Derivatives - Derivative Instruments Included in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	$ 2,097	$ 1,114
Fair value - Derivative Liabilities	911	874
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	615	346
Fair value - Derivative Liabilities	75	29
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	459	262
Fair value - Derivative Liabilities	3	2
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges \| Fair Value Hedging \| Interest Rate Swap \| Long-Term Debt
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,705	3,455
Fair value - Derivative Assets	459	262
Fair value - Derivative Liabilities	3	2
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	156	84
Fair value - Derivative Liabilities	72	27
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges \| Cash Flow Hedging \| Interest Rate Swap \| Commercial and Industrial Loans
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	8,000	8,000
Fair value - Derivative Assets	0	15
Fair value - Derivative Liabilities	72	27
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges \| Cash Flow Hedging \| Interest Rate Floor \| Commercial and Industrial Loans
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,000	3,000
Fair value - Derivative Assets	156	69
Fair value - Derivative Liabilities	0	0
Nondesignated
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,482	768
Fair value - Derivative Liabilities	836	845
Nondesignated \| Risk Management And Other Business Purposes
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	181	44
Fair value - Derivative Liabilities	163	147
Nondesignated \| Risk Management And Other Business Purposes \| Interest Rate Contract \| Servicing Contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,420	10,045
Fair value - Derivative Assets	178	40
Fair value - Derivative Liabilities	12	14
Nondesignated \| Risk Management And Other Business Purposes \| Forward Contracts \| Loans Held For Sale
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,693	926
Fair value - Derivative Assets	3	0
Fair value - Derivative Liabilities	5	8
Nondesignated \| Risk Management And Other Business Purposes \| Swap
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,834	2,174
Fair value - Derivative Assets	0	0
Fair value - Derivative Liabilities	146	125
Nondesignated \| Risk Management And Other Business Purposes \| Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	133
Fair value - Derivative Assets	0	4
Fair value - Derivative Liabilities	0	0
Nondesignated \| Customer Accommodation
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,301	724
Fair value - Derivative Liabilities	673	698
Nondesignated \| Customer Accommodation \| Interest Rate Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	71,511	55,012
Fair value - Derivative Assets	727	262
Fair value - Derivative Liabilities	169	278
Nondesignated \| Customer Accommodation \| Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,096	407
Fair value - Derivative Assets	24	7
Fair value - Derivative Liabilities	0	0
Nondesignated \| Customer Accommodation \| Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	8,144	6,511
Fair value - Derivative Assets	368	307
Fair value - Derivative Liabilities	353	278
Nondesignated \| Customer Accommodation \| TBAs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	28	18
Fair value - Derivative Assets	0	0
Fair value - Derivative Liabilities	0	0
Nondesignated \| Customer Accommodation \| Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	13,924	13,205
Fair value - Derivative Assets	182	148
Fair value - Derivative Liabilities	$ 151	$ 142

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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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.

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- Definition

Nominal or face amount used to calculate payment on derivative.

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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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