Mortgage Loans - Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Loans in Mortgage Portfolio [Line Items]
Total unpaid principal balance of mortgage loans	$ 4,072,636		$ 4,075,598
Cost basis and fair value adjustments, net	49,034		50,185
Allowance for loan losses for HFI loans	(11,335)	$ (5,899)	(11,347)	$ (5,629)
Total mortgage loans	4,110,335		4,114,436
Accrued interest receivable	9,780		9,821
Single-family
Loans in Mortgage Portfolio [Line Items]
Total unpaid principal balance of mortgage loans	3,636,329		3,644,158
Purchase of HFI loans:	67,467	239,468
Amortized cost	0	1,181
Lower of cost or fair value adjustment at time of redesignation	0	(13)
Allowance reversed at time of redesignation	0	63
Unpaid principal balance	1,842	0
Realized gains, net	17	0
Mortgage loans in process of foreclosure	4,600		4,600
Multifamily
Loans in Mortgage Portfolio [Line Items]
Total unpaid principal balance of mortgage loans	436,307		431,440
Purchase of HFI loans:	10,235	$ 16,009
Mortgage loans
Loans in Mortgage Portfolio [Line Items]
Accrued interest receivable	$ 9,500		$ 9,500

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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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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-Publisher FASB
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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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