Share-Based Compensation (Stock Option Activity) (Details 3) (Stock option [Member], USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, at the beginning of the period (in shares)	9.4
Weighted average exercise price (in dollars per share)	$ 65.07	$ 53.03
Weighted average remaining contractual life of options outstanding	6 years 8 months 12 days	5 years 2 months 24 days
Granted (in shares)	1.6
Weighted average exercise price granted (in dollars per share)	$ 108.32
Exercised (in shares)	(3.7)
Weighted average exercise price exercised (in dollars per share)	$ 52.59
Forfeited (in shares)	(0.1)
Weighted average exercise price forfeited (in dollars per share)	$ 74.77
Exercisable (in shares)	4.1
Weighted average exercise price exercisable (in dollars per share)	$ 49.92
Weighted average remaining contractual life of options exercisable	5 years 4 months 24 days
Aggregate intrinsic value of options exercisable	$ 334
Intrinsic value of options exercised	243	299	153
Outstanding, at the end of the period (in shares)	7.2	9.4
Aggregate intrinsic value of options outstanding (in dollars)	$ 485	$ 583