INFORMATION BY OPERATING SEGMENT (Tables)

12 Months Ended

Sep. 30, 2017

Segment Reporting [Abstract]

Schedule of operating segment information

	Gas Utility		Gas Marketing		Other			Eliminations			Consolidated
2017
Revenues from external customers	$	1,660.0	$	79.3	$	1.4		$	—		$	1,740.7
Intersegment revenues	7.9		—		6.3			(14.2		)	—
Total Operating Revenues	1,667.9		79.3		7.7			(14.2		)	1,740.7
Operating Expenses
Gas Utility
Natural and propane gas	645.9		—		—			(75.4		)	570.5
Other operation and maintenance	409.1		—		—			(4.1		)	405.0
Depreciation and amortization	153.5		—		—			—			153.5
Taxes, other than income taxes	137.8		—		—			—			137.8
Total Gas Utility Operating Expenses	1,346.3		—		—			(79.5		)	1,266.8
Gas Marketing and Other *	—		74.1		12.8			65.3			152.2
Total Operating Expenses	1,346.3		74.1		12.8			(14.2		)	1,419.0
Operating Income (Loss)	$	321.6	$	5.2	$	(5.1	)	$	—		$	321.7
Net Economic Earnings (Loss)	$	181.5	$	6.8	$	(20.7	)	$	—		$	167.6
Capital Expenditures	$	412.6	$	—	$	25.5		$	—		$	438.1

	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		12.6			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		12.6			(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

* Operating Expenses for “Gas Marketing and Other” include depreciation and amortization for Gas Marketing ($0.1 for 2017, $0.1 for 2016, and $0.3 for 2015) and for Other ($0.5 for 2017, $0.5 for 2016, and $0.6 for 2015).

Total Assets at End of Year	2017			2016			2015
Gas Utility	$	5,551.2		$	5,184.7		$	4,679.3
Gas Marketing	246.2			205.0			160.6
Other	2,239.5			1,836.6			1,554.5
Eliminations	(1,490.2		)	(1,161.9		)	(1,116.8		)
Total Assets	$	6,546.7		$	6,064.4		$	5,277.6

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

Reconciliation of Consolidated Net Income to Consolidated Net Economic Earnings	2017			2016			2015
Net Income	$	161.6		$	144.2		$	136.9
Adjustments, pre-tax:
Unrealized loss (gain) on energy-related derivatives	6.0			(0.1		)	(2.8		)
Lower of cost or market inventory adjustments	—			0.2			0.4
Realized (gain) loss on economic hedges prior      to the sale of the physical commodity	(0.3		)	(1.6		)	2.4
Acquisition, divestiture and restructuring activities	4.0			9.2			9.8
Gain on sale of property	—			—			(7.6		)
Income tax effect of adjustments	(3.7		)	(2.8		)	(0.8		)
Net Economic Earnings	$	167.6		$	149.1		$	138.3