OTHER INCOME, NET (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Income and Expenses [Abstract]
Non-service components of net periodic benefit costs	$ 16.7	$ 18.0	$ 16.7
AFUDC – Equity	11.8	5.7	4.6
Other, net	2.9	15.9	16.3
Other income, net	$ 31.4	$ 39.6	$ 37.6