Accumulated Other Comprehensive Income - Reclassification Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities gains (losses), net	$ 4	$ (14)
Interest and fees on loans and leases	1,714	983
Compensation and benefits	(757)	(711)
Income (loss) before income taxes	718	612
Applicable income tax expense	160	118
Net income	558	494
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income	(50)	61
Reclassification out of AOCI | Available-for-sale debt securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities gains (losses), net	0	3
Income (loss) before income taxes	0	3
Applicable income tax expense	0	(1)
Net income	0	2
Reclassification out of AOCI | Net unrealized gains on cash flow hedge
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest and fees on loans and leases	(65)	78
Income (loss) before income taxes	(65)	78
Applicable income tax expense	15	(18)
Net income	(50)	60
Reclassification out of AOCI | Net periodic benefit costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income (loss) before income taxes	0	(1)
Applicable income tax expense	0	0
Net income	0	(1)
Reclassification out of AOCI | Amortization of net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits	$ 0	$ (1)