SHAREHOLDERS' EQUITY (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		5 Months Ended	9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Apr. 26, 2018
Equity, Class of Treasury Stock [Line Items]
Cost of common stock repurchased and retired (in dollars)	$ 13.2	$ 0.0
Stock options exercised	0.1	0.1
Total value of stock options exercised	$ 1.4	$ 1.0
Foreign Currency Translation Adjustment (net of taxes)
Beginning balance	0.7	7.6		$ 7.6
Unrealized gains (losses)	(8.3)	12.4
Reclassification adjustments of (gains) losses into income	0.0	0.0
Tax benefit (provision)	0.0	0.0
Net change	(8.3)	12.4
Income tax reclassification adjustment		15.3
Ending Balance	(7.6)	35.3
Unrealized Gains (Losses) on Derivative Contracts (net of taxes)
Beginning balance	1.8	11.1		11.1
Unrealized gains (losses)	(6.6)	2.1
Reclassification adjustments of (gains) losses into income	2.2	(2.3)
Tax benefit (provision)	1.1	0.1
Net change	(3.3)	(0.1)
Income tax reclassification adjustment		2.4
Ending balance	(1.5)	13.4
Pension and Other Postretirement Benefits (net of taxes)
Beginning balance	(653.5)	(503.3)		(503.3)
Unrealized gains (losses)	0.0	0.0
Reclassification adjustments of (gains) losses into income	7.4	9.4
Tax benefit (provision)	(1.7)	(4.0)
Net change	5.7	5.4
Income tax reclassification adjustment		(103.6)
Ending balance	(647.8)	(601.5)
Accumulated Other Comprehensive Loss
Beginning balance	(651.0)	(484.6)		$ (484.6)
Unrealized gains (losses)	(14.9)	14.5
Reclassification adjustments of (gains) losses into income	9.6	7.1
Tax benefit (provision)	(0.6)	(3.9)
Net change	(5.9)	17.7
Income tax reclassification adjustment		(85.9)
Ending balance	$ (656.9)	$ (552.8)
2018 Share Repurchase Program | Common Stock
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchase program (in dollars)					$ 500.0
Total repurchased shares under this program (in shares)			2.7	0.6
Cost of common stock repurchased and retired (in dollars)			$ 63.3	$ 13.2
Remaining authorized repurchase amount (in dollars)			$ 436.7	$ 436.7