The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Nominal or face amount used to calculate payment on derivative.

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Derivative Instruments and Other Financial Instruments Used For Hedging - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flow hedges
Derivative, Notional Amount	$ 241,444	$ 201,094
Income from accumulated other comprehensive income expected to be reclassified to net interest income	$ 67
Cash flow hedges
Cash flow hedges
Weighted average remaining life of the currently active cash flow hedges	3 years 1 month 6 days
Other risk management \| Not designated as hedging instruments
Cash flow hedges
Net gain (losses) on derivatives included in other noninterest income	$ 2	(4)	$ (17)
Derivative, Notional Amount	1,948	1,704
ERROR in label resolution. \| Designated as hedging instrument \| Cash flow hedges \| LIBOR indexed loans
Cash flow hedges
Derivative, Notional Amount	69
Interest Rate Floor [Member] \| Designated as hedging instrument \| Cash flow hedges \| LIBOR indexed loans
Cash flow hedges
Derivative, Notional Amount	13,300
MUSA and Various other Non-Bank Subsidiaries
Cash flow hedges
Derivative, Notional Amount	$ 4,100	$ 4,000