Summary of Activity for Both Allowances (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts receivable allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of the Year	$ (28.0)	$ (33.0)	$ (24.6)
Additions	(44.3)	(40.6)	(46.5)
Write-offs and Adjustments	43.2	45.6	38.1
Balance at End of the Year	(29.1)	(28.0)	(33.0)
Deferred tax assets - valuation allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of the Year	(13.9)	(12.8)	(4.5)
Additions	(3.1)	(4.0)	(8.8)
Write-offs and Adjustments	1.8	2.9	0.5
Balance at End of the Year	$ (15.2)	$ (13.9)	$ (12.8)