OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits
Net Periodic Benefit Cost
Service cost	$ 27	$ 23
Interest cost	37	41
Expected return on assets	(40)	(39)
Amortization of prior service cost	1	1
Amortization of actuarial loss	15	12
Regulatory adjustment	(32)	(30)
Total net periodic benefit cost	8	8
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans	11
Expected contributions to pension and other postretirement benefit plans	154
Pension Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	8	7
Interest cost	10	12
Expected return on assets	(13)	(12)
Amortization of actuarial loss	4	4
Regulatory adjustment	(8)	(10)
Total net periodic benefit cost	1	1
Pension and Other Postretirement Benefit Contributions [Abstract]
Expected contributions to pension and other postretirement benefit plans	57
Pension Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	16	13
Interest cost	23	25
Expected return on assets	(25)	(24)
Amortization of prior service cost	(1)	1
Amortization of actuarial loss	9	6
Regulatory adjustment	(24)	(20)
Total net periodic benefit cost		1
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans	2
Expected contributions to pension and other postretirement benefit plans	70
Other Postretirement Benefits
Net Periodic Benefit Cost
Service cost	7	8
Interest cost	11	14
Expected return on assets	(15)	(13)
Amortization of prior service cost	(1)
Amortization of actuarial loss	2	3
Regulatory adjustment	2	3
Total net periodic benefit cost	6	15
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans	7
Expected contributions to pension and other postretirement benefit plans	26
Other Postretirement Benefits | San Diego Gas and Electric Company and Subsidiary [Member]
Net Periodic Benefit Cost
Service cost	2	2
Interest cost	2	2
Expected return on assets	(2)	(1)
Amortization of prior service cost	1	1
Total net periodic benefit cost	3	4
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans	3
Expected contributions to pension and other postretirement benefit plans	11
Other Postretirement Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	4	5
Interest cost	9	11
Expected return on assets	(12)	(11)
Amortization of prior service cost	(2)	(1)
Amortization of actuarial loss	2	3
Regulatory adjustment	2	3
Total net periodic benefit cost	3	10
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans	3
Expected contributions to pension and other postretirement benefit plans	$ 11