Goodwill and Other Intangible Assets - Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 1,510
Other	22	[1]
Ending Balance	1,532
United States (U.S.)
Goodwill [Roll Forward]
Beginning Balance	671
Other	0	[1]
Ending Balance	671
International
Goodwill [Roll Forward]
Beginning Balance	839
Other	22	[1]
Ending Balance	$ 861

[1] Includes adjustments for foreign currency translation.