WILDFIRE-RELATED CONTINGENCIES (2018 Camp Fire and 2017 Northern California Wildfires Accounting Charge) (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) wild_fire
Loss Contingencies [Line Items]
Accrued charges during period	$ 0
Wildfire-related claims	$ 25,500,000,000
2017 Northern California Wildfires, other than Tubbs and 37 Fires
Loss Contingencies [Line Items]
Number of fires with probable losses (wildfire) | wild_fire	37
2017 Northern California wildfires
Loss Contingencies [Line Items]
Number of fires with probable losses (wildfire) | wild_fire	19
Subrogated Insurance Claimholders | 2018 Camp Fire, 2017 Northern California Wildfires and 2015 Butte Fire
Loss Contingencies [Line Items]
Wildfire-related claims	$ 11,000,000,000
Professional Service Reimbursement | 2018 Camp Fire, 2017 Northern California Wildfires and 2015 Butte Fire
Loss Contingencies [Line Items]
Wildfire-related claims	47,500,000
Supporting Public Entities | 2018 Camp Fire, 2017 Northern California Wildfires and 2015 Butte Fire
Loss Contingencies [Line Items]
Wildfire-related claims	1,000,000,000
Individual Claimholders | 2018 Camp Fire, 2017 Northern California Wildfires and 2015 Butte Fire
Loss Contingencies [Line Items]
Wildfire-related claims	$ 13,500,000,000