COMMITMENTS AND CONTINGENCIES - LESSOR INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Fixed lease payments	$ 53	$ 50
San Diego Gas and Electric Company [Member]
Lessee, Lease, Description [Line Items]
Lease not yet commenced, 2021	3
Lease not yet commenced, 2022	10
Lease not yet commenced, 2023	10
Lease not yet commenced, 2024	10
Lease not yet commenced, 2025	10
Lease not yet commenced, thereafter	101
Assets Leased to Others [Member]
Lessee, Lease, Description [Line Items]
Depreciation expense	$ 10	$ 10

Lessor, Operating Lease, Lease Not Yet Commenced, After Year Four

No definition available.

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedAfterYearFour
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessor, Operating Lease, Lease Not Yet Commenced, Remainder of Fiscal Year

+ References

No definition available.

+ Details

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedRemainderOfFiscalYear
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessor, Operating Lease, Lease Not Yet Commenced, Year Four

+ References

No definition available.

+ Details

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedYearFour
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessor, Operating Lease, Lease Not Yet Commenced, Year One

+ References

No definition available.

+ Details

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedYearOne
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessor, Operating Lease, Lease Not Yet Commenced, YearThree

+ References

No definition available.

+ Details

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedYearThree
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessor, Operating Lease, Lease Not Yet Commenced, Year Two

+ References

No definition available.

+ Details

Name:	sre_LessorOperatingLeaseLeaseNotYetCommencedYearTwo
Namespace Prefix:	sre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

Name:	us-gaap_Depreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_LesseeLeaseDescriptionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of operating lease income from lease payments paid and payable to lessor. Excludes variable lease payments not included in measurement of lease receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 6A
-URI http://asc.fasb.org/extlink&oid=121640914&loc=SL77927221-108306

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919372-209981

+ Details

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

- Details

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

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_AssetsLeasedToOthersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: