Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net fair value of the interest rate lock commitments	$ 57
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 25 bps	13
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 50 bps	25
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 25 bps	13
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 50 bps	26
Change in fair value of interest rate lock commitments, due to 10% adverse changes in the assumed loan closing rates	6
Change in fair value of interest rate lock commitments, due to 20% adverse changes in the assumed loan closing rates	12
Change in fair value of interest rate lock commitments, due to 10% favorable changes in the assumed loan closing rates	6
Change in fair value of interest rate lock commitments, due to 20% favorable changes in the assumed loan closing rates	12
Private equity, observable price change adjustment	23	$ 13
Private equity, cumulative observable price change	69
Private equity, impairment	9	5
Gain from sale of certain private equity investments	4
Gain from sale of certain private equity investments	0	562	$ 205
Private equity, cumulative impairment	21
Other Real Estate Owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value adjustment	(4)	(3)
Other Real Estate Owned \| Transfer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value gains (losses)	(3)	(3)
Commercial \| Commercial loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value adjustment	(5)
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value changes included in earnings for instruments for which the fair value option was elected	75	37
FVO valuation adjustments related to instrument-specific credit risk	$ 1	$ 1

Sensitivity analysis of decrease in fair value of derivatives impact of fifty basis point increase in interest rate.

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Sensitivity analysis of decrease in fair value of derivatives impact of twenty five basis point increase in interest rate.

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Sensitivity analysis of increase in fair value of derivatives impact of fifty basis point decrease in interest rate.

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Sensitivity analysis of increase in fair value of derivatives impact of ten percent changes in assumed loan closing rates.

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Sensitivity analysis of increase in fair value of derivatives impact of twenty five basis point decrease in interest rate.

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Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Amount of gain (loss) on sale or disposal of an equity method investment.

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Amount of realized gain from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of loss from downward price adjustment on investment in equity security without readily determinable fair value.

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Amount of cumulative loss from downward price adjustment on investment in equity security without readily determinable fair value.

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Amount of gain from upward price adjustment on investment in equity security without readily determinable fair value.

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Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value.

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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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For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

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Amount of gain (loss) related to nonoperating activities, classified as other.

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The hypothetical financial impact of a 10 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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The hypothetical financial impact of a 20 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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