NON-OPERATING INCOME (EXPENSE) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Nonoperating Income (Expense) [Abstract]
Interest income	$ 2.0		$ 5.0	$ 8.0	$ 14.0
SERP market adjustments	(0.0)		0.0	1.0	0.0
Interest expense	(5.0)		(5.0)	(14.0)	(15.0)
Amortization of debt charges	0.0		0.0	(1.0)	(1.0)
Interest Costs Capitalized Adjustment	(1.0)
Interest Costs Capitalized			1.0	1.0	3.0
Interest expense, net	(4.0)		2.0	(5.0)	1.0
Net periodic pension cost, excluding service cost	(1.0)		(1.0)	(2.0)	(4.0)
Gain on acquisition of controlling interest	0.0	$ 14.0	0.0	14.0	0.0
Foreign currency gain (loss)	(0.0)		(1.0)	(4.0)	(1.0)
Other non-operating items	(1.0)		(2.0)	8.0	(4.0)
Total non-operating income (expense)	$ (5.0)		$ 0.0	$ 3.0	$ (4.0)