OTHER CONTINGENCIES AND COMMITMENTS (Gas Transmission and Storage Rate Case and Audit) (Details) - Disallowance of Plant Costs - USD ($) $ in Millions			1 Months Ended
	Jul. 07, 2021	Jun. 23, 2016	Jun. 30, 2020	Jul. 31, 2020	Jun. 01, 2020
Loss Contingencies [Line Items]
Gas transmission and storage capital disallowance		$ 696.0
Permanently disallowed capital		$ 120.0
Amount subject to audit			$ 576.0
Capital expenditures for future recovery					$ 512.0
2015 through 2022
Loss Contingencies [Line Items]
Capital expenditures for future recovery				$ 512.0
Capital expenditures for future recovery, seeking recovery				$ 416.3
Subsequent event | 2015 through 2022
Loss Contingencies [Line Items]
Capital expenditures for future recovery, pending authorization	$ 356.3
Subsequent event | 2015 through 2021
Loss Contingencies [Line Items]
Capital expenditures for future recovery, pending authorization	$ 313.3
Capital expenditures for future recovery, pending authorization, amortization period	60 months
Subsequent event | 2022
Loss Contingencies [Line Items]
Capital expenditures for future recovery, pending authorization	$ 43.0
Capital expenditures for future recovery, pending authorization, amortization period	12 months