SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - COLLECTION ALLOWANCES (Details) - Allowance, Credit Loss [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	$ 21	$ 25	$ 29
Provisions for uncollectible accounts	22	10	12
Write-offs of uncollectible accounts	(14)	(14)	(16)
Allowance balance at December 31	29	21	25
San Diego Gas and Electric Company [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	11	9	8
Provisions for uncollectible accounts	10	9	8
Write-offs of uncollectible accounts	(7)	(7)	(7)
Allowance balance at December 31	14	11	9
Southern California Gas Company [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	10	16	21
Provisions for uncollectible accounts	12	1	4
Write-offs of uncollectible accounts	(7)	(7)	(9)
Allowance balance at December 31	$ 15	$ 10	$ 16