Revenues - Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 807	$ 1,314	$ 2,843	$ 3,969
Western Hemisphere
Disaggregation of Revenue [Line Items]
Revenue	316	675	1,214	2,120
Western Hemisphere \| North America
Disaggregation of Revenue [Line Items]
Revenue	175	383	688	1,259
Western Hemisphere \| Latin America
Disaggregation of Revenue [Line Items]
Revenue	141	292	526	861
Eastern Hemisphere
Disaggregation of Revenue [Line Items]
Revenue	491	639	1,629	1,849
Eastern Hemisphere \| Middle East & North Africa and Asia
Disaggregation of Revenue [Line Items]
Revenue	319	377	1,063	1,129
Eastern Hemisphere \| Europe/Sub-Sahara Africa/Russia
Disaggregation of Revenue [Line Items]
Revenue	$ 172	$ 262	$ 566	$ 720

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
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details