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Anticipated contributions to the pension plans for fiscal year 2012 for non-qualified plans.

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

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Amount of actuarial gains from prior years under defined benefit plan as a percentage.

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Defined benefit plan benefit obligation settlement losses amortized over remaining actuarial life.

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Gains and losses not yet includible in pension/postretirement benefit cost are amortized only to the extent that such gain or loss exceeds 10% of the greater of the benefit obligation or the market-related value of plan assets.

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Disclosure under Missouri Public Service Commission Order, the return on plan assets if based on the market-related value of plan assets implemented prospectively over a four-year period.

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The amount of annual recovery of postretirement benefit costs allowed in rates by the Missouri Public Service Commission. The differences between these amounts and those calculated pursuant to GAAP are deferred as regulatory assets or liabilities.

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Amounts of Regulatory Assets For Which No Return On Investment During Recovery Period Is Provided

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Amounts of Regulatory Liabilities For Which No Return On Investment During Recovery Period Is Provided

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Remaining recovery period of regulatory liabilities for which no return on investment during recovery period is provided, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Amount of cost for defined contribution plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

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The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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