FAIR VALUE MEASUREMENTS - FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Carrying amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	$ 168	$ 184
Total long-term debt	14,971	15,068
Accumulated interest outstanding	19	17
Unamortized discount (net of premium) and debt issuance costs	105	109
Build-to-suit and capital lease obligations	382	383
Carrying amount [Member] \| Otay Mesa VIE [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, gross	302	305
Fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	164	175
Total long-term debt	15,619	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	78	91
Total long-term debt	15,123	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	86	84
Total long-term debt	496	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	4,493	4,654
Unamortized discount (net of premium) and debt issuance costs	43	45
Capital lease obligations	239	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	4,848	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	4,546	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	302	305
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	26	27
Southern California Gas Company [Member] \| Fair value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,121	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	3,121	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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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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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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Fair value portion of notes payable.

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