Goodwill and Other Intangibles (Changes in the Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
Balance as of January 1, as reported		$ 8,369	$ 7,889
Goodwill acquired		533	74
Other adjustments	[1]	198	12
Balance at September 30,		$ 9,100	$ 7,975

[1] (a) The increase in 2017 primarily reflects the impact of foreign exchange.