Note 6 - Financing (Tables)

6 Months Ended

Mar. 31, 2024

Notes Tables

Schedule of Short-Term Debt [Table Text Block]

	Spire (Parent Only)			Spire Missouri						Spire Alabama			Spire
	CP			Term			Spire			Spire			Consol-
	Program			Loan			Note			Note			idated
Six Months Ended March 31, 2024
Highest borrowings outstanding	$	1,135.0		$	200.0		$	643.6		$	132.5		$	1,275.0
Lowest borrowings outstanding		554.6			—			234.7			25.2			754.6
Weighted average borrowings		930.6			97.3			469.9			94.5			1,027.9
Weighted average interest rate		5.7	%		6.7	%		5.7	%		5.7	%		5.8	%
As of March 31, 2024
Borrowings outstanding	$	586.0		$	200.0		$	243.9		$	37.4		$	786.0
Weighted average interest rate		5.6	%		6.3	%		5.6	%		5.6	%		5.8	%
As of September 30, 2023
Borrowings outstanding	$	955.5		$	—		$	540.6		$	124.1		$	955.5
Weighted average interest rate		5.6	%		n/a			5.6	%		5.6	%		5.6	%
As of March 31, 2023
Borrowings outstanding	$	361.0		$	200.0		$	60.7		$	121.3		$	561.0
Weighted average interest rate		5.3	%		5.6	%		5.3	%		5.3	%		5.4	%

Summary Of Capitalized Interest [Table Text Block]

	Three Months Ended March 31,				Six Months Ended March 31,
	2024		2023		2024		2023
Spire	$	4.0	$	1.9	$	7.8	$	3.5
Spire Missouri		1.1		0.6		2.3		1.1
Spire Alabama		0.4		0.6		0.8		1.3