WILDFIRE-RELATED CONTINGENCIES (Insurance Receivable) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	$ 674
Accrued insurance recoveries	681
Reimbursements	(41)
Insurance Receivable, ending balance	1,314
2020 Zogg Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	219
Accrued insurance recoveries	112
Reimbursements	0
Insurance Receivable, ending balance	331
2019 Kincade Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	430
Accrued insurance recoveries	0
Reimbursements	(16)
Insurance Receivable, ending balance	414
2017 Northern California wildfires
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	25
Accrued insurance recoveries	0
Reimbursements	(25)
Insurance Receivable, ending balance	0
2021 Dixie Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	0
Accrued insurance recoveries	569
Reimbursements	0
Insurance Receivable, ending balance	569
Insurance receivable	$ 569