WILDFIRE-RELATED CONTINGENCIES (Insurance Receivable) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	$ 674
Accrued insurance recoveries	28
Reimbursements	0
Insurance Receivable, ending balance	702
2020 Zogg Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	219
Accrued insurance recoveries	28
Reimbursements	0
Insurance Receivable, ending balance	247
2019 Kincade Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	430
Accrued insurance recoveries	0
Reimbursements	0
Insurance Receivable, ending balance	430
2017 Northern California wildfires
Insurance Receivable [Roll Forward]
Insurance Receivable, beginning balance	25
Accrued insurance recoveries	0
Reimbursements	0
Insurance Receivable, ending balance	$ 25