Location and Fair Values of Derivative Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative
Asset Derivatives Fair Value	$ 15.1	$ 10.8
Liability Derivatives Fair Value	107.2	135.6
Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	15.1	10.8
Designated as Hedging Instrument | Other Liability
Derivative
Liability Derivatives Fair Value	75.1	133.7
Designated as Hedging Instrument | Interest Rate Swaps | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	6.1	9.2
Designated as Hedging Instrument | Interest Rate Swaps | Other Liability
Derivative
Liability Derivatives Fair Value	25.7	35.0
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	9.0	1.6
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative
Liability Derivatives Fair Value	49.4	98.7
Not Designated as Hedging Instrument | Other Liability
Derivative
Liability Derivatives Fair Value	66.7	55.1
Not Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative
Liability Derivatives Fair Value	30.3
Not Designated as Hedging Instrument | Credit Default Swaps | Other Liability
Derivative
Liability Derivatives Fair Value	1.8	1.9
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement | Other Liability
Derivative
Liability Derivatives Fair Value	$ 34.6	$ 53.2