DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE NOTIONALS (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Jan. 31, 2016
Other foreign currency derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 914		$ 550
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 753	$ 384
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2016	Dec. 31, 2016
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2028	Dec. 31, 2028
Fair Value Hedging [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 0	$ 300
Maturity date		Dec. 31, 2016
Sempra Mexico [Member] | Cross currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 408	$ 408
Sempra Mexico [Member] | Cross currency swaps [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2016	Dec. 31, 2016
Sempra Mexico [Member] | Cross currency swaps [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2023	Dec. 31, 2023
Sempra Mexico [Member] | Other foreign currency derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 1,481	$ 0
Sempra Mexico [Member] | Other foreign currency derivatives [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2016
Sempra Mexico [Member] | Other foreign currency derivatives [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2018
San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 307	$ 315
San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2016	Dec. 31, 2016
San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity date	Dec. 31, 2019	Dec. 31, 2019