Derivative Financial Instruments and Hedging Activities - Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Fair value of assets (liabilities) available for offset	$ 302	$ 320
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	108,673	113,871
Derivative asset, Fair value	636	502
Collateral available for netting	89	451
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	519	869
Cash held	210	30
Derivatives Designated as Hedges [Member] \| Other Assets [Member] \| Fair Value Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	9,458	9,533
Derivative asset, Fair value	234	42
Derivatives Designated as Hedges [Member] \| Other Assets [Member] \| Fair Value Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	1,796	1,829
Derivative asset, Fair value	22	37
Derivatives Designated as Hedges [Member] \| Other Assets [Member] \| Cash Flow Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	590	768
Derivative asset, Fair value	0	8
Derivatives Designated as Hedges [Member] \| Other Assets [Member] \| Cash Flow Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	4,429	2,075
Derivative asset, Fair value	40	43
Derivatives Designated as Hedges [Member] \| Other Liabilities [Member] \| Fair Value Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	23	231
Derivatives Designated as Hedges [Member] \| Other Liabilities [Member] \| Fair Value Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	71	60
Derivatives Designated as Hedges [Member] \| Other Liabilities [Member] \| Cash Flow Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	6	0
Derivatives Designated as Hedges [Member] \| Other Liabilities [Member] \| Cash Flow Hedging [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	119	58
Derivatives not Designated as Hedges [Member] \| Other Assets [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	92,400	99,666
Derivative asset, Fair value	340	372
Derivatives not Designated as Hedges [Member] \| Other Liabilities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Fair value	$ 300	$ 520

Derivative Assets (Liabilities), Net, Fair Value, Amount Not Offset Against Collateral

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- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

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Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

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- Definition

Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities.

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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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