Mortgage Loans - Loan Restructuring - Summary of Loans Restructured (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 19,867	$ 37,039
Restructured loans, percent of total financing receivable		1.00%
Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	10,491	$ 17,211
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,888	7,432
Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,808	6,392
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,813	1,225
Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	867	4,779
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 18,725	$ 36,743
Restructured loans, percent of total financing receivable	1.00%	1.00%
Single-family | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 9,919	$ 16,944
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,888	7,432
Single-family | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,808	6,392
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,813	1,196
Single-family | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	297	4,779
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 17,668	$ 33,954
Restructured loans, percent of total financing receivable	1.00%	1.00%
Single-family | 20- and 30-year or more, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 9,333	$ 15,662
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,661	6,784
Single-family | 20- and 30-year or more, amortizing fixed-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,629	5,858
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,778	1,103
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	267	4,547
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	682	1,437
Single-family | 15-year or less, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	419	803
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	159	394
Single-family | 15-year or less, amortizing fixed-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	104	239
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	1
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	72	$ 213
Restructured loans, percent of total financing receivable		1.00%
Single-family | Adjustable-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	46	$ 97
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	17	57
Single-family | Adjustable-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	8	54
Single-family | Adjustable-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0
Single-family | Adjustable-rate | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	5
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 303	$ 1,139
Restructured loans, percent of total financing receivable	1.00%	3.00%
Single-family | Other | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 121	$ 382
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	51	197
Single-family | Other | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	67	241
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	35	93
Single-family | Other | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	29	226
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1,142	296
Multifamily | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	572	267
Multifamily | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0
Multifamily | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	0
Multifamily | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	0	29
Multifamily | Payment Delay, Term Extension and Interest Rate Reduction
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 570	$ 0