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PENSION AND POST-RETIREMENT PLANS - STATUS (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Pension Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | $ 232.1 | $ 225.4 |
Service cost | 4.4 | 4.0 | $ 3.9
Interest cost | 8.6 | 9.7 | 9.7
Plan settlements |  | (0.3) |
Actuarial (gain) loss | (14.1) | 13.9 |
Benefits paid, net of subsidies received | (12.0) | (18.9) |
Expenses paid | (1.6) | (1.7) |
Benefit obligation at end of year | 217.4 | 232.1 | 225.4
Change in Plan Assets: |  |  |
Balance at the beginning of the period | 186.7 | 178.8 |
Actual return on plan assets | (10.9) | 25.8 |
Plan settlements |  | (0.3) |
Employer contribution | 0.0 | 3.0 | 7.5
Benefits paid, net of subsidies received | (12.0) | (18.9) |
Expenses paid | (1.6) | (1.7) |
Balance at the end of the period | 162.2 | 186.7 | 178.8
Funded Status and Recognized Liability | (55.2) | (45.4) |
Post-retirement Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | 27.7 | 25.2 |
Service cost | 0.6 | 0.5 | 1.5
Interest cost | 1.0 | 1.1 | 2.7
Plan participants' contributions | 0.9 | 1.1 |
Actuarial (gain) loss | (6.2) | 1.9 |
Benefits paid, net of subsidies received | (1.8) | (2.1) |
Benefit obligation at end of year | 22.2 | 27.7 | $ 25.2
Change in Plan Assets: |  |  |
Plan participants' contributions | 0.9 | 1.1 |
Employer contribution | 0.9 | 1.0 |
Benefits paid, net of subsidies received | (1.8) | (2.1) |
Funded Status and Recognized Liability | (22.2) | (27.7) |
Qualified Plan | Pension Benefits |  |  |
Change in Benefit Obligation: |  |  |
Benefit obligation at beginning of year | 229.9 |  |
Benefit obligation at end of year | 215.9 | 229.9 |
Change in Plan Assets: |  |  |
Balance at the beginning of the period | 184.7 |  |
Balance at the end of the period | $ 159.9 | $ 184.7 |

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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/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=82843861&loc=d3e1928-114920 + Details
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- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. + 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)(4) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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- Definition Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. + 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 (d)(5)(ii) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5)(iv)(01) -URI http://asc.fasb.org/extlink&oid=82843861&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 (b)(8) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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