OTHER FINANCIAL DATA - OTHER INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income [Line Items]
Allowance for equity funds used during construction	$ 27	$ 29	$ 139	$ 86
Investment gains	13	9	43	29
Gains (losses) on interest rate and foreign exchange instruments, net	5	(11)	99	(23)
Foreign currency transaction (losses) gains	(10)	(2)	7	(9)
Electrical infrastructure relocation income	2	1	2	4
Regulatory Interest, net	1	1	3	4
Sundry, net	3	(1)	8	7
Total	41	26	301	98
San Diego Gas and Electric Company [Member]
Other Income [Line Items]
Allowance for equity funds used during construction	15	11	46	35
Regulatory Interest, net	1	0	3	3
Total	16	11	49	38
Southern California Gas Company [Member]
Other Income [Line Items]
Allowance for equity funds used during construction	11	10	33	30
Regulatory Interest, net	0	1	0	1
Sundry, net	(3)	(3)	(5)	(7)
Total	$ 8	$ 8	$ 28	$ 24