OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (169)	$ (143)	[1]
Equity earnings (losses), before income tax	3	(22)	[1]
Equity (losses) earnings, net of income tax	(8)	17	[1]
Revenues: Energy-Related Businesses	333	180	[1]
Income before income taxes and equity (losses) earnings of certain unconsolidated subsidiaries	755	455	[1]
Income Tax Expense	(295)	(108)	[1]
Earnings Attributable to Noncontrolling Interests	(11)	(11)	[1]
Earnings (losses)	441	353	[1]
Total reclassifications for the period	8	(1)
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	6	(2)
Gain (Loss) on Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI	3	2
Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	(1)	(1)
Total reclassifications for the period	2	1
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 (losses) earnings of certain unconsolidated subsidiaries	12	1
Income Tax Expense	(4)	0
Net of income tax	8	1
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	(3)	4
Equity (losses) earnings, net of income tax	2	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues: Energy-Related Businesses	2	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 (losses), before income tax	2	3
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	9	(7)
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	(2)	(3)
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)	6	(2)
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(49)	(48)	[1]
Income before income taxes and equity (losses) earnings of certain unconsolidated subsidiaries	247	202	[1]
Income Tax Expense	(90)	(65)	[1]
Earnings Attributable to Noncontrolling Interests	(2)	(1)	[1]
Total reclassifications for the period	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
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)

[1] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.