OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 29	$ 55	$ 59
Interest cost	40	39	80	78
Expected return on assets	(41)	(44)	(83)	(88)
Amortization of prior service cost	3	2	6	5
Amortization of actuarial loss	7	11	13	19
Regulatory adjustment	(28)	(30)	(56)	(59)
Total net periodic benefit cost	8	7	15	14
Defined benefit plan, contributions by employer			23
Defined benefit plan, expected contributions in current fiscal year			123
Pension Benefits | San Diego Gas and Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	8	15	16
Interest cost	11	10	21	20
Expected return on assets	(13)	(13)	(25)	(27)
Amortization of prior service cost	1	1	1	1
Amortization of actuarial loss	2	2	5	4
Regulatory adjustment	(8)	(7)	(15)	(12)
Total net periodic benefit cost	1	1	2	2
Defined benefit plan, contributions by employer			2
Defined benefit plan, expected contributions in current fiscal year			4
Pension Benefits | Southern California Gas Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	18	19	35	38
Interest cost	25	24	50	49
Expected return on assets	(27)	(27)	(52)	(54)
Amortization of prior service cost	2	2	4	4
Amortization of actuarial loss	2	6	5	11
Regulatory adjustment	(20)	(23)	(41)	(47)
Total net periodic benefit cost	0	1	1	1
Defined benefit plan, contributions by employer			0
Defined benefit plan, expected contributions in current fiscal year			77
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	7	11	14
Interest cost	11	11	22	23
Expected return on assets	(18)	(17)	(35)	(34)
Amortization of prior service cost	0	0	0	(1)
Amortization of actuarial loss	0	0	0	0
Regulatory adjustment	2	0	4	0
Total net periodic benefit cost	1	1	2	2
Defined benefit plan, contributions by employer			2
Defined benefit plan, expected contributions in current fiscal year			6
Other Postretirement Benefits | San Diego Gas and Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2	4
Interest cost	2	2	4	4
Expected return on assets	(2)	(3)	(5)	(6)
Amortization of prior service cost	1	1	2	2
Amortization of actuarial loss	(1)	0	(1)	0
Regulatory adjustment	(1)	(2)	(2)	(4)
Total net periodic benefit cost	0	0	0	0
Defined benefit plan, contributions by employer			0
Defined benefit plan, expected contributions in current fiscal year			2
Other Postretirement Benefits | Southern California Gas Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	5	7	10
Interest cost	9	9	17	18
Expected return on assets	(14)	(14)	(28)	(28)
Amortization of prior service cost	(1)	(2)	(2)	(4)
Amortization of actuarial loss	0	0	0	0
Regulatory adjustment	3	2	6	4
Total net periodic benefit cost	$ 0	$ 0	0	$ 0
Defined benefit plan, contributions by employer			1
Defined benefit plan, expected contributions in current fiscal year			$ 1