CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER'S EQUITY (UNAUDITED) (USD $) In Millions, except Share data, unless otherwise specified	Total	Common Stock Issued	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Laclede Gas	Laclede Gas Common Stock Issued	Laclede Gas Paid-in Capital	Laclede Gas Retained Earnings	Laclede Gas Accumulated Other Comprehensive Income/(Loss)	Alagasco	Alagasco Common Stock Issued	Alagasco Paid-in Capital	Alagasco Retained Earnings
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)	$ 364.8	$ 0	$ 34.5	$ 330.3
BALANCE (in shares) at Sep. 30, 2013		32,696,836					24,549					1,972,052
Stockholders' Equity Rollforward
Net Income	35.6			35.6		35.3			35.3		19.8			19.8
Issuance of common stock to Laclede Group (in shares)							9
Issuance of common stock to Laclede						0.4		0.4
Dividend reinvestment plan	0.4		0.4
Dividend reinvestment plan (in shares)		8,129
Stock-based compensation costs	0.5		0.5			0.4		0.4
Equity Incentive Plan	0.4	0.1	0.3
Equity Incentive Plan (in shares)		46,290
Employees’ taxes paid associated with restricted shares withheld upon vesting	(1.1)		(1.1)
Tax benefit - stock compensation	0.4		0.4			0.4		0.4
Dividends declared:
Common stock	(14.4)			(14.4)		(14.4)			(14.4)
Other comprehensive loss, net of tax	(1.7)				(1.7)	0
BALANCE at Dec. 31, 2013	1,066.4	32.8	594.8	441.3	(2.5)	996.0	0.1	739.3	258.7	(2.1)	384.6	0	34.5	350.1
BALANCE (in shares) at Dec. 31, 2013		32,751,255					24,558					1,972,052
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	503.9	345.7
BALANCE (in shares) at Sep. 30, 2014		43,178,405					24,577					1,972,052
Stockholders' Equity Rollforward
Net Income	47.1			47.1		39.0			39.0		10.6			10.6
Dividend reinvestment plan	0.4		0.4
Dividend reinvestment plan (in shares)		8,199
Stock-based compensation costs	(2.0)		(2.0)			0.9		0.9
Equity Incentive Plan	2.8	0.1	2.7
Equity Incentive Plan (in shares)		102,534
Tax benefit - stock compensation	0.5		0.5			0.4		0.4
Dividends declared:
Common stock	(20.0)			(20.0)		(19.9)			(19.9)
Other comprehensive loss, net of tax	(3.7)				(3.7)	(0.8)				(0.8)
BALANCE at Dec. 31, 2014	$ 1,533.5	$ 43.3	$ 1,031.0	$ 464.6	$ (5.4)	$ 1,027.4	$ 0.1	$ 745.3	$ 284.7	$ (2.7)	$ 860.2	$ 0	$ 503.9	$ 356.3
BALANCE (in shares) at Dec. 31, 2014		43,289,138					24,577					1,972,052