PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Tables)

9 Months Ended

Jun. 30, 2018

Defined Contribution Plan [Abstract]

Schedule of net periodic cost

The net periodic pension cost included the following components:

	Three Months Ended June 30,						Nine Months Ended June 30,
	2018			2017			2018			2017
Spire
Service cost – benefits earned during the period	$	4.8		$	5.0		$	15.2		$	15.5
Interest cost on projected benefit obligation	6.5			7.0			20.3			20.8
Expected return on plan assets	(8.6		)	(9.4		)	(27.8		)	(29.0		)
Amortization of prior service (credit) cost	(0.2		)	0.2			(0.7		)	0.7
Amortization of actuarial loss	2.4			3.0			8.4			9.6
Loss on lump-sum settlements	7.5			—			16.9			11.9
Subtotal	12.4			5.8			32.3			29.5
Regulatory adjustment	2.1			3.1			30.4			0.3
Net pension cost	$	14.5		$	8.9		$	62.7		$	29.8

Spire Missouri
Service cost – benefits earned during the period	$	2.9		$	3.0		$	9.4		$	9.6
Interest cost on projected benefit obligation	4.6			4.8			14.4			14.5
Expected return on plan assets	(6.1		)	(6.8		)	(20.3		)	(21.2		)
Amortization of prior service cost	0.3			0.2			0.7			0.7
Amortization of actuarial loss	2.0			2.5			7.1			8.2
Loss on lump-sum settlements	5.2			—			14.6			11.5
Subtotal	8.9			3.7			25.9			23.3
Regulatory adjustment	2.4			1.3			26.7			(4.5		)
Net pension cost	$	11.3		$	5.0		$	52.6		$	18.8

Spire Alabama
Service cost – benefits earned during the period	$	1.6		$	1.6		$	4.9		$	4.7
Interest cost on projected benefit obligation	1.3			1.6			4.1			4.6
Expected return on plan assets	(1.6		)	(1.8		)	(5.0		)	(5.4		)
Amortization of prior service credit	(0.5		)	—			(1.4		)	—
Amortization of actuarial loss	0.4			0.5			1.3			1.4
Loss on lump-sum settlements	2.3			—			2.3			0.4
Subtotal	3.5			1.9			6.2			5.7
Regulatory adjustment	(0.6		)	1.6			3.0			4.3
Net pension cost	$	2.9		$	3.5		$	9.2		$	10.0

Net periodic postretirement benefit costs consisted of the following components:

	Three Months Ended June 30,						Nine Months Ended June 30,
	2018			2017			2018			2017
Spire
Service cost – benefits earned during the period	$	2.3		$	2.7		$	7.0		$	8.2
Interest cost on accumulated postretirement benefit obligation	2.2			2.2			6.6			6.5
Expected return on plan assets	(3.5		)	(3.5		)	(10.5		)	(10.3		)
Amortization of prior service credit	—			—			(0.1		)	—
Amortization of actuarial loss	0.2			0.6			0.6			1.8
Subtotal	1.2			2.0			3.6			6.2
Regulatory adjustment	0.7			(0.8		)	0.8			(2.4		)
Net postretirement benefit cost	$	1.9		$	1.2		$	4.4		$	3.8

Spire Missouri
Service cost – benefits earned during the period	$	2.2		$	2.6		$	6.7		$	7.8
Interest cost on accumulated postretirement benefit obligation	1.7			1.7			5.3			5.1
Expected return on plan assets	(2.4		)	(2.3		)	(7.3		)	(6.8		)
Amortization of prior service cost	0.1			0.1			0.2			0.2
Amortization of actuarial loss	0.3			0.6			0.7			1.9
Subtotal	1.9			2.7			5.6			8.2
Regulatory adjustment	1.1			(0.4		)	2.1			(1.1		)
Net postretirement benefit cost	$	3.0		$	2.3		$	7.7		$	7.1

Spire Alabama
Service cost – benefits earned during the period	$	0.1		$	—		$	0.2		$	0.2
Interest cost on accumulated postretirement benefit obligation	0.4			0.4			1.1			1.2
Expected return on plan assets	(1.1		)	(1.1		)	(3.1		)	(3.3		)
Amortization of prior service credit	(0.1		)	(0.1		)	(0.3		)	(0.2		)
Amortization of actuarial gain	(0.1		)	—			(0.1		)	(0.1		)
Subtotal	(0.8		)	(0.8		)	(2.2		)	(2.2		)
Regulatory adjustment	(0.5		)	(0.5		)	(1.4		)	(1.4		)
Net postretirement benefit income	$	(1.3	)	$	(1.3	)	$	(3.6	)	$	(3.6	)