WILDFIRE-RELATED CONTINGENCIES (Insurance Receivable) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	$ 2,238
Accrued insurance recoveries	649
Reimbursements	(2,213)
Insurance Receivable, Ending Balance	674
2020 Zogg Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	0
Accrued insurance recoveries	219
Reimbursements	0
Insurance Receivable, Ending Balance	219
2019 Kincade Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	0
Accrued insurance recoveries	430
Reimbursements	0
Insurance Receivable, Ending Balance	430
2018 Camp Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	1,380
Accrued insurance recoveries	0
Reimbursements	(1,380)
Insurance Receivable, Ending Balance	0
2017 Northern California wildfires
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	808
Accrued insurance recoveries	0
Reimbursements	(783)
Insurance Receivable, Ending Balance	25
2015 Butte Fire
Insurance Receivable [Roll Forward]
Insurance Receivable, Beginning Balance	50
Accrued insurance recoveries	0
Reimbursements	(50)
Insurance Receivable, Ending Balance	$ 0