v3.8.0.1
GENERAL INFORMATION AND OTHER FINANCIAL DATA - PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 09, 2018
Mar. 31, 2018
Mar. 31, 2017
Pension benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Reduction in plan assets due to settlement   $ 83  
Service cost   33 $ 28
Interest cost   35 37
Expected return on assets   (42) (40)
Prior service cost (credit)   3 3
Actuarial loss (gain)   9 8
Settlements   14 0
Net periodic benefit cost (credit)   52 36
Regulatory adjustment   (45) (12)
Total expense recognized   7 24
Contributions by employer   10  
Expected contributions in current fiscal year   226  
Pension benefits [Member] | San Diego Gas and Electric Company [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost   8 8
Interest cost   9 9
Expected return on assets   (13) (11)
Prior service cost (credit)   0 0
Actuarial loss (gain)   1 2
Settlements   14 0
Net periodic benefit cost (credit)   19 8
Regulatory adjustment   (19) (7)
Total expense recognized   0 1
Contributions by employer   2  
Expected contributions in current fiscal year   48  
Pension benefits [Member] | Southern California Gas Company [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost   22 18
Interest cost   23 24
Expected return on assets   (26) (26)
Prior service cost (credit)   2 2
Actuarial loss (gain)   6 4
Net periodic benefit cost (credit)   27 22
Regulatory adjustment   (26) (5)
Total expense recognized   1 17
Contributions by employer   0  
Expected contributions in current fiscal year   113  
Other postretirement benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost   6 6
Interest cost   9 9
Expected return on assets   (18) (16)
Prior service cost (credit)   0 0
Actuarial loss (gain)   (1) (1)
Settlements   0 0
Net periodic benefit cost (credit)   (4) (2)
Regulatory adjustment   4 2
Total expense recognized   0 0
Contributions by employer   1  
Expected contributions in current fiscal year   9  
Other postretirement benefits [Member] | San Diego Gas and Electric Company [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost   1 1
Interest cost   2 2
Expected return on assets   (3) (3)
Prior service cost (credit)   1 1
Actuarial loss (gain)   (1) 0
Settlements   0 0
Net periodic benefit cost (credit)   0 1
Regulatory adjustment   0 (1)
Total expense recognized   0 0
Contributions by employer   0  
Expected contributions in current fiscal year   3  
Other postretirement benefits [Member] | Southern California Gas Company [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost   4 4
Interest cost   7 7
Expected return on assets   (14) (13)
Prior service cost (credit)   (1) (1)
Actuarial loss (gain)   0 0
Net periodic benefit cost (credit)   (4) (3)
Regulatory adjustment   4 3
Total expense recognized   0 $ 0
Contributions by employer   1  
Expected contributions in current fiscal year   $ 2  
Oncor Holdings [Member] | Sempra Texas Holdings Corp [Member] | Sempra Texas Intermediate Holding Company LLC [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Increase in liability due to acquisition $ 21