Employee Benefit Plans (Fair Values of Pension Plan Assets by Category) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 154.3	$ 291.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.2	7.2
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	154.1	283.8
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	0.2	7.2
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	0.2	7.2
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	50.8	62.7
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	50.8	62.7
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	8.3	39.5
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	8.3	39.5
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	4.8	4.0
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	4.8	4.0
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
International Equity [Member] | Pension Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		2.7
International Equity [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
International Equity [Member] | Pension Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		2.7
International Equity [Member] | Pension Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Fixed Income [Member] | Commingled Pools / Collective Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	54.6	146.2
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	54.6	146.2
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	13.6	12.0
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	13.6	12.0
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	22.0	8.9
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	22.0	8.9
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
Blend [Domain] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Blend [Domain] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		7.8
Blend [Domain] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Blend [Domain] | Pension Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 7.8