Net Income Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
NUMERATOR:
Net income	$ 465	$ 224	$ 617	$ 283
Incremental income effect of interest on 5.25% convertible notes	1	1	2	1
Net income after assumed conversion	$ 466	$ 225	$ 619	$ 284
DENOMINATOR:
Weighted-average shares outstanding, basic	690	714	694	719
Dilutive effect of Employee stock options and restricted stock units	2	2	3	2
Dilutive effect of 5.25% convertible notes	6	6	6	6
Adjusted weighted-average shares outstanding, diluted	698	722	703	727
NET INCOME PER SHARE:
Basic	$ 0.67	$ 0.31	$ 0.89	$ 0.39
Diluted	$ 0.67	$ 0.31	$ 0.88	$ 0.39
Stock options and restricted stock units
Potentially dilutive amounts excluded from calculations:
Potentially dilutive amounts excluded from calculations:	0	10	0	15