SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - WILDFIRE FUND (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Loss Contingencies [Line Items]
Noncurrent portion of the Wildfire Fund asset		$ 363,000,000	$ 392,000,000
San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Initial liability cap		950,000,000
Initial shareholder contributions		322,500,000		$ 322,500,000
Additional annual contributions, aggregate value		129,000,000
Wildfire fund asset				$ 451,500,000
Annual contributions		12,900,000
Wildfire fund obligations in current liabilities		$ 13,000,000	13,000,000
Amortization of wildfire fund asset		15 years
Current portion of Wildfire fund		$ 29,000,000	29,000,000
Noncurrent portion of the Wildfire Fund asset		363,000,000	392,000,000
Noncurrent Wildfire Fund obligation		75,000,000	86,000,000
Amortization of Wildfire Fund asset		29,000,000	12,000,000
Accretion of Wildfire Fund obligation		2,000,000	$ 1,000,000
San Diego Gas and Electric Company [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Fire risk mitigation capital improvements	$ 215,000,000
Wildfire Fund [Member]
Loss Contingencies [Line Items]
Wildfire fund, threshold amount to seek payment	$ 1,000,000,000
Wildfire fund, threshold percentage of equity portion of electric transmission	20.00%
Liquidity fund, maximum borrowing capacity		10,500,000,000
Initial shareholder contributions		7,500,000,000
Additional annual contributions, aggregate value		$ 3,000,000,000
Period of annual contributions		10 years
PG&E [Member]
Loss Contingencies [Line Items]
Initial shareholder contributions		$ 4,800,000,000
Additional annual contributions, aggregate value		1,900,000,000
Edison [Member]
Loss Contingencies [Line Items]
Initial shareholder contributions		2,400,000,000
Additional annual contributions, aggregate value		$ 945,000,000