COMMITMENTS AND CONTINGENCIES - LONG-TERM PURCHASE COMMITMENT (Details)		1 Months Ended		12 Months Ended
	Mar. 13, 2017 USD ($)	May 31, 2017 USD ($)	May 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2011 USD ($) MMcf
Long-term Purchase Commitment [Line Items]
Litigation settlement payable	$ 118,000,000
Sempra LNG & Midstream [Member]
Long-term Purchase Commitment [Line Items]
Loss on release of pipeline capacity			$ 206,000,000
Litigation settlement payable		$ 57,000,000	47,000,000
San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Litigation settlement payable	$ 24,000,000
Sempra LNG & Midstream [Member]
Long-term Purchase Commitment [Line Items]
Loss on release of pipeline capacity			206,000,000
Loss on release of pipeline capacity net of tax			$ 123,000,000
Natural Gas Contracts [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				$ 292,000,000
2019				146,000,000
2020				48,000,000
2021				47,000,000
2022				45,000,000
Thereafter				127,000,000
Total Contractual Commitments				705,000,000
Purchases				1,429,000,000	$ 1,169,000,000	$ 1,200,000,000
Natural Gas Contracts [Member] | SoCalGas [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				108,000,000
2019				59,000,000
2020				29,000,000
2021				28,000,000
2022				28,000,000
Thereafter				81,000,000
Total Contractual Commitments				333,000,000
Purchases				1,213,000,000	966,000,000	975,000,000
Natural Gas Storage and Transportation Contracts [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				231,000,000
2019				146,000,000
2020				48,000,000
2021				46,000,000
2022				44,000,000
Thereafter				127,000,000
Total Contractual Commitments				642,000,000
Natural Gas Transportation Contracts [Member] | SoCalGas [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				108,000,000
2019				59,000,000
2020				29,000,000
2021				27,000,000
2022				27,000,000
Thereafter				81,000,000
Total Contractual Commitments				331,000,000
Natural Gas Supply Contracts [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				61,000,000
2019				0
2020				0
2021				1,000,000
2022				1,000,000
Thereafter				0
Total Contractual Commitments				63,000,000
Natural Gas Supply Contracts [Member] | SoCalGas [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				0
2019				0
2020				0
2021				1,000,000
2022				1,000,000
Thereafter				0
Total Contractual Commitments				2,000,000
Purchased Power Contracts [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				702,000,000
2019				690,000,000
2020				631,000,000
2021				633,000,000
2022				598,000,000
Thereafter				5,726,000,000
Total Contractual Commitments				8,980,000,000
Purchases				1,694,000,000	1,667,000,000	1,573,000,000
Purchased Power Contracts [Member] | SDG&E [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				577,000,000
2019				571,000,000
2020				510,000,000
2021				510,000,000
2022				496,000,000
Thereafter				5,457,000,000
Total Contractual Commitments				8,121,000,000
Purchases				781,000,000	752,000,000	715,000,000
Sunrise Powerlink Construction [Member] | SDG&E [Member]
Other Commitment, Fiscal Year Maturity [Abstract]
2018				3,000,000
2019				3,000,000
2020				3,000,000
2021				3,000,000
2022				3,000,000
Thereafter				104,000,000
Total Commitment				$ 119,000,000
Annual estimated escalation percentage				2.00%
Commitment period				52 years
Present value of future payments				$ 119,000,000
Continental Forge [Member] | Sempra LNG & Midstream [Member]
Other Commitment, Fiscal Year Maturity [Abstract]
Commitment period							18 years
Amount of Natural Gas to be Sold | MMcf							500
Reduction in price index							$ 0.02
Liquefied Natural Gas Contracts [Member] | Sempra LNG & Midstream [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				302,000,000
2019				383,000,000
2020				391,000,000
2021				403,000,000
2022				411,000,000
Thereafter				2,935,000,000
Total Contractual Commitments				4,825,000,000
Nuclear Plant Maintenance [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment				10,000,000
Infrastructure Construction And Improvements [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				257,000,000
2019				62,000,000
2020				44,000,000
2021				24,000,000
2022				16,000,000
Thereafter				124,000,000
Total Contractual Commitments				527,000,000
Infrastructure Construction And Improvements [Member] | San Diego Gas and Electric Company [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				1,000,000
2019				1,000,000
2020				1,000,000
Infrastructure Construction And Improvements [Member] | California Utilities [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
Total Contractual Commitments				10,000,000
Infrastructure Construction And Improvements [Member] | Southern California Gas Company [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				3,000,000
2019				2,000,000
2020				2,000,000
Infrastructure Construction And Improvements [Member] | SDG&E [Member]
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment				117,000,000
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				78,000,000
2019				9,000,000
2020				19,000,000
2021				5,000,000
2022				1,000,000
Thereafter				5,000,000
Infrastructure Construction And Improvements [Member] | Sempra South American Utilities [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				16,000,000
Infrastructure Improvements For Natural Gas And Electric Transmission And Distribution [Member] | SDG&E [Member]
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment				$ 72,000,000
Long-term Contracts [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Purchase Commitment Component Percentage				43.00%
Other Owned Generation [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Purchase Commitment Component Percentage				56.00%
Spot Market Purchases [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Purchase Commitment Component Percentage				1.00%
Renewable Energy Contracts Expiring Through 2041 [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Purchase Commitment Component Percentage				37.00%
Sempra Renewables Construction [Member] | Sempra Renewables [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				$ 80,000,000
2019				4,000,000
2020				3,000,000
2021				2,000,000
Total Contractual Commitments				89,000,000
Sempra Natural Gas Construction [Member] | Sempra LNG & Midstream [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				6,000,000
San Luis Rey Synchronous Condensor And Bay Boulevard Substation [Member] | SDG&E [Member]
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment				35,000,000
Pipelines [Member] | Sempra Mexico [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
2018				73,000,000
2019				46,000,000
2020				19,000,000
2021				17,000,000
2022				15,000,000
Thereafter				119,000,000
Total Contractual Commitments				289,000,000
Renewable Energy PPAs [Member] | SDG&E [Member]
Unrecorded Unconditional Purchase Obligation, Rolling Maturity [Abstract]
Total Contractual Commitments				5,400,000,000
Power Purchase Agreements [Member]
Long-term Purchase Commitment [Line Items]
2018				192,000,000
Power Purchase Agreements [Member] | San Diego Gas and Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Capital lease depreciation expense				$ 8,000,000	$ 4,000,000	$ 4,000,000