GENERAL INFORMATION AND OTHER FINANCIAL DATA - ASSET RETIREMENT OBLIGATIONS (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Asset Retirement Obligations, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 2,877	$ 2,553
Accretion expense	90	81
Liabilities incurred	7	22
Asset Retirement Obligations Reclassification	(60)	0
Payments	(34)	(44)
Revisions	28	(8)
Ending balance	2,908	2,604
TdM [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligations Reclassifications from Held for Sale	5
San Diego Gas and Electric Company [Member]
Asset Retirement Obligations, Roll Forward Analysis [Roll Forward]
Beginning balance	839	830
Accretion expense	29	30
Liabilities incurred	0	17
Asset Retirement Obligations Reclassification	0	0
Payments	(31)	(43)
Revisions	29	0
Ending balance	866	834
Southern California Gas Company [Member]
Asset Retirement Obligations, Roll Forward Analysis [Roll Forward]
Beginning balance	1,953	1,659
Accretion expense	58	49
Liabilities incurred	0	0
Asset Retirement Obligations Reclassification	0	0
Payments	(2)	(1)
Revisions	(2)	(8)
Ending balance	2,007	$ 1,699
Sempra Renewables [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligations Reclassification to Held for Sale	57
Sempra LNG & Midstream [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligations Reclassification to Held for Sale	$ 8