ACQUISITION AND DIVESTITURE ACTIVITY - ASSETS HELD FOR SALE (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	9 Months Ended
	Feb. 29, 2016 MW	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)
Assets Held for Sale [Line Items]
Impairment of equity method investment				$ 131
Impairment of equity method investment after-tax				111
Sempra Mexico [Member] | TdM [Member]
Assets Held for Sale [Line Items]
Power generating capacity | MW	625
Impairment of equity method investment		$ 131
Impairment of equity method investment after-tax		111
Deferred tax expense from the outside basis difference			$ 32
Deferred Tax Benefit From The Outside Basis Difference		31
Sempra Mexico [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | TdM [Member]
Assets Held for Sale, Assets [Abstract]
Cash and cash equivalents		1		1
Inventories		8		8
Other current assets		25		25
Deferred income taxes		5		5
Other assets		22		22
Property, plant and equipment, net		120		120
Total assets held for sale		181		181
Assets Held for Sale, Liabilities [Abstract]
Accounts payable		1		1
Other current liabilities		7		7
Asset retirement obligations		4		4
Other liabilities		23		23
Total liabilities held for sale		$ 35		$ 35