CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) PARENTHETICAL (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Plan and Restoration of Retirement Income Plan:
Amortization of deferred net loss, net of tax	$ 0.3	$ 0.4	$ 1.2	$ 1.4
Amortization of prior service cost, net of tax	0	0.1	0	0.1
Postretirement plans:
Amortization of deferred net loss, net of tax	0.2	0.2	0.8	0.2
Amortization of deferred net transition obligation, net of tax	0	0	0	0.1
Amortization of prior service cost, net of tax	(0.2)	0	(0.8)	(0.1)
Prior service cost arising during the period, net of tax	0	0	6.2	0
Deferred commodity contract hedging losses reclassified in net income, net of tax	3.4	2.1	10.3	7.3
Deferred commodity contracts hedging gains (losses), net of tax	0.1	(6.6)	(2.7)	(5.6)
Deferred interest rate swaps hedging gains, net of tax	$ 0	$ 0	$ 0.2	$ 0.1