OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (136)	$ (143)	$ (421)	$ (416)
Equity earnings, before income tax	12	33	4	79
Remeasurement of equity method investment	617	0	617	0
Equity earnings, net of income tax	19	27	69	64
Revenues: Energy-Related Businesses	271	268	613	762
Income before income taxes and equity earnings of certain unconsolidated subsidiaries	982	270	1,325	1,272
Income Tax Expense	(282)	(15)	(284)	(276)
Earnings Attributable to Noncontrolling Interests	(97)	(34)	(118)	(79)
Earnings (losses)	622	248	991	980
Total reclassifications for the period, net of tax	7	6	12	9
Gains (Losses) on Cash Flow hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	5	1	8	2
Gain (Loss) on Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI	4	7	8	11
Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	(2)	(2)	(4)	(4)
Total reclassifications for the period, net of tax	2	5	4	7
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes and equity earnings of certain unconsolidated subsidiaries	12	5	23	13
Income Tax Expense	(3)	(1)	(4)	(1)
Net of income tax	9	4	19	12
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate and foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	4	5	11	14
Remeasurement of equity method investment	7	0	7	0
Equity earnings, net of income tax	(2)	0	4	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Equity earnings, before income tax	3	3	8	9
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Commodity contracts not subject to rate recovery [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues: Energy-Related Businesses	0	(3)	(7)	(10)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Noncontrolling Interests [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings Attributable to Noncontrolling Interests	(4)	(3)	(11)	(10)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings (losses)	5	1	8	2
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(49)	(51)	(145)	(155)
Income before income taxes and equity earnings of certain unconsolidated subsidiaries	285	257	622	680
Income Tax Expense	(91)	(75)	(204)	(217)
Earnings Attributable to Noncontrolling Interests	(11)	(12)	1	(20)
Total reclassifications for the period, net of tax	0	0	0	0
San Diego Gas and Electric Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	3	3	9	9
San Diego Gas and Electric Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Noncontrolling Interests [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings Attributable to Noncontrolling Interests	(3)	(3)	(9)	(9)
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(25)	(23)	(71)	(61)
Income before income taxes and equity earnings of certain unconsolidated subsidiaries	21	(28)	274	368
Income Tax Expense	(21)	20	(75)	(91)
Total reclassifications for the period, net of tax	1	0	1	0
Southern California Gas Company [Member] | Gains (Losses) on Cash Flow hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	1		1
Southern California Gas Company [Member] | Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	0		0
Southern California Gas Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 1	$ 0	$ 1	$ 0