WILDFIRE-RELATED CONTINGENCIES (2019 Kincade Fire, 2020 Zogg Fire and 2021 Dixie Fire) (Details) numberOfPeople in Millions, $ in Millions				3 Months Ended			9 Months Ended	12 Months Ended
	Oct. 22, 2021 USD ($) a	Oct. 18, 2021 USD ($)	Nov. 04, 2019 numberOfPeople	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 29, 2021 USD ($) complaint civil_case numberOfPlaintiff	Oct. 27, 2021 numberOfClaimHolder plaintiff complaint	Sep. 24, 2021 felony death misdemeanor	Jul. 25, 2021 a	Jul. 18, 2021 a fuse structure fatality	May 11, 2021 count	Apr. 06, 2021 felony misdemeanor firefighter_structure minor	Sep. 27, 2020 a structure fatality injury	Oct. 23, 2019 a structure numberOfFatality injury customer
Loss Contingencies [Line Items]
Insurance settlements receivable | $				$ 1,314.0			$ 1,314.0	$ 674.0
Number of felonies counts of involuntary manslaughter (felony) | felony											4
Probable of recovery | $							1,156.0
FERC
Loss Contingencies [Line Items]
Probable of recovery | $							98.0
WEMA
Loss Contingencies [Line Items]
Probable of recovery | $							339.0
Noncurrent assets – other
Loss Contingencies [Line Items]
Wildfire fund receivables | $				150.0			150.0
2019 Kincade Fire
Loss Contingencies [Line Items]
Number of acres burned (acre) | a																	77,758
Number of fatalities (fatality) | numberOfFatality																	0
Number of injuries (injury) | 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 (structure) | 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			0.2
Number of customers without power (customer) | customer																	27,837
Potential loss contingency | $						$ 800.0	800.0	625.0
Potential loss contingency, additional | $						175.0
Insurance settlements receivable | $				414.0			414.0	430.0
2019 Kincade Fire | Subsequent event
Loss Contingencies [Line Items]
Number of complaint (complaint) | complaint										64
Number of plaintiffs represented by complaints (plaintiff) | plaintiff										1,377
Fire fighting costs recovery requested | $		$ 90.0
Settlement agreement, proposed payment to California General Fund | $									$ 40.0
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 (injury) | injury																1
Number of structures destroyed (structure) | structure																204
Number of structures damaged (structure) | structure																27
Number of felonies counts of recklessly causing a fire (felony) | felony											3
Number of misdemeanors related to negligently causing a fire (misdemeanor) | misdemeanor											1
Potential loss contingency | $					$ 375.0		375.0	275.0
Potential loss contingency, additional | $					$ 75.0	$ 25.0
Insurance settlements receivable | $				331.0			331.0	219.0
Number of single family homes destroyed (structure) | structure																63
Number of count related to unlawfully causing a fire (count) | misdemeanor											1
Number of misdemeanors related to negligently causing a fire by device (misdemeanor) | misdemeanor											1
Number of misdemeanors related to failure to comply with regulations (misdemeanor) | misdemeanor											1
Liability insurance coverage | $				611.0			611.0
Initial self-insured retention per occurrence | $				60.0			60.0
Legal fees | $							16.0
2020 Zogg Fire | Subsequent event
Loss Contingencies [Line Items]
Number of complaint (complaint) | complaint									17
Number of plaintiffs represented by complaints (plaintiff) | numberOfPlaintiff									315
Number of civil cases (civil case) | civil_case									5
2020 Zogg Fire | Maximum
Loss Contingencies [Line Items]
Liability insurance coverage | $								867.5
Zogg Complaint, 2020
Loss Contingencies [Line Items]
Number of fatalities (fatality) | death											4
Number of felonies (felony) | felony											11
Number of misdemeanors (misdemeanor) | misdemeanor											20
Number of felonies counts of recklessly causing a fire (felony) | felony											6
Number of misdemeanors related to negligently causing a fire (misdemeanor) | misdemeanor											2
Number of misdemeanors related to recklessly or negligently emitting air contaminants (misdemeanor) | misdemeanor											5
Number of felonies counts of recklessly causing a fire to property of another (felony) | felony											1
Number of misdemeanors related to failure to maintain firebreak (misdemeanor) | misdemeanor											1
Number of misdemeanors related to failure to maintain firebreak (misdemeanor) | misdemeanor											1
Number of count related to unlawfully causing a fire (count) | misdemeanor											2
Number of misdemeanors related to negligently causing a fire by device (misdemeanor) | misdemeanor											2
Number of misdemeanors related to failure to comply with regulations (misdemeanor) | misdemeanor											2
Number of misdemeanors related to recklessly emitting air contamination that results in an unreasonable risk of great bodily injury (misdemeanor) | misdemeanor											5
Daniel Fire, 2020
Loss Contingencies [Line Items]
Number of felonies counts of recklessly causing a fire (felony) | felony											1
Ponder Fire, 2020
Loss Contingencies [Line Items]
Number of felonies counts of recklessly causing a fire (felony) | felony											1
Number of misdemeanors related to negligently causing a fire (misdemeanor) | misdemeanor											1
Number of count related to unlawfully causing a fire (count) | misdemeanor											1
Number of misdemeanors related to negligently causing a fire by device (misdemeanor) | misdemeanor											1
Number of misdemeanors related to failure to comply with regulations (misdemeanor) | misdemeanor											1
Woody Fire, 2021
Loss Contingencies [Line Items]
Number of felonies counts of recklessly causing a fire (felony) | felony											1
2021 Dixie Fire
Loss Contingencies [Line Items]
Number of acres burned (acre) | a													963,309
Number of fatalities (fatality) | fatality													1
Number of structures destroyed (structure) | structure													1,329
Number of structures damaged (structure) | structure													95
Potential loss contingency | $				1,150.0
Insurance settlements receivable | $				569.0			569.0	$ 0.0
Number of residential structures destroyed (structure) | structure													717
Number of fuses opened (fuse) | fuse													2
Number of fuses (fuse) | fuse													3
Insurance receivable | $				569.0			569.0
2021 Dixie Fire | Subsequent event
Loss Contingencies [Line Items]
Number of complaint (complaint) | numberOfClaimHolder										10
Number of plaintiffs represented by complaints (plaintiff) | numberOfClaimHolder										676
Costs incurred | $	$ 630.0
2021 Dixie Fire | Subsequent event | National Park
Loss Contingencies [Line Items]
Number of acres burned (acre) | a	70,000
2021 Dixie Fire | Subsequent event | National Forrest
Loss Contingencies [Line Items]
Number of acres burned (acre) | a	685,000
2021 Fly Fire
Loss Contingencies [Line Items]
Number of acres burned (acre) | a												4,300
Percentage of fire contained												5.00%
Zogg Fire, 2020 and Dixie Fire, 2021
Loss Contingencies [Line Items]
Liability insurance coverage | $				$ 900.0			$ 900.0