Significant Accounting Policies - Revised Statements of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash provided by operating activities	$ 272.8	$ 652.4	$ 288.7
Net cash provided by financing activities	(832.9)	$ (953.3)	7,789.3
As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash provided by operating activities	265.2		278.3
Net cash provided by financing activities	(825.3)		7,799.7
Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net cash provided by operating activities	7.6		10.4
Net cash provided by financing activities	$ (7.6)		$ (10.4)