Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator for Basic and Diluted Earnings Per Share - [Abstract]
Net Income	$ 1,190,952	$ 100,541	$ 2,526,272	$ 152,111
Denominator for Basic Earnings Per Share - [Abstract]
Weighted Average Shares	577,254	574,783	576,431	574,370
Denominator for Diluted Earnings Per Share - [Abstract]
Adjusted Diluted Weighted Average Shares	581,559	578,736	580,442	578,453
Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract]
Anti-dilutive Securities excluded from Diluted Earnings Per Share Calculation	500	4,200	200	3,600
Net Income Per Share
Basic	$ 2.06	$ 0.17	$ 4.38	$ 0.26
Diluted	$ 2.05	$ 0.17	$ 4.35	$ 0.26
Stock Options And SARs [Member]
Potential Dilutive Common Shares - [Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments	1,432	1,451	1,317	1,518
Restricted Stock/Units and Performance Units/Stock [Member]
Potential Dilutive Common Shares - [Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments	2,873	2,502	2,694	2,565