Derivative Instruments and Other Financial Instruments Used For Hedging - Notional and Fair Value Amounts (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	$ 241,444	$ 201,094
Fair Value, Asset Derivatives	1,233	871
Fair Value, Liability Derivatives	523	804
Interest rate contracts \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	214,805	189,478
Fair Value, Asset Derivatives	981	531
Fair Value, Liability Derivatives	446	600
Interest rate contracts \| Cash flow hedges \| Designated as hedging instrument
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	13,319	674
Fair Value, Asset Derivatives	0	6
Fair Value, Liability Derivatives	0	0
Commodity contracts \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	9	336
Fair Value, Asset Derivatives	0	25
Fair Value, Liability Derivatives	0	18
Foreign exchange contracts \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	11,219	8,475
Fair Value, Asset Derivatives	230	260
Fair Value, Liability Derivatives	64	168
Equity contracts \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	72	300
Fair Value, Asset Derivatives	8	22
Fair Value, Liability Derivatives	8	13
Other derivative contracts(2) \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	72	127
Fair Value, Asset Derivatives	0	0
Fair Value, Liability Derivatives	0	0
Trading \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	226,177	198,716
Fair Value, Asset Derivatives	1,219	838
Fair Value, Liability Derivatives	518	799
Other risk management \| Not designated as hedging instruments
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	1,948	1,704
Fair Value, Asset Derivatives	14	27
Fair Value, Liability Derivatives	5	5
MUSA and Various other Non-Bank Subsidiaries
Derivative Instruments and Other Financial Instruments
Derivative, Notional Amount	$ 4,100	$ 4,000

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.

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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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