FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of 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)

Spire

As of June 30, 2018
Cash and cash equivalents	$	6.9	$	6.9	$	6.9	$	—
Short-term debt	191.0		191.0		—		191.0
Long-term debt, including current portion	2,180.0		2,173.7		—		2,173.7
As of September 30, 2017
Cash and cash equivalents	$	7.4	$	7.4	$	7.4	$	—
Short-term debt	477.3		477.3		—		477.3
Long-term debt, including current portion	2,095.0		2,210.3		—		2,210.3
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

Spire Missouri

As of June 30, 2018
Cash and cash equivalents	$	3.5	$	3.5	$	3.5	$	—
Short-term debt	128.6		128.6		—		128.6
Long-term debt, including current portion	974.2		1,005.0		—		1,005.0
As of September 30, 2017
Cash and cash equivalents	$	2.5	$	2.5	$	2.5	$	—
Short-term debt	203.0		203.0		—		203.0
Long-term debt, including current portion	973.9		1,056.9		—		1,056.9
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

Spire Alabama

As of June 30, 2018
Short-term debt	$	69.6	$	69.6	$	—	$	69.6
Long-term debt	322.5		317.0		—		317.0
As of September 30, 2017
Cash and cash equivalents	$	0.1	$	0.1	$	0.1	$	—
Short-term debt	169.9		169.9		—		169.9
Long-term debt	247.8		269.4		—		269.4
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