Financing (Tables)

3 Months Ended

Dec. 31, 2025

Debt Disclosure [Abstract]

Schedule of Short-Term Debt

Information about short-term borrowings, including Spire Missouri’s and Spire Alabama’s borrowings from Spire, is presented in the following table. As of December 31, 2025, $224.1 of Spire’s CP Program borrowings was used to support lending to the Utilities.

	Spire (Parent Only)			Spire Missouri				Spire Alabama			Spire
	CP				Spire			Spire			Consol-
	Program				Note			Note			idated
Three Months Ended December 31, 2025
Highest borrowings outstanding	$	1,399.2			$	594.7		$	174.6		$	1,399.2
Lowest borrowings outstanding		385.0				416.0			120.3			385.0
Weighted average borrowings		1,036.3				485.8			145.0			1,036.3
Weighted average interest rate		4.1	%			4.2	%		4.2	%		4.1	%
As of December 31, 2025
Borrowings outstanding	$	412.0			$	465.7		$	164.6		$	412.0
Weighted average interest rate		3.9	%			3.9	%		3.9	%		3.9	%
As of September 30, 2025
Borrowings outstanding	$	1,317.0			$	566.3		$	130.1		$	1,317.0
Weighted average interest rate		4.4	%			4.4	%		4.4	%		4.4	%
As of December 31, 2024
Borrowings outstanding	$	1,158.0			$	580.9		$	67.0		$	1,158.0
Weighted average interest rate		4.4	%			4.8	%		4.8	%		4.4	%

Summary of Capitalized Interest

Interest expense shown on the statements of income is net of the capitalized interest amounts shown in the following table.

	Three Months Ended December 31,
	2025		2024
Spire	$	3.3	$	6.3
Spire Missouri		1.4		1.2
Spire Alabama		1.7		0.8