Anticipated contributions to the pension plans for the next fiscal year for qualified trusts.

No definition available.

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- Definition

Reflects the upper limit on age eligibility, post early retirement, when medical insurance is available to retiree.

+ References

No definition available.

+ Details

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- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

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- Definition

Amount of (increase) decrease to benefit obligation of defined benefit plan from remeasurement due to settlement. Excludes decrease to benefit obligation for settlement payment.

+ References

+ Details

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- Definition

Amount of payment, which decreases benefit obligation of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. Excludes decreases to benefit obligation for remeasurement due to settlement.

+ References

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Pension Plans and Other Postretirement Benefits - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2017
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical insurance available until age is reached after early retirement		65 years
Pension Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlement benefits paid	$ 39,500,000
Settlement loss	$ 9,400,000
Pension Plans \| Spire Missouri
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rates	3.75%		4.00%
Employer contributions		$ 8,500,000
Anticipated contributions to pension plans for qualified trust		18,200,000
Other Pension Plan \| Spire Missouri
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rates	3.70%		4.00%
Postretirement Plans \| Spire Missouri
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		0
Anticipated contributions to pension plans for qualified trust		0
Postretirement Plans \| Spire Alabama
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions		0
Anticipated contributions to pension plans for qualified trust		$ 0