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	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized	$ 3	$ 37	$ 20	$ 79
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(2)		(4)
Recognized on derivatives	5		16
Recognized on hedged items	(5)		(16)
Net income (expense) recognized	(2)	(4)	(4)	(8)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(1)		(1)
Recognized on derivatives	3		6
Recognized on hedged items	(3)		(6)
Net income (expense) recognized	(1)	(1)	(1)	(1)
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(7)		1
Recognized on derivatives	(62)		(243)
Recognized on hedged items	75		267
Net income (expense) recognized	$ 6	$ 42	$ 25	$ 88

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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