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Employee Benefits Employee Benefits, Benefit obligations and funded status of our Canadian pension and the VEBAs (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014
Change in plan assets: |  |
Net Asset In Respect Of Vebas | $ 0.0 | $ 340.1
Net liabilities of Salaried VEBA | 19.0 | 17.2
Accrued Annual Veba Contribution | 19.6 | 13.7
Union VEBA |  |
Change in benefit obligation: |  |
Obligation at beginning of year | 391.5 |
Defined Benefit Plan, Settlements, Benefit Obligation | (391.5) |
Obligation at end of year | 0.0 | 391.5
Change in plan assets: |  |
Fair value of plan assets at beginning of year | 731.6 |
Defined Benefit Plan, Settlements, Plan Assets | (778.3) |
Fair value of plan assets at end of year | 0.0 | 731.6
Defined Benefit Plan, Funded Status of Plan | 0.0 | 340.1
Prior Service Cost Due to a New Death Benefit |  | 15.9
Actuarial (Gain) Loss Due To Change In Discount Rate |  | 45.0
Actuarial (gain) loss due to changes in prescription drug claim costs and Retiree Drug Subsidy assumptions |  | (18.0)
Actuarial (Gain) Loss Due To Changes In Administrative Costs |  | 0.4
Prior Service Cost Due to Increase in the Annual Healthcare Reimbursement |  | 60.5
Accrued Veba contingent contribution - total | 46.7 |
Accrued Annual Veba Contribution | 16.8 |
Salaried VEBA |  |
Change in benefit obligation: |  |
Obligation at beginning of year | 79.4 |
Obligation at end of year | 77.9 | 79.4
Change in plan assets: |  |
Fair value of plan assets at beginning of year | 62.2 |
Fair value of plan assets at end of year | 58.9 | 62.2
Defined Benefit Plan, Funded Status of Plan | (19.0) | (17.2)
Prior Service Cost resulting from a change in benefit cost for plan participants |  | 14.0
Prior Service Cost Due to Increase in the Annual Healthcare Reimbursement | 13.2 |
Accrued Annual Veba Contribution | 2.8 |
VEBAs |  |
Change in benefit obligation: |  |
Obligation at beginning of year | 470.9 | 374.7
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss) | 0.0 | 0.0
Defined Benefit Plan, Service Cost | 0.0 | 2.2
Defined Benefit Plan, Interest Cost | 2.7 | 16.7
Defined Benefit Plan, Plan Amendments | 13.2 | 90.4
Defined Benefit Plan, Actuarial Gain (Loss) | 11.2 | (10.2)
Benefits paid by VEBA | (6.2) | (24.7)
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received | 0.0 | 1.4
Obligation at end of year | 77.9 | 470.9
Change in plan assets: |  |
Fair value of plan assets at beginning of year | 793.8 | 780.7
Defined Benefit Plan, Actual Return on Plan Assets | 0.1 | 22.7
Defined Benefit Plan, Contributions by Employer | 49.5 | 13.7
Benefits paid by VEBA | (6.2) | (24.7)
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received | 0.0 | 1.4
Fair value of plan assets at end of year | 58.9 | 793.8
Defined Benefit Plan, Funded Status of Plan | (19.0) | 322.9
Actuarial (gain) loss due to projected lower benefit utilization | 5.5 | 53.6
Actuarial (Gain) Loss Due To Change In Discount Rate | (2.0) |
Actuarial (Gain) Loss Due To Changes In Census Data | (3.7) | 37.2
Canadian pension plan |  |
Change in benefit obligation: |  |
Obligation at beginning of year | 7.0 | 6.6
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss) | (1.0) | (0.5)
Defined Benefit Plan, Service Cost at Balance Sheet Exchange Rate | 0.2 | 0.2
Defined Benefit Plan, Interest Cost at Balance Sheet Exchange Rate | 0.2 | 0.3
Defined Benefit Plan, Actuarial Gain (Loss) | 0.1 | (0.7)
Defined Benefit Plan, Benefits Paid | 0.2 | 0.3
Obligation at end of year | 6.1 | 7.0
Change in plan assets: |  |
Fair value of plan assets at beginning of year | 6.3 | 6.2
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets | (1.0) | (0.5)
Defined Benefit Plan, Actual Return on Plan Assets | 0.3 | 0.6
Defined Benefit Plan, Contributions by Employer | 0.3 | 0.3
Defined Benefit Plan, Benefits Paid | 0.2 | 0.3
Fair value of plan assets at end of year | 5.7 | 6.3
Defined Benefit Plan, Funded Status of Plan | $ (0.4) | $ (0.7)

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- Definition The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost) -URI http://asc.fasb.org/extlink&oid=6504192 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost) -URI http://asc.fasb.org/extlink&oid=6504226 + Details
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- Definition 1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date. + 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) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Projected Benefit Obligation -URI http://asc.fasb.org/extlink&oid=6522206 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Accumulated Postretirement Benefit Obligation -URI http://asc.fasb.org/extlink&oid=6503904 + Details
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- Definition The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Benefits -URI http://asc.fasb.org/extlink&oid=49170737 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(6) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Postretirement Benefits -URI http://asc.fasb.org/extlink&oid=6521376 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(5) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total. + 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 (c) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919 + Details
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- Definition The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Plan Amendment -URI http://asc.fasb.org/extlink&oid=49173939 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Service Cost (Component of Net Periodic Pension Cost) -URI http://asc.fasb.org/extlink&oid=6525008 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)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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