CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER'S EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Common Stock Issued	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Laclede Gas	Laclede Gas Common Stock Issued	Laclede Gas Paid-in Capital	Laclede Gas Retained Earnings	Laclede Gas Accumulated Other Comprehensive Loss	Alagasco	Alagasco Common Stock Issued	Alagasco Paid-in Capital	Alagasco Retained Earnings
Beginning Balance at Sep. 30, 2013	$ 1,046.3	$ 32.7	$ 594.3	$ 420.1	$ (0.8)	$ 973.9	$ 0.1	$ 738.1	$ 237.8	$ (2.1)	$ 364.7	$ 0.0	$ 34.5	$ 330.2
Beginning Balance, Shares at Sep. 30, 2013		32,696,836					24,549					1,972,052
Stockholders' Equity Rollforward
Common stock offering (in shares)		10,350,000					28
Common stock offering	457.1	$ 10.4	446.7			1.1		1.1
Equity units offering	(19.7)		(19.7)
Net Income	99.5			99.5		91.5			91.5		62.3			62.3
Dividend reinvestment plan (in shares)		25,548
Dividend reinvestment plan	1.1		1.1
Stock-based compensation costs	4.2		4.2			3.1		3.1
Equity Incentive Plan (in shares)		86,715
Equity Incentive Plan	1.5	$ 0.1	1.4
Employees’ taxes paid associated with restricted shares withheld upon vesting	(1.1)		(1.1)
Tax benefit - stock compensation	0.6		0.6			0.5		0.5
Dividends declared	(48.0)			(48.0)		(43.2)			(43.2)		(21.6)			(21.6)
Other comprehensive loss, net of tax	(7.7)				(7.7)	0.1				0.1
Ending Balance at Jun. 30, 2014	1,533.8	$ 43.2	1,027.5	471.6	(8.5)	1,027.0	$ 0.1	742.8	286.1	(2.0)	405.4	$ 0.0	34.5	370.9
Ending Balance, Shares at Jun. 30, 2014		43,159,099					24,577					1,972,052
Beginning Balance at Sep. 30, 2014	1,508.4	$ 43.2	1,029.4	437.5	(1.7)	1,007.8	$ 0.1	744.0	265.6	(1.9)	849.6	$ 0.0	503.9	345.7
Beginning Balance, Shares at Sep. 30, 2014		43,178,405					24,577					1,972,052
Stockholders' Equity Rollforward
Net Income	155.6			155.6		108.9			108.9		57.6			57.6
Dividend reinvestment plan (in shares)		6,999
Dividend reinvestment plan	1.2		1.2
Stock-based compensation costs	1.4		1.4			2.7		2.7
Equity Incentive Plan (in shares)		131,409
Equity Incentive Plan	3.1	$ 0.1	3.0
Tax benefit - stock compensation	0.6		0.6			0.5		0.5
Dividends declared	(60.2)			(60.2)		(59.7)			(59.7)
Other comprehensive loss, net of tax	(1.5)				(1.5)	(0.1)				(0.1)
Purchase accounting adjustments											4.2		4.2
Return of capital to Laclede Group											(27.0)		(27.0)
Ending Balance at Jun. 30, 2015	$ 1,608.6	$ 43.3	$ 1,035.6	$ 532.9	$ (3.2)	$ 1,060.1	$ 0.1	$ 747.2	$ 314.8	$ (2.0)	$ 884.4	$ 0.0	$ 481.1	$ 403.3
Ending Balance, Shares at Jun. 30, 2015		43,316,813					24,577					1,972,052