DERIVATIVE FINANCIAL INSTRUMENTS - BALANCE SHEET (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	$ 58,000,000	$ 80,000,000
Additional margin posted for commodity contracts not subject to rate recovery	43,000,000	19,000,000
Additional margin posted for commodity contracts subject to rate recovery	25,000,000	33,000,000
Total	126,000,000	132,000,000
Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	85,000,000	235,000,000
Additional margin posted for commodity contracts not subject to rate recovery	0	0
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	85,000,000	235,000,000
Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	(53,000,000)	(70,000,000)
Additional margin posted for commodity contracts not subject to rate recovery	0	0
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	(53,000,000)	(70,000,000)
Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	(192,000,000)	(218,000,000)
Additional margin posted for commodity contracts not subject to rate recovery	0	0
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	(192,000,000)	(218,000,000)
Designated as Hedging Instrument [Member] | Current assets: Other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments	0	2,000,000
Designated as Hedging Instrument [Member] | Other assets: Other long-term assets [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments	3,000,000	0
Designated as Hedging Instrument [Member] | Current liabilities: Other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments	(17,000,000)	(3,000,000)
Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments	(140,000,000)	(147,000,000)
Not Designated as Hedging Instrument [Member] | Current assets: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Foreign exchange instruments	41,000,000
Associated offsetting foreign exchange instruments	(20,000,000)
Commodity contracts not subject to rate recovery	34,000,000	153,000,000
Associated offsetting commodity contracts not subject to rate recovery	(32,000,000)	(133,000,000)
Commodity contracts subject to rate recovery	41,000,000	64,000,000
Associated offsetting commodity contracts subject to rate recovery	(6,000,000)	(6,000,000)
Associated cash collateral commodity contracts subject to rate recovery	0	0
Not Designated as Hedging Instrument [Member] | Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Foreign exchange instruments	0
Associated offsetting foreign exchange instruments	0
Commodity contracts not subject to rate recovery	11,000,000	7,000,000
Associated offsetting commodity contracts not subject to rate recovery	(2,000,000)	(3,000,000)
Commodity contracts subject to rate recovery	76,000,000	233,000,000
Associated offsetting commodity contracts subject to rate recovery	(3,000,000)	(2,000,000)
Associated cash collateral commodity contracts subject to rate recovery	0	0
Not Designated as Hedging Instrument [Member] | Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Foreign exchange instruments	(20,000,000)
Associated offsetting foreign exchange instruments	20,000,000
Commodity contracts not subject to rate recovery	(41,000,000)	(164,000,000)
Associated offsetting commodity contracts not subject to rate recovery	32,000,000	133,000,000
Commodity contracts subject to rate recovery	(47,000,000)	(42,000,000)
Associated offsetting commodity contracts subject to rate recovery	6,000,000	6,000,000
Associated cash collateral commodity contracts subject to rate recovery	14,000,000	0
Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Foreign exchange instruments	0
Associated offsetting foreign exchange instruments	0
Commodity contracts not subject to rate recovery	(10,000,000)	(6,000,000)
Associated offsetting commodity contracts not subject to rate recovery	2,000,000	3,000,000
Commodity contracts subject to rate recovery	(47,000,000)	(72,000,000)
Associated offsetting commodity contracts subject to rate recovery	3,000,000	2,000,000
Associated cash collateral commodity contracts subject to rate recovery	0	2,000,000
San Diego Gas and Electric Company [Member] | Current assets: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	26,000,000	54,000,000
Additional margin posted for commodity contracts subject to rate recovery	16,000,000	28,000,000
Total	42,000,000	82,000,000
San Diego Gas and Electric Company [Member] | Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	73,000,000	231,000,000
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	73,000,000	231,000,000
San Diego Gas and Electric Company [Member] | Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	(23,000,000)	(32,000,000)
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	(23,000,000)	(32,000,000)
San Diego Gas and Electric Company [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	(44,000,000)	(68,000,000)
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	(44,000,000)	(68,000,000)
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Current assets: Other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments		0
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Other assets: Other long-term assets [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments		0
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Current liabilities: Other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments		(1,000,000)
San Diego Gas and Electric Company [Member] | Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Derivative Instruments in Hedges, at Fair Value, Net [Abstract]
Interest rate and foreign exchange instruments		0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Current assets: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	30,000,000	60,000,000
Associated offsetting commodity contracts subject to rate recovery	(4,000,000)	(6,000,000)
Associated cash collateral commodity contracts subject to rate recovery	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	76,000,000	233,000,000
Associated offsetting commodity contracts subject to rate recovery	(3,000,000)	(2,000,000)
Associated cash collateral commodity contracts subject to rate recovery	0	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	(41,000,000)	(37,000,000)
Associated offsetting commodity contracts subject to rate recovery	4,000,000	6,000,000
Associated cash collateral commodity contracts subject to rate recovery	14,000,000	0
San Diego Gas and Electric Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	(47,000,000)	(72,000,000)
Associated offsetting commodity contracts subject to rate recovery	3,000,000	2,000,000
Associated cash collateral commodity contracts subject to rate recovery	0	2,000,000
Southern California Gas Company [Member] | Current assets: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	9,000,000	4,000,000
Additional margin posted for commodity contracts subject to rate recovery	9,000,000	5,000,000
Total	18,000,000	9,000,000
Southern California Gas Company [Member] | Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	0	0
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	0	0
Southern California Gas Company [Member] | Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	(4,000,000)	(5,000,000)
Additional margin posted for commodity contracts subject to rate recovery	0	0
Total	(4,000,000)	(5,000,000)
Southern California Gas Company [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Net amount presented on balance sheet	0	0
Additional margin posted 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: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	11,000,000	4,000,000
Associated offsetting commodity contracts subject to rate recovery	(2,000,000)
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Other assets: Other long-term assets [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	0	0
Associated offsetting commodity contracts subject to rate recovery	0
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Current liabilities: Other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	(6,000,000)	(5,000,000)
Associated offsetting commodity contracts subject to rate recovery	2,000,000
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Deferred credits and other liabilities: Deferred credits and other [Member]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net [Abstract]
Commodity contracts subject to rate recovery	0	$ 0
Associated offsetting commodity contracts subject to rate recovery	$ 0