Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Pension and other employee benefits, tax	$ 8.8
Unrealized holding gain/(loss) on available-for-sale securities, tax	0.1	$ 0.0	$ 1.3
Hedging activities, tax	$ 3.3