Accounts Receivable - Transactions Affecting Allowance for Doubtful Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Balance, beginning of year	$ 44.3	$ 44.8	$ 49.6
Provisions charged to expense	15.4	16.9	18.2
Write-offs and other	(18.2)	(17.4)	(23.0)
Balance, end of year	$ 41.5	$ 44.3	$ 44.8