Pension And Other Postretirement Benefits Benefit Obligation (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Vesting percentage		100.00%
Required term of service to be eligible for plan match	one year of service and 1,000 hours
Award vesting period		3 years
Estimated nonqualified benefits in next fiscal year		$ 1.8
Estimated future employer contributions in next fiscal year		40.0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		11.7	$ 81.6
Accumulated benefit obligation		746.8	636.3
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 4.4	$ 4.0