Derivative Financial Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	$ 7,978	$ 32,681
Derivative Asset, Fair Value, Gross Asset	153	526
Gains/(Losses)	9	37
Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	543	2,341
Derivative Asset, Fair Value, Gross Asset	1	42
Gains/(Losses)	(24)	(60)
Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	3,122	8,950
Derivative Asset, Fair Value, Gross Asset	72	232
Gains/(Losses)	(62)	(182)
Assets \| LPCs
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	203	1,165
Derivative Asset, Fair Value, Gross Asset	2	8
Gains/(Losses)	(1)	(30)
Assets \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	4,653	22,566
Derivative Asset, Fair Value, Gross Asset	79	286
Gains/(Losses)	72	249
Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	3,001	10,615
Derivative financial instruments	68	116
Gains/(Losses)	52	(41)
Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	551	240
Derivative financial instruments	5	1
Gains/(Losses)	5	1
Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	658	3,974
Derivative financial instruments	8	38
Gains/(Losses)	6	37
Liabilities \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	695	6,341
Derivative financial instruments	6	76
Gains/(Losses)	(2)	(80)
Liabilities \| Swap futures
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	1,097	60
Derivative financial instruments	49	1
Gains/(Losses)	$ 43	$ 1

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

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

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