GENERAL INFORMATION AND OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 42	$ 36	$ 83	$ 73
Interest cost	29	28	59	56
Expected return on assets	(45)	(43)	(91)	(86)
Amortization of:
Prior service cost (credit)	2	2	5	5
Actuarial loss (gain)	5	11	11	22
Settlement charges			0	7
Net periodic benefit cost (credit)	33	34	67	77
Regulatory adjustments	24	22	(3)	(7)
Total expense recognized	57	56	64	70
Pension benefits | San Diego Gas and Electric Company
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	9	20	17
Interest cost	6	6	13	12
Expected return on assets	(11)	(13)	(22)	(25)
Amortization of:
Actuarial loss (gain)	1	1	1	1
Net periodic benefit cost (credit)	6	3	12	5
Regulatory adjustments	7	11	2	9
Total expense recognized	13	14	14	14
Pension benefits | Southern California Gas Company
Defined Benefit Plan Disclosure [Line Items]
Service cost	28	25	56	50
Interest cost	21	20	41	40
Expected return on assets	(33)	(30)	(64)	(58)
Amortization of:
Prior service cost (credit)	2	2	4	4
Actuarial loss (gain)	4	10	8	19
Net periodic benefit cost (credit)	22	27	45	55
Regulatory adjustments	17	11	(5)	(16)
Total expense recognized	39	38	40	39
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5	13	11
Interest cost	7	7	14	14
Expected return on assets	(16)	(15)	(32)	(30)
Amortization of:
Prior service cost (credit)	0	0	(1)	(1)
Actuarial loss (gain)	(3)	(2)	(7)	(4)
Settlement charges			0	0
Net periodic benefit cost (credit)	(6)	(5)	(13)	(10)
Regulatory adjustments	6	5	13	10
Total expense recognized	0	0	0	0
Other postretirement benefits | San Diego Gas and Electric Company
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	2
Interest cost	2	2	3	3
Expected return on assets	(3)	(3)	(5)	(5)
Amortization of:
Actuarial loss (gain)	0	(1)	(1)	(1)
Net periodic benefit cost (credit)	0	(1)	0	(1)
Regulatory adjustments	0	1	0	1
Total expense recognized	0	0	0	0
Other postretirement benefits | Southern California Gas Company
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	4	10	8
Interest cost	6	6	11	11
Expected return on assets	(14)	(12)	(27)	(24)
Amortization of:
Prior service cost (credit)	0	0	(1)	(1)
Actuarial loss (gain)	(3)	(2)	(6)	(3)
Net periodic benefit cost (credit)	(6)	(4)	(13)	(9)
Regulatory adjustments	6	4	13	9
Total expense recognized	$ 0	$ 0	$ 0	$ 0