Share-Based Compensation (Stock Option Activity) (Details 3) - Stock option [Member] - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, at the beginning of the period (in shares)	7.3
Weighted average exercise price (in dollars per share)	$ 84.85	$ 81.11
Weighted average remaining contractual life of options outstanding	6 years 8 months 12 days	6 years 8 months 12 days
Granted (in shares)	2.0
Weighted average exercise price granted (in dollars per share)	$ 87.90
Aggregate intrinsic value of options outstanding (in dollars)	$ 241	$ 222
Exercised (in shares)	(0.8)
Weighted average exercise price exercised (in dollars per share)	$ 55.24
Forfeited (in shares)	(0.3)
Weighted average exercise price forfeited (in dollars per share)	$ 98.63
Exercisable (in shares)	4.8
Weighted average exercise price exercisable (in dollars per share)	$ 72.40
Weighted average remaining contractual life of options exercisable	5 years 4 months 24 days
Aggregate intrinsic value of options exercisable	$ 196
Outstanding, at the end of the period (in shares)	8.2	7.3
Intrinsic value of options exercised	$ 37	$ 111	$ 243