Loans and Leases - Loans by FICO Score (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 56,687	$ 58,232
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	10,865	11,725
Consumer | Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1,023	1,747
Financing receivable, originated year two	1,612	1,670
Financing receivable, originated year three	1,346	1,093
Financing receivable, originated year four	829	920
Financing receivable, originated year five	709	1,054
Financing receivable, originated prior to year five	3,195	2,821
Revolving loans	1,842	2,055
Revolving Loans converted to term loans	309	365
Loans and leases	10,865	11,725
Consumer | Consumer real estate | FICO score 740 or greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	645	1,186
Financing receivable, originated year two	1,144	1,167
Financing receivable, originated year three	950	703
Financing receivable, originated year four	520	610
Financing receivable, originated year five	460	674
Financing receivable, originated prior to year five	2,083	1,719
Revolving loans	1,165	1,275
Revolving Loans converted to term loans	138	159
Loans and leases	7,105	7,493
Consumer | Consumer real estate | FICO score 720-739
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	75	157
Financing receivable, originated year two	148	158
Financing receivable, originated year three	123	100
Financing receivable, originated year four	87	77
Financing receivable, originated year five	59	92
Financing receivable, originated prior to year five	222	197
Revolving loans	167	186
Revolving Loans converted to term loans	26	29
Loans and leases	907	996
Consumer | Consumer real estate | FICO score 700-719
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	70	122
Financing receivable, originated year two	104	107
Financing receivable, originated year three	83	78
Financing receivable, originated year four	60	76
Financing receivable, originated year five	66	73
Financing receivable, originated prior to year five	229	221
Revolving loans	161	177
Revolving Loans converted to term loans	28	34
Loans and leases	801	888
Consumer | Consumer real estate | FICO score 660-699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	50	130
Financing receivable, originated year two	129	141
Financing receivable, originated year three	102	123
Financing receivable, originated year four	101	75
Financing receivable, originated year five	62	85
Financing receivable, originated prior to year five	275	296
Revolving loans	225	264
Revolving Loans converted to term loans	53	59
Loans and leases	997	1,173
Consumer | Consumer real estate | FICO score 620-659
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	12	45
Financing receivable, originated year two	38	61
Financing receivable, originated year three	61	37
Financing receivable, originated year four	24	28
Financing receivable, originated year five	18	35
Financing receivable, originated prior to year five	136	127
Revolving loans	77	92
Revolving Loans converted to term loans	29	36
Loans and leases	395	461
Consumer | Consumer real estate | FICO score less than 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	171	107
Financing receivable, originated year two	49	36
Financing receivable, originated year three	27	52
Financing receivable, originated year four	37	54
Financing receivable, originated year five	44	95
Financing receivable, originated prior to year five	250	261
Revolving loans	47	61
Revolving Loans converted to term loans	35	48
Loans and leases	660	714
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	96	122
Financing receivable, originated year two	83	91
Financing receivable, originated year three	64	107
Financing receivable, originated year four	79	78
Financing receivable, originated year five	59	63
Financing receivable, originated prior to year five	265	279
Revolving loans	340	373
Revolving Loans converted to term loans	16	15
Loans and leases	1,002	1,128
Consumer | Credit Card and Other | FICO score 740 or greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	44	57
Financing receivable, originated year two	45	52
Financing receivable, originated year three	37	59
Financing receivable, originated year four	43	37
Financing receivable, originated year five	27	23
Financing receivable, originated prior to year five	104	116
Revolving loans	136	159
Revolving Loans converted to term loans	7	5
Loans and leases	443	508
Consumer | Credit Card and Other | FICO score 720-739
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	9	7
Financing receivable, originated year two	7	7
Financing receivable, originated year three	6	9
Financing receivable, originated year four	5	8
Financing receivable, originated year five	7	8
Financing receivable, originated prior to year five	27	27
Revolving loans	37	91
Revolving Loans converted to term loans	2	2
Loans and leases	100	159
Consumer | Credit Card and Other | FICO score 700-719
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	5	9
Financing receivable, originated year two	8	8
Financing receivable, originated year three	6	9
Financing receivable, originated year four	7	8
Financing receivable, originated year five	5	4
Financing receivable, originated prior to year five	33	38
Revolving loans	37	37
Revolving Loans converted to term loans	1	3
Loans and leases	102	116
Consumer | Credit Card and Other | FICO score 660-699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	21	30
Financing receivable, originated year two	11	12
Financing receivable, originated year three	8	15
Financing receivable, originated year four	12	9
Financing receivable, originated year five	7	9
Financing receivable, originated prior to year five	47	48
Revolving loans	92	46
Revolving Loans converted to term loans	3	3
Loans and leases	201	172
Consumer | Credit Card and Other | FICO score 620-659
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	2	5
Financing receivable, originated year two	4	5
Financing receivable, originated year three	3	7
Financing receivable, originated year four	6	5
Financing receivable, originated year five	4	10
Financing receivable, originated prior to year five	28	24
Revolving loans	18	20
Revolving Loans converted to term loans	2	1
Loans and leases	67	77
Consumer | Credit Card and Other | FICO score less than 620
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	15	14
Financing receivable, originated year two	8	7
Financing receivable, originated year three	4	8
Financing receivable, originated year four	6	11
Financing receivable, originated year five	9	9
Financing receivable, originated prior to year five	26	26
Revolving loans	20	20
Revolving Loans converted to term loans	1	1
Loans and leases	89	96
HELOC | Consumer | Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,151	$ 2,420
Revolving loans converted to term loan during period	19
Credit Card And Other, Other Consumer Loans | Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving loans converted to term loan during period	$ 3