Derivative Financial Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Assets
Derivatives, Fair Value [Line Items]
Outstanding Notional	$ 32,681	$ 8,649
Fair Value	526	294
Gains/(Losses)	37	141
Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Outstanding Notional	2,341	2,598
Fair Value	42	111
Gains/(Losses)	(60)	79
Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional	8,950	6,923
Fair Value	232	263
Gains/(Losses)	(182)	128
Assets \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional	1,165	834
Fair Value	8	25
Gains/(Losses)	(30)	13
Assets \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Outstanding Notional	22,566	886
Fair Value	286	6
Gains/(Losses)	249	0
Assets \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional		6
Fair Value		0
Gains/(Losses)		0
Liabilities
Derivatives, Fair Value [Line Items]
Outstanding Notional	10,615	10,267
Derivative financial instruments	116	223
Gains/(Losses)	(41)	208
Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional	240	22
Derivative financial instruments	1	0
Gains/(Losses)	1	0
Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional	3,974	10
Derivative financial instruments	38	0
Gains/(Losses)	37	(3)
Liabilities \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Outstanding Notional	6,341	10,229
Derivative financial instruments	76	223
Gains/(Losses)	(80)	211
Liabilities \| Swap futures
Derivatives, Fair Value [Line Items]
Outstanding Notional	60
Derivative financial instruments	1
Gains/(Losses)	$ 1
Liabilities \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional		6
Derivative financial instruments		0
Gains/(Losses)		$ 0

Nominal or face amount used to calculate payments on the derivative asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-Topic 815
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Nominal or face amount used to calculate payments on the derivative liability.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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.

+ References

No definition available.

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