SHAREHOLDERS' EQUITY (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended		41 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Apr. 26, 2018
Equity, Class of Treasury Stock [Line Items]
Cost of common stock repurchased and retired (in dollars)							$ 68.3	$ 0.0
Stock Repurchased and Retired During Period, Value							68.3
Effective Tax Rate, Discrete Items, net benefit (expense)	$ 1.1			$ (1.7)			$ 96.7	$ (2.8)
Stock options exercised, Shares							2,800,000	100,000
Stock options exercised, Value							$ 58.3	$ 0.5
Foreign Currency Translation Adjustment (net of taxes)
Beginning balance			$ 19.4			$ (8.4)	19.4	(8.4)
Unrealized (losses) gains	(14.0)	$ 2.4	(11.4)	17.0	$ 8.2	(9.0)
Reclassification adjustments of losses (gains) into income	0.0	0.0	0.0	0.0	0.0	0.0
Tax benefit (provision)	0.0	0.0	0.0	0.0	0.0	0.0
Net change							(23.0)	16.2
Ending Balance	(3.6)			7.8			(3.6)	7.8	$ (3.6)
Unrealized (Losses) Gains on Derivative Contracts (net of taxes)
Beginning balance			21.4			(13.6)	21.4	(13.6)
Unrealized (losses) gains	41.7	41.8	122.0	26.0	29.9	(35.1)
Reclassification adjustments of losses (gains) into income	(23.5)	(20.4)	(112.8)	0.1	9.3	11.6
Tax benefit (provision)	(4.4)	(5.1)	(2.2)	(6.3)	(9.2)	5.6
Net change	13.8			19.8			37.1	31.9
Ending balance	58.5			18.3			58.5	18.3	58.5
Pension and Other Postretirement Benefits (net of taxes)
Beginning balance			(730.7)			(781.4)	(730.7)	(781.4)
Unrealized (losses) gains	0.0	0.0	0.0	0.0	0.0	0.0
Reclassification adjustments of losses (gains) into income	13.4	13.7	13.7	11.5	11.6	11.9
Tax benefit (provision)	(2.7)	(3.0)	(3.1)	(2.6)	(2.6)	(2.7)
Net change							32.0	27.1
Ending balance	(698.7)			(754.3)			(698.7)	(754.3)	(698.7)
Accumulated Other Comprehensive Loss
Beginning balance			(689.9)			(803.4)	(689.9)	(803.4)
Unrealized (losses) gains	27.7	44.2	110.6	43.0	38.1	(44.1)
Reclassification adjustments of losses (gains) into income	(10.1)	(6.7)	(99.1)	11.6	20.9	23.5
Tax benefit (provision)	(7.1)	$ (8.1)	$ (5.3)	(8.9)	$ (11.8)	$ 2.9
Net change							46.1	75.2
Ending balance	(643.8)			$ (728.2)			(643.8)	$ (728.2)	(643.8)
Common Stock | 2018 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchase program (in dollars)										$ 500.0
Cost of common stock repurchased and retired (in dollars)									264.2
Remaining authorized repurchase amount (in dollars)	$ 235.8						$ 235.8		$ 235.8
Stock Repurchased and Retired During Period, Shares							1,500,000	0	11,500,000