Mortgage Loans - Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 4,102,632	$ 4,075,598
Cost basis and fair value adjustments, net	41,729	50,185
Allowance for loan losses	(8,730)	(11,347)	$ (5,629)	$ (10,552)
Total mortgage loans	4,135,631	4,114,436
Accrued interest receivable related to consolidated trusts	10,724	9,821
Mortgage loans
Loans in Mortgage Portfolio [Line Items]
Accrued interest receivable related to consolidated trusts	10,400	9,500
Single-family
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	3,641,385	3,644,158
Purchase of HFI loans:	315,990	614,836	1,354,705
Amortized cost	3,334	7,825	16,606
Single family loans redesignated from HFI to HFS, lower of cost or fair value adjustment at time of redesignation	(658)	(679)	(372)
Related allowance	42	373	1,605
Single family loans redesignated from HFS to HFI, amortized cost	372	2,004	5
Single-family loans sold, unpaid principal balance	2,573	8,069	16,977
Single-family loans sold, realized gain, net	10	126	1,624
Mortgage loans in process of foreclosure	4,600	4,600
Multifamily
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	461,247	431,440
Purchase of HFI loans:	$ 52,829	$ 69,206	$ 69,185

Financing Receivable Reclassification To Be Held For Investment

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Represents premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield and fair value adjustments.

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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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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount of financing receivable reclassified to held-for-sale.

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Amount of increase in financing receivable from purchase. Excludes net investment in lease.

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Amount of decrease in financing receivable from sale and reclassification to held-for-sale. Excludes net investment in lease.

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Amount of expense reversal of allowance for credit loss on financing receivable transferred to held-for-sale classification.

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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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Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

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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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