SHAREHOLDERS' EQUITY (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended				6 Months Ended		26 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Apr. 26, 2018
Equity, Class of Treasury Stock [Line Items]
Cost of common stock repurchased and retired (in dollars)					$ 0.0	$ 26.7
Stock options exercised					0.1	0.1
Total value of stock options exercised		$ 0.7	$ 0.1	$ 1.4	$ 0.7	$ 1.5
Foreign Currency Translation Adjustment (net of taxes)
Beginning balance		(8.4)		0.7	(8.4)	0.7
Unrealized (losses) gains	$ 8.2	(9.0)	3.3	(8.3)
Reclassification adjustments of losses into income	0.0	0.0	0.0	0.0
Tax benefit (provision)	0.0	0.0	0.0	0.0
Net change					(0.8)	(5.0)
Ending Balance	(9.2)		(4.3)		(9.2)	(4.3)	$ (9.2)
Unrealized (Losses) Gains on Derivative Contracts (net of taxes)
Beginning balance		(13.6)		1.8	(13.6)	1.8
Unrealized (losses) gains	29.9	(35.1)	(22.2)	(6.6)
Reclassification adjustments of losses into income	9.3	11.6	6.3	2.2
Tax benefit (provision)	(9.2)	5.6	3.8	1.1
Net change	30.0		(12.1)		12.1	(15.4)
Ending balance	(1.5)		(13.6)		(1.5)	(13.6)	(1.5)
Pension and Other Postretirement Benefits (net of taxes)
Beginning balance		(781.4)		(653.5)	(781.4)	(653.5)
Unrealized (losses) gains	0.0	0.0	0.0	0.0
Reclassification adjustments of losses into income	11.6	11.9	7.1	7.4
Tax benefit (provision)	(2.6)	(2.7)	(1.8)	(1.7)
Net change					18.2	11.0
Ending balance	(763.2)		(642.5)		(763.2)	(642.5)	(763.2)
Accumulated Other Comprehensive Loss
Beginning balance		(803.4)		(651.0)	(803.4)	(651.0)
Unrealized (losses) gains	38.1	(44.1)	(18.9)	(14.9)
Reclassification adjustments of losses into income	20.9	23.5	13.4	9.6
Tax benefit (provision)	(11.8)	$ 2.9	2.0	$ (0.6)
Net change					29.5	(9.4)
Ending balance	(773.9)		$ (660.4)		$ (773.9)	(660.4)	(773.9)
2018 Share Repurchase Program | Common Stock
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchase program (in dollars)								$ 500.0
Cost of common stock repurchased and retired (in dollars)						$ 26.7	$ 195.9
Total repurchased shares under this program (in shares)					0.0	1.2	10.1
Remaining authorized repurchase amount (in dollars)	$ 304.1				$ 304.1		$ 304.1