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Employee Benefit Plans (Fair Values of Pension Plan Assets by Category) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 179.7 | $ 154.3
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.4 | 0.2
Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 179.3 | 154.1
Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Cash and Cash Equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.4 | 0.2
Cash and Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.4 | 0.2
Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
U.S. Equity [Member] | Commingled Pools / Collective Trusts [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 47.0 | 50.8
U.S. Equity [Member] | Commingled Pools / Collective Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
U.S. Equity [Member] | Commingled Pools / Collective Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 47.0 | 50.8
U.S. Equity [Member] | Commingled Pools / Collective Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Equity [Member] | Commingled Pools / Collective Trusts [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 23.0 | 8.3
International Equity [Member] | Commingled Pools / Collective Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Equity [Member] | Commingled Pools / Collective Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 23.0 | 8.3
International Equity [Member] | Commingled Pools / Collective Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Equity [Member] | Trust for Benefit of Employees [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 5.1 | 4.8
International Equity [Member] | Trust for Benefit of Employees [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Equity [Member] | Trust for Benefit of Employees [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 5.1 | 4.8
International Equity [Member] | Trust for Benefit of Employees [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Commingled Pools / Collective Trusts [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 64.9 | 54.6
Fixed Income [Member] | Commingled Pools / Collective Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Commingled Pools / Collective Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 64.9 | 54.6
Fixed Income [Member] | Commingled Pools / Collective Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Trust for Benefit of Employees [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 14.1 | 13.6
Fixed Income [Member] | Trust for Benefit of Employees [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Trust for Benefit of Employees [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 14.1 | 13.6
Fixed Income [Member] | Trust for Benefit of Employees [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Pension Fund [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 25.2 | 22.0
Fixed Income [Member] | Pension Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income [Member] | Pension Fund [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 25.2 | 22.0
Fixed Income [Member] | Pension Fund [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0

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