WILDFIRE-RELATED CONTINGENCIES (Clean-up and Repair Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Capital expenditures	$ 368	$ 501	$ 403
Total long-term regulatory assets	4,964	3,793
Catastrophic event memorandum account
Loss Contingencies [Line Items]
Total long-term regulatory assets	790	274
Pacific Gas & Electric Co
Loss Contingencies [Line Items]
Capital expenditures	368	501	$ 403
Total long-term regulatory assets	4,964	$ 3,793
Pacific Gas & Electric Co | 2018 Camp fire
Loss Contingencies [Line Items]
Service restoration and repair costs	354
Capital expenditures	183
Pacific Gas & Electric Co | 2017 Northern California wildfires
Loss Contingencies [Line Items]
Service restoration and repair costs	327
Capital expenditures	157
Pacific Gas & Electric Co | Catastrophic event memorandum account | 2017 Northern California wildfires
Loss Contingencies [Line Items]
Total long-term regulatory assets	$ 82