STATEMENTS OF CHANGES IN CONSOLIDATED EQUITY - USD ($) $ in Millions	Total	[CommonStockMember]	[AdditionalPaidInCapitalMember]	[RetainedEarningsMember]	[TreasuryStockMember]	[AccumulatedOtherComprehensiveIncomeMember]	[NoncontrollingInterestMember]
Total Stockholders' Equity at Dec. 31, 2014	$ 2,709.3	$ 11.0	$ 1,164.2	$ 2,398.9	$ (44.3)	$ (931.4)	$ 110.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(142.6)			(151.0)			8.4
Other comprehensive income (loss)	2.2					6.0	(3.8)
Cash dividends on common stock	(57.9)			(57.9)
Dividends to noncontrolling interests	(16.0)						(16.0)
Redeemable noncontrolling interest	0.0			(0.3)			0.3
Employee stock plans	10.5		(5.4)	(8.0)	23.9
Total Stockholders' Equity at Sep. 30, 2015	2,505.5	11.0	1,158.8	2,181.7	(20.4)	(925.4)	99.8
Total Stockholders' Equity at Dec. 31, 2015	2,184.4	11.0	1,161.7	1,945.9	(21.3)	(1,014.5)	101.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(640.8)			(650.8)			10.0
Other comprehensive income (loss)	48.2					52.8	(4.6)
Cash dividends on common stock	(25.8)			(25.8)
Purchase of subsidiary shares from noncontrolling interest	(0.1)						(0.1)
Dividends to noncontrolling interests	(16.0)						(16.0)
Employee stock plans	12.8		21.6	(2.2)	(6.6)
Total Stockholders' Equity at Sep. 30, 2016	$ 1,562.7	$ 11.0	$ 1,183.3	$ 1,267.1	$ (27.9)	$ (961.7)	$ 90.9