Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable [Line Items]
Current	$ 147,152	$ 146,985
30-89 Days Past Due	948	1,044
90 Days Or More Past Due	431	462
Nonperforming	526	522
Total	149,057	149,013
Commercial | Commercial and industrial
Financing Receivable [Line Items]
Current	61,746	61,701
30-89 Days Past Due	36	34
90 Days Or More Past Due	0	0
Nonperforming	196	200
Total	61,978	61,935
Commercial | CRE
Financing Receivable [Line Items]
Current	20,751	20,990
30-89 Days Past Due	3	5
90 Days Or More Past Due	0	0
Nonperforming	75	65
Total	20,829	21,060
Commercial | Lease financing
Financing Receivable [Line Items]
Current	2,094	2,014
30-89 Days Past Due	3	1
90 Days Or More Past Due	0	0
Nonperforming	1	3
Total	2,098	2,018
Retail | Residential mortgage
Financing Receivable [Line Items]
Current	30,596	30,413
30-89 Days Past Due	478	456
90 Days Or More Past Due	377	405
Nonperforming	121	119
Total	31,572	31,393
Retail | Direct
Financing Receivable [Line Items]
Current	11,337	11,463
30-89 Days Past Due	67	61
90 Days Or More Past Due	7	7
Nonperforming	53	53
Total	11,464	11,584
Retail | Indirect
Financing Receivable [Line Items]
Current	17,122	16,901
30-89 Days Past Due	316	436
90 Days Or More Past Due	5	6
Nonperforming	80	82
Total	17,523	17,425
Revolving credit
Financing Receivable [Line Items]
Current	3,111	3,090
30-89 Days Past Due	27	28
90 Days Or More Past Due	14	14
Nonperforming	0	0
Total	3,152	3,132
PCI
Financing Receivable [Line Items]
Current	395	413
30-89 Days Past Due	18	23
90 Days Or More Past Due	28	30
Nonperforming	0	0
Total	$ 441	$ 466