Derivative Instruments Designated as Fair Value Hedges (Detail) (Interest expense net [Member], Interest rate swaps [Member], Fair Value Hedging, USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest expense net [Member] \| Interest rate swaps [Member] \| Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain on Instrument	$ 2.7	$ 21.2	$ 7.8	$ 25.2
Loss on Hedged Item	$ (2.7)	$ (21.2)	$ (7.8)	$ (25.2)

The amount of gain recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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The amount of loss recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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