Shares and Stockholders' Equity (Changes In Common stock (Number Of Shares)) (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes In Common Stock (Number Of Shares) [Line Items]
Balance as of beginning-of-year	196,668,532
Balance as of end-of-year	192,329,691	196,668,532
Common Stock [Member]
Changes In Common Stock (Number Of Shares) [Line Items]
Balance as of beginning-of-year	196,668,532	205,862,760	218,090,114
Stock issued for exercise of warrants		258,633	212,670
Stock compensation/issued for benefit plans	547,209	942,318	800,325
Retirement/cancellation of shares	(4,886,050)	(10,395,179)	(13,240,349)
Balance as of end-of-year	192,329,691	196,668,532	205,862,760
Common stock as of End-of-Year
Basic basis	192,329,691	196,668,532	205,862,760
Diluted basis	193,672,296	199,196,043	209,034,686