Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Adjustment to pension and other benefit plans, tax impact	$ (1.0)	$ (1.2)	$ (1.9)	$ (2.5)
Unrealized gain or loss on investment, tax impact	0.0	(0.1)	(0.4)	(0.3)
Other Comprehensive Income, Unrealized Gain (loss) on derivatives arising during the period, tax	$ 0.3	$ 0.0	$ 0.4	$ 1.0