STATEMENTS OF CHANGES IN CONSOLIDATED EQUITY - USD ($) $ in Millions	Total	[CommonStockMember]	[AdditionalPaidInCapitalMember]	[RetainedEarningsMember]	[TreasuryStockMember]	[AccumulatedOtherComprehensiveIncomeMember]	[NoncontrollingInterestMember]
Total Stockholders' Equity at Dec. 31, 2017	$ 1,844.5	$ 12.7	$ 1,596.3	$ 1,184.3	$ (26.1)	$ (1,027.8)	$ 105.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	191.7			181.3			10.4
Other comprehensive income (loss)	31.3					36.5	(5.2)
Cumulative effect of adoption of new accounting standard	15.5			15.5
Dividends to noncontrolling interests	(10.0)						(10.0)
Sales of subsidiary shares to noncontrolling interest	2.7						2.7
Employee stock plans	7.5		12.2	(0.2)	(4.5)
Total Stockholders' Equity at Sep. 30, 2018	2,083.2	12.7	1,608.5	1,380.9	(30.6)	(991.3)	103.0
Total Stockholders' Equity at Jun. 30, 2018	2,041.9	12.7	1,604.1	1,330.4	(30.6)	(991.6)	116.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	55.6			50.5			5.1
Other comprehensive income (loss)	(8.7)					0.3	(9.0)
Dividends to noncontrolling interests	(10.0)						(10.0)
Employee stock plans	4.4		4.4	0.0	0.0
Total Stockholders' Equity at Sep. 30, 2018	2,083.2	12.7	1,608.5	1,380.9	(30.6)	(991.3)	103.0
Total Stockholders' Equity at Dec. 31, 2018	1,991.6	12.7	1,615.4	1,422.0	(30.6)	(1,133.8)	105.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	210.1			201.1			9.0
Other comprehensive income (loss)	69.4					72.4	(3.0)
Employee stock plans	8.8		(3.3)	(0.3)	12.4
Total Stockholders' Equity at Sep. 30, 2019	2,279.9	12.7	1,612.1	1,622.8	(18.2)	(1,061.4)	111.9
Total Stockholders' Equity at Jun. 30, 2019	2,138.6	12.7	1,604.6	1,511.8	(18.3)	(1,084.4)	112.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	115.3			111.0			4.3
Other comprehensive income (loss)	18.4					23.0	(4.6)
Employee stock plans	7.6		7.5	0.0	0.1
Total Stockholders' Equity at Sep. 30, 2019	$ 2,279.9	$ 12.7	$ 1,612.1	$ 1,622.8	$ (18.2)	$ (1,061.4)	$ 111.9