CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 167.2	$ 158.6	$ 252.7	$ 243.6
Other comprehensive income (loss), net of tax
Deferred commodity contracts hedging losses reclassified in net income, net of tax of $0.1, $0.1, $0.6 and $0.4, respectively	0.4	0.3	1.2	0.7
Deferred commodity contracts hedging gains (losses), net of tax of $0.1, ($0.2), ($0.1) and ($0.3), respectively	0.1	(0.4)	(0.2)	(0.6)
Other comprehensive income (loss), net of tax	0.5	(0.1)	1.0	0.1
Comprehensive income (loss)	$ 167.7	$ 158.5	$ 253.7	$ 243.7