INCOME TAXES - UNRECOGNIZED TAX BENEFITS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits
Beginning balance	$ 89	$ 90	$ 87
Increase in prior period tax positions	7	22	2
Decrease in prior period tax positions	(1)	(15)	(2)
Increase in current period tax positions	24	4	6
Settlements with taxing authorities	0	(12)	(3)
Ending balance	119	89	90
Of the total, amounts related to tax positions that, if recognized, in future years, would decrease the effective tax rate	(107)	(77)	(87)
Of the total, amounts related to tax positions that, if recognized, in future years, would increase the effective tax rate	24	20	36
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Accrued interest and penalties	1	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense [Abstract]
Interest income and penalties on unrecognized income tax benefits	1	0	0
San Diego Gas and Electric Company [Member]
Reconciliation of Unrecognized Tax Benefits
Beginning balance	10	22	20
Increase in prior period tax positions	1	9	0
Decrease in prior period tax positions	0	(11)	0
Increase in current period tax positions	0	0	2
Settlements with taxing authorities	0	(10)	0
Ending balance	11	10	22
Of the total, amounts related to tax positions that, if recognized, in future years, would decrease the effective tax rate	(9)	(7)	(19)
Of the total, amounts related to tax positions that, if recognized, in future years, would increase the effective tax rate	1	1	13
Southern California Gas Company [Member]
Reconciliation of Unrecognized Tax Benefits
Beginning balance	35	29	27
Increase in prior period tax positions	2	3	0
Decrease in prior period tax positions	0	0	(2)
Increase in current period tax positions	24	4	4
Settlements with taxing authorities	0	(1)	0
Ending balance	61	35	29
Of the total, amounts related to tax positions that, if recognized, in future years, would decrease the effective tax rate	(51)	(26)	(29)
Of the total, amounts related to tax positions that, if recognized, in future years, would increase the effective tax rate	$ 23	$ 20	$ 24