Segment Information Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net	$ 1,490	$ 1,460	$ 1,363	$ 1,386	$ 1,406	$ 1,356	$ 1,402	$ 1,585	$ 5,699	$ 5,749	$ 9,433
Long-lived Assets	2,893				4,629				2,893	4,629
Eastern Hemisphere [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									2,762	2,807	4,157
Long-lived Assets	1,330				2,578				1,330	2,578
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									1,555	1,523	2,864
Long-lived Assets	870				1,008				870	1,008
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									890	1,064	1,782
Long-lived Assets	575				903				575	903
Europe/Sub-Sahara Africa/Russia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									999	939	1,613
Long-lived Assets	532				629				532	629
Middle East and North Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									1,464	1,513	1,843
Long-lived Assets	528				1,595				528	1,595
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									299	355	701
Long-lived Assets	270				354				270	354
Western Hemisphere [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									2,937	2,942	5,276
Long-lived Assets	1,563				2,051				1,563	2,051
CANADA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									492	355	$ 630
Long-lived Assets	$ 118				$ 140				$ 118	$ 140