Loans and Leases - Schedule Of Loans By Portfolio Segment (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 58,600	$ 58,232
Allowance for loan and lease losses	(914)	(963)	$ (444)	$ (307)
Net loans and leases	57,686	57,269
Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Property, plant, and equipment and finance lease right-of-use asset	614	587
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	33,951	33,104
Commercial | Commercial and Industrial, Excluding Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	28,421	27,700
Commercial | Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,530	5,404
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	33,951	33,104
Allowance for loan and lease losses	(442)	(453)	(255)	(142)
Commercial | Commercial and industrial | Paycheck Protection Plan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,100	4,100
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	12,470	12,275
Allowance for loan and lease losses	(232)	(242)	(48)	(29)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,053	11,725
Consumer | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,270	2,420
Consumer | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	8,783	9,305
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,126	1,128
Allowance for loan and lease losses	$ (18)	$ (26)	$ (19)	$ (15)