Location and Fair Values of Derivative Financial Instruments (Detail) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Designated as Hedging Instrument | Interest Rate Swaps | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	$ 84.8	$ 98.4
Designated as Hedging Instrument | Interest Rate Swaps | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	33.2	39.1
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	0.2	0.7
Designated as Hedging Instrument | Foreign Exchange Contracts | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	170.4	160.5
Designated as Hedging Instrument | Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value		99.1
Designated as Hedging Instrument | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value		199.6
Not Designated as Hedging Instrument | Embedded Derivative in Modified Coinsurance Arrangement | Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	87.0	96.3
Other Long term Investments
Derivative [Line Items]
Asset Derivatives Fair Value	85.0
Other Liability
Derivative [Line Items]
Liability Derivatives Fair Value	$ 203.6