Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	$ 492		$ 496		$ 936	$ 1,003
Income tax expense	48		88		105	159
Other expense	66		40		112	118
Amounts reclassified from AOCI	(177)	$ (198)	(311)	$ (236)	(374)	(546)
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	4		0		5	0
Reclassification out of Accumulated Other Comprehensive Income | Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	4		(2)		3	(4)
Income tax expense	(1)		0		(1)	1
Amounts reclassified from AOCI	3		(2)		2	(3)
Reclassification out of Accumulated Other Comprehensive Income | Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense	(1)		0		(1)	(1)
Other expense	2		2		4	4
Amounts reclassified from AOCI	$ 1		$ 2		$ 3	$ 3