Derivatives and Hedging Activities - Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	$ 440,000,000	$ 9,000,000	$ (77,000,000)
Net Gains (Losses) Reclassified From OCI Into Income	46,000,000	(37,000,000)	15,000,000
Net Gains (Losses) Recognized in Other Income	0	0	0
Interest Income [Member] \| Interest Rate [Member] \| Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	442,000,000	(13,000,000)	(59,000,000)
Net Gains (Losses) Reclassified From OCI Into Income	15,000,000	(68,000,000)	19,000,000
Net Gains (Losses) Recognized in Other Income	0	0	0
Interest Expense [Member] \| Interest Rate [Member] \| Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	(1,000,000)	2,000,000	0
Net Gains (Losses) Reclassified From OCI Into Income	(1,000,000)	(2,000,000)	(4,000,000)
Net Gains (Losses) Recognized in Other Income	0	0	0
Investment Banking and Debt Placement Fees [Member] \| Interest Rate [Member] \| Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	3,000,000	1,000,000	(1,000,000)
Net Gains (Losses) Reclassified From OCI Into Income	0	2,000,000	0
Net Gains (Losses) Recognized in Other Income	0	0	0
Other Income [Member] \| Foreign Exchange Contract [Member] \| Net Investment Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	(4,000,000)	19,000,000	(17,000,000)
Net Gains (Losses) Reclassified From OCI Into Income	32,000,000	31,000,000	0
Net Gains (Losses) Recognized in Other Income	$ 0	$ 0	$ 0

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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