Amounts Outstanding for Loans and Leases by Segment and Class (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 29,660.8	$ 29,385.5
Allowance for Credit Losses Assigned to Loans and Leases	(279.2)	(278.1)
Net Loans and Leases	29,381.6	29,107.4
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and Institutional	7,738.2	7,375.8
Commercial Real Estate	3,018.9	2,955.8
Lease Financing, net	892.6	975.1
Non-U.S.	1,349.7	954.7
Other	281.3	358.6
Total Loans and Leases	13,280.7	12,620.0
Allowance for Credit Losses Assigned to Loans and Leases	(146.1)	(140.9)
Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential Real Estate	10,093.9	10,271.3
Private Client	6,247.8	6,445.6
Other	38.4	48.6
Total Loans and Leases	16,380.1	16,765.5
Allowance for Credit Losses Assigned to Loans and Leases	$ (133.1)	$ (137.2)