AOCI Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance, beginning of period	$ 4,826.4
Increase (decrease), before reclassifications	(78.4)	$ (75.0)	$ 245.5
Income tax impact, before reclassifications	11.9	(3.0)	1.6
Other comprehensive income (loss) before reclassifications, net of income taxes	(66.5)	(78.0)	247.1
Increase (decrease), reclassified	0.6	(0.9)	1.6
Income tax impact, reclassified	(0.1)	0.3	(0.4)
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	0.5	(0.6)	1.2
Net current period other comprehensive income (loss), net of income taxes	(66.0)	(78.6)	248.3
Adoption of accounting standards				$ (0.2)
Balance, end of period	3,542.8	4,826.4
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance, beginning of period	(74.3)	10.9	(240.7)
Balance, January 1, 2018				10.9
Increase (decrease), before reclassifications	(46.6)	(85.2)	251.6
Income tax impact, before reclassifications	4.5	0.0	0.0
Other comprehensive income (loss) before reclassifications, net of income taxes	(42.1)	(85.2)	251.6
Increase (decrease), reclassified	0.0	0.0	0.0
Income tax impact, reclassified	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	0.0	0.0	0.0
Net current period other comprehensive income (loss), net of income taxes	(42.1)	(85.2)	251.6
Adoption of accounting standards				0.0
Balance, end of period	(116.4)	(74.3)	10.9
Unrealized Gain (Loss) on Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance, beginning of period	0.0	0.0	0.0
Balance, January 1, 2018				0.0
Increase (decrease), before reclassifications	0.1	0.0	0.0
Income tax impact, before reclassifications	0.0	0.0	0.0
Other comprehensive income (loss) before reclassifications, net of income taxes	0.1	0.0	0.0
Increase (decrease), reclassified	0.0	0.0	0.0
Income tax impact, reclassified	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	0.0	0.0	0.0
Net current period other comprehensive income (loss), net of income taxes	0.1	0.0	0.0
Adoption of accounting standards				0.0
Balance, end of period	0.1	0.0	0.0
Unrealized Pension Costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance, beginning of period	(3.9)	(10.3)	(7.0)
Balance, January 1, 2018				(10.5)
Increase (decrease), before reclassifications	(31.9)	10.2	(6.1)
Income tax impact, before reclassifications	7.4	(3.0)	1.6
Other comprehensive income (loss) before reclassifications, net of income taxes	(24.5)	7.2	(4.5)
Increase (decrease), reclassified	0.6	(0.9)	1.6
Income tax impact, reclassified	(0.1)	0.3	(0.4)
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	0.5	(0.6)	1.2
Net current period other comprehensive income (loss), net of income taxes	(24.0)	6.6	(3.3)
Adoption of accounting standards				(0.2)
Balance, end of period	(27.9)	(3.9)	(10.3)
Total Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance, beginning of period	(78.2)	0.6	(247.7)
Balance, January 1, 2018				$ 0.4
Balance, end of period	$ (144.2)	$ (78.2)	$ 0.6