DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE INSTRUMENTS ON THE CONDENSED BALANCE SHEET (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Other current assets [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	$ 40	$ 58
Additional cash collateral for commodity contracts not subject to rate recovery	37	43
Additional cash collateral for commodity contracts subject to rate recovery	19	25
Total	96	126
Other long-term assets [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	81	85
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	81	85
Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(124)	(53)
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	(124)	(53)
Deferred credits and other liabilities [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(266)	(192)
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	(266)	(192)
Designated as Hedging Instrument [Member] | Other current assets [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	15	0
Designated as Hedging Instrument [Member] | Other long-term assets [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	0	3
Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	(29)	(17)
Designated as Hedging Instrument [Member] | Deferred credits and other liabilities [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	(210)	(140)
Not Designated as Hedging Instrument [Member] | Other current assets [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	23	41
Associated offsetting foreign exchange instruments	(23)	(20)
Commodity contracts not subject to rate recovery	69	34
Associated offsetting commodity contracts	(65)	(32)
Commodity contracts subject to rate recovery	23	41
Associated offsetting commodity contracts	(2)	(6)
Associated offsetting cash collateral	0	0
Not Designated as Hedging Instrument [Member] | Other long-term assets [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	0	0
Associated offsetting foreign exchange instruments	0	0
Commodity contracts not subject to rate recovery	9	11
Associated offsetting commodity contracts	(3)	(2)
Commodity contracts subject to rate recovery	77	76
Associated offsetting commodity contracts	(2)	(3)
Associated offsetting cash collateral	0	0
Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	(82)	(20)
Associated offsetting foreign exchange instruments	23	20
Commodity contracts not subject to rate recovery	(69)	(41)
Associated offsetting commodity contracts	65	32
Commodity contracts subject to rate recovery	(47)	(47)
Associated offsetting commodity contracts	2	6
Associated offsetting cash collateral	13	14
Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	0	0
Associated offsetting foreign exchange instruments	0	0
Commodity contracts not subject to rate recovery	(11)	(10)
Associated offsetting commodity contracts	3	2
Commodity contracts subject to rate recovery	(50)	(47)
Associated offsetting commodity contracts	2	3
Associated offsetting cash collateral	0	0
San Diego Gas and Electric Company [Member] | Other current assets [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	18	26
Additional cash collateral for commodity contracts subject to rate recovery	15	16
Total	33	42
San Diego Gas and Electric Company [Member] | Other long-term assets [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	75	73
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	75	73
San Diego Gas and Electric Company [Member] | Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(28)	(23)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(28)	(23)
San Diego Gas and Electric Company [Member] | Deferred credits and other liabilities [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(48)	(44)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(48)	(44)
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Other current assets [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	20	30
Associated offsetting commodity contracts	(2)	(4)
Associated offsetting cash collateral	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Other long-term assets [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	77	76
Associated offsetting commodity contracts	(2)	(3)
Associated offsetting cash collateral	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(43)	(41)
Associated offsetting commodity contracts	2	4
Associated offsetting cash collateral	13	14
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(50)	(47)
Associated offsetting commodity contracts	2	3
Associated offsetting cash collateral	0	0
Southern California Gas Company [Member] | Other current assets [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	3	9
Additional cash collateral for commodity contracts subject to rate recovery	4	9
Total	7	18
Southern California Gas Company [Member] | Other long-term assets [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] | Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(4)	(4)
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(4)	(4)
Southern California Gas Company [Member] | Deferred credits and other liabilities [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] | Other current assets [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	3	11
Associated offsetting commodity contracts		(2)
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Other long-term assets [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	0	0
Associated offsetting commodity contracts		0
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	(4)	(6)
Associated offsetting commodity contracts		2
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities [Member]
Derivatives not designated as hedging instruments:
Commodity contracts subject to rate recovery	$ 0	0
Associated offsetting commodity contracts		$ 0