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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net income (expense) recognized	$ 87	$ (15)	$ 186	$ (45)
AFS securities
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	0	0	0	0
Recognized on derivatives	0	1	0	(16)
Recognized on hedged items	(3)	(3)	(7)	10
Net income (expense) recognized	(3)	(2)	(7)	(6)
Loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	(1)	0	(1)	0
Recognized on derivatives	0	0	(3)	(22)
Recognized on hedged items	0	(1)	1	21
Net income (expense) recognized	(1)	(1)	(3)	(1)
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Amounts related to interest settlements	78	(17)	182	(55)
Recognized on derivatives	(99)	35	831	343
Recognized on hedged items	112	(30)	(817)	(326)
Net income (expense) recognized	$ 91	$ (12)	$ 196	$ (38)

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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