Accumulated Other Comprehensive Income - Reclassification Out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities (losses) gains, net	$ (32)	$ 10	$ (47)	$ 13
Interest and fees on loans and leases	1,081	1,035	2,062	2,064
Compensation and benefits	584	638	1,295	1,343
Income (loss) before income taxes	724	911	1,335	1,794
Applicable income tax expense	(162)	(202)	(279)	(391)
Net income	562	709	1,056	1,403
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income	43	61	105	105
Reclassification out of AOCI | Available-for-sale debt securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Securities (losses) gains, net	0	7	3	(9)
Income (loss) before income taxes	0	7	3	(9)
Applicable income tax expense	0	(2)	(1)	2
Net income	0	5	2	(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	58	73	136	146
Income (loss) before income taxes	58	73	136	146
Applicable income tax expense	(13)	(15)	(30)	(31)
Net income	45	58	106	115
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	(2)	(3)	(3)	(4)
Applicable income tax expense	0	1	0	1
Net income	(2)	(2)	(3)	(3)
Reclassification out of AOCI | Amortization of net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits	(1)	(2)	(2)	(3)
Reclassification out of AOCI | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and benefits	$ (1)	$ (1)	$ (1)	$ (1)