OTHER CONTINGENCIES AND COMMITMENTS (Interim Rate Relief Subject to Refund) (Details) $ in Millions	Sep. 21, 2021 USD ($)	Mar. 31, 2022 USD ($)	Mar. 17, 2022 USD ($)	Oct. 23, 2020 USD ($)	Sep. 30, 2020 USD ($)	Aug. 07, 2019 USD ($)	Apr. 25, 2019 USD ($)	Mar. 30, 2018 USD ($) catastrophicEvent
CEMA Interim Rate Relief
Loss Contingencies [Line Items]
Cost recovery			$ 683			$ 763	$ 373
CEMA Interim Rate Relief | Mid 2016 - Early 2017
Loss Contingencies [Line Items]
Cost recovery								$ 183
Number of catastrophic events | catastrophicEvent								7
CEMA Interim Rate Relief | 2016 to 2017
Loss Contingencies [Line Items]
Cost recovery								$ 405
WMCE Interim Rate Relief
Loss Contingencies [Line Items]
Expenses and capital expenditures, disallowed costs					$ 1,180
Expenses and capital expenditures, capital expenditures					801
Cost recovery, increase to revenue requirement					$ 1,280
Interim rate relief				$ 447
Amortization period	17 months
Additional revenue requirement	$ 591
Additional amortization period	24 months
WMCE Interim Rate Relief | Fire hazard prevention memorandum account
Loss Contingencies [Line Items]
Cost recovery		$ 293
WMCE Interim Rate Relief | Fire risk and wildfire mitigation memorandum account
Loss Contingencies [Line Items]
Cost recovery		740
WMCE Interim Rate Relief | Catastrophic event memorandum account
Loss Contingencies [Line Items]
Cost recovery		$ 251