OTHER CONTINGENCIES AND COMMITMENTS (Order Instituting Investigation Narrative) (Details) $ in Millions	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 08, 2020 party	Apr. 20, 2020 USD ($)	Dec. 17, 2019 USD ($)
Loss Contingencies [Line Items]
Expenses and capital expenditures, disallowed costs			$ 1,621
Expenses and capital expenditures, disallowed capital, approved					$ 198
Shareholder-funded system enhancement initiatives, approved					64
Fine payable to general fund, suspended					$ 200
Number of parties filed separate applications for rehearing | party				2
Forecast
Loss Contingencies [Line Items]
Expenses and capital expenditures, remaining disallowance		$ 4
Pacific Gas & Electric Co | Vegetation Management Support Costs (FHPMA)
Loss Contingencies [Line Items]
Expenses and capital expenditures			$ 36
Pacific Gas & Electric Co | Vegetation Management Support Costs (FHPMA) | Forecast
Loss Contingencies [Line Items]
Expenses and capital expenditures, disallowed capital, charges recorded	$ 118	$ 80
Pacific Gas & Electric Co | Pending Litigation | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Expenses and capital expenditures						$ 1,625
Shareholder-funded system enhancement initiatives, amount						$ 50