DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE INSTRUMENTS ON THE CONDENSED BALANCE SHEET (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	$ 19,000,000	$ 50,000,000
Additional cash collateral for commodity contracts not subject to rate recovery	15,000,000	2,000,000
Additional cash collateral for commodity contracts subject to rate recovery	19,000,000	28,000,000
Total	53,000,000	80,000,000
Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	93,000,000	60,000,000
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	93,000,000	60,000,000
Current liabilities: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	(88,000,000)	(49,000,000)
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	(88,000,000)	(49,000,000)
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	(371,000,000)	(193,000,000)
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	(371,000,000)	(193,000,000)
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	3,000,000	4,000,000
Commodity contracts not subject to rate recovery	0	13,000,000
Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives designated as hedging instruments:
Interest rate and foreign exchange instruments	0	1,000,000
Commodity contracts not subject to rate recovery	0	0
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	(20,000,000)	(15,000,000)
Commodity contracts not subject to rate recovery	(4,000,000)	0
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	(224,000,000)	(156,000,000)
Commodity contracts not subject to rate recovery	0	0
Not Designated as Hedging Instrument [Member] | Current assets: Fixed-price contracts and other derivatives [Member]
Derivatives not designated as hedging instruments:
Foreign exchange instruments	2,000,000
Commodity contracts not subject to rate recovery	122,000,000	245,000,000
Associated offsetting commodity contracts	(114,000,000)	(232,000,000)
Associated offsetting cash collateral	0	(6,000,000)
Commodity contracts subject to rate recovery	11,000,000	28,000,000
Associated offsetting commodity contracts	(5,000,000)	(2,000,000)
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
Commodity contracts not subject to rate recovery	25,000,000	32,000,000
Associated offsetting commodity contracts	(15,000,000)	(20,000,000)
Associated offsetting cash collateral	(2,000,000)	0
Commodity contracts subject to rate recovery	86,000,000	49,000,000
Associated offsetting commodity contracts	(1,000,000)	(2,000,000)
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	(25,000,000)
Commodity contracts not subject to rate recovery	(128,000,000)	(239,000,000)
Associated offsetting commodity contracts	114,000,000	232,000,000
Associated offsetting cash collateral	17,000,000	4,000,000
Commodity contracts subject to rate recovery	(59,000,000)	(61,000,000)
Associated offsetting commodity contracts	5,000,000	2,000,000
Associated offsetting cash collateral	12,000,000	28,000,000
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
Commodity contracts not subject to rate recovery	(17,000,000)	(21,000,000)
Associated offsetting commodity contracts	15,000,000	20,000,000
Associated offsetting cash collateral	2,000,000	0
Commodity contracts subject to rate recovery	(165,000,000)	(64,000,000)
Associated offsetting commodity contracts	1,000,000	2,000,000
Associated offsetting cash collateral	17,000,000	26,000,000
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	5,000,000	25,000,000
Additional cash collateral for commodity contracts not subject to rate recovery	1,000,000	1,000,000
Additional cash collateral for commodity contracts subject to rate recovery	17,000,000	27,000,000
Total	23,000,000	53,000,000
San Diego Gas and Electric Company [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	85,000,000	47,000,000
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	85,000,000	47,000,000
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	(53,000,000)	(44,000,000)
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	(53,000,000)	(44,000,000)
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	(165,000,000)	(59,000,000)
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	(165,000,000)	(59,000,000)
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	(13,000,000)	(14,000,000)
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	(18,000,000)	(23,000,000)
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 not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	8,000,000	27,000,000
Associated offsetting commodity contracts	(3,000,000)	(2,000,000)
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 not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	86,000,000	49,000,000
Associated offsetting commodity contracts	(1,000,000)	(2,000,000)
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 not subject to rate recovery		(1,000,000)
Associated offsetting cash collateral		1,000,000
Commodity contracts subject to rate recovery	(55,000,000)	(60,000,000)
Associated offsetting commodity contracts	3,000,000	2,000,000
Associated offsetting cash collateral	12,000,000	28,000,000
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 not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	(165,000,000)	(64,000,000)
Associated offsetting commodity contracts	1,000,000	2,000,000
Associated offsetting cash collateral	17,000,000	26,000,000
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	1,000,000	1,000,000
Additional cash collateral for commodity contracts not subject to rate recovery	1,000,000
Additional cash collateral for commodity contracts subject to rate recovery	2,000,000	1,000,000
Total	4,000,000	2,000,000
Southern California Gas Company [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Net amounts presented on the balance sheet	0	0
Additional cash collateral for commodity contracts not subject to rate recovery	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	0	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	(2,000,000)	(1,000,000)
Additional cash collateral for commodity contracts not subject to rate recovery	0
Additional cash collateral for commodity contracts subject to rate recovery	0	0
Total	(2,000,000)	(1,000,000)
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 not subject to rate recovery	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 not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	3,000,000	1,000,000
Associated offsetting commodity contracts	(2,000,000)
Southern California Gas Company [Member] | Not Designated as Hedging Instrument [Member] | Other assets: Sundry [Member]
Derivatives not designated as hedging instruments:
Commodity contracts not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	0	0
Associated offsetting commodity contracts	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 not subject to rate recovery		(1,000,000)
Associated offsetting cash collateral		1,000,000
Commodity contracts subject to rate recovery	(4,000,000)	(1,000,000)
Associated offsetting commodity contracts	2,000,000
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 not subject to rate recovery		0
Associated offsetting cash collateral		0
Commodity contracts subject to rate recovery	0	$ 0
Associated offsetting commodity contracts	$ 0