Retirement Plans And Postretirement Benefits (Net Postretirement Benefit Costs And Postretirement Projected Benefit Obligation) (Details)	5 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.86%		3.61%
Discount rate		3.79%	3.86%
Postretirement Benefit Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.10%		4.80%
Health care cost trend on covered charges, Initial	6.67%		6.80%
Health care cost trend on covered charges, Ultimate	6.48%		5.96%
Health care cost trend on covered charges, Years to ultimate	2 years		8 years
Postretirement Benefit Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.91%		5.10%
Health care cost trend on covered charges, Initial	6.55%		6.67%
Health care cost trend on covered charges, Ultimate	6.18%		6.48%
Health care cost trend on covered charges, Years to ultimate	0 years		1 year