Earnings Per Share (Schedule Of Weighted Average Number Of Shares Outstanding Excluded From The Computation Of Diluted Earnings Per Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Performance Awards [Member] | Antidilutive or Performance Condition not met [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings	5,700	2,800	2,500
Performance Shares [Member] | Antidilutive or Performance Condition not met [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings	1,300	600	300
Restricted Stock Units (RSUs) [Member] | Antidilutive or Performance Condition not met [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings	1,000
Antidilutive due to Net Loss [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings	1,600	4,100