Mortgage Loans - Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,899,025	$ 3,589,868
Cost basis and fair value adjustments, net	74,846	74,576
Allowance for loan losses for HFI loans	(5,629)	(10,552)
Total mortgage loans	3,968,242	3,653,892
Lower of cost or fair value adjustment at time of redesignation	(107)	153	$ (6)
Single-family loans sold, unpaid principal balance	16,977	9,519	19,737
Single-family loans sold, realized gain, net	1,624	831	1,238
Single-family
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	3,495,573	3,216,146
Single family loans redesignated from HFI to HFS, amortized cost	16,606	8,309	18,245
Lower of cost or fair value adjustment at time of redesignation	(372)	(291)	(995)
Allowance reversed at time of redesignation	1,605	963	2,484
Single family loans redesignated from HFS to HFI, amortized cost	5	144	28
Allowance established at time of redesignation	(1)	(15)	$ (1)
Mortgage loans in process of foreclosure	4,400	5,000
Multifamily
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	403,452	373,722
Mortgage loans
Loans in Mortgage Portfolio [Line Items]
Accrued interest receivable	$ 9,100	$ 9,800

Financing Receivable Reclassification To Be Held For Investment

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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 of other addition (reduction) in allowance reserve for credit loss.

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The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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

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

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Amount of decrease from sale and reclassification to held-for-sale of 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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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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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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