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PENSION AND POST-RETIREMENT PLANS - STATUS (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Pension Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | $ 239.9 | $ 217.4 |
Service cost | 5.1 | 4.7 | $ 4.4
Interest cost | 7.9 | 9.3 | 8.6
Actuarial (gain) loss | 23.9 | 22.2 |
Benefits paid, net of subsidies received | (12.5) | (12.2) |
Expenses paid | (1.2) | (1.5) |
Benefit obligation at end of year | 263.1 | 239.9 | 217.4
Change in Plan Assets: |  |  |
Balance at the beginning of the period | 194.8 | 162.2 |
Actual return on plan assets | 22.7 | 36.3 |
Employer contribution | 9.0 | 10.0 | 0.0
Benefits paid, net of subsidies received | (12.5) | (12.2) |
Expenses paid | (1.2) | (1.5) |
Balance at the end of the period | 212.8 | 194.8 | 162.2
Funded Status and Recognized Liability | (50.3) | (45.1) |
Post-retirement Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | 26.0 | 22.2 |
Service cost | 0.5 | 0.4 | 0.6
Interest cost | 0.8 | 0.9 | 1.0
Plan participants' contributions | 0.8 | 0.8 |
Actuarial (gain) loss | 2.7 | 3.4 |
Benefits paid, net of subsidies received | (1.7) | (1.7) |
Benefit obligation at end of year | 29.1 | 26.0 | $ 22.2
Change in Plan Assets: |  |  |
Plan participants' contributions | 0.8 | 0.8 |
Employer contribution | 0.9 | 0.9 |
Benefits paid, net of subsidies received | (1.7) | (1.7) |
Funded Status and Recognized Liability | (29.1) | (26.0) |
Qualified Plan | Pension Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | 238.3 |  |
Benefit obligation at end of year | 261.4 | 238.3 |
Change in Plan Assets: |  |  |
Balance at the beginning of the period | 192.2 |  |
Balance at the end of the period | $ 210.0 | $ 192.2 |

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- Definition Amount of payment to participant of defined benefit plan, net of subsidies received, which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References No definition available. + Details
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- Definition Amount of payment to participant under defined benefit plan, net of subsidies received, which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References No definition available. + Details
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- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 + Details
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