Loans and Leases (Narrative) (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022 USD ($) contract loan	Jun. 30, 2021 USD ($) contract loan	Jun. 30, 2022 USD ($) loan contract	Jun. 30, 2021 USD ($) contract loan	Dec. 31, 2021 USD ($) loan contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 41,207,800,000		$ 41,207,800,000		$ 40,480,600,000
Other U.S. loans and non-U.S. loans, short duration advances	2,600,000,000		2,600,000,000		1,600,000,000
Demand deposits	$ 16,800,000		$ 16,800,000		8,000,000
Number of loan partially forgiven | loan	1		1
Loans approved and partially forgiven	$ 200,000		$ 200,000
Financing receivable, nonaccrual, interest income	1,000,000	$ 800,000	2,100,000	$ 1,700,000
Financing receivable, nonaccrual troubled debt restructuring	37,600,000		37,600,000		76,700,000
Financing receivable, recorded investment	16,200,000		16,200,000		16,500,000
Financing receivable, troubled debt restructuring, commitment to lend	200,000		200,000		200,000
Foreclosed real estate properties, carrying value	100,000		100,000		$ 3,000,000.0
Loans in process of foreclosure	$ 1,400,000		$ 1,400,000
Number of loans and leases | contract	0	6	3	15
Financing receivable, percentage of loans granted payment deferral in past due or nonaccrual status	4.00%		4.00%		10.00%
CARES Act
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, number of contracts paid off | loan			87		148
Financing receivable, non-TDR modifications, recorded investment paid off			$ 85,700,000		$ 209,400,000
CARES Act | Active Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans and leases | contract			0		3
Financing Receivable, Non-TDR Modifications, Recorded Investment			$ 605,700,000		$ 2,000,000
CARES Act | Completed Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans and leases | contract			291,000,000		390,000,000
Financing Receivable, Non-TDR Modifications, Recorded Investment					$ 835,600,000
Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans approved for forgiveness | loan	39		182		1,301
Loans approved and fully forgiven	$ 10,500,000		$ 51,800,000		$ 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	0	0	0
Lease Agreements
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, held-for-sale, not part of disposal group, after valuation allowance	$ 0		$ 0		0
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, held-for-sale, not part of disposal group, after valuation allowance	0		0		12,300,000
Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 20,781,000,000		$ 20,781,000,000		21,993,200,000
Number of loans and leases | contract	0	5	2	7
Personal | Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral required on Residential real estate loan, lower limit	65.00%		65.00%
Collateral required on Residential real estate loan, upper limit	80.00%		80.00%
Loans and leases	$ 6,383,200,000		$ 6,383,200,000		6,319,900,000
Number of loans and leases | contract	0	5	2	7
Personal | Home Equity Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Draw period for credit line products			10 years
Loans and leases	$ 252,000,000		$ 252,000,000		$ 258,200,000
Percentage of total equity credit lines	98.00%		98.00%		97.00%
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 20,426,800,000		$ 20,426,800,000		$ 18,487,400,000
Number of loans and leases | contract	0	1	1	8
Commercial | Commercial and Institutional
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 12,138,400,000		$ 12,138,400,000		11,489,200,000
Number of loans and leases | contract	0	0	1	6
Commercial | Commercial and Institutional | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 5,300,000		$ 5,300,000		$ 56,900,000
Number of contracts | loan	30,000,000		30,000,000		213,000,000
Financing receivable, average balance per loan	$ 200,000		$ 200,000		$ 300,000