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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized	$ 86	$ (14)	$ 99	$ (30)
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	0	0	0
Recognized on derivatives	0	(10)	0	(17)
Recognized on hedged items	(2)	8	(4)	13
Net income (expense) recognized	(2)	(2)	(4)	(4)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	0	0	0
Recognized on derivatives	0	(14)	(3)	(22)
Recognized on hedged items	(1)	14	1	22
Net income (expense) recognized	(1)	0	(2)	0
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	88	(16)	104	(38)
Recognized on derivatives	8	192	930	308
Recognized on hedged items	(7)	(188)	(929)	(296)
Net income (expense) recognized	$ 89	$ (12)	$ 105	$ (26)

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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