NEW ACCOUNTING STANDARDS (Details) - USD ($)
shares in Thousands, $ in Millions
 3 Months Ended 6 Months Ended 9 Months Ended
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Sep. 30, 2015
Jun. 30, 2016
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               $ 107
Net cash provided by financing activities           $ 1,848 $ 29  
Net cash provided by operating activities           $ 1,691 $ 2,089  
Reduction in weighted-average common shares outstanding for diluted EPS (in shares) (252,405)     (251,024)   (251,976) (250,665)  
San Diego Gas and Electric Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               23
Net cash provided by financing activities           $ 52 $ (272)  
Net cash provided by operating activities           933 1,094  
Southern California Gas Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               15
Net cash provided by financing activities           491 544  
Net cash provided by operating activities           409 $ 690  
Effect of Early Adoption of New Accounting Pronouncement [Member] | Accounting Standards Update 2016-09 [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Excess tax benefits           34    
Net cash provided by financing activities           (34)    
Net cash provided by operating activities           34    
Reduction in weighted-average common shares outstanding for diluted EPS (in shares)   (98) (75)   (89)      
Deferred tax assets, net               107
Effect of Early Adoption of New Accounting Pronouncement [Member] | Accounting Standards Update 2016-09 [Member] | San Diego Gas and Electric Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Excess tax benefits           7    
Net cash provided by operating activities           7    
Deferred tax assets, net               23
Effect of Early Adoption of New Accounting Pronouncement [Member] | Accounting Standards Update 2016-09 [Member] | Southern California Gas Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Excess tax benefits           4    
Net cash provided by operating activities           $ 4    
Deferred tax assets, net               15
Effect of Early Adoption of New Accounting Pronouncement [Member] | Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               107
Effect of Early Adoption of New Accounting Pronouncement [Member] | Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member] | San Diego Gas and Electric Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               23
Effect of Early Adoption of New Accounting Pronouncement [Member] | Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member] | Southern California Gas Company [Member]                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Cumulative-effect adjustment               $ 15