Fair Value of Financial Instruments (Tables)

6 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

The carrying amounts and estimated fair values of financial instruments not measured at fair value on a recurring basis are shown in the following tables, classified according to the fair value hierarchy. There were no such instruments classified as Level 3 (significant unobservable inputs) as of March 31, 2021, September 30, 2020, and March 31, 2020.

					Classification of Estimated Fair Value
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)
Spire
As of March 31, 2021
Cash and cash equivalents	$	104.0	$	104.0	$	104.0	$	—
Notes payable		653.5		653.5		—		653.5
Long-term debt, including current portion		2,803.3		3,090.9		—		3,090.9
As of September 30, 2020
Cash and cash equivalents	$	4.1	$	4.1	$	4.1	$	—
Notes payable		648.0		648.0		—		648.0
Long-term debt, including current portion		2,484.1		2,908.6		—		2,908.6
As of March 31, 2020
Cash and cash equivalents	$	108.4	$	108.4	$	108.4	$	—
Notes payable		560.6		560.6		—		560.6
Long-term debt, including current portion		2,490.2		2,671.0		—		2,671.0
Spire Missouri
As of March 31, 2021
Notes payable	$	250.0	$	250.0	$	—	$	250.0
Notes payable – associated companies		369.4		369.4		—		369.4
Long-term debt		1,092.4		1,254.2		—		1,254.2
As of September 30, 2020
Notes payable – associated companies	$	301.2	$	301.2	$	—	$	301.2
Long-term debt		1,092.0		1,313.5		—		1,313.5
As of March 31, 2020
Cash and cash equivalents	$	5.1	$	5.1	$	5.1	$	—
Notes payable		185.1		185.1		—		185.1
Notes payable – associated companies		39.6		39.6		—		39.6
Long-term debt		1,098.7		1,231.2		—		1,231.2
Spire Alabama
As of March 31, 2021
Cash and cash equivalents	$	18.2	$	18.2	$	18.2	$	—
Notes receivable – associated companies		20.0		20.0		—		20.0
Long-term debt, including current portion		621.1		682.3		—		682.3
As of September 30, 2020
Notes payable – associated companies	$	121.3	$	121.3	$	—	$	121.3
Long-term debt, including current portion		471.8		576.9		—		576.9
As of March 31, 2020
Cash and cash equivalents	$	0.1	$	0.1	$	0.1	$	—
Notes payable		50.0		50.0		—		50.0
Notes payable – associated companies		33.0		33.0		—		33.0
Long-term debt		471.7		535.1		—		535.1