Location and Fair Values of Derivative Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivative
Asset Derivatives Fair Value	$ 49.8	$ 28.0
Designated as Hedging Instrument | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	49.8	28.0
Designated as Hedging Instrument | Other Liability
Derivative
Liability Derivatives Fair Value	18.3	60.4
Designated as Hedging Instrument | Interest Rate Swaps | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	2.4	5.7
Designated as Hedging Instrument | Interest Rate Swaps | Other Liability
Derivative
Liability Derivatives Fair Value	12.3	20.8
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Long-term Investments
Derivative
Asset Derivatives Fair Value	47.4	22.3
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative
Liability Derivatives Fair Value	6.0	39.6
Not Designated as Hedging Instrument | Other Liability
Derivative
Liability Derivatives Fair Value	119.5	82.4
Not Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative
Liability Derivatives Fair Value	31.6	31.3
Not Designated as Hedging Instrument | Credit Risk Contract | Other Liability
Derivative
Liability Derivatives Fair Value	0.3	1.2
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement | Other Liability
Derivative
Liability Derivatives Fair Value	$ 87.6	$ 49.9