Derivative Financial Instruments - Amounts Related to Fair Value Hedges (Details) - Fair Value Hedges - Interest Rate Contracts - Net interest income - 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]
Net income (expense) recognized	$ (3)	$ 27	$ 17	$ 106
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0		(4)
Recognized on derivatives	4		20
Recognized on hedged items	(6)		(22)
Net income (expense) recognized	(2)	(3)	(6)	(10)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0		(1)
Recognized on derivatives	4		10
Recognized on hedged items	(4)		(10)
Net income (expense) recognized	0	0	(1)	(2)
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(13)		(12)
Recognized on derivatives	(50)		(293)
Recognized on hedged items	62		329
Net income (expense) recognized	$ (1)	$ 30	$ 24	$ 118

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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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.

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Amount of gain (loss) on derivative instrument designated and qualifying as fair value hedge included in assessment of hedge effectiveness, recognized in earnings.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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