Net Income 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	$ 152	$ 59
Incremental income effect of interest on 5.25% convertible notes	1	0
Net income after assumed conversion	$ 153	$ 59
DENOMINATOR:
Weighted-average shares outstanding, basic	698	725
Dilutive effect of Employee stock options and restricted stock units	3	2
Dilutive effect of 5.25% convertible notes	6	0
Adjusted weighted-average shares outstanding, diluted	707	727
NET INCOME PER SHARE:
Basic	$ 0.22	$ 0.08
Diluted	$ 0.22	$ 0.08
Stock options and restricted stock units
Potentially dilutive amounts excluded from calculations:
Potentially dilutive amounts excluded from calculations:	0	17
5.25% convertible notes
Potentially dilutive amounts excluded from calculations:
Potentially dilutive amounts excluded from calculations:	0	6