WILDFIRE-RELATED CONTINGENCIES (Loss Recoveries) (Details) - USD ($) $ in Millions	Jul. 08, 2019	Jun. 30, 2019	Sep. 30, 2018	Jul. 31, 2018
2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Liability insurance coverage			$ 1,400	$ 842
Initial self-insured retention per occurrence			10	10
Further retention per occurrence				$ 40
Liability insurance coverage, general liability			700
Liability insurance coverage, property damages			700
Liability insurance coverage, property damages, reinsurance			$ 200
2018 Camp fire
Loss Contingencies [Line Items]
Estimated insurance recoveries		$ 1,380
2017 Northern California wildfires
Loss Contingencies [Line Items]
Estimated insurance recoveries		$ 842
Subsequent Event | 2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Customer Harm Threshold, potential regulatory adjustment, percentage	20.00%
Customer Harm Threshold, potential regulatory adjustment, percentage of total disallowed wildlife liability	5.00%