General Devaluation (Details) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2015 USD ($)	Jun. 30, 2015	Mar. 31, 2015 unit	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Number of Reportable Segments | unit			5
Foreign Exchange Related Charges	$ 26			$ 0	$ 68	$ 0
ANGOLA [Member]
Net Monetary Asset Position	139				139
Angola, Kwanza
Foreign Exchange Related Charges	$ 20				36
Foreign Currency Devaluation, Percent	10.00%	11.00%
Kazakhstan, Tenge
Foreign Exchange Related Charges	$ 6
Foreign Currency Devaluation, Percent	31.00%
Venezuelan bolívar fuerte
Foreign Exchange Related Charges					$ 26