FAIR VALUE MEASUREMENTS - FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized discount (net of premium) and debt issuance costs	$ 202	$ 143
Capital lease obligations and build-to-suit	1,419	877
Level 3 [Member] | Otay Mesa VIE [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	220	295
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	688	598
Long-term amounts due to unconsolidated affiliates	37	35
Total long-term debt	22,067	17,138
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	695	618
Long-term amounts due to unconsolidated affiliates	35	32
Total long-term debt	21,625	18,409
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
Long-term amounts due to unconsolidated affiliates	0	0
Total long-term debt	0	817
Fair Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	648	510
Long-term amounts due to unconsolidated affiliates	35	32
Total long-term debt	21,274	17,134
Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term amounts due from unconsolidated affiliates	47	108
Long-term amounts due to unconsolidated affiliates	0	0
Total long-term debt	351	458
San Diego Gas and Electric Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized discount (net of premium) and debt issuance costs	49	45
Capital lease obligations	1,272	732
San Diego Gas and Electric Company [Member] | Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	4,996	4,868
San Diego Gas and Electric Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	5,117	5,368
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	4,897	5,073
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	220	295
Southern California Gas Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized discount (net of premium) and debt issuance costs	32	24
Capital lease obligations	3	1
Southern California Gas Company [Member] | Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,459	3,009
Southern California Gas Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	3,505	3,192
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	3,505	3,192
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