Pension And Other Postretirement Benefits Benefit Obligation (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pension And Other Postretirement Benefits [Abstract]
Vesting percentage			100.00%
Required term of service to be eligible for plan match			one year of service and 1,000 hours of service
Award vesting period			3 years
Employer contributions	$ 10,000,000.0	$ 0	$ 21,800,000	$ 1,700,000
Expected employer contributions remainder of year	$ 20,000,000.0		$ 20,000,000.0