Accumulated Other Comprehensive Income - Reclassification Out of AOCI (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities gains (losses), net		$ 15	$ 18	$ (84)
Income before income taxes		2,916	2,988	3,093
Applicable income tax expense		(602)	(639)	(647)
Interest and fees on loans and leases		7,477	7,334	4,954
Compensation and benefits	[1]	(2,763)	(2,694)	(2,554)
Net Income		2,314	2,349	2,446
Interest on securities		1,839	1,770	1,517
Other noninterest expense	[1]	973	1,225	932
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net Income		(390)	(261)	74
Reclassification out of AOCI | Net unrealized gains on available-for-sale debt securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities gains (losses), net		(18)	(1)	2
Income before income taxes		(18)	(1)	2
Applicable income tax expense		4	0	0
Net Income		(14)	(1)	2
Reclassification out of AOCI | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale Transferred to Held-to-Maturity, Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before income taxes		(129)	0	0
Applicable income tax expense		28	0	0
Net Income		(101)	0	0
Interest on securities		(129)	0	0
Reclassification out of AOCI | Cash flow hedge derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before income taxes		(351)	(334)	99
Applicable income tax expense		81	77	(22)
Interest and fees on loans and leases		(351)	(334)	99
Net Income		(270)	(257)	77
Reclassification out of AOCI | Amortization of net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before income taxes		(3)	(4)	(6)
Applicable income tax expense		0	1	1
Compensation and benefits		(2)	(2)	(3)
Net Income		(3)	(3)	(5)
Reclassification out of AOCI | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits		(1)	(2)	(3)
Reclassification out of AOCI | Other
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before income taxes		(2)	0	0
Applicable income tax expense		0	0	0
Net Income		(2)	0	0
Other noninterest expense		$ (2)	$ 0	$ 0

[1] During the fourth quarter of 2024, certain noninterest income and noninterest expense line items were reclassified to better align disclosures to business activities. These reclassifications were retrospectively applied to all prior periods presented. Total noninterest income and noninterest expense did not change as a result of these reclassifications. Refer to Note 1 for additional information.