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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized	$ (15)	$ (3)	$ (45)	$ 17
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	0	0	(4)
Recognized on derivatives	1	4	(16)	20
Recognized on hedged items	(3)	(6)	10	(22)
Net income (expense) recognized	(2)	(2)	(6)	(6)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	0	0	(1)
Recognized on derivatives	0	4	(22)	10
Recognized on hedged items	(1)	(4)	21	(10)
Net income (expense) recognized	(1)	0	(1)	(1)
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(17)	(13)	(55)	(12)
Recognized on derivatives	35	(50)	343	(293)
Recognized on hedged items	(30)	62	(326)	329
Net income (expense) recognized	$ (12)	$ (1)	$ (38)	$ 24

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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