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Pension and Postretirement Health and Life Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 7 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended
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Dec. 31, 2013 | Jun. 30, 2011 | Mar. 31, 2011 | Aug. 04, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2013 Pension Plan, Defined Benefit [Member] | Jun. 30, 2013 Pension Plan, Defined Benefit [Member] | Dec. 31, 2014 Pension Plan, Defined Benefit [Member] | Dec. 31, 2013 Pension Plan, Defined Benefit [Member] | Dec. 31, 2012 Pension Plan, Defined Benefit [Member] | Dec. 31, 2011 Pension Plan, Defined Benefit [Member] | Dec. 31, 2014 Other Postretirement Benefit Plan, Defined Benefit [Member] | Dec. 31, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member] | Dec. 31, 2012 Other Postretirement Benefit Plan, Defined Benefit [Member] | Dec. 31, 2011 Other Postretirement Benefit Plan, Defined Benefit [Member]
Approximate Number of Plan Participants |  |  |  |  |  |  |  |  | 6,100 |  |  | 6,100 |  |  |  | 4,000 |  |
Defined Benefit Plan, Accumulated Benefit Obligation |  |  |  |  |  |  |  |  | $ 906.0 |  |  | $ 906.0 | $ 1,040.4 |  |  |  |  |
Curtailment (gain) loss |  | 1.9 | 3.2 |  |  |  |  |  |  | 0.7 |  | (12.6) | 0 | (3.2) |  | 1.0 | 0 | (1.9)
Decrease in pension liability, curtailments |  |  |  |  |  |  |  |  |  | 32.7 |  | 20.1 | 0 |  |  | (24.6) | 0 |
Additional credited service charge |  |  |  |  |  |  |  |  | 22.9 |  |  |  |  |  |  |  |  |
Increase in pension liability, additional credit service |  |  |  |  |  |  |  |  | 47.9 |  |  |  |  |  |  |  |  |
Net defined benefit plan costs for former Portsmouth employees |  |  |  |  |  | 8.9 | 13.2 |  |  |  |  |  |  |  |  |  |  |
Expected defined benefit plan contributions for next fiscal year |  |  |  |  | 37.7 |  |  |  |  |  |  |  |  |  |  |  |  |
Expected defined benefit plan contributions for next fiscal year under ERISA |  |  |  |  | 35.5 |  |  |  |  |  |  |  |  |  |  |  |  |
Expected defined benefit plan contributions for next fiscal year for non-qualified plans |  |  |  |  | 2.2 |  |  |  |  |  |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax |  |  |  |  |  | 187.8 | (55.1) | (136.2) |  |  | 1.3 |  |  |  | 0.5 |  |  |
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax |  |  |  |  |  |  |  |  |  |  | 0.1 | 0 | 0 | 0 |  | (27.8) | 0 | 0
Defined Contribution Plan, Cost Recognized |  |  |  |  |  | 6.3 | 6.1 | 7.7 |  |  |  |  |  |  |  |  |  |
Defined Contribution Plan, Employer Matching Contribution, Percent | 7.00% |  |  | 4.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Executive Deferred Compensation Plan, Cost Recognized |  |  |  |  |  |  | $ 0.1 | $ 0.1 |  |  |  |  |  |  |  |  |  |

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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 -URI http://asc.fasb.org/extlink&oid=6503844 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=28358780&loc=SL7669646-108580 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(10) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Plan Curtailment -URI http://asc.fasb.org/extlink&oid=6520938 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 15 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=7577095&loc=d3e8001-114927 + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Plan Curtailment -URI http://asc.fasb.org/extlink&oid=6520938 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 15 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=7577095&loc=d3e8001-114927 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 15 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=7577095&loc=d3e8001-114927 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942 + Details
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- Definition Expected defined benefit plan contributions for next fiscal year for non-qualified plans + References No definition available. + Details
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- Definition Expected defined benefit plan contributions for next fiscal year under ERISA + References No definition available. + Details
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- Definition Net Defined Benefit Plan Costs For Former Portsmouth Employees charged directly to cost of sales. + References No definition available. + Details
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