- and 30-year or more, amortizing fixed-rate \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	59,886	64,826
Single-family \| 20- and 30-year or more, amortizing fixed-rate \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	30,127	33,764
Single-family \| 20- and 30-year or more, amortizing fixed-rate \| 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	8,662	10,205
Single-family \| 20- and 30-year or more, amortizing fixed-rate \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	21,097	20,857
Single-family \| 20- and 30-year or more, amortizing fixed-rate \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,176,040	3,175,684
Single-family \| 15-year or less, amortizing fixed-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	313,647	322,584
Loans 90 Days or More Delinquent and Accruing Interest	5	7
Nonaccrual Loans with No Allowance	235	193
Single-family \| 15-year or less, amortizing fixed-rate \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	1,992	2,170
Single-family \| 15-year or less, amortizing fixed-rate \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	1,199	1,313
Single-family \| 15-year or less, amortizing fixed-rate \| 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	267	310
Single-family \| 15-year or less, amortizing fixed-rate \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	526	547
Single-family \| 15-year or less, amortizing fixed-rate \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	311,655	320,414
Single-family \| Adjustable-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	31,020	28,606
Loans 90 Days or More Delinquent and Accruing Interest	0	1
Nonaccrual Loans with No Allowance	17	17
Single-family \| Adjustable-rate \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	279	294
Single-family \| Adjustable-rate \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	151	155
Single-family \| Adjustable-rate \| 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	31	43
Single-family \| Adjustable-rate \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	97	96
Single-family \| Adjustable-rate \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	30,741	28,312
Single-family \| Other
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	17,019	17,626
Loans 90 Days or More Delinquent and Accruing Interest	11	12
Nonaccrual Loans with No Allowance	127	133
Single-family \| Other \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	880	936
Single-family \| Other \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	419	455
Single-family \| Other \| 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	119	127
Single-family \| Other \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	342	354
Single-family \| Other \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	16,139	16,690
Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	531,713	523,953
Loans 90 Days or More Delinquent and Accruing Interest	7	18
Nonaccrual Loans with No Allowance	$ 2,022	1,985
Multifamily \| Minimum
Table Footnote [Abstract]
Serious delinquency, days past due	60 days
Multifamily \| Maximum
Table Footnote [Abstract]
Serious delinquency, days past due	89 days
Multifamily \| Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 3,807	3,759
Multifamily \| 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	373	519
Multifamily \| Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,434	3,240
Multifamily \| Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 527,906	$ 520,194

Financing Receivable, Excluding Fair Value Option, before Allowance for Credit Loss

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Amortized cost of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

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