Revenues - Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 903	$ 821	$ 1,735	$ 2,036
Western Hemisphere
Disaggregation of Revenue [Line Items]
Revenue	425	310	815	898
Western Hemisphere \| North America
Disaggregation of Revenue [Line Items]
Revenue	220	172	434	513
Western Hemisphere \| Latin America
Disaggregation of Revenue [Line Items]
Revenue	205	138	381	385
Eastern Hemisphere
Disaggregation of Revenue [Line Items]
Revenue	478	511	920	1,138
Eastern Hemisphere \| Middle East & North Africa and Asia
Disaggregation of Revenue [Line Items]
Revenue	289	341	556	744
Eastern Hemisphere \| Europe/Sub-Sahara Africa/Russia
Disaggregation of Revenue [Line Items]
Revenue	$ 189	$ 170	$ 364	$ 394

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details