COMMITMENTS AND CONTINGENCIES - FUTURE MINIMUM LEASE PAYMENTS UNDER TOPIC 840 (Details) $ in Millions	Dec. 31, 2018 USD ($)
Capital Leases [Abstract]
2019	$ 215
2020	210
2021	211
2022	211
2023	211
Thereafter	3,196
Total undiscounted lease payments	4,254
Less: estimated executory costs	(480)
Less: imputed interest	(2,483)
Total future minimum lease payments	1,291
Leases, Operating [Abstract]
2019	77
2020	55
2021	53
2022	50
2023	42
Thereafter	253
Total undiscounted lease payments	530
HQ Build To Suit Lease [Member]
Capital Leases [Abstract]
2019	10
2020	11
2021	11
2022	11
2023	11
Thereafter	217
Total undiscounted lease payments	271
San Diego Gas and Electric Company [Member]
Capital Leases [Abstract]
2019	212
2020	210
2021	211
2022	211
2023	211
Thereafter	3,196
Total undiscounted lease payments	4,251
Less: estimated executory costs	(480)
Less: imputed interest	(2,483)
Total future minimum lease payments	1,288
Leases, Operating [Abstract]
2019	23
2020	22
2021	22
2022	21
2023	17
Thereafter	48
Total undiscounted lease payments	153
Southern California Gas Company [Member]
Capital Leases [Abstract]
2019	3
2020	0
2021	0
2022	0
2023	0
Thereafter	0
Total undiscounted lease payments	3
Less: estimated executory costs	0
Less: imputed interest	0
Total future minimum lease payments	3
Leases, Operating [Abstract]
2019	26
2020	22
2021	21
2022	20
2023	16
Thereafter	28
Total undiscounted lease payments	$ 133