Activity for the Company's stock options (Details) - Stock Options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of period, shares	3,689	3,142	3,552
Granted, shares	1,301	1,234	276
Exercised, shares	(579)	(640)	(543)
Canceled, shares	(72)	(47)	(143)
Outstanding, end of period, shares	4,339	3,689	3,142
Weighted average remaining contractual life (in years)	7 years	7 years	7 years
Options exercisable, end of period, shares	1,354	1,317	1,128
Options expected to vest, end of period, shares	2,730
Weighted average fair value of options granted (in dollars per share)	$ 59.86	$ 55.08	$ 41.52
Outstanding, beginning of period, weighted average exercise price (in dollars per share)	86.29	59.86	54.35
Granted, weighted average exercise price (in dollars per share)	160.16	136.75	108.89
Exercised, weighted average exercise price (in dollars per share)	65.34	52.50	51.22
Canceled, weighted average exercise price (in dollars per share)	140.36	104.57	50.54
Outstanding, end of period, weighted average exercise price (in dollars per share)	110.34	86.29	59.86
Options exercisable, end of period, weighted average exercise price (in dollars per share)	55.95	$ 55.65	$ 52.07
Options expected to vest, end of period, weighted average exercise price (in dollars per share)	$ 132.41
Exercised, aggregate intrinsic value	$ 68	$ 55	$ 33
Outstanding, end of period, aggregate intrinsic value	316
Options exercisable, end of period, aggregate intrinsic value	172
Options expected to vest, end of period, aggregate intrinsic value	$ 139