Equity Equity (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	$ (778.8)	$ (1,290.5)
Other comprehensive income before reclassifications	(170.5)	386.3
Amounts reclassified from accumulated other comprehensive income	38.7	40.1
Provision for income taxes	(9.2)	(12.8)
Net current period other comprehensive income (loss)	(141.0)	413.6
Balance at September 30:	(919.8)	(876.9)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	(289.2)	(739.0)
Other comprehensive income before reclassifications	(175.2)	401.4
Amounts reclassified from accumulated other comprehensive income	0.0	0.0
Provision for income taxes	0.0	0.0
Net current period other comprehensive income (loss)	(175.2)	401.4
Balance at September 30:	(464.4)	(337.6)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	4.7	2.9
Other comprehensive income before reclassifications	(0.5)	(1.3)
Amounts reclassified from accumulated other comprehensive income	0.4	2.4
Provision for income taxes	0.2	0.0
Net current period other comprehensive income (loss)	0.1	1.1
Balance at September 30:	4.8	4.0
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31:	(494.3)	(554.4)
Other comprehensive income before reclassifications	5.2	(13.8)
Amounts reclassified from accumulated other comprehensive income	38.3	37.7
Provision for income taxes	(9.4)	(12.8)
Net current period other comprehensive income (loss)	34.1	11.1
Balance at September 30:	$ (460.2)	$ (543.3)