Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income		$ 523.0		$ 424.4	$ 403.1
Foreign currency translation, net	[1]	43.5		(78.5)	(44.5)
Unrealized gain from hedge accounting, net		0.2	[2]	0.0	0.0
Other comprehensive income (loss), net of tax		43.7		(78.5)	(44.5)
Comprehensive income		566.7		345.9	358.6
Tax expense (benefit) on foreign currency translation		0.2		$ 0.2	$ 0.3
Tax expense (benefit) on unrealized loss from hedge accounting		$ 0.1

[1] Net of tax expense of $0.2 million, $0.2 million and $0.3 million, respectively.

[2] Net of tax expense of $0.1 million for 2017.