Stock-Based Compensation (Schedule of Stock-Based Compensation Activity) (Details) - Employee Stock Option $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Outstanding at January 1, 2016 | shares	6,590
Granted | shares	1,627
Exercised | shares	(1,249)
Forfeited or expired | shares	(175)
Outstanding at December 31, 2016 | shares	6,793
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Outstanding at January 1, Weighted-Average Exercise Price | $ / shares	$ 92.35
Granted, Weighted-Average Exercise Price | $ / shares	126.17
Exercised, Weighted-Average Exercise Price | $ / shares	85.75
Forfeited or expired, Weighted-Average Exercise Price | $ / shares	112.24
Outstanding at December 31, Weighted-Average Exercise Price | $ / shares	$ 101.16
Exercisable at December 31, 2016 | shares	3,667
Exercisable at December 31, Weighted-Average Exercise Price | $ / shares	$ 86.87
Outstanding at December 31, Weighted-Average Remaining Contractual Term	6 years 7 months 13 days
Exercisable at December 31, Weighted-Average Remaining Contractual Term	4 years 10 months 10 days
Outstanding at December 31, Aggregate Intrinsic Value | $	$ 107
Exercisable at December 31, Aggregate Intrinsic Value | $	$ 100