Location and Fair Values of Derivative Financial Instruments (Detail) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Designated as Hedging Instrument | Interest Rate Swaps | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	$ 140.8	$ 98.4
Designated as Hedging Instrument | Interest Rate Swaps | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	33.5	39.1
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	2.4	0.7
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	121.2	160.5
Designated as Hedging Instrument | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	143.2	99.1
Designated as Hedging Instrument | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	154.7	199.6
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	$ 120.7	$ 96.3