Entity Information (USD $)	6 Months Ended
	Mar. 31, 2012	Apr. 26, 2012	Mar. 31, 2011
Entity Registrant Name	Laclede Gas Company
Entity Central Index Key	0000057183
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		11,746
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q2