Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate (in hundredths)	21.00%	35.00%
State income tax provisions, net of federal income tax benefit (in hundredths)	7.20%	0.20%
Pension/OPEB remeasurement	(11.90%)
Tax reserve adjustment (in hundredths)	1.20%	(0.60%)
Changes in certain deferred tax balances (in hundredths)	14.20%
Shared-based payments (in hundreths)	10.60%	(1.80%)
Federal research and development tax credit (in hundreths)	(2.00%)	0.90%
All other, net (in hundredths)	0.80%	0.50%
Effective tax rate (in hundredths)	41.10%	34.20%