Audit Information	12 Months Ended
Dec. 31, 2021
Auditor [Line Items]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Las Vegas, Nevada
Auditor Firm ID	238
Southwest Gas Corporation
Auditor [Line Items]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Las Vegas, Nevada
Auditor Firm ID	238

PCAOB issued Audit Firm Identifier

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form 10-K
-Number 249
-Section 310

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form 20-F
-Number 249
-Section 220
-Subsection f

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form 40-F
-Number 249
-Section 240
-Subsection f

Name:	dei_AuditorFirmId
Namespace Prefix:	dei_
Data Type:	dei:nonemptySequenceNumberItemType
Balance Type:	na
Period Type:	duration