Note 5 - Financing (Tables)

3 Months Ended

Dec. 31, 2022

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, 2022
Highest borrowings outstanding	$	1,230.0		$	—		$	651.2		$	274.0		$	1,230.0
Lowest borrowings outstanding		829.5			—			439.6			76.7			829.5
Weighted average borrowings		1,071.3			—			529.6			138.3			1,071.3
Weighted average interest rate		4.4	%		n/a			4.3	%		4.2	%		4.4	%
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	%
As of September 30, 2022
Borrowings outstanding	$	1,037.5		$	—		$	445.3		$	260.9		$	1,037.5
Weighted average interest rate		3.3	%		0.0	%		3.3	%		3.3	%		3.3	%
As of December 31, 2021
Borrowings outstanding	$	596.0		$	250.0		$	180.4		$	173.7		$	846.0
Weighted average interest rate		0.4	%		0.7	%		0.4	%		0.4	%		0.5	%

Summary Of Capitalized Interest [Table Text Block]

	Three Months Ended December 31,
	2022		2021
Spire	$	1.6	$	1.1
Spire Missouri		0.5		—
Spire Alabama		0.7		0.8