CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income	$ 25.2	$ 43.2
Pension Plan and Restoration of Retirement Income Plan:
Amortization of deferred net loss, net of tax of $0.4 and $0.8, respectively	0.8	0.4
Postretirement Benefit Plans:
Amortization of deferred net loss, net of tax of $0.0 and $0.2, respectively	0.0	0.2
Amortization of prior service cost, net of tax of ($0.2) and ($0.3), respectively	(0.4)	(0.4)
Other comprehensive income, net of tax	0.4	0.2
Comprehensive income	$ 25.6	$ 43.4