OTHER FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Sales	$ 1,619.9	$ 1,554.9	$ 1,526.5	$ 1,567.1	$ 1,385.7	$ 1,452.7	$ 1,364.0	$ 1,348.2	$ 6,268.4	$ 5,550.6	$ 2,854.4
Cost of goods sold	1,396.2	1,345.6	1,404.1	1,393.7	1,227.0	1,284.4	1,236.9	1,175.4	5,539.6	4,923.7	2,486.8
Net income (loss)	$ 489.3	$ 52.7	$ (5.9)	$ 13.4	$ 17.5	$ 17.5	$ (1.0)	$ (37.9)	$ 549.5	$ (3.9)	$ (1.4)
Earnings per Share, Basic [Abstract]
Basic net income (loss) per share (in dollars per share)	$ 2.93	$ 0.32	$ (0.04)	$ 0.08	$ 0.11	$ 0.11	$ (0.01)	$ (0.23)	$ 3.31	$ (0.02)	$ (0.01)
Earnings per Share, Diluted [Abstract]
Diluted net (loss) income per share (in dollars per share)	2.89	0.31	(0.04)	0.08	0.10	0.11	(0.01)	(0.23)	3.26	(0.02)	$ (0.01)
Common dividends per share (in dollars per share)	0.20	0.20	0.20	0.20	0.20	0.20	0.20	0.20	0.80	0.80
Market price of common stock [Abstract]
High (in dollars per share)	37.52	34.85	33.67	33.88	26.93	26.46	24.99	17.75	37.52	26.93
Low (in dollars per share)	$ 33.34	$ 28.45	$ 27.79	$ 25.43	$ 19.62	$ 18.24	$ 16.55	$ 12.29	$ 25.43	$ 12.29