Financing Arrangements and Long-term Debt (Tables)

3 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Spire Missouri and Alabama Short-term Borrowings

Information about Spire’s consolidated short-term borrowings and about Spire Missouri’s and Spire Alabama’s borrowings from Spire is presented in the following table. As of December 31, 2020, $455.5 of Spire’s short-term borrowings were used to support lending to the Utilities.

	Spire (Parent Only)								Spire Missouri					Spire Alabama					Spire
	Credit		Term			CP			Credit		Spire			Credit		Spire			Consol-
	Facility		Loan			Program			Facility		Note			Facility		Note			idated
Three Months Ended December 31, 2020
Weighted average borrowings	$	—	$	125.5		$	609.2		$	—	$	341.3		$	—	$	111.6		$	734.7
Lowest borrowings outstanding		—		—			497.0			—		292.8			—		1.5			631.1
Highest borrowings outstanding		—		150.0			701.1			—		396.7			—		152.2			850.5
Weighted average interest rate	n/a			1.1	%		0.2	%	n/a			0.2	%	n/a			0.2	%		0.4	%
As of December 31, 2020
Borrowings outstanding	$	—	$	—		$	696.1		$	—	$	393.7		$	—	$	27.0		$	696.1
Weighted average interest rate	n/a		n/a				0.3	%	n/a			0.3	%	n/a			0.3	%		0.3	%
As of September 30, 2020
Borrowings outstanding	$	—	$	150.0		$	498.0		$	—	$	301.2		$	—	$	121.3		$	648.0
Weighted average interest rate	n/a			1.1	%		0.2	%	n/a			0.2	%	n/a			0.2	%		0.6	%
As of December 31, 2019
Borrowings outstanding	$	—	$	—		$	518.9		$	—	$	288.1		$	—	$	67.1		$	518.9
Weighted average interest rate	n/a		n/a				2.1	%	n/a			2.1	%	n/a			2.1	%		2.1	%

Summary Capitalized Interest

Interest expense shown on Spire’s consolidated statements of income and Spire Missouri’s statements of comprehensive income is net of the capitalized interest amounts shown in the following table.

	Three Months Ended December 31,
	2020		2019
Spire	$	0.9	$	2.2
Spire Missouri		—		0.3
Spire Alabama		0.6		0.6