Stock Based Awards and Other Equity Instruments - Summary of Stock Option (Details) - Stock Options $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Options Outstanding
Options Outstanding, Beginning balance | shares	5,720
Options Outstanding, Granted | shares	1,033
Options Outstanding, Exercised | shares	(554)	[1]
Options Outstanding, Cancelled or expired | shares	(165)
Options Outstanding, Ending balance | shares	6,034
Options Outstanding, Exercisable | shares	2,874
Options Outstanding, Vested and expected to vest | shares	5,647
Weighted Average Exercise Price per share
Options Outstanding, Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 53.71
Options Granted, Weighted Average Exercise Price | $ / shares	63.44
Options Exercised, Weighted Average Exercise Price | $ / shares	29.34	[1]
Options Cancelled or expired, Weighted Average Exercise Price | $ / shares	69.53
Options Outstanding, Weighted Average Exercise Price, Ending balance | $ / shares	57.18
Options Exercisable, Weighted Average Exercise Price | $ / shares	42.45
Options Vested and expected to vest, Weighted Average Exercise Price | $ / shares	$ 56.59
Weighted Average Remaining Contractual Life and Aggregate Intrinsic Value
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 10 months 24 days
Options Exercisable, Weighted Average Remaining Contractual Life	4 years 7 months 6 days
Options Vested and expected to vest, Weighted Average Remaining Contractual Life	5 years 8 months 12 days
Options Outstanding, Aggregate Intrinsic Value | $	$ 78
Options Exercisable, Aggregate Intrinsic Value | $	71
Options Vested and expected to vest, Aggregate Intrinsic Value | $	$ 77

[1] Inclusive of 246,826 options which were not converted into shares due to net share settlement in order to cover the aggregate exercise price and the minimum amount of required employee withholding taxes. Potential shares that had been convertible under stock options that were withheld under net share settlement remain in the authorized but unissued pool under the 2011 Plan and can be reissued by the Company. Total payments for the employees’ tax obligations to the taxing authorities due to net share settlements are reflected as a financing activity within the unaudited condensed consolidated statements of cash flows.