REVENUES - CONTRACT LIABILITIES (Details)	9 Months Ended
	Sep. 30, 2018 USD ($)
Contract with Customer, Liability [Roll Forward]
Opening balance, January 1, 2018	$ 0
Adoption of ASC 606 adjustment	(68,000,000)
Revenue from performance obligations satisfied during reporting period	23,000,000
Payments received in advance	(25,000,000)
Closing balance, June 30, 2018	(70,000,000)
Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, June 30, 2018	(6,000,000)
Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, June 30, 2018	(64,000,000)
San Diego Gas and Electric Company [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, June 30, 2018	0
Southern California Gas Company [Member]
Contract with Customer, Liability [Roll Forward]
Closing balance, June 30, 2018	$ 0