Asset Quality - Changes in Allowance for Loan and Lease Losses by Loan Category (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 1,099	$ 1,220	$ 1,061	$ 1,626
Provision	88	(107)	203	(377)
Charge-offs	(68)	(66)	(178)	(272)
Recoveries	25	37	58	107
Ending balance	1,144	1,084	1,144	1,084
Total ALLL, including discontinued operations, beginning balance	1,123	1,250	1,089	1,662
Total provision, including discontinued operations	86	(108)	199	(383)
Total charge-offs, including discontinued operations	(69)	(67)	(182)	(275)
Total recoveries, including discontinued operations	26	38	60	109
Total ALLL, including discontinued operations, ending balance	1,166	1,113	1,166	1,113
Provision (credit) for losses on lending-related commitments	21	0	34	(45)
Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	709	795	688	1,099
Provision	66	(89)	142	(284)
Charge-offs	(52)	(28)	(130)	(185)
Recoveries	16	27	39	75
Ending balance	739	705	739	705
Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	390	425	373	527
Provision	22	(18)	61	(93)
Charge-offs	(16)	(38)	(48)	(87)
Recoveries	9	10	19	32
Ending balance	405	379	405	379
Commercial and Industrial | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	503	499	445	678
Provision	52	(30)	160	(135)
Charge-offs	(49)	(27)	(118)	(141)
Recoveries	13	20	32	60
Ending balance	519	462	519	462
Commercial mortgage | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	156	227	182	327
Provision	13	(44)	(8)	(112)
Charge-offs	(3)	0	(10)	(39)
Recoveries	2	1	4	8
Ending balance	168	184	168	184
Construction | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	21	35	29	47
Provision	1	(8)	(8)	(20)
Charge-offs	0	0	0	0
Recoveries	0	0	1	0
Ending balance	22	27	22	27
Total commercial real estate loans | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	177	262	211	374
Provision	14	(52)	(16)	(132)
Charge-offs	(3)	0	(10)	(39)
Recoveries	2	1	5	8
Ending balance	190	211	190	211
Commercial lease financing | Total commercial loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	29	34	32	47
Provision	0	(7)	(2)	(17)
Charge-offs	0	(1)	(2)	(5)
Recoveries	1	6	2	7
Ending balance	30	32	30	32
Real estate — residential mortgage | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	122	86	95	102
Provision	15	(1)	38	(17)
Charge-offs	(1)	2	2	1
Recoveries	1	1	2	2
Ending balance	137	88	137	88
Home equity loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	95	136	110	171
Provision	(3)	(13)	(19)	(44)
Charge-offs	0	(1)	(1)	(7)
Recoveries	1	2	3	4
Ending balance	93	124	93	124
Consumer direct loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	112	115	105	128
Provision	4	(5)	25	(7)
Charge-offs	(8)	(7)	(25)	(22)
Recoveries	4	2	7	6
Ending balance	112	105	112	105
Credit cards | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	59	68	61	87
Provision	7	(4)	17	(13)
Charge-offs	(7)	(6)	(22)	(21)
Recoveries	2	1	5	6
Ending balance	61	59	61	59
Consumer indirect loans | Total consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2	20	2	39
Provision	(1)	5	0	(12)
Charge-offs	0	(26)	(2)	(38)
Recoveries	1	4	2	14
Ending balance	2	3	2	3
Discontinued operations
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	24	30	28	36
Provision	(2)	(1)	(4)	(6)
Charge-offs	(1)	(1)	(4)	(3)
Recoveries	1	1	2	2
Ending balance	$ 22	$ 29	$ 22	$ 29