WILDFIRE-RELATED CONTINGENCIES (Clean-up and Repair Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Capital expenditures	$ 826	$ 368	$ 501
Total long-term regulatory assets	6,066	4,964
Catastrophic event memorandum account
Loss Contingencies [Line Items]
Total long-term regulatory assets	656	790
Pacific Gas & Electric Co
Loss Contingencies [Line Items]
Capital expenditures	826	368	$ 501
Total long-term regulatory assets	6,066	$ 4,964
Pacific Gas & Electric Co | 2018 Camp fire
Loss Contingencies [Line Items]
Clean-up and repair costs	772
Capital expenditures	323
Pacific Gas & Electric Co | 2017 Northern California wildfires
Loss Contingencies [Line Items]
Clean-up and repair costs	357
Capital expenditures	180
Pacific Gas & Electric Co | Catastrophic event memorandum account | 2018 Camp fire
Loss Contingencies [Line Items]
Total long-term regulatory assets	0
Pacific Gas & Electric Co | Catastrophic event memorandum account | 2017 Northern California wildfires
Loss Contingencies [Line Items]
Total long-term regulatory assets	$ 69