Note 6 - Financing (Tables)

3 Months Ended

Dec. 31, 2023

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
Three Months Ended December 31, 2023
Highest borrowings outstanding	$	1,135.0		$	—	$	643.6		$	132.5		$	1,135.0
Lowest borrowings outstanding		955.5			—		526.5			107.9			955.5
Weighted average borrowings		1,043.5			—		583.3			119.8			1,043.5
Weighted average interest rate		5.7	%		n/a		5.7	%		5.7	%		5.7	%
As of December 31, 2023
Borrowings outstanding	$	1,047.5		$	—	$	633.3		$	128.5		$	1,047.5
Weighted average interest rate		5.7	%		n/a		5.7	%		5.7	%		5.7	%
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 December 31, 2022
Borrowings outstanding	$	1,227.0		$	—	$	651.2		$	145.8		$	1,227.0
Weighted average interest rate		4.9	%		n/a		4.9	%		4.9	%		4.9	%

Summary Of Capitalized Interest [Table Text Block]

	Three Months Ended December 31,
	2023		2022
Spire	$	3.8	$	1.6
Spire Missouri		1.2		0.5
Spire Alabama		0.4		0.7