SHAREHOLDERS' EQUITY (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended			32 Months Ended
	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Oct. 07, 2019	Aug. 05, 2019	Apr. 26, 2018
Equity, Class of Treasury Stock [Line Items]
Cost of common stock repurchased and retired		$ 0.0	$ 145.9	$ 50.0
Stock options exercised (in shares)		0.1	0.1	0.2
Total value of stock options exercised		$ 1.9	$ 1.7	$ 3.4
Foreign currency translation adjustment [Roll Forward]
Beginning balance	$ 7.6	(8.4)	0.7	7.6
Unrealized (losses) gains		27.8	(9.1)	(22.2)
Reclassification adjustments of (gains) losses into income		0.0	0.0	0.0
Tax benefit (provision)		0.0	0.0	0.0
Net change		27.8	(9.1)	(22.2)
Ending balance		19.4	(8.4)	0.7	$ 19.4
Unrealized gains (losses) on derivative contracts (net of taxes) [Roll Forward]
Beginning balance	11.1	(13.6)	1.8	11.1
Unrealized (losses) gains		31.1	(47.1)	(1.1)
Reclassification adjustments of (gains) losses into income		14.9	26.9	(14.3)
Tax benefit (provision)		(11.0)	4.8	3.7
Net change		35.0	(15.4)	(11.7)
Ending balance		21.4	(13.6)	1.8	21.4
Pension and postretirement benefits (net of taxes) [Roll Forward]
Beginning balance	(503.3)	(781.4)	(653.5)	(503.3)
Unrealized (losses) gains		26.6	(183.9)	(98.5)
Reclassification adjustments of (gains) losses into income		46.3	29.1	37.0
Tax benefit (provision)		(22.2)	26.9	14.9
Net change		50.7	(127.9)	(46.6)
Ending balance		(730.7)	(781.4)	(653.5)	(730.7)
Accumulated other comprehensive loss [Roll Forward]
Beginning balance	(484.6)	(803.4)	(651.0)	(484.6)
Unrealized (losses) gains		85.5	(240.1)	(121.8)
Reclassification adjustments of (gains) losses into income		61.2	56.0	22.7
Tax benefit (provision)		(33.2)	31.7	18.6
Net change		113.5	(152.4)	(80.5)
Ending balance		$ (689.9)	$ (803.4)	$ (651.0)	(689.9)
Income Tax Reclassification Adjustment, Foreign Currency Translation	15.3
Income Tax Reclassification Adjustment, Derivative Contracts	2.4
Income Tax Reclassification Adjustment, Pension and Postretirement Benefits	(103.6)
Income Tax Accounting Standard Adoption	$ (85.9)
Common Stock | 2018 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchase program (in dollars)								$ 500.0
Stock Repurchased and Retired During Period, Shares		0.0	8.0
Cost of common stock repurchased and retired			$ 145.9		$ 195.9
Total repurchased shares under this program (in shares)					10.1
Remaining authorized repurchase amount (in dollars)		$ 304.1			$ 304.1
Accelerated Share Repurchase [Member] | Common Stock | 2018 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Accelerated Share Repurchase Contract Payment							$ 100.0
Accelerated Share Repurchase Program Reduction to Authorized Repurchase Amount							$ 100.0
Accelerated Share Repurchase Total Shares Repurchased						5.7