Goodwill and Other Intangibles (Changes in the Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Goodwill [Roll Forward]
Balance as of January 1,		$ 9,089	$ 8,369
Goodwill acquired		15	363
Other adjustments	[1]	90	37
Balance at March 31,		$ 9,194	$ 8,769

[1] The increase in 2018 primarily reflects the impact of foreign exchange.