Comprehensive Income (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Comprehensive Income [Abstract]
Net income	$ 8.7	$ 25.7	$ 32.6	$ 71.9
Employee benefit plans - amortization of net loss and prior service costs	1.8	1.5	4.0	5.9
Other	0	0	0.1	0.1
Comprehensive income (net of tax)	$ 10.5	$ 27.2	$ 36.7	$ 77.9