Equity Equity (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	$ (964.1)	$ (778.8)
Other comprehensive income before reclassifications	(3.6)	141.4
Amounts reclassified from accumulated other comprehensive income	13.0	13.6
Provision for income taxes	(3.9)	(2.9)
Other comprehensive income (loss)	5.9	152.5
Balance at September 30:	(958.6)	(626.7)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	(516.8)	(289.2)
Other comprehensive income before reclassifications	(2.4)	143.9
Amounts reclassified from accumulated other comprehensive income	0.0	0.0
Provision for income taxes	0.0	0.0
Other comprehensive income (loss)	(2.4)	143.9
Balance at September 30:	(519.2)	(145.3)
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	5.5	152.1
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	6.7	4.7
Other comprehensive income before reclassifications	(1.5)	2.1
Amounts reclassified from accumulated other comprehensive income	0.1	1.0
Provision for income taxes	(0.4)	(0.3)
Other comprehensive income (loss)	(1.8)	2.8
Balance at September 30:	4.9	7.5
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	(454.0)	(494.3)
Other comprehensive income before reclassifications	0.3	(4.6)
Amounts reclassified from accumulated other comprehensive income	12.9	12.6
Provision for income taxes	(3.5)	(2.6)
Other comprehensive income (loss)	9.7	5.4
Balance at September 30:	$ (444.3)	$ (488.9)