Derivatives - Schedule of Gains (Losses) for Derivatives Designated as Fair Value Hedges (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the condensed consolidated statements of operations	$ (0.8)	$ 1.7	$ (1.3)
Interest Rate Swap | Investment and other (income) expense-net
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the condensed consolidated statements of operations	(2.1)	22.5	(5.7)
Hedged Items | Investment and other (income) expense-net
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the condensed consolidated statements of operations	$ 1.3	$ (20.8)	$ 4.4