Mortgage Loans Held for Sale - Activities of Mortgage Loans Held for Sale (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance - beginning of year	$ 5,720	$ 4,077
Loans sold	(96,077)	(66,545)
Mortgage loans originated and purchased, net of fees	84,684	63,233
Repurchase of loans out of Ginnie Mae securitizations(1)	10,156	4,822
Net change in unrealized gain on retained loans held for sale	(107)	123
Net transfers of mortgage loans held for sale(2)	5	10
Balance - end of year	$ 4,381	$ 5,720

Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Transfer from(to) Other Assets

No definition available.

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- Definition

Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Changes in Fair Value

+ References

No definition available.

+ Details

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- Definition

Repurchase of Ginnie Mae Receivables

+ References

No definition available.

+ Details

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- Definition

Amount, before valuation allowance, of financing receivable classified as held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124265262&loc=d3e48678-111004

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Amount, after allowance for bad debt, of additions to loan receivables held-for-sale that are not part of a disposal group.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

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- Definition

Amount, after allowance for bad debt, of deductions to loan receivables held-for-sale that are not part of a disposal group.

+ References

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