Financial Derivatives (Gains (Losses) Recognized on Fair Value and Cash Flow Hedges in the Consolidated Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Loans	$ 2,452	$ 2,140	$ 7,025	$ 6,084
Investment Securities	584	501	1,653	1,489
Borrowed Funds	421	280	1,173	793
Other	301	313	880	918
Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Borrowed Funds [Member] \| Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	107	50	577	61
Derivatives	(137)	(56)	(632)	(84)
Amounts related to interest settlements on derivatives	24	53	57	190
Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Investment Securities [Member] \| Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	(31)	(8)	(145)	4
Derivatives	30	9	149	(3)
Amounts related to interest settlements on derivatives	2	(9)		(34)
Cash Flow Hedging [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Loans [Member] \| Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of derivative gains (losses) reclassified from accumulated OCI	6	38	43	128
Cash Flow Hedging [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Other [Member] \| Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of derivative gains (losses) reclassified from accumulated OCI	1	2	8	5
Cash Flow Hedging [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member] \| Investment Securities [Member] \| Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of derivative gains (losses) reclassified from accumulated OCI	$ 2	$ 5	$ 9	$ 16

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

+ References

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