Regulatory Matters (Tables)

9 Months Ended

Jun. 30, 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 June 30, 2026, September 30, 2025, and June 30, 2025.


		June 30,				September 30,				June 30,
Spire		2026				2025				2025
Regulatory Assets:
Current:
Pension and postretirement benefit costs		$	3.2			$	—			$	—
Unamortized purchased gas adjustments			15.7				16.5				1.2
Other			59.7				61.8				33.8
Total Current Regulatory Assets			78.6				78.3				35.0
Noncurrent:
Pension and postretirement benefit costs			203.4				217.8				236.4
Cost of removal			711.8				688.3				687.2
Future income taxes due from customers			155.7				154.2				155.0
Energy efficiency			67.2				65.0				63.7
Unamortized purchased gas adjustments			2.1				9.0				—
Other			254.8				189.2				151.1
Total Noncurrent Regulatory Assets			1,395.0				1,323.5				1,293.4
Total Regulatory Assets		$	1,473.6			$	1,401.8			$	1,328.4
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	3.5			$	34.9			$	44.0
Other			7.8				4.5				4.6
Total Current Regulatory Liabilities			11.3				39.4				48.6
Noncurrent:
Deferred taxes due to customers			128.0				100.3				103.7
Pension and postretirement benefit costs			304.7				300.1				261.1
Accrued cost of removal			276.0				138.2				138.3
Unamortized purchased gas adjustments			37.0				6.5				44.8
Other			31.9				32.9				34.1
Total Noncurrent Regulatory Liabilities			777.6				578.0				582.0
Total Regulatory Liabilities		$	788.9			$	617.4			$	630.6


		June 30,				September 30,				June 30,
Spire Missouri		2026				2025				2025
Regulatory Assets:
Current:
Unamortized purchased gas adjustments		$	1.8			$	14.9			$	—
Other			5.9				34.0				8.7
Total Current Regulatory Assets			7.7				48.9				8.7
Noncurrent:
Future income taxes due from customers			148.3				146.6				147.2
Pension and postretirement benefit costs			144.1				157.0				172.5
Energy efficiency			67.2				65.0				63.7
Unamortized purchased gas adjustments			2.1				9.0				—
Cost of removal			98.3				98.8				91.4
Other			209.2				176.8				138.7
Total Noncurrent Regulatory Assets			669.2				653.2				613.5
Total Regulatory Assets		$	676.9			$	702.1			$	622.2
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	3.5			$	13.9			$	14.0
Total Current Regulatory Liabilities			3.5				13.9				14.0
Noncurrent:
Deferred taxes due to customers			79.0				88.8				92.0
Pension and postretirement benefit costs			267.3				261.2				227.2
Accrued cost of removal			98.9				96.0				96.9
Unamortized purchased gas adjustments			37.0				6.5				44.8
Other			27.3				28.8				30.2
Total Noncurrent Regulatory Liabilities			509.5				481.3				491.1
Total Regulatory Liabilities		$	513.0			$	495.2			$	505.1


		June 30,				September 30,				June 30,
Spire Alabama		2026				2025				2025
Regulatory Assets:
Current:
Unamortized purchased gas adjustments		$	10.7			$	—			$	—
Other			15.1				16.1				13.2
Total Current Regulatory Assets			25.8				16.1				13.2
Noncurrent:
Future income taxes due from customers			1.4				1.6				1.6
Pension and postretirement benefit costs			56.1				59.1				61.8
Cost of removal			609.7				589.6				595.7
Other			0.4				0.3				0.5
Total Noncurrent Regulatory Assets			667.6				650.6				659.6
Total Regulatory Assets		$	693.4			$	666.7			$	672.8
Regulatory Liabilities:
Current:
Unamortized purchased gas adjustments		$	—			$	20.2			$	29.3
Other			1.9				0.1				—
Total Current Regulatory Liabilities			1.9				20.3				29.3
Noncurrent:
Pension and postretirement benefit costs			25.4				26.5				23.0
Other			2.6				2.7				2.8
Total Noncurrent Regulatory Liabilities			28.0				29.2				25.8
Total Regulatory Liabilities		$	29.9			$	49.5			$	55.1

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:


		June 30,				September 30,				June 30,
		2026				2025				2025
Spire
Pension and postretirement benefit costs		$	118.7			$	119.1			$	127.2
Future income taxes due from customers			154.3				152.7				153.4
Unamortized purchased gas adjustments			3.8				23.9				—
Other			188.0				177.0				111.7
Total Regulatory Assets Not Earning a Return		$	464.8			$	472.7			$	392.3

Spire Missouri
Pension and postretirement benefit costs		$	118.7			$	119.1			$	127.2
Future income taxes due from customers			148.3				146.6				147.2
Unamortized purchased gas adjustments			3.8				23.9				—
Other			188.0				177.0				111.7
Total Regulatory Assets Not Earning a Return		$	458.8			$	466.6			$	386.1