Schedule II Valuation and Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts
Changes in valuation allowances and reserves
Balance at beginning of year	$ 1.5	$ 1.9	$ 2.1
Charged to expenses/(recovery)		(0.1)	0.1
Deductions and other	(0.3)	(0.3)	(0.3)
Balance at end of year	1.2	1.5	1.9
Allowance for deferred tax assets
Changes in valuation allowances and reserves
Balance at beginning of year	36.5	30.8	16.1
Charged to expenses/(recovery)	10.5	11.2	14.7
Deductions and other	(7.6)	(5.5)
Balance at end of year	$ 39.4	$ 36.5	$ 30.8