Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 83.0	$ 68.0	$ 201.1	$ 83.2
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	(40.9)	27.1	(15.5)	30.2
Unrealized holding gains on financial investments		0.3		0.2
Post retirement benefit obligations	(0.4)		(1.0)
Comprehensive income	41.7	95.4	184.6	113.6
Comprehensive loss attributable to redeemable noncontrolling interest	0.3	0.3	0.6	0.6
Comprehensive income excluding redeemable noncontrolling interest	42.0	95.7	185.2	114.2
Change in redemption value of redeemable noncontrolling interest	(0.3)	(0.3)	(0.6)	(0.6)
Comprehensive income allocated to participating securities	(0.6)	(0.9)	(1.4)	(1.0)
Comprehensive income allocated to common stockholders, net of tax	$ 41.1	$ 94.5	$ 183.2	$ 112.6