Equity, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	$ 3,674.9
Balance at end of period	3,989.8	$ 3,674.9
Accumulated Other Comprehensive Loss
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	(469.0)	(349.5)	$ (205.8)
Other comprehensive income (loss) before reclassification, net of tax	250.9	(135.8)	(161.9)
Amounts reclassified from Accumulated other comprehensive income (loss) to earnings, net of tax	17.1	16.3	18.2
Balance at end of period	(201.0)	(469.0)	(349.5)
Foreign Currency Translation Adjustments
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	(273.5)	(164.9)	(13.4)
Other comprehensive income (loss) before reclassification, net of tax	240.3	(108.6)	(151.5)
Balance at end of period	(33.2)	(273.5)	(164.9)
Foreign currency translation adjustments, tax	0.0	0.0	0.0
Unrealized Gain (Loss) on Cash Flow Hedges
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	(0.1)	(1.7)	(1.3)
Other comprehensive income (loss) before reclassification, net of tax	(0.1)	1.6	(0.4)
Balance at end of period	(0.2)	(0.1)	(1.7)
Unrealized loss on cash flow hedges, tax	0.1	(0.3)	0.1
Defined Benefit Plan Adjustment
Increase (Decrease) In Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	(195.4)	(182.9)	(191.1)
Other comprehensive income (loss) before reclassification, net of tax	10.7	(28.8)	(10.0)
Amounts reclassified from Accumulated other comprehensive income (loss) to earnings, net of tax	17.1	16.3	18.2
Balance at end of period	(167.6)	(195.4)	(182.9)
Defined benefit plan, before reclassification, tax	(3.4)	12.3	5.5
Amounts reclassified from Accumulated Other Comprehensive Income (Loss), tax	$ (9.1)	$ (8.9)	$ (10.1)