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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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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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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Derivative Instruments and Other Financial Instruments Used For Hedging - Amount and Location of Gains and Losses for Derivatives Designated as Cash Flow Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Cash flow hedges
Notional Amount	$ 296,524		$ 296,524		$ 201,094
Income from accumulated other comprehensive income expected to be reclassified to net interest income			$ 74
Interest rate contracts, Amount of Gain or (Loss) Recognized in OCI on Derivative Instruments (Effective Portion)	41
Unrealized net gains (losses) on hedges arising during the period, before tax	41
Cash Flow Hedges
Cash flow hedges
Derivative, Average Remaining Maturity			2 years 9 months 18 days
Interest rate contracts, Amount of Gain or (Loss) Recognized in OCI on Derivative Instruments (Effective Portion)	41	$ 0	$ 110	$ (98)
Interest rate contracts, Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(27)	(11)	(67)	(19)
Unrealized net gains (losses) on hedges arising during the period, before tax	41	0	110	(98)
Cash Flow Hedges \| Noninterest expense
Cash flow hedges
Interest rate contracts, (Gain) Loss Recognized in Income on Derivative Instruments (Ineffective Portion)		0		(1)
Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts
Cash flow hedges
Notional Amount	10,819		10,819		$ 674
Interest rate contracts, Amount of Gain or (Loss) Recognized in OCI on Derivative Instruments (Effective Portion)	41	0	110	(98)
Unrealized net gains (losses) on hedges arising during the period, before tax	41	0	110	(98)
Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts \| Interest income
Cash flow hedges
Interest rate contracts, Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(27)	(11)	(67)	(19)
Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts \| Interest expense
Cash flow hedges
Interest rate contracts, Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0	0	0
Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts \| Noninterest expense
Cash flow hedges
Interest rate contracts, (Gain) Loss Recognized in Income on Derivative Instruments (Ineffective Portion)		$ 0		$ (1)
Libor Indexed Loans [Member] \| Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts
Cash flow hedges
Notional Amount	10,800		10,800
Libor Indexed Short Term Borrowings [Member] \| Cash Flow Hedges \| Designated as Hedging Instrument \| Interest rate derivative contracts
Cash flow hedges
Notional Amount	$ 69		$ 69