Schedule II (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	$ 3.7		$ 1.6		$ 1.7
Valuation Allowances and Reserves, Charged to Cost and Expense	3.3		5.8		2.7
Valuation Allowances and Reserves, Deductions	4.4	[1]	3.7	[1]	2.8	[1]
Valuation Allowances and Reserves, Ending Balance	$ 2.6		$ 3.7		$ 1.6

[1] Uncollectible accounts receivable written off, net of recoveries.