OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Net Periodic Benefit Cost
Service cost	$ 29	$ 26	$ 59	$ 52
Interest cost	39	41	78	82
Expected return on assets	(44)	(43)	(88)	(86)
Amortization of prior service cost	2	3	5	5
Amortization of actuarial loss	11	5	19	10
Settlement	0	6	0	9
Regulatory adjustment	(30)	0	(59)	(24)
Total net periodic benefit cost	7	38	14	48
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			17
Expected contributions to benefit plans			36
Pension Benefits | San Diego Gas and Electric Company [Member]
Net Periodic Benefit Cost
Service cost	8	7	16	15
Interest cost	10	11	20	22
Expected return on assets	(13)	(14)	(27)	(28)
Amortization of prior service cost	1	1	1	1
Amortization of actuarial loss	2	1	4	2
Settlement	0	2	0	2
Regulatory adjustment	(7)	6	(12)	1
Total net periodic benefit cost	1	14	2	15
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			2
Expected contributions to benefit plans			3
Pension Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	19	16	38	32
Interest cost	24	26	49	51
Expected return on assets	(27)	(26)	(54)	(52)
Amortization of prior service cost	2	2	4	4
Amortization of actuarial loss	6	2	11	4
Regulatory adjustment	(23)	(6)	(47)	(25)
Total net periodic benefit cost	1	14	1	14
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to pension plans			1
Expected contributions to benefit plans			7
Other Postretirement Benefits
Net Periodic Benefit Cost
Service cost	7	6	14	12
Interest cost	11	12	23	24
Expected return on assets	(17)	(16)	(34)	(32)
Amortization of prior service cost	0	(1)	(1)	(2)
Amortization of actuarial loss	0	0	0	0
Settlement	0	0	0	0
Regulatory adjustment	0	0	0	0
Total net periodic benefit cost	1	1	2	2
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			1
Expected contributions to benefit plans			11
Other Postretirement Benefits | San Diego Gas and Electric Company [Member]
Net Periodic Benefit Cost
Service cost	2	1	4	3
Interest cost	2	2	4	4
Expected return on assets	(3)	(3)	(6)	(6)
Amortization of prior service cost	1	1	2	2
Amortization of actuarial loss	0	0	0	0
Settlement	0	0	0	0
Regulatory adjustment	(2)	(1)	(4)	(3)
Total net periodic benefit cost	0	0	0	0
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			0
Expected contributions to benefit plans			8
Other Postretirement Benefits | Southern California Gas Company [Member]
Net Periodic Benefit Cost
Service cost	5	4	10	8
Interest cost	9	10	18	19
Expected return on assets	(14)	(13)	(28)	(26)
Amortization of prior service cost	(2)	(2)	(4)	(4)
Amortization of actuarial loss	0	0	0	0
Regulatory adjustment	2	1	4	3
Total net periodic benefit cost	$ 0	$ 0	0	$ 0
Pension and Other Postretirement Benefit Contributions [Abstract]
Contributions to other postretirement benefit plans			0
Expected contributions to benefit plans			$ 0