Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 50	$ 44	$ 107	$ 88
Options, grants in period (in shares)	4,000,000
Options, grants in period, weighted average grant date fair value (in dollars per share)	$ 13.03
Options, grants in period, weighted average exercise price (in dollars per share)	$ 104.82
Options, outstanding (in shares)	25,000,000		25,000,000
Options, outstanding, weighted average exercise price (in dollars per share)	$ 67.62		$ 67.62
Options, outstanding, weighted average remaining contractual term (in years)	4 years 1 month 17 days
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 17	19	$ 39	45
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 33	$ 25	$ 68	$ 43
Equity instruments other than options, grants in period (in shares)	2,000,000
Equity instruments other than options, grants in period, weighted average grant date fair value (in dollars per share)	$ 104.73
Equity instruments other than options, nonvested (in shares)	5,000,000		5,000,000
Equity instruments other than options, nonvested, weighted average grant date fair value (in dollars per share)	$ 58.12		$ 58.12