CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) Parenthetical (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Pension Plan and Restoration of Retirement Income Plan:
Amortization of deferred net loss	$ 0.3	$ 0.8	$ 0.6	$ 1.2
Postretirement Benefit Plans:
Amortization of deferred net loss	0.2	0.3	0.3	0.6
Amortization of prior service cost	(0.3)	(0.2)	(0.6)	(0.5)
Deferred commodity contracts hedging gains reclassified in net income	0	0	0	(0.1)
Amortization of deferred interest rate swap hedging losses	$ 0	$ 0	$ 0.1	$ 0.1