Regulatory Matters (Tables)

6 Months Ended

Mar. 31, 2026

Regulated Operations [Abstract]

Schedule of Regulatory Assets and Liabilities

The following regulatory assets and regulatory liabilities were reflected in the balance sheets of the Company, Spire Missouri and Spire Alabama as of March 31, 2026, September 30, 2025, and March 31, 2025.


		March 31,				September 30,				March 31,
Spire		2026				2025				2025
Regulatory Assets:
Current:
Pension and postretirement benefit costs		$	3.4			$	—			$	—
Unamortized purchased gas adjustments			11.8				16.5				0.3
Other			63.5				61.8				42.0
Total Current Regulatory Assets			78.7				78.3				42.3
Noncurrent:
Pension and postretirement benefit costs			211.2				217.8				241.3
Cost of removal			708.1				688.3				679.9
Future income taxes due from customers			155.1				154.2				153.7
Energy efficiency			66.9				65.0				63.6
Unamortized purchased gas adjustments			—				9.0				—
Other			252.8				189.2				148.7
Total Noncurrent Regulatory Assets			1,394.1				1,323.5				1,287.2
Total Regulatory Assets		$	1,472.8			$	1,401.8			$	1,329.5
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	4.6			$	34.9			$	46.3
Other			8.0				4.5				5.3
Total Current Regulatory Liabilities			12.6				39.4				51.6
Noncurrent:
Deferred taxes due to customers			131.5				100.3				107.1
Pension and postretirement benefit costs			305.4				300.1				256.1
Accrued cost of removal			275.8				138.2				138.5
Unamortized purchased gas adjustments			61.6				6.5				100.2
Other			31.7				32.9				35.1
Total Noncurrent Regulatory Liabilities			806.0				578.0				637.0
Total Regulatory Liabilities		$	818.6			$	617.4			$	688.6


		March 31,				September 30,				March 31,
Spire Missouri		2026				2025				2025
Regulatory Assets:
Current:
Unamortized purchased gas adjustments		$	3.0			$	14.9			$	—
Other			9.6				34.0				15.5
Total Current Regulatory Assets			12.6				48.9				15.5
Noncurrent:
Future income taxes due from customers			147.6				146.6				145.9
Pension and postretirement benefit costs			150.2				157.0				175.0
Energy efficiency			66.9				65.0				63.6
Unamortized purchased gas adjustments			—				9.0				—
Cost of removal			101.3				98.8				93.5
Other			205.4				176.8				135.8
Total Noncurrent Regulatory Assets			671.4				653.2				613.8
Total Regulatory Assets		$	684.0			$	702.1			$	629.3
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	4.6			$	13.9			$	12.0
Total Current Regulatory Liabilities			4.6				13.9				12.0
Noncurrent:
Deferred taxes due to customers			82.3				88.8				95.3
Pension and postretirement benefit costs			267.4				261.2				221.6
Accrued cost of removal			98.5				96.0				97.8
Unamortized purchased gas adjustments			61.6				6.5				100.2
Other			27.5				28.8				31.2
Total Noncurrent Regulatory Liabilities			537.3				481.3				546.1
Total Regulatory Liabilities		$	541.9			$	495.2			$	558.1


		March 31,				September 30,				March 31,
Spire Alabama		2026				2025				2025
Regulatory Assets:
Current:
Unamortized purchased gas adjustments		$	6.1			$	—			$	—
Other			12.2				16.1				13.8
Total Current Regulatory Assets			18.3				16.1				13.8
Noncurrent:
Future income taxes due from customers			1.4				1.6				1.7
Pension and postretirement benefit costs			57.1				59.1				63.9
Cost of removal			602.9				589.6				586.4
Other			0.5				0.3				0.5
Total Noncurrent Regulatory Assets			661.9				650.6				652.5
Total Regulatory Assets		$	680.2			$	666.7			$	666.3
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	—			$	20.2			$	33.4
Other			2.2				0.1				0.5
Total Current Regulatory Liabilities			2.2				20.3				33.9
Noncurrent:
Pension and postretirement benefit costs			25.7				26.5				23.6
Other			2.7				2.7				2.8
Total Noncurrent Regulatory Liabilities			28.4				29.2				26.4
Total Regulatory Liabilities		$	30.6			$	49.5			$	60.3

Schedule of Regulatory Assets Not Earning Return

A portion of the Company’s and Spire Missouri’s regulatory assets are not earning a return, as shown in the table below:


		March 31,				September 30,				March 31,
		2026				2025				2025
Spire
Pension and postretirement benefit costs		$	118.9			$	119.1			$	129.9
Future income taxes due from customers			153.7				152.7				152.0
Unamortized purchased gas adjustments			3.0				23.9				—
Other			185.3				177.0				113.8
Total Regulatory Assets Not Earning a Return		$	460.9			$	472.7			$	395.7

Spire Missouri
Pension and postretirement benefit costs		$	118.9			$	119.1			$	129.9
Future income taxes due from customers			147.6				146.6				145.9
Unamortized purchased gas adjustments			3.0				23.9				—
Other			185.3				177.0				113.8
Total Regulatory Assets Not Earning a Return		$	454.8			$	466.6			$	389.6