Benefit Plans (Allocation of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 244.1	$ 214.5
Weighted average asset allocations	100.00%	100.00%
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 0.0
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2.2	1.7
Cash [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2.2	$ 1.7
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	33.00%	23.00%
Target allocation	30.00%	65.00%
International Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 15.5	$ 17.7
International Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.3	$ 17.7
International Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.2
International Mutual Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	65.00%	74.00%
Target allocation	70.00%	35.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	2.00%	3.00%
Target allocation	0.00%
Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 21.7	$ 13.9
Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.8	13.9
Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17.9
Mutual Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0
Pension Plan Assets In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39.4	33.3
Pension Plan Assets In The Fair Value Hierarchy [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.3	33.3
Pension Plan Assets In The Fair Value Hierarchy [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32.1
Pension plan assets measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 204.7	$ 181.2
Minimum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.27
Minimum [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.67
Minimum [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	—
Maximum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.33
Maximum [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.73
Maximum [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.03