Derivative Instruments and Other Financial Instruments Used For Hedging - Amount of Net Gains (Losses) for Derivatives Classified as Trading (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Trading Derivatives
Trading Derivatives
Gains (Losses) Recognized in Income on Trading Derivatives	$ (36)	$ 175	$ 7
Trading Derivatives \| Interest rate contracts
Trading Derivatives
Gains (Losses) Recognized in Income on Trading Derivatives	(93)	95	(49)
Trading Derivatives \| Equity contracts
Trading Derivatives
Gains (Losses) Recognized in Income on Trading Derivatives	6	36	12
Trading Derivatives \| Foreign exchange contracts
Trading Derivatives
Gains (Losses) Recognized in Income on Trading Derivatives	51	44	43
Trading Derivatives \| Commodity contracts
Trading Derivatives
Gains (Losses) Recognized in Income on Trading Derivatives	$ 0	0	1
Fair Value Hedging \| Designated as hedging instrument
Trading Derivatives
Derivative Instrument		(2)	(4)
Hedged Item		2	3
Hedge Ineffectiveness		0	(1)
Fair Value Hedging \| Designated as hedging instrument \| Interest rate contracts
Trading Derivatives
Derivative Instrument		(2)	(4)
Hedged Item		2	3
Hedge Ineffectiveness		$ 0	$ (1)

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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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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No definition available.

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Amount of gain (loss) resulting from the difference between the acquisition price and the selling price or fair value of trading assets and trading liabilities, conducted separately from customer trading activities. Includes, but is not limited to, changes in fair value of trading assets and trading liabilities.

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