Amounts Outstanding for Loans and Leases by Segment and Class (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 28,810.4	$ 29,504.5
Allowance for Credit Losses Assigned to Loans and Leases	(290.4)	(297.9)
Net Loans and Leases	28,520.0	29,206.6
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and Institutional	7,209.6	7,468.5
Commercial Real Estate	2,845.0	2,859.8
Lease Financing, net	988.7	1,035.0
Non-U.S.	1,394.2	1,192.3
Other	182.1	341.6
Total Loans and Leases	12,619.6	12,897.2
Allowance for Credit Losses Assigned to Loans and Leases	(156.6)	(166.1)
Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential Real Estate	10,293.9	10,375.2
Private Client	5,842.6	6,130.1
Other	54.3	102.0
Total Loans and Leases	16,190.8	16,607.3
Allowance for Credit Losses Assigned to Loans and Leases	$ (133.8)	$ (131.8)