Loans and Leases - Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 54,859,000,000	$ 58,232,000,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	31,068,000,000	33,104,000,000
C&I | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	7,421,000,000	9,331,000,000
Financing receivable, originated year two	3,676,000,000	5,308,000,000
Financing receivable, originated year three	3,556,000,000	2,812,000,000
Financing receivable, originated year four	1,606,000,000	1,829,000,000
Financing receivable, originated year five	1,253,000,000	1,240,000,000
Financing receivable, originated prior to year five	2,358,000,000	2,267,000,000
LMC, Non-Revolving Loans	4,518,000,000	5,404,000,000
Revolving loans	6,615,000,000	4,793,000,000
Revolving Loans converted to term loans	65,000,000	120,000,000
Loans and leases	31,068,000,000	33,104,000,000
Revolving loans converted to term loan during period	0	50,000,000
C&I | PD Grade 1 -12 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	7,372,000,000	9,060,000,000
Financing receivable, originated year two	3,576,000,000	5,138,000,000
Financing receivable, originated year three	3,439,000,000	2,628,000,000
Financing receivable, originated year four	1,455,000,000	1,748,000,000
Financing receivable, originated year five	1,193,000,000	1,161,000,000
Financing receivable, originated prior to year five	2,267,000,000	2,145,000,000
LMC, Non-Revolving Loans	4,518,000,000	5,404,000,000
Revolving loans	6,386,000,000	4,571,000,000
Revolving Loans converted to term loans	13,000,000	60,000,000
Loans and leases	30,219,000,000	31,915,000,000
C&I | PD Grades 13 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	25,000,000	89,000,000
Financing receivable, originated year two	39,000,000	93,000,000
Financing receivable, originated year three	50,000,000	70,000,000
Financing receivable, originated year four	48,000,000	31,000,000
Financing receivable, originated year five	36,000,000	37,000,000
Financing receivable, originated prior to year five	43,000,000	64,000,000
LMC, Non-Revolving Loans	0	0
Revolving loans	100,000,000	127,000,000
Revolving Loans converted to term loans	4,000,000	1,000,000
Loans and leases	345,000,000	512,000,000
C&I | PD Grades 14 15 16 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	24,000,000	182,000,000
Financing receivable, originated year two	61,000,000	77,000,000
Financing receivable, originated year three	67,000,000	114,000,000
Financing receivable, originated year four	103,000,000	50,000,000
Financing receivable, originated year five	24,000,000	42,000,000
Financing receivable, originated prior to year five	48,000,000	58,000,000
LMC, Non-Revolving Loans	0	0
Revolving loans	129,000,000	95,000,000
Revolving Loans converted to term loans	48,000,000	59,000,000
Loans and leases	504,000,000	677,000,000
Commercial real estate | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	12,109,000,000	12,275,000,000
Commercial real estate | CRE (b) | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	3,492,000,000	2,555,000,000
Financing receivable, originated year two	2,091,000,000	3,348,000,000
Financing receivable, originated year three	2,590,000,000	1,888,000,000
Financing receivable, originated year four	1,057,000,000	1,257,000,000
Financing receivable, originated year five	744,000,000	1,044,000,000
Financing receivable, originated prior to year five	1,919,000,000	1,887,000,000
Revolving loans	216,000,000	277,000,000
Revolving Loans converted to term loans	0	19,000,000
Loans and leases	12,109,000,000	12,275,000,000
Commercial real estate | PD Grade 1 -12 | CRE (b) | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	3,441,000,000	2,477,000,000
Financing receivable, originated year two	2,065,000,000	3,311,000,000
Financing receivable, originated year three	2,514,000,000	1,750,000,000
Financing receivable, originated year four	929,000,000	1,140,000,000
Financing receivable, originated year five	691,000,000	946,000,000
Financing receivable, originated prior to year five	1,822,000,000	1,800,000,000
Revolving loans	204,000,000	259,000,000
Revolving Loans converted to term loans	0	19,000,000
Loans and leases	11,666,000,000	11,702,000,000
Commercial real estate | PD Grades 13 | CRE (b) | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	4,000,000	48,000,000
Financing receivable, originated year two	26,000,000	24,000,000
Financing receivable, originated year three	52,000,000	117,000,000
Financing receivable, originated year four	125,000,000	75,000,000
Financing receivable, originated year five	20,000,000	71,000,000
Financing receivable, originated prior to year five	65,000,000	54,000,000
Revolving loans	0	0
Revolving Loans converted to term loans	0	0
Loans and leases	292,000,000	389,000,000
Commercial real estate | PD Grades 14 15 16 | CRE (b) | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	47,000,000	30,000,000
Financing receivable, originated year two	0	13,000,000
Financing receivable, originated year three	24,000,000	21,000,000
Financing receivable, originated year four	3,000,000	42,000,000
Financing receivable, originated year five	33,000,000	27,000,000
Financing receivable, originated prior to year five	32,000,000	33,000,000
Revolving loans	12,000,000	18,000,000
Revolving Loans converted to term loans	0	0
Loans and leases	$ 151,000,000	$ 184,000,000