Mortgage Loans - Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Loans in Mortgage Portfolio [Line Items]
Total UPB of mortgage loans	$ 4,100,111		$ 4,100,111		$ 4,095,866
Cost basis and fair value adjustments, net	28,055		28,055		31,811
Allowance for loan losses for HFI loans	(8,513)		(8,513)		(8,364)
Total mortgage loans	4,119,653		4,119,653		4,119,313
Accrued interest receivable, net	12,287		12,287		11,689
Single-family
Loans in Mortgage Portfolio [Line Items]
Total UPB of mortgage loans	3,565,196		3,565,196		3,570,904
Purchase of HFI loans:	110,645	$ 83,567	209,110	$ 147,194
Amortized cost	541	194	541	704
Lower of cost or fair value adjustment at time of redesignation	(82)	(21)	(82)	(90)
Allowance reversed at time of redesignation	(3)		(3)
Allowance reversed at time of redesignation		3		20
UPB	0	660	0	660
Realized gains (losses), net	0	7	0	7
Multifamily
Loans in Mortgage Portfolio [Line Items]
Total UPB of mortgage loans	534,915		534,915		524,962
Purchase of HFI loans:	13,997	$ 16,636	30,849	$ 28,150
Mortgage loans
Loans in Mortgage Portfolio [Line Items]
Accrued interest receivable, net	$ 11,600		$ 11,600		$ 11,300

Financing Receivable, Transfer to Held-for-Sale, Allowance for Credit Loss, Adjustment, Other

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Financing Receivable, Transfer to Held-for-Sale, Allowance For Credit Loss, Expense Reversal, Net

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Mortgage Loans, Cost Basis and Fair Value Adjustments, Net

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Represents principal amount outstanding of mortgage loans.

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Amount, after allowance for credit loss, of accrued interest on financing receivable.

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The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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