Notional and Fair Value Amounts of Client-related and Trading Derivative Financial Instruments (Detail) (Client Related and Trading, USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional Value	$ 276,139.1	$ 262,922.5
Fair Value Asset	4,854.3	4,255.0
Fair Value Liability	4,805.7	4,173.3
Foreign Exchange Contracts
Derivative [Line Items]
Notional Value	270,476.9	257,568.7
Fair Value Asset	4,731.2	4,149.5
Fair Value Liability	4,686.4	4,072.0
Interest Rate Contracts
Derivative [Line Items]
Notional Value	5,662.2	5,353.8
Fair Value Asset	123.1	105.5
Fair Value Liability	$ 119.3	$ 101.3