FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

12 Months Ended

Sep. 30, 2018

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 were as follows:

					Classification of Estimated Fair Value
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)
Spire
As of September 30, 2018
Cash and cash equivalents	$	4.4	$	4.4	$	4.4	$	—
Short-term debt	553.6		553.6		—		553.6
Long-term debt, including current portion	2,075.6		2,074.0		—		2,074.0
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

Spire Missouri

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

Fair value of financial instruments

Spire Missouri
As of September 30, 2018
Cash and cash equivalents	$	2.0	$	2.0	$	2.0	$	—
Short-term debt	345.3		345.3		—		345.3
Long-term debt, including current portion	874.4		906.6		—		906.6
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

Spire Alabama

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

Fair value of financial instruments

Spire Alabama
As of September 30, 2018
Short-term debt	$	142.5	$	142.5	$	—	$	142.5
Long-term debt	322.6		321.7		—		321.7
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