FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Jun. 30, 2017

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair value of financial instruments

The carrying amounts and estimated fair values of financial instruments not measured at fair value on a recurring basis are shown below and classified according to the fair value hierarchy. There were no such instruments classified as Level 3 (significant unobservable inputs) as of June 30, 2017, September 30, 2016, or June 30, 2016.

		Classification of Estimated Fair Value
Carrying Amount	Fair Value	Quoted Prices in Active Markets (Level 1)	Significant Observable Inputs (Level 2)

Spire

As of June 30, 2017
Cash and cash equivalents	$	8.3	$	8.3	$	8.3	$	—
Short-term debt	450.7		450.7		—		450.7
Long-term debt	1,925.3		2,033.0		—		2,033.0
As of September 30, 2016
Cash and cash equivalents	$	5.2	$	5.2	$	5.2	$	—
Short-term debt	398.7		398.7		—		398.7
Long-term debt, including current portion	2,070.7		2,257.1		—		2,257.1
As of June 30, 2016
Cash and cash equivalents	$	4.9	$	4.9	$	4.9	$	—
Short-term debt	97.6		97.6		—		97.6
Long-term debt	1,839.8		2,014.3		—		2,014.3

Laclede Gas

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair value of financial instruments

As of June 30, 2017
Cash and cash equivalents	$	2.6	$	2.6	$	2.6	$	—
Short-term debt	260.2		260.2		—		260.2
Long-term debt	804.5		883.9		—		883.9
As of September 30, 2016
Cash and cash equivalents	$	2.1	$	2.1	$	2.1	$	—
Short-term debt	243.7		243.7		—		243.7
Long-term debt	804.1		900.4		—		900.4
As of June 30, 2016
Cash and cash equivalents	$	1.5	$	1.5	$	1.5	$	—
Short-term debt	136.4		136.4		—		136.4
Long-term debt	803.9		901.8		—		901.8

Alagasco

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair value of financial instruments

					Classification of Estimated Fair Value
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)
Alagasco
As of June 30, 2017
Cash and cash equivalents	$	0.1	$	0.1	$	0.1	$	—
Short-term debt	114.9		114.9		—		114.9
Long-term debt	247.7		267.6		—		267.6
As of September 30, 2016
Short-term debt	$	82.0	$	82.0	$	—	$	82.0
Long-term debt	247.6		275.5		—		275.5
As of June 30, 2016
Short-term debt	$	37.8	$	37.8	$	—	$	37.8
Long-term debt	247.6		272.5		—		272.5