Derivative Instruments and Hedging Activities - Derivative Instruments Designated as Fair Value Hedges (Detail) - Interest Rate Swaps [Member] - Interest Expense [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Instrument	$ 3.1	$ (8.0)	$ 13.9	$ (0.8)
Gain (Loss) on Hedged Item	$ (3.1)	$ 8.0	$ (13.9)	$ 0.8