Transactions Affecting Allowance for Doubtful Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance, beginning of year	$ 49.6	$ 62.6	$ 71.0
Provisions charged to expense	18.2	8.7	18.8
Write-offs and other	(23.0)	(21.7)	(27.2)
Balance, end of year	$ 44.8	$ 49.6	$ 62.6