Net Income Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
NUMERATOR:
Net income	$ 329	$ 259	$ 946	$ 542
Incremental income effect of interest on 5.25% convertible notes	1	1	3	2
Net income after assumed conversion	$ 330	$ 260	$ 949	$ 544
DENOMINATOR:
Weighted-average shares outstanding, basic	683	703	690	714
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	691	711	699	722
NET INCOME PER SHARE:
Basic	$ 0.48	$ 0.37	$ 1.37	$ 0.76
Diluted	$ 0.48	$ 0.37	$ 1.36	$ 0.75
Stock options and restricted stock units
Potentially dilutive amounts excluded from calculations:
Potentially dilutive amounts excluded from calculations:	0	9	0	10

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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