Note 7 - Fair Value of Financial Instruments (Tables)

3 Months Ended

Dec. 31, 2023

Notes Tables

Fair Value, by Balance Sheet Grouping [Table Text Block]

					Classification of Estimated Fair Value
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)
Spire
As of December 31, 2023
Cash and cash equivalents	$	4.8	$	4.8	$	4.8	$	—
Notes payable		1,047.5		1,047.5		—		1,047.5
Long-term debt, including current portion		3,704.8		3,481.5		—		3,481.5
As of September 30, 2023
Cash and cash equivalents	$	5.6	$	5.6	$	5.6	$	—
Notes payable		955.5		955.5		—		955.5
Long-term debt, including current portion		3,710.6		3,270.2		—		3,270.2
As of December 31, 2022
Cash and cash equivalents	$	4.8	$	4.8	$	4.8	$	—
Notes payable		1,227.0		1,227.0		—		1,227.0
Long-term debt, including current portion		3,412.9		3,083.7		—		3,083.7
Spire Missouri
As of December 31, 2023
Notes payable – associated companies	$	633.3	$	633.3	$	—	$	633.3
Long-term debt, including current portion		1,785.8		1,689.5		—		1,689.5
As of September 30, 2023
Cash and cash equivalents	$	0.8	$	0.8	$	0.8	$	—
Notes payable – associated companies		540.6		540.6		—		540.6
Long-term debt		1,785.4		1,592.4		—		1,592.4
As of December 31, 2022
Notes payable – associated companies	$	651.2	$	651.2	$	—	$	651.2
Long-term debt, including current portion		1,638.1		1,497.7		—		1,497.7
Spire Alabama
As of December 31, 2023
Notes payable – associated companies	$	128.5	$	128.5	$	—	$	128.5
Long-term debt		746.0		701.7		—		701.7
As of September 30, 2023
Cash and cash equivalents	$	1.2	$	1.2	$	1.2	$	—
Notes payable – associated companies		124.1		124.1		—		124.1
Long-term debt		745.9		648.0		—		648.0
As of December 31, 2022
Notes payable – associated companies	$	145.8	$	145.8	$	—	$	145.8
Long-term debt		745.6		674.5		—		674.5