CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 73.4	$ 78.6	$ 85.5	$ 85.0
Other comprehensive income (loss), net of tax
Deferred commodity contracts hedging losses, net of tax of $0.3 million, $0, $0.3 million and $0.1 million, respectively	0.5	0	0.5	0.2
Other comprehensive income (loss), net of tax	0.5	0	0.5	0.2
Comprehensive income (loss)	$ 73.9	$ 78.6	$ 86.0	$ 85.2