Segment Information Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net	$ 2,012	$ 2,237	$ 2,390	$ 2,794	$ 3,727	$ 3,877	$ 3,711	$ 3,596	$ 9,433	$ 14,911	$ 15,263
Long-lived Assets	5,858				7,365				5,858	7,365
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									2,864	5,567	5,147
Long-lived Assets	1,505				2,114				1,505	2,114
Middle East and North Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									1,843	2,038	2,197
Long-lived Assets	1,686				1,987				1,686	1,987
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									1,782	2,381	2,835
Long-lived Assets	1,143				1,226				1,143	1,226
Europe/Sub-Sahara Africa/Russia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									1,613	2,584	2,693
Long-lived Assets	862				1,158				862	1,158
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									701	1,057	1,148
Long-lived Assets	471				616				471	616
CANADA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue, Net									630	1,284	$ 1,243
Long-lived Assets	$ 191				$ 264				$ 191	$ 264