Notional and Fair Value Amounts of Client-related and Trading Derivative Financial Instruments (Detail) (Client Related and Trading, USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivative [Line Items]
Notional Value	$ 275,079.2	$ 218,193.3
Fair Value Asset	4,767.3	1,915.9
Fair Value Liability	4,724.3	1,904.4
Foreign Exchange Contracts
Derivative [Line Items]
Notional Value	269,992.6	213,246.7
Fair Value Asset	4,624.5	1,735.3
Fair Value Liability	4,588.7	1,730.4
Interest Rate Option Contracts
Derivative [Line Items]
Notional Value	36.2	31.4
Fair Value Asset	0.1
Fair Value Liability	0.1
Interest Rate Swap Contracts
Derivative [Line Items]
Notional Value	5,050.4	4,915.2
Fair Value Asset	142.7	180.6
Fair Value Liability	$ 135.5	$ 174.0