Accumulated Other Comprehensive Income - Reclassification Out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities (losses) gains, net	$ (7)	$ 62	$ 40
Interest and fees on loans and leases	4,079	4,424	5,051
Compensation and benefits	2,626	2,590	2,418
Applicable income tax expense	747	370	690
Net Income	2,770	1,427	2,512
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net Income	213	214	12
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 (losses) gains, net	(4)	45	9
Income before income taxes	(4)	45	9
Applicable income tax expense	1	(11)	(2)
Net Income	(3)	34	7
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	293	237	16
Income before income taxes	293	237	16
Applicable income tax expense	(70)	(50)	(3)
Net Income	223	187	13
Reclassification out of AOCI | Net periodic benefit costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before income taxes	(9)	(9)	(9)
Applicable income tax expense	2	2	1
Net Income	(7)	(7)	(8)
Reclassification out of AOCI | Amortization of net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits	(6)	(6)	(6)
Reclassification out of AOCI | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits	$ (3)	$ (3)	$ (3)