Loans and Leases (Narrative) (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($) loan	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 39,239,100,000		$ 40,480,600,000
Other U.S. loans and non-U.S. loans, short duration advances	1,900,000,000		1,600,000,000
Demand deposits	9,700,000		8,000,000
Financing receivable, nonaccrual, interest income	1,100,000	$ 900,000
Financing receivable, nonaccrual troubled debt restructuring	46,100,000		76,700,000
Financing receivable, recorded investment	18,300,000		16,500,000
Financing receivable, troubled debt restructuring, commitment to lend	200,000		200,000
Unpaid Principal balance	600,000	43,200,000
Recorded investment	600,000	41,200,000
Foreclosed real estate properties, carrying value	200,000		$ 3,000,000.0
Loans in process of foreclosure	$ 1,700,000
Financing receivable, percentage of loans granted payment deferral in past due or nonaccrual status	3.00%
CARES Act
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, number of contracts paid off | loan	38
Financing receivable, non-TDR modifications, recorded investment paid off	$ 112,900,000
Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans approved for forgiveness | loan	143		1,301
Loans approved and fully forgiven	$ 39,200,000		$ 231,500,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, troubled debt restructuring, subsequent default, number of contracts | loan			0	1
Unpaid Principal balance		5,500,000
Recorded investment		5,500,000
Lease Agreements
Accounts, Notes, Loans and Financing Receivable [Line Items]
Held for Sale	0		$ 0
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Held for Sale	10,800,000		12,300,000
Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	20,014,400,000		21,993,200,000
Unpaid Principal balance	100,000	300,000
Recorded investment	$ 100,000	200,000
Personal | Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral required on Residential real estate loan, lower limit	65.00%
Collateral required on Residential real estate loan, upper limit	80.00%
Loans and leases	$ 6,220,200,000		6,319,900,000
Unpaid Principal balance	100,000	300,000
Recorded investment	$ 100,000	200,000
Personal | Home Equity Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Draw period for credit line products	10 years
Loans and leases	$ 233,500,000		$ 258,200,000
Percentage of total equity credit lines	97.00%		97.00%
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 19,224,700,000		$ 18,487,400,000
Unpaid Principal balance	500,000	42,900,000
Recorded investment	500,000	41,000,000.0
Commercial | Commercial and Institutional
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,756,600,000		$ 11,489,200,000
Unpaid Principal balance	500,000	19,600,000
Recorded investment	500,000	$ 19,600,000
Commercial | Commercial and Institutional | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 16,300,000
Number of contracts | loan	73,000,000
Financing receivable, average balance per loan	$ 200,000