| Document and Entity Information - USD ($) $ in Thousands | 12 Months Ended | ||
| Sep. 30, 2018 | Nov. 29, 2018 | Mar. 31, 2018 | |
| Document Information [Line Items] | |||
| Entity Registrant Name | Washington Gas Light Company | ||
| Entity Central Index Key | 104,819 | ||
| Document Type | 10-K/A | ||
| Document Period End Date | Sep. 30, 2018 | ||
| Amendment Flag | true | ||
| Document Fiscal Year Focus | 2,018 | ||
| Document Fiscal Period Focus | FY | ||
| Current Fiscal Year End Date | --09-30 | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Public Float | $ 0 | ||
| Entity Common Stock, Shares Outstanding | 46,479,536 | ||
| Entity Emerging Growth Company | false | ||
| Entity Small Business | false | ||
| Entity Shell Company | false | ||
| Amendment Description | <div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">WGL Holdings, Inc. (WGL) and Washington Gas Light Company (Washington Gas) are filing this Amendment No. 1 (“Form 10-K/A”) to their Annual Report on Form 10-K (“Form 10-K”) for the fiscal year ended September 30, 2018 filed with the Securities and Exchange Commission on November 20, 2018, solely to amend Exhibit 23, the Consent of Deloitte & Touche LLP. The companies are amending their Form 10-K filing due to a typographical error with respect to the date contained in the consent included in the original filing, which referenced the incorrect date of the audit opinion. There are no other changes to the Form 10-K or the consent.</font></div></div>" id="sjs-B21"><div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">WGL Holdings, Inc. (WGL) and Washington Gas Light Company (Washington Gas) are filing this Amendment No. 1 (“Form 10-K/A”) to their Annual Report on Form 10-K (“Form 10-K”) for the fiscal year ended September 30, 2018 filed with the Securities and Exchange Commission on November 20, 2018, solely to amend Exhibit 23, the Consent of Deloitte & Touche LLP. The companies are amending their Form 10-K filing due to a typographical error with respect to the date contained in the consent included in the original filing, which referenced the incorrect date of the audit opinion. There are no other changes to the Form 10-K or the consent.</font></div></div> |
