OTHER CONTINGENCIES AND COMMITMENTS (Other Matters) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Jan. 31, 2020 USD ($)	Jan. 17, 2020 USD ($)	Dec. 17, 2019 USD ($)	Dec. 05, 2019 USD ($)	Oct. 03, 2019 USD ($)	Dec. 06, 2018 consultant
Loss Contingencies [Line Items]
Expenses and capital expenditures, disallowed capital, gross	$ 344
Expenses and capital expenditures, disallowed capital, net	403
Expenses and capital expenditures, expected charges to be recorded	59
Settlement agreement, proposed payment to California general fund					$ 2
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Accrual	44
Pacific Gas & Electric Co | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Settlement agreement, proposed penalty						$ 65
Settlement agreement, proposed payment to California general fund						5
Settlement agreement, proposed payment to shareholders' funded initiatives						$ 60
Pacific Gas & Electric Co | Unfavorable Regulatory Action | Subsequent Event
Loss Contingencies [Line Items]
Settlement agreement, compliance audits cost			$ 6
Settlement agreement, additional fine			$ 39
Pacific Gas & Electric Co | Vegetation Management Support Costs (FHPMA)
Loss Contingencies [Line Items]
Expenses and capital expenditures	36
Expenses and capital expenditures, expected charges to be recorded	29
Expenses and capital expenditures, charges recorded	55
Pacific Gas & Electric Co | Pending Litigation | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Expenses and capital expenditures	1,625			$ 1,625
Shareholder-funded system enhancement initiatives, amount				$ 50
Expenses and capital expenditures, difference	$ 1,420
Number of consultants retained | consultant							2
Pacific Gas & Electric Co | Pending Litigation | Unfavorable Regulatory Action | Subsequent Event
Loss Contingencies [Line Items]
Expenses and capital expenditures		$ 1,675