Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable [Line Items]
Current	$ 150,702	$ 146,985
30-89 Days Past Due	1,016	1,044
90 Days Or More Past Due	407	462
Nonperforming	461	522
Total	152,586	149,013
Commercial | Commercial and industrial
Financing Receivable [Line Items]
Current	63,468	61,701
30-89 Days Past Due	32	34
90 Days Or More Past Due	0	0
Nonperforming	193	200
Total	63,693	61,935
Commercial | CRE
Financing Receivable [Line Items]
Current	20,686	20,990
30-89 Days Past Due	3	5
90 Days Or More Past Due	0	0
Nonperforming	33	65
Total	20,722	21,060
Commercial | Lease financing
Financing Receivable [Line Items]
Current	2,196	2,014
30-89 Days Past Due	5	1
90 Days Or More Past Due	0	0
Nonperforming	2	3
Total	2,203	2,018
Retail | Residential mortgage
Financing Receivable [Line Items]
Current	31,673	30,413
30-89 Days Past Due	480	456
90 Days Or More Past Due	350	405
Nonperforming	104	119
Total	32,607	31,393
Retail | Direct
Financing Receivable [Line Items]
Current	11,370	11,463
30-89 Days Past Due	58	61
90 Days Or More Past Due	10	7
Nonperforming	54	53
Total	11,492	11,584
Retail | Indirect
Financing Receivable [Line Items]
Current	17,734	16,901
30-89 Days Past Due	393	436
90 Days Or More Past Due	7	6
Nonperforming	75	82
Total	18,209	17,425
Revolving credit
Financing Receivable [Line Items]
Current	3,197	3,090
30-89 Days Past Due	28	28
90 Days Or More Past Due	14	14
Nonperforming	0	0
Total	3,239	3,132
PCI
Financing Receivable [Line Items]
Current	378	413
30-89 Days Past Due	17	23
90 Days Or More Past Due	26	30
Nonperforming	0	0
Total	$ 421	$ 466