OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (159)	$ (142)	[1]	$ (328)	$ (285)	[1]
Equity earnings (losses), before income tax	18	14	[1]	21	(8)	[1]
Equity earnings (losses), net of income tax	0	33	[1]	(8)	50	[1]
Revenues: Energy-Related Businesses	336	162	[1]	669	342	[1]
Income before income taxes and equity (losses) earnings of certain unconsolidated subsidiaries	415	(112)	[1]	1,170	343	[1]
Income Tax (Expense) Benefit	(167)	106	[1]	(462)	(2)	[1]
Losses (Earnings) Attributable to Noncontrolling Interests	12	(10)	[1]	1	(21)	[1]
Earnings (losses)	259	16	[1]	700	369	[1]
Total reclassifications for the period	1	6		9	5
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	0	5		6	3
Gain (Loss) on Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI	2	2		5	4
Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	(1)	(1)		(2)	(2)
Total reclassifications for the period	1	1		3	2
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	3	10		15	11
Income Tax (Expense) Benefit	(1)	(1)		(5)	(1)
Net of income tax	2	9		10	10
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	(1)	3		(4)	7
Equity earnings (losses), net of income tax	3	5		5	6
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	(1)	0		1	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	2		4	5
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]
Losses (Earnings) Attributable to Noncontrolling Interests	(2)	(4)		(4)	(7)
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)	0	5		6	3
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(49)	(48)		(98)	(96)	[1]
Income before income taxes and equity (losses) earnings of certain unconsolidated subsidiaries	207	135		454	337	[1]
Income Tax (Expense) Benefit	(54)	(48)		(144)	(113)	[1]
Losses (Earnings) Attributable to Noncontrolling Interests	(4)	13		(6)	12	[1]
Total reclassifications for the period	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		6	6
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]
Losses (Earnings) Attributable to Noncontrolling Interests	(3)	(3)		(6)	(6)
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(26)	(24)		(51)	(46)	[1]
Income before income taxes and equity (losses) earnings of certain unconsolidated subsidiaries	78	(29)		379	253	[1]
Income Tax (Expense) Benefit	(19)	29		(117)	(54)	[1]
Total reclassifications for the period	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	0			0
Southern California Gas Company [Member] | Gain (Loss) on Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI	1	$ 0		1	$ 0
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	$ 1			$ 1

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