Stock Based Awards and Other Equity Instruments - Summary of Stock Option (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Options Outstanding
Options Outstanding, Beginning balance	9,470
Options Outstanding, Assumed from acquisition	101
Options Outstanding, Granted	579
Options Outstanding, Exercised	(1,202)	[1]
Options Outstanding, Cancelled or expired	(297)
Options Outstanding, Ending balance	8,651
Options Outstanding, Exercisable	4,080
Options Outstanding, Vested and expected to vest	8,445
Weighted Average Exercise Price per share
Options Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 40.18
Options Assumed from acquisition, Weighted Average Exercise Price	$ 16.36
Options Granted, Weighted Average Exercise Price	$ 95.87
Options Exercised, Weighted Average Exercise Price	$ 32.87	[1]
Options Cancelled or expired, Weighted Average Exercise Price	$ 45.40
Options Outstanding, Weighted Average Exercise Price, Ending balance	$ 44.47
Options Exercisable, Weighted Average Exercise Price	$ 32.05
Options Vested and expected to vest, Weighted Average Exercise Price	$ 44.11
Weighted Average Remaining Contractual Life and Aggregate Intrinsic Value
Options Outstanding, Weighted Average Remaining Contractual Life	5 years
Options Exercisable, Weighted Average Remaining Contractual Life	2 years 8 months 12 days
Options Vested and expected to vest, Weighted Average Remaining Contractual Life	4 years 10 months 24 days
Options Outstanding, Aggregate Intrinsic Value	$ 273
Options Exercisable, Aggregate Intrinsic Value	174
Options Vested and expected to vest, Aggregate Intrinsic Value	$ 269

[1] Inclusive of 628,010 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 which had been convertible under stock options that were withheld under net share settlement remain in the authorized but unissued pool under the 2011 Incentive Plan and can be reissued by the Company. We began net-share settling the majority of our stock option exercises during the third quarter of 2013. Total payments for the employees’ tax obligations to the taxing authorities due to net share settlements are reflected as a financing activity within the consolidated statements of cash flows.