Asset Quality - Changes in Allowance for Loan and Lease Losses by Loan Category (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 1,105	$ 1,438	$ 1,061	$ 1,626
Provision	38	(196)	115	(270)
Charge-offs	(59)	(71)	(110)	(206)
Recoveries	15	49	33	70
Ending balance	1,099	1,220	1,099	1,220
Total ALLL, including discontinued operations, beginning balance	1,132	1,471	1,089	1,662
Total provision, including discontinued operations	35	(198)	113	(275)
Total charge-offs, including discontinued operations	(60)	(72)	(113)	(208)
Total recoveries, including discontinued operations	16	49	34	71
Total ALLL, including discontinued operations, ending balance	1,123	1,250	1,123	1,250
Provision (credit) for losses on lending-related commitments	7	(26)	13	(45)
Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	717	937	688	1,099
Provision	23	(135)	76	(195)
Charge-offs	(42)	(45)	(78)	(157)
Recoveries	11	38	23	48
Ending balance	709	795	709	795
Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	388	501	373	527
Provision	15	(61)	39	(75)
Charge-offs	(17)	(26)	(32)	(49)
Recoveries	4	11	10	22
Ending balance	390	425	390	425
Commercial and Industrial | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	489	596	445	678
Provision	45	(88)	108	(105)
Charge-offs	(39)	(41)	(69)	(114)
Recoveries	8	32	19	40
Ending balance	503	499	503	499
Commercial mortgage | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	172	256	182	327
Provision	(14)	(31)	(21)	(68)
Charge-offs	(3)	(4)	(7)	(39)
Recoveries	1	6	2	7
Ending balance	156	227	156	227
Construction | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	25	45	29	47
Provision	(5)	(10)	(9)	(12)
Charge-offs	0	0	0	0
Recoveries	1	0	1	0
Ending balance	21	35	21	35
Total commercial real estate loans | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	197	301	211	374
Provision	(19)	(41)	(30)	(80)
Charge-offs	(3)	(4)	(7)	(39)
Recoveries	2	6	3	7
Ending balance	177	262	177	262
Commercial lease financing | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	31	40	32	47
Provision	(3)	(6)	(2)	(10)
Charge-offs	0	0	(2)	(4)
Recoveries	1	0	1	1
Ending balance	29	34	29	34
Real estate — residential mortgage | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	108	100	95	102
Provision	11	(13)	23	(16)
Charge-offs	2	(1)	3	(1)
Recoveries	1	0	1	1
Ending balance	122	86	122	86
Home equity loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	104	157	110	171
Provision	(10)	(18)	(16)	(31)
Charge-offs	0	(4)	(1)	(6)
Recoveries	1	1	2	2
Ending balance	95	136	95	136
Consumer direct loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	111	126	105	128
Provision	10	(6)	21	(2)
Charge-offs	(10)	(7)	(17)	(15)
Recoveries	1	2	3	4
Ending balance	112	115	112	115
Credit cards | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	63	80	61	87
Provision	3	(6)	10	(9)
Charge-offs	(8)	(9)	(15)	(15)
Recoveries	1	3	3	5
Ending balance	59	68	59	68
Consumer indirect loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2	38	2	39
Provision	1	(18)	1	(17)
Charge-offs	(1)	(5)	(2)	(12)
Recoveries	0	5	1	10
Ending balance	2	20	2	20
Discontinued operations
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27	33	28	36
Provision	(3)	(2)	(2)	(5)
Charge-offs	(1)	(1)	(3)	(2)
Recoveries	1	0	1	1
Ending balance	$ 24	$ 30	$ 24	$ 30