Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock, Common [Member]
Balance at Dec. 31, 2014	$ 17,712,582	$ 205,492	$ 2,837,150	$ (23,056)	$ 14,763,098	$ (70,102)
Net Income (Loss)	(4,524,515)	0	0	0	(4,524,515)	0
Common Stock Issued Under Stock Plans	15,371	5	15,366	0	0	0
Dividends, Common Stock	$ (367,767)	0	0	0	(367,767)	0
Common Stock Dividends Declared (in dollars per share)	$ 0.670
Other Comprehensive Income (Loss)	$ (10,282)	0	0	(10,282)	0	0
Change in Treasury Stock - Stock Compensation Plans, Net	(41,471)	0	(41,342)	0	0	(129)
Excess Tax Benefit from Stock-Based Compensation	26,058	0	26,058	0	0	0
Restricted Stock and Restricted Stock Units, Net	0	5	(44,339)	0	0	44,334
Stock-Based Compensation Expenses	130,577	0	130,577	0	0	0
Treasury Stock Issued as Compensation	2,482	0	(9)	0	0	2,491
Balance at Dec. 31, 2015	12,943,035	205,502	2,923,461	(33,338)	9,870,816	(23,406)
Net Income (Loss)	(1,096,686)	0	0	0	(1,096,686)	0
Common Stock Issued for the Yates Transaction	2,397,887	252	2,397,635	0	0	0
Common Stock Issued Under Stock Plans	16,397	9	16,388	0	0	0
Dividends, Common Stock	$ (376,012)	0	0	0	(376,012)	0
Common Stock Dividends Declared (in dollars per share)	$ 0.670
Other Comprehensive Income (Loss)	$ 14,328	0	0	14,328	0	0
Change in Treasury Stock - Stock Compensation Plans, Net	(75,226)	0	(27,018)	0	0	(48,208)
Excess Tax Benefit from Stock-Based Compensation	29,357	0	29,357	0	0	0
Restricted Stock and Restricted Stock Units, Net	0	7	(47,509)	0	0	47,502
Stock-Based Compensation Expenses	128,090	0	128,090	0	0	0
Treasury Stock Issued as Compensation	411	0	(19)	0	0	430
Balance at Dec. 31, 2016	13,981,581	205,770	5,420,385	(19,010)	8,398,118	(23,682)
Net Income (Loss)	2,582,579	0	0	0	2,582,579
Common Stock Issued Under Stock Plans	7,089	7	7,082	0	0	0
Dividends, Common Stock	$ (387,164)	0	0	0	(387,164)	0
Common Stock Dividends Declared (in dollars per share)	$ 0.670
Other Comprehensive Income (Loss)	$ (287)	0	0	(287)	0	0
Change in Treasury Stock - Stock Compensation Plans, Net	(36,743)	0	(27,348)	0	0	(9,395)
Restricted Stock and Restricted Stock Units, Net	0	11	2,552	0	0	(2,563)
Stock-Based Compensation Expenses	133,849	0	133,849	0	0	0
Treasury Stock Issued as Compensation	2,369	0	27	0	0	2,342
Balance at Dec. 31, 2017	$ 16,283,273	$ 205,788	$ 5,536,547	$ (19,297)	$ 10,593,533	$ (33,298)