DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE INSTRUMENTS ON THE CONDENSED BALANCE SHEET (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	$ 37	$ 47
Additional cash collateral for commodity contracts not subject to rate recovery	14	2
Additional cash collateral for commodity contracts subject to rate recovery	19	17
Total	70	66
Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	103	105
Additional cash collateral for commodity contracts not subject to rate recovery	0	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	103	105
Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(67)	(103)
Additional cash collateral for commodity contracts not subject to rate recovery	0	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(67)	(103)
Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(243)	(281)
Additional cash collateral for commodity contracts not subject to rate recovery	0	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(243)	(281)
Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	7	5
Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	2	2
Designated as Hedging Instrument [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	(8)	(51)
Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	(138)	(165)
Not Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	9	0
Commodity contracts not subject to rate recovery	44	81
Associated offsetting commodity contracts	(37)	(67)
Commodity contracts subject to rate recovery	16	28
Associated offsetting commodity contracts	(2)	0
Associated offsetting cash collateral	0	0
Not Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	0	0
Commodity contracts not subject to rate recovery	13	8
Associated offsetting commodity contracts	(10)	(5)
Commodity contracts subject to rate recovery	99	101
Associated offsetting commodity contracts	(1)	(1)
Associated offsetting cash collateral	0	0
Not Designated as Hedging Instrument [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	0	(1)
Commodity contracts not subject to rate recovery	(44)	(72)
Associated offsetting commodity contracts	37	67
Commodity contracts subject to rate recovery	(63)	(65)
Associated offsetting commodity contracts	2	0
Associated offsetting cash collateral	9	19
Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	0	0
Commodity contracts not subject to rate recovery	(11)	(6)
Associated offsetting commodity contracts	10	5
Commodity contracts subject to rate recovery	(109)	(120)
Associated offsetting commodity contracts	1	1
Associated offsetting cash collateral	4	4
San Diego Gas and Electric Company [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	12	26
Additional cash collateral for commodity contracts subject to rate recovery	18	16
Total	30	42
San Diego Gas and Electric Company [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	97	100
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	97	100
San Diego Gas and Electric Company [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(56)	(54)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(56)	(54)
San Diego Gas and Electric Company [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(104)	(118)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(104)	(118)
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate instruments	0	0
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives designated as hedging instruments:
Interest rate instruments	0	0
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate instruments	(7)	(10)
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives designated as hedging instruments:
Interest rate instruments	0	(3)
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	14	26
Associated offsetting commodity contracts	(2)	0
Associated offsetting cash collateral	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	98	101
Associated offsetting commodity contracts	(1)	(1)
Associated offsetting cash collateral	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(60)	(63)
Associated offsetting commodity contracts	2	0
Associated offsetting cash collateral	9	19
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(109)	(120)
Associated offsetting commodity contracts	1	1
Associated offsetting cash collateral	4	4
Southern California Gas Company [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	2	2
Additional cash collateral for commodity contracts subject to rate recovery	1	1
Total	3	3
Southern California Gas Company [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	1	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	1	0
Southern California Gas Company [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(3)	(2)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(3)	(2)
Southern California Gas Company [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	0	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	0	0
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	2	2
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	1	0
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(3)	(2)
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	0	$ 0
Sempra Renewables [Member] | Disposal Group Held-for-sale [Member]
Derivatives not designated as hedging instruments:
Fixed-price contracts and other derivatives, current	1
Fixed-price contracts and other derivatives, noncurrent	$ 2