Goodwill Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 27
Goodwill [Roll Forward]
Beginning Balance	2,727	$ 2,797
Goodwill, Written off Related to Sale of Business Unit	(10)	(162)
Goodwill, Reclassification to Assets Held for Sale	(7)
Foreign currency translation	(107)	92
Ending Balance	713	2,727	$ 2,797
Equity Investment Impairment	(1,917)	0	0
Western Hemisphere [Member]
Goodwill [Roll Forward]
Beginning Balance	1,958	2,065
Goodwill, Written off Related to Sale of Business Unit	(10)	(162)
Goodwill, Reclassification to Assets Held for Sale	(5)
Foreign currency translation	(69)	55
Ending Balance	494	1,958	2,065
Equity Investment Impairment	1,380
Eastern Hemisphere [Member]
Goodwill [Line Items]
Goodwill, Acquired During Period	27
Goodwill [Roll Forward]
Beginning Balance	769	732
Goodwill, Written off Related to Sale of Business Unit	0	0
Goodwill, Reclassification to Assets Held for Sale	(2)
Foreign currency translation	(38)	37
Ending Balance	219	$ 769	$ 732
Equity Investment Impairment	537
Western Hemisphere [Member]
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 0