Allowance for Credit Losses and Credit Quality - Schedule of Nonaccrual Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	$ 677,302	$ 169,658
Nonaccrual with no ACL	138,579
Financial Asset Originated | Commercial Loan and Lease Portfolio
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	504,700	94,504
Nonaccrual with no ACL	134,976
Financial Asset Originated | Commercial Loan and Lease Portfolio | Commercial and industrial
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	259,439	53,812
Nonaccrual with no ACL	55,773
Financial Asset Originated | Commercial Loan and Lease Portfolio | Commercial real estate
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	154,439	29,735
Nonaccrual with no ACL	79,203
Financial Asset Originated | Commercial Loan and Lease Portfolio | Lease financing
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	90,822	10,957
Nonaccrual with no ACL	0
Financial Asset Originated | Consumer Loan Portfolio
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	172,602	75,154
Nonaccrual with no ACL	3,603
Financial Asset Originated | Consumer Loan Portfolio | Residential mortgage
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	97,653	38,577
Nonaccrual with no ACL	49
Financial Asset Originated | Consumer Loan Portfolio | Home equity
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	69,383	35,863
Nonaccrual with no ACL	23
Financial Asset Originated | Consumer Loan Portfolio | Consumer installment
Allowance for loan and lease losses, other credit loss reserves
Total nonaccrual	5,566	$ 714
Nonaccrual with no ACL	$ 3,531