Derivative Instruments - Effect of Derivative Instruments in Consolidated Statements of Comprehensive Loss (Detail) (Interest rate contracts [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivatives designated as hedging instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain)or Loss Recognized in AOCL (Effective Portion)	$ 0	$ 64.3	$ 99.2
Derivatives designated as hedging instruments [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Reclassified from AOCL into Net Loss (Effective Portion )	28.4	265.7	36.3
Amount of (Gain) or Loss Recognized in Net Loss (Ineffective Portion)	0	(53.4)	(76.6)
Derivatives not designated as hedging instruments [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Net Loss	$ (29.6)	$ (16.9)	$ 1.9