PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Tables)

3 Months Ended

Dec. 31, 2017

Defined Contribution Plan [Abstract]

Schedule of Net Periodic Cost

The net periodic pension cost included the following components:

	Three Months Ended December 31,
	2017			2016
Spire
Service cost – benefits earned during the period	$	5.2		$	5.3
Interest cost on projected benefit obligation	6.9			6.9
Expected return on plan assets	(9.7		)	(9.9		)
Amortization of prior service (credit) cost	(0.3		)	0.2
Amortization of actuarial loss	3.1			3.4
Subtotal	5.2			5.9
Regulatory adjustment	4.3			4.6
Net pension cost	$	9.5		$	10.5

Spire Missouri
Service cost – benefits earned during the period	$	3.3		$	3.3
Interest cost on projected benefit obligation	4.9			4.8
Expected return on plan assets	(7.2		)	(7.3		)
Amortization of prior service cost	0.2			0.2
Amortization of actuarial loss	2.6			2.9
Subtotal	3.8			3.9
Regulatory adjustment	2.4			2.8
Net pension cost	$	6.2		$	6.7

Spire Alabama
Service cost – benefits earned during the period	$	1.6		$	1.6
Interest cost on projected benefit obligation	1.4			1.5
Expected return on plan assets	(1.7		)	(1.8		)
Amortization of prior service credit	(0.5		)	—
Amortization of actuarial loss	0.5			0.5
Subtotal	1.3			1.8
Regulatory adjustment	1.7			1.6
Net pension cost	$	3.0		$	3.4

Net periodic postretirement benefit costs consisted of the following components:

	Three Months Ended December 31,
	2017			2016
Spire
Service cost – benefits earned during the period	$	2.3		$	2.8
Interest cost on accumulated postretirement benefit obligation	2.2			2.1
Expected return on plan assets	(3.5		)	(3.4		)
Amortization of actuarial loss	0.2			0.6
Subtotal	1.2			2.1
Regulatory adjustment	0.1			(0.8		)
Net postretirement benefit cost	$	1.3		$	1.3

Spire Missouri
Service cost – benefits earned during the period	$	2.2		$	2.6
Interest cost on accumulated postretirement benefit obligation	1.8			1.7
Expected return on plan assets	(2.4		)	(2.3		)
Amortization of prior service cost	0.1			0.1
Amortization of actuarial loss	0.2			0.6
Subtotal	1.9			2.7
Regulatory adjustment	0.5			(0.4		)
Net postretirement benefit cost	$	2.4		$	2.3

Spire Alabama
Service cost – benefits earned during the period	$	—		$	0.1
Interest cost on accumulated postretirement benefit obligation	0.4			0.4
Expected return on plan assets	(1.0		)	(1.1		)
Amortization of prior service credit	(0.1		)	(0.1		)
Subtotal	(0.7		)	(0.7		)
Regulatory adjustment	(0.4		)	(0.4		)
Net postretirement benefit income	$	(1.1	)	$	(1.1	)