OTHER COMPREHENSIVE INCOME (Changes in Accumulated Other Comprehensive Income, Net of Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance	$ (181.3)	$ (197.7)
Other comprehensive income (loss) before reclassifications	13.4	(8.3)	$ (26.9)
Amounts reclassified from AOCI	15.2	24.7	1.4
Net current period OCI changes	28.6	16.4	(25.5)
AOCI, Ending balance	(152.7)	(181.3)	(197.7)
Amortization of Interest Rate Hedges Losses [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance	(24.0)	(11.0)
Other comprehensive income (loss) before reclassifications	0.0	(14.7)	0.0
Amounts reclassified from AOCI	1.5	1.7	0.2
Net current period OCI changes	1.5	(13.0)	0.2
AOCI, Ending balance	(22.5)	(24.0)	(11.0)
Amortization of Pension and Postretirement Plan Actuarial Loss and Prior Service Cost [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance	(157.3)	(186.7)
Other comprehensive income (loss) before reclassifications	13.4	6.4	(26.9)
Amounts reclassified from AOCI	13.7	23.0	1.2
Net current period OCI changes	27.1	29.4	(25.7)
AOCI, Ending balance	$ (130.2)	$ (157.3)	(186.7)
Scenario, Previously Reported [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance			(172.2)
Scenario, Previously Reported [Member] | Amortization of Interest Rate Hedges Losses [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance			(11.2)
Scenario, Previously Reported [Member] | Amortization of Pension and Postretirement Plan Actuarial Loss and Prior Service Cost [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning balance			$ (161.0)