Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable [Line Items]
Current	$ 310,765	$ 295,181
30-89 Days Past Due	1,901	2,213
90 Days Or More Past Due	1,072	1,994
Nonperforming	1,087	454
Total	314,825	299,842
Commercial: | Commercial and industrial
Financing Receivable [Line Items]
Current	146,422	129,873
30-89 Days Past Due	282	94
90 Days Or More Past Due	9	1
Nonperforming	428	212
Total	147,141	130,180
Commercial: | CRE
Financing Receivable [Line Items]
Current	27,912	26,817
30-89 Days Past Due	6	5
90 Days Or More Past Due	3	0
Nonperforming	42	10
Total	27,963	26,832
Commercial: | Commercial construction
Financing Receivable [Line Items]
Current	6,877	6,204
30-89 Days Past Due	1	1
90 Days Or More Past Due	0	0
Nonperforming	13	0
Total	6,891	6,205
Commercial: | Lease financing
Financing Receivable [Line Items]
Current	5,716	6,112
30-89 Days Past Due	10	2
90 Days Or More Past Due	1	0
Nonperforming	56	8
Total	5,783	6,122
Consumer: | Residential Mortgage
Financing Receivable [Line Items]
Current	50,249	50,975
30-89 Days Past Due	703	498
90 Days Or More Past Due	521	543
Nonperforming	198	55
Total	51,671	52,071
Consumer: | Residential home equity and direct
Financing Receivable [Line Items]
Current	26,626	26,846
30-89 Days Past Due	108	122
90 Days Or More Past Due	9	9
Nonperforming	192	67
Total	26,935	27,044
Consumer: | Indirect auto
Financing Receivable [Line Items]
Current	24,079	23,771
30-89 Days Past Due	265	560
90 Days Or More Past Due	10	11
Nonperforming	155	100
Total	24,509	24,442
Consumer: | Indirect other
Financing Receivable [Line Items]
Current	11,536	11,011
30-89 Days Past Due	50	85
90 Days Or More Past Due	3	2
Nonperforming	3	2
Total	11,592	11,100
Consumer: | Student
Financing Receivable [Line Items]
Current	6,564	5,905
30-89 Days Past Due	442	650
90 Days Or More Past Due	478	188
Nonperforming	0	0
Total	7,484	6,743
Credit card
Financing Receivable [Line Items]
Current	4,784	5,541
30-89 Days Past Due	34	56
90 Days Or More Past Due	38	22
Nonperforming	0	0
Total	$ 4,856	5,619
PCI
Financing Receivable [Line Items]
Current		2,126
30-89 Days Past Due		140
90 Days Or More Past Due		1,218
Nonperforming		0
Total		$ 3,484