Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from 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]
Interest and fees on loans and leases	$ 3,874	$ 3,575	$ 2,292
Income tax expense	211	212	247
Other expense	190	182	186
Amounts reclassified from AOCI	(794)	(916)	(912)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amounts reclassified from AOCI	126	59	23
Reclassification out of Accumulated Other Comprehensive Income | Securities AFS
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities gains (losses), net	91	0	0
Income tax expense	(22)	0	0
Amounts reclassified from AOCI	(69)	0	0
Reclassification out of Accumulated Other Comprehensive Income | Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest and fees on loans and leases	65	69	20
Income tax expense	(16)	(17)	(5)
Amounts reclassified from AOCI	49	52	15
Reclassification out of Accumulated Other Comprehensive Income | Pension and Post-retirement Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	(3)	(2)	(2)
Other expense	11	9	10
Amounts reclassified from AOCI	$ 8	$ 7	$ 8