Stock Based Awards and Other Equity Instruments - Summary of Stock Option (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Options Outstanding
Options Outstanding, Beginning balance	8,651
Options Outstanding, Granted	368
Options Outstanding, Exercised	(585)	[1]
Options Outstanding, Cancelled or expired	(91)
Options Outstanding, Ending balance	8,343
Options Outstanding, Exercisable	4,630
Options Outstanding, Vested and expected to vest	8,153
Weighted Average Exercise Price per share
Options Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 44.47
Options Granted, Weighted Average Exercise Price	$ 86.07
Options Exercised, Weighted Average Exercise Price	$ 34.30	[1]
Options Cancelled or expired, Weighted Average Exercise Price	$ 51.97
Options Outstanding, Weighted Average Exercise Price, Ending balance	$ 46.94
Options Exercisable, Weighted Average Exercise Price	$ 34.42
Options Vested and expected to vest, Weighted Average Exercise Price	$ 46.51
Weighted Average Remaining Contractual Life and Aggregate Intrinsic Value
Options Outstanding, Weighted Average Remaining Contractual Life	4 years 10 months 24 days
Options Exercisable, Weighted Average Remaining Contractual Life	3 years 1 month 6 days
Options Vested and expected to vest, Weighted Average Remaining Contractual Life	4 years 9 months 18 days
Options Outstanding, Aggregate Intrinsic Value	$ 312
Options Exercisable, Aggregate Intrinsic Value	227
Options Vested and expected to vest, Aggregate Intrinsic Value	$ 307

[1] Inclusive of 203,689 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 Incentive 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 consolidated statements of cash flows.