FAIR VALUE MEASUREMENTS - FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency effect on loan	$ 6
Carrying amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	345	$ 184
Total long-term debt	15,519	15,068
Accumulated interest outstanding	22	17
Unamortized discount (net of premium) and debt issuance costs	114	109
Build-to-suit and capital lease obligations	882	383
Carrying amount [Member] \| Otay Mesa VIE [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, gross	300	305
Fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	320	175
Total long-term debt	16,394	15,947
Fair value [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	0	0
Total long-term debt	0	0
Fair value [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	228	91
Total long-term debt	15,900	15,455
Fair value [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	92	84
Total long-term debt	494	492
San Diego Gas and Electric Company [Member] \| Carrying amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	4,891	4,654
Unamortized discount (net of premium) and debt issuance costs	48	45
Capital lease obligations	737	240
San Diego Gas and Electric Company [Member] \| Fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	5,332	5,032
San Diego Gas and Electric Company [Member] \| Fair value [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	0	0
San Diego Gas and Electric Company [Member] \| Fair value [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	5,032	4,727
San Diego Gas and Electric Company [Member] \| Fair value [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	300	305
Southern California Gas Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Capital lease obligations	1
Southern California Gas Company [Member] \| Carrying amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,009	3,009
Unamortized discount (net of premium) and debt issuance costs	25	27
Southern California Gas Company [Member] \| Fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,169	3,131
Southern California Gas Company [Member] \| Fair value [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	0	0
Southern California Gas Company [Member] \| Fair value [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,169	3,131
Southern California Gas Company [Member] \| Fair value [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	$ 0	$ 0

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Value of the investment at close of period. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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