Goodwill and Other Intangibles (Changes in the Carrying Amount of Goodwill) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Goodwill [Roll Forward]
Balance as of January 1, as reported	$ 7,241		$ 6,893
Goodwill acquired	12		267
Other adjustments	(93)	[1]	(1)	[1]
Balance at March 31,	$ 7,160		$ 7,159

[1] Primarily reflects the impact of foreign exchange in each period.