Loans and ACL - Risk Rating (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Financing Receivable
Loans and leases		$ 299,734	$ 299,842
2020		70,929
2019		51,905
2018		33,350
2017		20,386
2016		14,865
Prior		40,413
Revolving Credit		66,107
Loans Converted to Term		2,012
Other (1)	[1]	(233)
Credit card
Financing Receivable
Loans and leases		4,839
2020		0
2019		0
2018		0
2017		0
2016		0
Prior		0
Revolving Credit		4,802
Loans Converted to Term		37
Other (1)	[1]	0
Commercial: | Commercial & Industrial
Financing Receivable
Loans and leases		138,354	130,180
2020		35,828
2019		19,852
2018		14,042
2017		7,961
2016		5,463
Prior		9,362
Revolving Credit		46,174
Loans Converted to Term		252
Other (1)	[1]	(580)
Commercial: | Commercial & Industrial | Pass
Financing Receivable
Loans and leases		131,258	127,229
2020		34,858
2019		18,881
2018		13,312
2017		7,713
2016		5,174
Prior		8,888
Revolving Credit		42,780
Loans Converted to Term		231
Other (1)	[1]	(579)
Commercial: | Commercial & Industrial | Special mention
Financing Receivable
Loans and leases		3,435	1,264
2020		471
2019		434
2018		343
2017		98
2016		120
Prior		157
Revolving Credit		1,808
Loans Converted to Term		5
Other (1)	[1]	(1)
Commercial: | Commercial & Industrial | Substandard
Financing Receivable
Loans and leases		3,129	1,475
2020		461
2019		445
2018		339
2017		121
2016		144
Prior		256
Revolving Credit		1,353
Loans Converted to Term		12
Other (1)	[1]	(2)
Commercial: | Commercial & Industrial | Nonperforming
Financing Receivable
Loans and leases		532	212
2020		38
2019		92
2018		48
2017		29
2016		25
Prior		61
Revolving Credit		233
Loans Converted to Term		4
Other (1)	[1]	2
Commercial: | CRE
Financing Receivable
Loans and leases		26,595	26,832
2020		5,145
2019		7,990
2018		5,451
2017		3,158
2016		1,738
Prior		2,560
Revolving Credit		622
Loans Converted to Term		0
Other (1)	[1]	(69)
Commercial: | CRE | Pass
Financing Receivable
Loans and leases		22,459	26,393
2020		4,563
2019		6,600
2018		4,427
2017		2,752
2016		1,473
Prior		2,096
Revolving Credit		617
Loans Converted to Term		0
Other (1)	[1]	(69)
Commercial: | CRE | Special mention
Financing Receivable
Loans and leases		1,689	145
2020		171
2019		599
2018		585
2017		116
2016		77
Prior		141
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | CRE | Substandard
Financing Receivable
Loans and leases		2,372	284
2020		410
2019		776
2018		438
2017		281
2016		182
Prior		280
Revolving Credit		5
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | CRE | Nonperforming
Financing Receivable
Loans and leases		75	10
2020		1
2019		15
2018		1
2017		9
2016		6
Prior		43
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | Commercial construction
Financing Receivable
Loans and leases		6,491	6,205
2020		1,123
2019		2,358
2018		2,026
2017		299
2016		33
Prior		111
Revolving Credit		536
Loans Converted to Term		3
Other (1)	[1]	2
Commercial: | Commercial construction | Pass
Financing Receivable
Loans and leases		5,987	6,037
2020		1,052
2019		2,141
2018		1,889
2017		232
2016		27
Prior		110
Revolving Credit		534
Loans Converted to Term		0
Other (1)	[1]	2
Commercial: | Commercial construction | Special mention
Financing Receivable
Loans and leases		175	37
2020		0
2019		108
2018		64
2017		1
2016		0
Prior		0
Revolving Credit		2
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | Commercial construction | Substandard
Financing Receivable
Loans and leases		315	131
2020		70
2019		106
2018		73
2017		59
2016		6
Prior		1
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | Commercial construction | Nonperforming
Financing Receivable
Loans and leases		14	0
2020		1
2019		3
2018		0
2017		7
2016		0
Prior		0
Revolving Credit		0
Loans Converted to Term		3
Other (1)	[1]	0
Commercial: | Lease Financing
Financing Receivable
Loans and leases		5,240	6,122
2020		1,380
2019		1,217
2018		801
2017		764
2016		248
Prior		803
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	27
Commercial: | Lease Financing | Pass
Financing Receivable
Loans and leases		5,065	6,039
2020		1,377
2019		1,139
2018		775
2017		746
2016		241
Prior		760
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	27
Commercial: | Lease Financing | Special mention
Financing Receivable
Loans and leases		72	19
2020		1
2019		39
2018		20
2017		5
2016		0
Prior		7
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | Lease Financing | Substandard
Financing Receivable
Loans and leases		75	56
2020		0
2019		34
2018		3
2017		4
2016		3
Prior		31
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Commercial: | Lease Financing | Nonperforming
Financing Receivable
Loans and leases		28	8
2020		2
2019		5
2018		3
2017		9
2016		4
Prior		5
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Consumer: | Residential Mortgage
Financing Receivable
Loans and leases		47,272	52,071
2020		8,200
2019		6,742
2018		3,751
2017		4,387
2016		5,438
Prior		18,590
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	164
Consumer: | Residential Mortgage | Performing
Financing Receivable
Loans and leases		46,956	52,016
2020		8,197
2019		6,729
2018		3,735
2017		4,374
2016		5,424
Prior		18,333
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	164
Consumer: | Residential Mortgage | Nonperforming
Financing Receivable
Loans and leases		316	55
2020		3
2019		13
2018		16
2017		13
2016		14
Prior		257
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Consumer: | Residential home equity and direct
Financing Receivable
Loans and leases		26,064	27,044
2020		4,514
2019		3,130
2018		1,418
2017		482
2016		215
Prior		564
Revolving Credit		13,973
Loans Converted to Term		1,720
Other (1)	[1]	48
Consumer: | Residential home equity and direct | Performing
Financing Receivable
Loans and leases		25,859	26,977
2020		4,513
2019		3,126
2018		1,416
2017		481
2016		214
Prior		557
Revolving Credit		13,886
Loans Converted to Term		1,619
Other (1)	[1]	47
Consumer: | Residential home equity and direct | Nonperforming
Financing Receivable
Loans and leases		205	67
2020		1
2019		4
2018		2
2017		1
2016		1
Prior		7
Revolving Credit		87
Loans Converted to Term		101
Other (1)	[1]	1
Consumer: | Indirect auto
Financing Receivable
Loans and leases		26,150	24,442
2020		10,283
2019		7,486
2018		4,059
2017		2,428
2016		1,235
Prior		518
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	141
Consumer: | Indirect auto | Performing
Financing Receivable
Loans and leases		25,995	24,342
2020		10,270
2019		7,436
2018		4,015
2017		2,401
2016		1,220
Prior		506
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	147
Consumer: | Indirect auto | Nonperforming
Financing Receivable
Loans and leases		155	100
2020		13
2019		50
2018		44
2017		27
2016		15
Prior		12
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	(6)
Consumer: | Indirect Other
Financing Receivable
Loans and leases		11,177	11,100
2020		4,434
2019		3,020
2018		1,707
2017		826
2016		431
Prior		720
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	39
Consumer: | Indirect Other | Performing
Financing Receivable
Loans and leases		11,172	11,098
2020		4,433
2019		3,019
2018		1,706
2017		826
2016		431
Prior		718
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	39
Consumer: | Indirect Other | Nonperforming
Financing Receivable
Loans and leases		5	2
2020		1
2019		1
2018		1
2017		0
2016		0
Prior		2
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	0
Consumer: | Student
Financing Receivable
Loans and leases		7,552	$ 6,743
Consumer: | Student | Performing
Financing Receivable
Loans and leases		7,552
2020		22
2019		110
2018		95
2017		81
2016		64
Prior		7,185
Revolving Credit		0
Loans Converted to Term		0
Other (1)	[1]	$ (5)

[1] Includes certain deferred fees and costs, unapplied payments and other adjustments.