Derivative Instruments - Effect of Derivative Instruments in Consolidated Statements of Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in AOCL (effective portion)	$ 0	$ 0	$ 64.3
Loss reclassified from AOCL into net loss (effective portion)	4.0	28.4	265.7
Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in AOCL (effective portion)	0	0	64.3
Interest Expense [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss reclassified from AOCL into net loss (effective portion)	4.0	28.4	265.7
Gain recognized in net loss (ineffective portion)	$ 0	$ 0	$ (53.4)