COMMITMENTS AND CONTINGENCIES - OTHER LITIGATION (Details) £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Oct. 01, 2015 GBP (£)	Oct. 01, 2014 GBP (£)
Wind Farm [Member] | San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Estimated Tax Equity Investment	$ 285
So Cal Gas PCB Litigation [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number Of Lawsuits	7
Number of Lawsuits Settled	6
Mobile Gas Litigation [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number Of Lawsuits	14
Number of Lawsuits Settled	11
Loss Contingency Number Of Plaintiffs	250
HMRC VAT Claim [Member]
Loss Contingencies [Line Items]
VAT Tax Claim Paid Upon Appeal | £		£ 156	£ 86
Investment in RBS Sempra Commodities LLP	$ 67