SAN ONOFRE NUCLEAR GENERATING STATION (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Jointly Owned Utility Plant Interests [Line Items]
Anticipated term of dismantlement work	10 years
San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Percent of dismantlement work expense (as a percent)	20.00%
ARO related to decommissioning costs	$ 566
Cost study estimate decommissioning escalated	$ 886
Jointly Owned Nuclear Power Plant [Member] \| San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, proportionate ownership share (as a percent)	20.00%
SONGS 2 and 3 Decommissioning [Member] \| San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Nuclear decommissioning trust authorized withdrawal amount		$ 89

Authorized Recovery Amount, Nuclear Decommissioning Trust Funding.

No definition available.

Name:	sre_AuthorizedRecoveryAmountNuclearDecommissioningTrustFunding
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total Estimated Nuclear Decommissioning Costs, Latest Cost Study Escalated.

+ References

No definition available.

+ Details

Name:	sre_CostStudyEstimateDecommissioningEscalated
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Decommissioning Liability

+ References

No definition available.

+ Details

Name:	sre_DecommissioningLiability
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Environmental Exit Costs, Anticipated Cost, Percentage

+ References

No definition available.

+ Details

Name:	sre_EnvironmentalExitCostsAnticipatedCostPercentage
Namespace Prefix:	sre_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Environmental Exit Costs, Anticipated Term

+ References

No definition available.

+ Details

Name:	sre_EnvironmentalExitCostsAnticipatedTerm
Namespace Prefix:	sre_
Data Type:	xbrli:durationItemType
Balance Type:	na
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_JointlyOwnedUtilityPlantInterestsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-URI http://asc.fasb.org/extlink&oid=115995737&loc=d3e659983-123033

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=us-gaap_JointlyOwnedNuclearPowerPlantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=sre_SONGS2and3DecommissioningMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: