Mortgage Loans - Loan Restructuring - Summary of Loans Restructured (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 16,631	$ 19,867
Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	5,791	10,491
Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,726	3,888
Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	4,804	2,808
Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,252	1,813
Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	58	867
Single-family
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	16,614	$ 18,725
Restructured loans, percent of total financing receivable (* less than)		1.00%
Single-family | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	5,786	$ 9,919
Single-family | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,726	3,888
Single-family | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	4,804	2,808
Single-family | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	2,252	1,813
Single-family | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	46	297
Single-family | 20- and 30-year or more, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 15,865	$ 17,668
Restructured loans, percent of total financing receivable (* less than)	1.04%	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	$ 5,504	$ 9,333
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	3,539	3,661
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	4,567	2,629
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	2,223	1,778
Single-family | 20- and 30-year or more, amortizing fixed-rate | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	32	267
Single-family | 15-year or less, amortizing fixed-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	496	$ 682
Restructured loans, percent of total financing receivable (* less than)		0.50%
Single-family | 15-year or less, amortizing fixed-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	220	$ 419
Single-family | 15-year or less, amortizing fixed-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	121	159
Single-family | 15-year or less, amortizing fixed-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	153	104
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	0
Single-family | 15-year or less, amortizing fixed-rate | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	0
Single-family | Adjustable-rate
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	63	$ 72
Restructured loans, percent of total financing receivable (* less than)		0.50%
Single-family | Adjustable-rate | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	29	$ 46
Single-family | Adjustable-rate | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	18	17
Single-family | Adjustable-rate | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	15	8
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, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	1	1
Single-family | Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 190	$ 303
Restructured loans, percent of total financing receivable (* less than)	1.00%	1.00%
Single-family | Other | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 33	$ 121
Single-family | Other | Payment Deferral
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	48	51
Single-family | Other | Trial Modification and Repayment Plans
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	69	67
Single-family | Other | Payment Delay and Term Extension
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	28	35
Single-family | Other | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	12	29
Multifamily
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 17	$ 1,142
Restructured loans, percent of total financing receivable (* less than)	0.50%	0.50%
Multifamily | Forbearance Plan
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 5	$ 572
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	0
Multifamily | Payment Delay, Term Extension, Interest Rate Reduction and Other
Loans in Mortgage Portfolio [Line Items]
Restructured loans, amortized cost	$ 12	$ 570