Types and Classifications of Derivative Instruments Designated as Hedges (Detail) (Asset And Liability Management, USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Notional Value	$ 6,441.4	$ 6,545.8
Fair Value Asset	119.0	135.1
Fair Value Liability	84.6	136.5
FAIR VALUE HEDGES | Senior Notes and Long- Term Subordinated Debt | Interest Rate Swap Contracts
Derivative [Line Items]
Notional Value	1,250.0	1,250.0
Fair Value Asset	90.7	83.6
Fair Value Liability	2.0	33.4
FAIR VALUE HEDGES | Available for Sale Investment Securities | Interest Rate Swap Contracts
Derivative [Line Items]
Notional Value	3,114.3	3,296.9
Fair Value Asset	17.2	31.5
Fair Value Liability	39.5	44.8
CASH FLOW HEDGES | Forecasted Foreign Currency Denominated Transactions | Foreign Exchange Contracts
Derivative [Line Items]
Notional Value	333.2	314.0
Fair Value Asset	9.5	10.2
Fair Value Liability	3.2	5.5
CASH FLOW HEDGES | Available for Sale Investment Securities | Interest Rate Swap Contracts
Derivative [Line Items]
Notional Value	10.0
Net Investment Hedges | Net Investments in Non-U.S. Affiliates | Foreign Exchange Contracts
Derivative [Line Items]
Notional Value	1,733.9	1,684.9
Fair Value Asset	1.6	9.8
Fair Value Liability	$ 39.9	$ 52.8