Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator for Basic and Diluted Earnings Per Share - [Abstract]
Net Income (Loss)	$ (42,467)	$ 615,122	$ (942,038)	$ 2,098,389
Denominator for Basic Earnings Per Share - [Abstract]
Weighted Average Shares	579,055	577,839	578,740	577,498
Denominator for Diluted Earnings Per Share - [Abstract]
Adjusted Diluted Weighted Average Shares	579,055	581,271	578,740	581,190
Net Income (Loss) Per Share
Basic	$ (0.07)	$ 1.06	$ (1.63)	$ 3.63
Diluted	$ (0.07)	$ 1.06	$ (1.63)	$ 3.61
Stock Options, SARs and ESPP [Member]
Potential Dilutive Common Shares - [Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments	0	203	0	371
Net Income (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	9,400	6,800	9,400	6,200
Restricted Stock/Units and Performance Units/Stock
Potential Dilutive Common Shares - [Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments	0	3,229	0	3,321
Restricted Stock [Member]
Net Income (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,900		4,900