Derivative Financial Instruments - Amounts Related to Cash Flow Hedges (Details) - Interest Rate Contracts - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023		Jun. 30, 2022
Cash Flow Hedges | Commercial loans
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Pre-tax gain (loss) recognized in OCI	$ (419)	$ 59	$ (256)		$ 59
Cash Flow Hedges | Commercial loans | Interest Expense
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Pre-tax gain (loss) reclassified from AOCI into expense	(5)	0	(5)		0
Cash Flow Hedges | Long-term debt | Interest Expense
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Pre-tax gain (loss) reclassified from AOCI into expense	0	(5)	0		(11)
Fair value hedges | Net interest income
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Net income (expense) recognized	59	74	113		153
Fair value hedges | Long-term debt | Net interest income
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Amounts related to interest settlements	(47)	3	(93)		19
Recognized on derivatives	(291)	(38)	(135)		(467)
Recognized on hedged items	299	82	157		568
Net income (expense) recognized	(39)	47	(71)		120
Fair value hedges | Investment securities | Net interest income
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Amounts related to interest settlements	87	9	163		4
Recognized on derivatives	42	60	(53)		474
Recognized on hedged items	(31)	(42)	75		(444)
Net income (expense) recognized	$ 98	$ 27	$ 185	[1]	$ 34	[1]

[1] Includes $12 million and $22 million of income recognized for the three and six months ended June 30, 2023, respectively, and $17 million and $25 million for the three and six months ended June 30, 2022, respectively, from securities with terminated hedges that were reclassified to HTM. The income recognized was offset by the amortization of the fair value mark.