OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension Benefits
Net Periodic Benefit Cost
Service cost	$ 28	$ 23	$ 82	$ 68
Interest cost	35	40	111	122
Expected return on assets	(39)	(38)	(121)	(116)
Amortization of prior service cost	1	0	3	2
Amortization of actuarial loss	11	12	41	35
Settlement	1	1	1	8
Regulatory adjustment	(14)	9	(65)	(9)
Total net periodic benefit cost	23	47	52	110
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			48
Expected contributions to pension and other postretirement benefit plans	132		132
Pension Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	8	7	24	21
Interest cost	9	11	30	34
Expected return on assets	(13)	(11)	(39)	(35)
Amortization of prior service cost	0	0	1	1
Amortization of actuarial loss	3	4	10	11
Settlement	1	(1)	1	1
Regulatory adjustment	3	7	(3)	7
Total net periodic benefit cost	11	17	24	40
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			26
Expected contributions to pension and other postretirement benefit plans	53		53
Pension Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	17	13	50	40
Interest cost	22	24	68	74
Expected return on assets	(24)	(23)	(73)	(72)
Amortization of prior service cost	0	0	1	1
Amortization of actuarial loss	6	6	23	17
Settlement			0	1
Regulatory adjustment	(17)	2	(62)	(16)
Total net periodic benefit cost	4	22	7	45
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			8
Expected contributions to pension and other postretirement benefit plans	59		59
Other Postretirement Benefits
Net Periodic Benefit Cost
Service cost	8	4	21	19
Interest cost	10	11	33	39
Expected return on assets	(15)	(13)	(44)	(40)
Amortization of prior service cost	(1)	0	(3)	(2)
Amortization of actuarial loss	0	2	5	9
Settlement	0	0	0	0
Regulatory adjustment	3	3	7	8
Total net periodic benefit cost	5	7	19	33
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
Other Postretirement Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	2	1	6	5
Interest cost	2	2	6	6
Expected return on assets	(3)	(1)	(7)	(5)
Amortization of prior service cost	1	1	3	3
Amortization of actuarial loss	0	0	0	0
Settlement	0	0	0	0
Regulatory adjustment	1	1	1	2
Total net periodic benefit cost	3	4	9	11
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			9
Expected contributions to pension and other postretirement benefit plans	12		12
Other Postretirement Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	5	2	13	12
Interest cost	8	9	26	31
Expected return on assets	(12)	(10)	(36)	(33)
Amortization of prior service cost	(2)	(1)	(6)	(5)
Amortization of actuarial loss	0	1	4	8
Settlement			0	0
Regulatory adjustment	2	2	6	6
Total net periodic benefit cost	1	3	7	19
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			7
Expected contributions to pension and other postretirement benefit plans	$ 7		$ 7