Asset Quality - Schedule of Changes in Allowance for Loan and Lease Losses by Loan Category (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 1,508	$ 1,337
Provision	115	88
Charge-offs	(97)	(60)
Recoveries	16	15
Ending balance	1,542	1,380
Total ALLL, including discontinued operations, beginning balance	1,524	1,358
Total provision, including discontinued operations	115	87
Total charge-offs, including discontinued operations	(98)	(61)
Total recoveries, including discontinued operations	16	15
Total ALLL, including discontinued operations, ending balance	1,557	1,399
Provision (credit) for losses on lending-related commitments	(14)	51
Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,060	864
Provision	128	50
Charge-offs	(67)	(39)
Recoveries	10	9
Ending balance	1,131	884
Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	448	473
Provision	(13)	38
Charge-offs	(30)	(21)
Recoveries	6	6
Ending balance	411	496
Commercial and Industrial | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	556	601
Provision	151	31
Charge-offs	(62)	(35)
Recoveries	8	8
Ending balance	653	605
Total commercial real estate loans | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	471	231
Provision	(16)	20
Charge-offs	(5)	(5)
Recoveries	0	0
Ending balance	450	246
Real estate — commercial mortgage | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	419	203
Provision	(25)	20
Charge-offs	(5)	(5)
Recoveries	0	0
Ending balance	389	218
Real estate — construction | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	52	28
Provision	9	0
Charge-offs	0	0
Recoveries	0	0
Ending balance	61	28
Commercial lease financing | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	33
Provision	(7)
Charge-offs	0
Recoveries	2
Ending balance	28
Commercial lease financing | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		32
Provision		(1)
Charge-offs		1
Recoveries		1
Ending balance		33
Real estate — residential mortgage | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	162	196
Provision	(42)	15
Charge-offs	(1)	0
Recoveries	2	1
Ending balance	121	212
Home equity loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	86	98
Provision	(7)	(2)
Charge-offs	(1)	(1)
Recoveries	1	1
Ending balance	79	96
Other consumer loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	122	113
Provision	25	12
Charge-offs	(16)	(11)
Recoveries	2	3
Ending balance	133	117
Credit cards | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	78	66
Provision	11	13
Charge-offs	(12)	(9)
Recoveries	1	1
Ending balance	78	71
Discontinued operations
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	16	21
Provision	0	(1)
Charge-offs	(1)	(1)
Recoveries	0	0
Ending balance	$ 15	$ 19