WILDFIRE-RELATED CONTINGENCIES (2019 Kincade Fire, 2020 Zogg Fire and 2021 Dixie Fire) (Details) $ in Millions		3 Months Ended		6 Months Ended	12 Months Ended
	Nov. 04, 2019 numberOfPeople	Jun. 30, 2021 USD ($) localPublicEntity	Mar. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 28, 2021 complaint civil_case plaintiff numberOfPlaintiff	Jul. 25, 2021 a	Jul. 18, 2021 a structure fuse injury fatality	May 11, 2021 count	Apr. 06, 2021 felony misdemeanor minor firefighter_structure	Sep. 27, 2020 a structure fatality injury	Oct. 23, 2019 a structure numberOfFatality customer injury
Loss Contingencies [Line Items]
Insurance settlements receivable | $		$ 782.0		$ 782.0	$ 674.0
2019 Kincade Fire
Loss Contingencies [Line Items]
Number of acres burned (acre) | a												77,758
Number of fatalities (fatality) | numberOfFatality												0
Number of injuries (injuries) | injury												4
Number of structures destroyed (structure) | structure												374
Number of residences destroyed (residence) | structure												174
Number of commercial structures destroyed (structure) | structure												11
Number of other buildings destroyed (structures) | structure												189
Number of structures damaged (structure) | structure												60
Number of residential structures damaged (structure) | structure												35
Number of commercial structures damaged (structure) | structure												1
Number of other structures damaged (structure) | structure												24
Number of people part of mandatory evacuation order (people) | numberOfPeople	200,000
Number of customers without power (customer) | customer												27,837
Potential loss contingency | $		$ 800.0	$ 800.0	800.0	625.0
Potential loss contingency, additional | $			175.0
Number of settlement agreements entered into with local public entities (local public entity) | localPublicEntity		8
Settlement amount | $		$ 31.0		31.0
Insurance settlements receivable | $		430.0		430.0	430.0
2019 Kincade Fire | Subsequent event
Loss Contingencies [Line Items]
Number of complaint (complaint) | complaint						30
Number of plaintiffs represented by complaints (plaintiff) | plaintiff						607
2019 Kincade Fire | Pacific Gas & Electric Co (Utility)
Loss Contingencies [Line Items]
Number of demurrer filed (count) | count									25
Number of criminal complaints (count) | count									33
2019 Kincade Fire | Sonoma Contry District Attorney | Pacific Gas & Electric Co (Utility)
Loss Contingencies [Line Items]
Number of felonies (felony) | felony										5
Number of misdemeanors (misdemeanor) | misdemeanor										28
Number of felonies counts of recklessly causing a fire (felony) | felony										3
Number of firefighters and/or burned inhabited and other structures (firefighter/structure) | firefighter_structure										6
Number of felonies counts of emission of air contaminants (felony) | felony										2
Number of minors (minor) | minor										2
Number of misdemeanors related to carelessly or negligently throwing or placing substances that may cause a fire (misdemeanor) | misdemeanor										1
Number of misdemeanors related to negligently causing a fire (misdemeanor) | misdemeanor										1
Number of misdemeanors related to violation by a public utility (misdemeanor) | misdemeanor										3
Number of misdemeanors related to recklessly or negligently emitting air contaminants (misdemeanor) | misdemeanor										23
2020 Zogg Fire
Loss Contingencies [Line Items]
Number of acres burned (acre) | a											56,338
Number of fatalities (fatality) | fatality											4
Number of injuries (injuries) | injury											1
Number of structures destroyed (structure) | structure											204
Number of structures damaged (structure) | structure											27
Potential loss contingency | $		375.0		375.0	275.0
Potential loss contingency, additional | $		75.0	$ 25.0
Settlement amount | $		100.0
Insurance settlements receivable | $		327.0		327.0	219.0
Number of single family homes destroyed (structure) | structure											63
Liability insurance coverage | $		611.0		611.0
Initial self-insured retention per occurrence | $		$ 60.0		60.0
Legal fees | $				$ 12.0
2020 Zogg Fire | Subsequent event
Loss Contingencies [Line Items]
Number of complaint (complaint) | complaint						11
Number of plaintiffs represented by complaints (plaintiff) | numberOfPlaintiff						297
Number of civil cases (civil case) | civil_case						5
2020 Zogg Fire | Maximum
Loss Contingencies [Line Items]
Liability insurance coverage | $					$ 867.5
2021 Dixie Fire | Subsequent event
Loss Contingencies [Line Items]
Number of acres burned (acre) | a								2,180
Number of fatalities (fatality) | fatality								0
Number of injuries (injuries) | injury								0
Number of structures destroyed (structure) | structure								54
Number of structures damaged (structure) | structure								7
Number of fuses (fuse) | fuse								3
Number of fuses blown (fuse) | fuse								2
2021 Fly Fire | Subsequent event
Loss Contingencies [Line Items]
Number of acres burned (acre) | a							4,300
Percentage of fire contained							5.00%