WILDFIRE-RELATED CONTINGENCIES (2018 Camp Fire and 2017 Northern California Wildfires Accounting Charge) (Details) $ in Millions		3 Months Ended			6 Months Ended	12 Months Ended
	Jul. 23, 2019 USD ($)	Jun. 30, 2019 USD ($) wildfire	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) wildfire	Dec. 31, 2018 USD ($)
2018 Camp fire
Loss Contingencies [Line Items]
Accrued losses		$ 1,900			$ 12,400	$ 10,500
2017 Northern California wildfires
Loss Contingencies [Line Items]
Number of fires with probable losses (wildfire) | wildfire		21			21
Loss from claims related to wildfire		$ 2,000	$ 1,000	$ 2,500	$ 5,500	$ 3,500
2017 Northern California Wildfires, other than Tubbs and 37 Fires
Loss Contingencies [Line Items]
Number of fires with probable losses (wildfire) | wildfire		19			19
Number of fires with probable losses, as previously determined (wildfire) | wildfire		17			17
2017 Northern California Wildfires, Youngs and Pressley Fires
Loss Contingencies [Line Items]
Number of fires with probable losses (wildfire) | wildfire		2			2
2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Loss from claims related to wildfire					$ 17,900
2018 Camp Fire and 2017 Northern California Wildfires, Clean-up and Fire Suppression Costs
Loss Contingencies [Line Items]
Loss from claims related to wildfire					900
Subrogated Insurance Claimholders | 2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Loss from claims related to wildfire					8,500
Individual Claimholders | 2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Loss from claims related to wildfire					7,500
Supporting Public Entities | 2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Loss from claims related to wildfire					$ 1,000
Subsequent Event | Subrogated Insurance Claimholders | 2018 Camp Fire and 2017 Northern California Wildfires
Loss Contingencies [Line Items]
Insurance claims (in excess of)	$ 20,000
Plan of reorganization, settlement value of insurance claims	$ 15,800