Mortgage Loans Held for Sale - Activities of Mortgage Loans Held for Sale (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance - beginning of year	$ 4,077	$ 1,631
Loans sold	(66,545)	(41,269)
Mortgage loans originated and purchased, net of fees	63,233	40,793
Repurchase of loans out of Ginnie Mae securitizations	4,822	2,895
Net change in unrealized gain on loans held for sale	123	9
Net transfer of mortgage loans held for sale	10	18
Balance - end of year	$ 5,720	$ 4,077

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

No definition available.

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- Definition

Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Transfer from Held-for-sale to Held For Investment or Other Assets

+ 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=121593590&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=120238483&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=121593590&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

+ Details

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