Loans and Leases - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Millions	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	$ 56,246		$ 57,730
Total Accruing	56,343		57,847
Current, Non-Accruing	205		205
Total Non-Accruing	344		386
Loans and leases	56,687		58,232
Allowance for loan and lease losses	815	$ 914	963	$ 538	$ 445	$ 307
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	83		100
Past Due, Non-Accruing	8		66
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	14		17
Past Due, Non-Accruing	131		115
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	32,364		32,945
Total Accruing	32,405		32,960
Current, Non-Accruing	93		88
Total Non-Accruing	123		144
Loans and leases	32,528		33,104
Allowance for loan and lease losses	385	442	453	319	255	142
Commercial | Commercial and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	40		15
Past Due, Non-Accruing	2		12
Commercial | Commercial and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1		0
Past Due, Non-Accruing	28		44
Commercial | Commercial and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	27,488		27,541
Total Accruing	27,529		27,556
Current, Non-Accruing	93		88
Total Non-Accruing	123		144
Nonaccrual, no allowance	103		101
Loans and leases	27,652		27,700
Commercial | Commercial and industrial | C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	40		15
Past Due, Non-Accruing	2		12
Commercial | Commercial and industrial | C&I | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1		0
Past Due, Non-Accruing	28		44
Commercial | Commercial and industrial | Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,876		5,404
Total Accruing	4,876		5,404
Current, Non-Accruing	0		0
Total Non-Accruing	0		0
Loans and leases	4,876		5,404
Commercial | Commercial and industrial | Loans to mortgage companies | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0		0
Past Due, Non-Accruing	0		0
Commercial | Commercial and industrial | Loans to mortgage companies | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0		0
Past Due, Non-Accruing	0		0
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	12,292		12,275
Allowance for loan and lease losses	210	232	242	57	48	29
Commercial | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing			12,194
Total Accruing			12,217
Current, Non-Accruing			10
Total Non-Accruing			58
Loans and leases	12,292		12,275
Commercial | Commercial real estate | CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing			23
Past Due, Non-Accruing			42
Commercial | Commercial real estate | CRE | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing			0
Past Due, Non-Accruing			6
Commercial real estate | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	12,216
Total Accruing	12,222
Current, Non-Accruing	18
Total Non-Accruing	70
Loans and leases	12,292
Commercial real estate | Commercial real estate | CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	6
Past Due, Non-Accruing	0
Commercial real estate | Commercial real estate | CRE | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0
Past Due, Non-Accruing	52
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]
Current, Accruing	10,674		11,474
Total Accruing	10,716		11,543
Current, Non-Accruing	93		106
Total Non-Accruing	149		182
Loans and leases	10,865		11,725
Allowance for loan and lease losses	203	222	242	144	123	121
Consumer | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	30		53
Past Due, Non-Accruing	6		12
Consumer | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	12		16
Past Due, Non-Accruing	50		64
Consumer | Consumer Real Estate | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	2,083		2,336
Total Accruing	2,097		2,360
Current, Non-Accruing	41		43
Total Non-Accruing	54		60
Nonaccrual, no allowance	23
Loans and leases	2,151		2,420
Consumer | Consumer Real Estate | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	6		13
Past Due, Non-Accruing	2		3
Consumer | Consumer Real Estate | HELOC | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	8		11
Past Due, Non-Accruing	11		14
Consumer | Consumer Real Estate | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	8,591		9,138
Total Accruing	8,619		9,183
Current, Non-Accruing	52		63
Total Non-Accruing	95		122
Nonaccrual, no allowance	8
Loans and leases	8,714		9,305
Consumer | Consumer Real Estate | Real estate installment loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	24		40
Past Due, Non-Accruing	4		9
Consumer | Consumer Real Estate | Real estate installment loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	4		5
Past Due, Non-Accruing	39		50
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	992		1,117
Total Accruing	1,000		1,127
Current, Non-Accruing	1		1
Total Non-Accruing	2		2
Loans and leases	1,002		1,128
Allowance for loan and lease losses	17	$ 18	26	$ 18	$ 19	$ 15
Consumer | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	7		9
Past Due, Non-Accruing	0		0
Consumer | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1		1
Past Due, Non-Accruing	1		1
Consumer | Credit Card and Other | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	267		279
Total Accruing	270		283
Current, Non-Accruing	0		0
Total Non-Accruing	0		0
Loans and leases	270		283
Consumer | Credit Card and Other | Credit Card | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	2		3
Past Due, Non-Accruing	0		0
Consumer | Credit Card and Other | Credit Card | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1		1
Past Due, Non-Accruing	0		0
Consumer | Credit Card and Other | Other Consumer Loans Class
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	725		838
Total Accruing	730		844
Current, Non-Accruing	1		1
Total Non-Accruing	2		2
Loans and leases	732		845
Consumer | Credit Card and Other | Other Consumer Loans Class | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	5		6
Past Due, Non-Accruing	0		0
Consumer | Credit Card and Other | Other Consumer Loans Class | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0		0
Past Due, Non-Accruing	$ 1		$ 1