Net Income (Loss) per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator:
Net income (loss)	$ (2,326)	$ 677
Denominator:
Weighted average shares of common stock - basic	1,276	1,295
Dilutive effect of equity incentive awards	0	24
Weighted average shares of common stock - diluted	1,276	1,319
Net income (loss) per share:
Basic	$ (1.82)	$ 0.52
Diluted	$ (1.82)	$ 0.51
Common stock equivalents excluded from income per diluted share because their effect would have been anti-dilutive	51	1