Commitments and Contingencies (Tables)

12 Months Ended

Sep. 30, 2019

Commitments And Contingencies Disclosure [Abstract]

Aggregate Rental Expense and Annual Minimum Rental Commitments

Aggregate rental expense and annual minimum rental commitments under all leases having an initial or remaining non-cancelable term of more than one year are shown below.

	Aggregate Rental Expense						Minimum Rental Commitments
	2019		2018		2017		2020		2021		2022		2023		2024		Later		Total
Spire	$	10.9	$	10.0	$	9.7	$	8.2	$	7.0	$	6.8	$	6.1	$	4.8	$	36.5	$	69.4
Spire Missouri		3.7		3.6		4.8		0.5		0.2		—		—		—		—		0.7
Spire Alabama		5.2		4.7		4.6		2.9		2.1		2.1		2.1		0.7		—		9.9