COMMITMENTS AND CONTINGENCIES - OPERATING LEASES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Annual Rent Escalation [Abstract]
Minimum annual rent escalation	2.00%
Maximum annual rent escalation	5.00%
Operating Leases, Rent Expense, Net [Abstract]
Rent expense	$ 109	$ 77	$ 78
Future minimum lease payments
2018	85
2019	57
2020	51
2021	48
2022	42
Thereafter	300
Total	583
Future estimated rental payments
2018	13
2019	12
2020	12
2021	12
2022	13
Thereafter	46
Total	108
Total future rental commitments
2018	98
2019	69
2020	63
2021	60
2022	55
Thereafter	346
Total	$ 691
San Diego Gas and Electric Company [Member]
Operating Leases, Annual Rent Escalation [Abstract]
Minimum annual rent escalation	2.00%
Maximum annual rent escalation	5.00%
Operating Leases, Rent Expense, Net [Abstract]
Rent expense	$ 28	28	27
Future minimum lease payments
2018	22
2019	21
2020	20
2021	19
2022	18
Thereafter	54
Total	154
Future estimated rental payments
2018	2
2019	2
2020	2
2021	2
2022	2
Thereafter	3
Total	13
Total future rental commitments
2018	24
2019	23
2020	22
2021	21
2022	20
Thereafter	57
Total	167
Utility Subsidiaries [Member]
Operating Leases, Annual Rent Escalation [Abstract]
Aggregate maximum lease limit	250
Lease limit utilized	$ 133
Southern California Gas Company [Member]
Operating Leases, Annual Rent Escalation [Abstract]
Minimum annual rent escalation	2.00%
Maximum annual rent escalation	5.00%
Operating Leases, Rent Expense, Net [Abstract]
Rent expense	$ 43	$ 38	$ 39
Future minimum lease payments
2018	29
2019	25
2020	20
2021	19
2022	13
Thereafter	36
Total	142
Future estimated rental payments
2018	11
2019	10
2020	10
2021	10
2022	11
Thereafter	43
Total	95
Total future rental commitments
2018	40
2019	35
2020	30
2021	29
2022	24
Thereafter	79
Total	$ 237