Pension and Postretirement Health and Life Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended
Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2015	Jun. 30, 2013
Additional credited service charge			$ 22.9
Increase in pension liability, additional credit service			47.9us-gaap_DefinedBenefitPlanOtherChanges
Fresh-Start Adjustment, Increase (Decrease), Accumulated Other Comprehensive Income (Loss)		121.7
Defined Contribution Plan, Cost Recognized	0.9	4.1	6.3
Scenario, Forecast [Member]
Expected defined benefit plan contributions for next fiscal year for non-qualified plans				9.7
Pension Plan, Defined Benefit [Member]
Approximate Number of Plan Participants	5,800
Defined Benefit Plan, Accumulated Benefit Obligation	961.4		906.0
Curtailment (gain) loss	0	2.2	(12.6)		0.7
Decrease in pension liability, curtailments	0	2.8	20.1		(32.7)
Defined Benefit Plan, Lump Sum Benefits Paid	(17.9)	(24.7)	(47.2)
Defined Benefit Plan, Actuarial Gain (Loss)	18.7	96.0	(121.0)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	0	0	0
Other Postretirement Benefit Plan, Defined Benefit [Member]
Approximate Number of Plan Participants	4,000
Curtailment (gain) loss	0	0	1.0
Decrease in pension liability, curtailments	0	0	(24.6)
Defined Benefit Plan, Lump Sum Benefits Paid	0	0	0
Defined Benefit Plan, Actuarial Gain (Loss)	4.3	8.3	(25.2)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(6.8)	0	(27.8)
Pension Plan C [Member]
Defined Benefit Plan, Actuarial Gain (Loss)		$ 2.2

Approximate Number of Plan Participants

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Defined Benefit Plan, Lump Sum Benefits Paid

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- Definition

Expected defined benefit plan contributions for next fiscal year for non-qualified plans

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- Definition

For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

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- Definition

Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Gain or Loss

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- Definition

Amount before tax, after reclassification adjustments, of prior service cost (credit) that has not been recognized in the income statement.

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- Definition

The amount of decrease that is related to an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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-Glossary Plan Curtailment

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- Definition

Changes in the defined benefit obligation, not otherwise separately disclosed in the financial statements.

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The amount of net gain (loss) recognized in net periodic benefit cost as a result of an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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- Definition

Amount of net gain (loss) recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include, but are not limited to, lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contracts to cover vested benefits.

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The amount of the cost recognized during the period for defined contribution plans.

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Amount of fresh-start adjustment to accumulated other comprehensive Income or Loss.

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