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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized	$ (14)	$ 3	$ (30)	$ 20
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	(2)	0	(4)
Recognized on derivatives	(10)	5	(17)	16
Recognized on hedged items	8	(5)	13	(16)
Net income (expense) recognized	(2)	(2)	(4)	(4)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	(1)	0	(1)
Recognized on derivatives	(14)	3	(22)	6
Recognized on hedged items	14	(3)	22	(6)
Net income (expense) recognized	0	(1)	0	(1)
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(16)	(7)	(38)	1
Recognized on derivatives	192	(62)	308	(243)
Recognized on hedged items	(188)	75	(296)	267
Net income (expense) recognized	$ (12)	$ 6	$ (26)	$ 25

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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