INFORMATION BY OPERATING SEGMENT (Tables)

12 Months Ended

Sep. 30, 2016

Segment Reporting [Abstract]

Schedule of operating segment information

	Gas Utility		Gas Marketing			Other				Eliminations			Consolidated
2016
Revenues from external customers	$	1,457.2	$	78.5		$	1.6			$	—		$	1,537.3
Intersegment revenues	2.2		—			3.2				(5.4		)	—
Total Operating Revenues	1,459.4		78.5			4.8				(5.4		)	1,537.3
Operating Expenses
Gas Utility
Natural and propane gas	539.7		—			—				(47.5		)	492.2
Other operation and maintenance	379.3		—			—				(1.8		)	377.5
Depreciation and amortization	136.9		—			—				—			136.9
Taxes, other than income taxes	125.2		—			—				—			125.2
Total Gas Utility Operating Expenses	1,181.1		—			—				(49.3		)	1,131.8
Gas Marketing and Other	—		66.7		(a)	12.6			(b)	43.9			123.2
Total Operating Expenses	1,181.1		66.7			12.6				(5.4		)	1,255.0
Operating Income (Loss)	278.3		11.8			(7.8		)		—			282.3
Net Economic Earnings (Loss)	160.3		6.4			(17.6		)		—			149.1
Capital Expenditures	291.7		—			1.6				—			293.3

	Gas Utility		Gas Marketing			Other				Eliminations			Consolidated
2015
Revenues from external customers	$	1,891.8	$	82.9		$	1.7			$	—		$	1,976.4
Intersegment revenues	4.0		70.5			2.0				(76.5		)	—
Total Operating Revenues	1,895.8		153.4			3.7				(76.5		)	1,976.4
Operating Expenses
Gas Utility
Natural and propane gas	957.6		—			—				(75.2		)	882.4
Other operation and maintenance	391.6		—			—				(1.0		)	390.6
Depreciation and amortization	129.9		—			—				—			129.9
Taxes, other than income taxes	142.1		—			—				—			142.1
Total Gas Utility Operating Expenses	1,621.2		—			—				(76.2		)	1,545.0
Gas Marketing and Other	—		146.6		(a)	12.6			(b)	(0.3		)	158.9
Total Operating Expenses	1,621.2		146.6			12.6				(76.5		)	1,703.9
Operating Income (Loss)	274.6		6.8			(8.9		)		—			272.5
Net Economic Earnings (Loss)	150.4		4.2			(16.3		)		—			138.3
Capital Expenditures	284.4		—			5.4				—			289.8

	Gas Utility		Gas Marketing			Other				Eliminations			Consolidated
2014
Revenues from external customers	$	1,462.6	$	162.6		$	2.0			$	—		$	1,627.2
Intersegment revenues	5.2		84.0			1.8				(91.0		)	—
Total Operating Revenues	1,467.8		246.6			3.8				(91.0		)	1,627.2
Operating Expenses
Gas Utility
Natural and propane gas	821.8		—			—				(90.1		)	731.7
Other operation and maintenance	288.7		—			—				(0.9		)	287.8
Depreciation and amortization	82.4		—			—				—			82.4
Taxes, other than income taxes	112.0		—			—				—			112.0
Total Gas Utility Operating Expenses	1,304.9		—			—				(91.0		)	1,213.9
Gas Marketing and Other	—		226.4		(a)	20.5			(b)	—			246.9
Total Operating Expenses	1,304.9		226.4			20.5				(91.0		)	1,460.8
Operating Income (Loss)	162.9		20.2			(16.7		)		—			166.4
Net Economic Earnings (Loss)	92.8		10.2			(2.9		)		—			100.1
Capital Expenditures	168.6		—			2.4				—			171.0

(a) Depreciation and amortization for Gas Marketing are included in Gas Marketing Expenses on the Consolidated Statements of Income ($0.1 for 2016, $0.3 for 2015, and $0.4 for 2014).

(b) Depreciation, amortization, and accretion for Other are included in the Other Operating Expenses on the Consolidated Statements of Income ($0.5 for 2016, $0.6 for 2015, and $0.5 for 2014).

Total Assets at End of Year	2016			2015			2014
Gas Utility	$	5,191.9		$	4,686.2		$	4,520.0
Gas Marketing	205.0			160.6			156.7
Other	1,842.4			1,560.2			1,575.7
Eliminations	(1,161.9		)	(1,116.8		)	(1,178.4		)
Total Assets	$	6,077.4		$	5,290.2		$	5,074.0

Schedule of the reconciliation of consolidated net economic earnings to consolidated net income

Reconciliation of Consolidated Net Income to Consolidated Net Economic Earnings	2016			2015			2014
Net Income (GAAP)	$	144.2		$	136.9		$	84.6
Unrealized gain on energy-related derivatives	(0.1		)	(2.8		)	(1.6		)
Lower of cost or market inventory adjustments	0.2			0.4			(1.1		)
Realized (gain) loss on economic hedges prior      to the sale of the physical commodity	(1.6		)	2.4			(0.4		)
Acquisition, divestiture and restructuring activities	9.2			9.8			29.5
Gain on sale of property	—			(7.6		)	—
Income tax effect of adjustments	(2.8		)	(0.8		)	(10.9		)
Net Economic Earnings	$	149.1		$	138.3		$	100.1