Equity and Accumulated Other Comprehensive Income (Change in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 168.9	$ 242.9
Amounts reclassified from accumulated other comprehensive income (loss)	30.3	56.7
Ending Balance	131.8	168.9
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(228.2)	(275.6)
Other comprehensive income (loss) before reclassifications	26.9	(12.2)
Amounts reclassified from accumulated other comprehensive income (loss)	36.0	59.6
Net current - period other comprehensive income (loss)	62.9	47.4
Ending Balance	(165.3)	(228.2)
Change of fair value of pension benefit obligation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(58.2)	(64.6)
Other comprehensive income (loss) before reclassifications	(1.6)	9.3
Amounts reclassified from accumulated other comprehensive income (loss)	(5.7)	(2.9)
Net current - period other comprehensive income (loss)	(7.3)	6.4
Ending Balance	(65.5)	(58.2)
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(286.4)	(340.2)
Other comprehensive income (loss) before reclassifications	25.3	(2.9)
Amounts reclassified from accumulated other comprehensive income (loss)	30.3	56.7
Net current - period other comprehensive income (loss)	55.6	53.8
Ending Balance	$ (230.8)	$ (286.4)