SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - COLLECTION ALLOWANCES (Details) - Allowance, Credit Loss [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	$ 33	$ 35	$ 32
Provisions for uncollectible accounts	14	16	23
Write-offs of uncollectible accounts	(17)	(18)	(20)
Allowance balance at December 31	30	33	35
San Diego Gas and Electric Company [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	9	8	9
Provisions for uncollectible accounts	9	8	6
Write-offs of uncollectible accounts	(7)	(7)	(7)
Allowance balance at December 31	11	9	8
Southern California Gas Company [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance balance at January 1	16	21	17
Provisions for uncollectible accounts	1	4	14
Write-offs of uncollectible accounts	(7)	(9)	(10)
Allowance balance at December 31	$ 10	$ 16	$ 21