CONTINGENCIES AND COMMITMENTS (Wildfire Insurance) (Details) - USD ($)	3 Months Ended	6 Months Ended
	Sep. 30, 2018	Jun. 30, 2018
Loss Contingencies [Line Items]
Costs for insurance coverage	$ 360,000,000	$ 50,000,000
Insurance Coverage for Wildfire Events
Loss Contingencies [Line Items]
Liability insurance coverage	1,400,000,000.0
Insurance Coverage for Wildfire Liabilities
Loss Contingencies [Line Items]
Liability insurance coverage	700,000,000
Catastrophic bond reinsurance instrument	10,000,000
Insurance Coverage for Property Damages
Loss Contingencies [Line Items]
Liability insurance coverage	700,000,000
Catastrophic bond reinsurance instrument	$ 200,000,000