Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance (in shares) at Dec. 31, 2012		454
Beginning Balance at Dec. 31, 2012	$ 8,192	$ 5	$ (1,837)	$ 8,347	$ (239)	$ 1,916
Net income (loss)	274					274
Total other comprehensive income (loss)	54				54
Exercise of common stock options (in shares)		5
Exercise of common stock options	4			4
Excess tax benefits from stock-based compensation	73			73
Stock-based compensation and issuance of employee benefit plan stock	1,149			1,149
Ending Balance (in shares) at Dec. 31, 2013		459
Ending Balance at Dec. 31, 2013	9,746	$ 5	(1,837)	9,573	(185)	2,190
Net income (loss)	(241)					(241)
Total other comprehensive income (loss)	(326)				(326)
Exercise of common stock options (in shares)		6
Exercise of common stock options	2			2
Excess tax benefits from stock-based compensation	6			6
Stock-based compensation and issuance of employee benefit plan stock	1,510			1,510
Issuance of common stock for acquisition activity	44			44
Ending Balance (in shares) at Dec. 31, 2014		465
Ending Balance at Dec. 31, 2014	10,741	$ 5	(1,837)	11,135	(511)	1,949
Net income (loss)	596					596
Total other comprehensive income (loss)	(212)				(212)
Exercise of common stock options (in shares)		6
Exercise of common stock options	4			4
Excess tax benefits from stock-based compensation	119			119
Stock-based compensation and issuance of employee benefit plan stock	2,131			2,131
Issuance of common stock for acquisition activity	5			5
Ending Balance (in shares) at Dec. 31, 2015		471
Ending Balance at Dec. 31, 2015	$ 13,384	$ 5	$ (1,837)	$ 13,394	$ (723)	$ 2,545