DERIVATIVE FINANCIAL INSTRUMENTS - CASH FLOW HEDGES (Details) $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on cash flow hedges to be reclassified from AOCI within 12 months	$ 15
Maximum remaining term of cash flow hedges	13 years
Equity Method Investee [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum remaining term of cash flow hedges	17 years
San Diego Gas and Electric Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum remaining term of cash flow hedges	1 year
Southern California Gas Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on cash flow hedges to be reclassified from AOCI within 12 months	$ (1)
Noncontrolling Interest [Member] \| Otay Mesa VIE [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on cash flow hedges to be reclassified from AOCI within 12 months	$ (4)

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

+ Details

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum period the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

+ Details

Name:	us-gaap_MaximumLengthOfTimeHedgedInInterestRateCashFlowHedge1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_EquityMethodInvesteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=sre_SanDiegoGasAndElectricCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=sre_SouthernCaliforniaGasCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=sre_OtayMesaVieMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: