OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Southern California Gas Company [Member]
Remeasurement Due To Collective Bargaining Agreement [Line Items]
Discount Rate For Remeasurement			4.65%
Decrease In Recorded Liability From Remeasurement			$ 66
Pension Benefits
Net Periodic Benefit Cost
Service cost	23	20	68	63
Interest cost	40	41	122	126
Expected return on assets	(38)	(36)	(116)	(109)
Amortization of prior service cost		1	2	3
Amortization of actuarial loss	12	8	35	26
Settlement	1	1	8	11
Regulatory adjustment	9	31	(9)	6
Total net periodic benefit cost	47	66	110	126
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			111
Expected contributions to pension and other postretirement benefit plans	123		123
Pension Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	7	6	21	21
Interest cost	11	12	34	37
Expected return on assets	(11)	(10)	(35)	(35)
Amortization of prior service cost			1	1
Amortization of actuarial loss	4	2	11	7
Settlement	(1)		1	1
Regulatory adjustment	7	15	7	13
Total net periodic benefit cost	17	25	40	45
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			36
Expected contributions to pension and other postretirement benefit plans	45		45
Pension Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	13	10	40	34
Interest cost	24	24	74	74
Expected return on assets	(23)	(21)	(72)	(64)
Amortization of prior service cost		1	1	2
Amortization of actuarial loss	6	4	17	12
Settlement			1	1
Regulatory adjustment	2	16	(16)	(7)
Total net periodic benefit cost	22	34	45	52
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			45
Expected contributions to pension and other postretirement benefit plans	47		47
Other Postretirement Benefits
Net Periodic Benefit Cost
Service cost	4	8	19	23
Interest cost	11	16	39	49
Expected return on assets	(13)	(12)	(40)	(36)
Amortization of prior service cost			(2)
Amortization of actuarial loss	2	4	9	13
Regulatory adjustment	3	2	8	6
Total net periodic benefit cost	7	18	33	55
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			32
Expected contributions to pension and other postretirement benefit plans	41		41
Other Postretirement Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	1	1	5	5
Interest cost	2	2	6	7
Expected return on assets	(1)	(1)	(5)	(5)
Amortization of prior service cost	1	1	3	3
Regulatory adjustment	1	1	2	2
Total net periodic benefit cost	4	4	11	12
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			10
Expected contributions to pension and other postretirement benefit plans	13		13
Other Postretirement Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	2	7	12	17
Interest cost	9	12	31	39
Expected return on assets	(10)	(10)	(33)	(30)
Amortization of prior service cost	(1)	(1)	(5)	(3)
Amortization of actuarial loss	1	4	8	13
Regulatory adjustment	2	1	6	4
Total net periodic benefit cost	3	13	19	40
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			19
Expected contributions to pension and other postretirement benefit plans	$ 23		$ 23