v3.19.3.a.u2
Income And Other Taxes (Remaining Tax Years Subject To Examination By Major Tax Jurisdiction) (Details)
 12 Months Ended
Dec. 31, 2019
Abu Dhabi [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2018
Abu Dhabi [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Angola [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2018
Angola [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Australia [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2010
Australia [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Belgium [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2017
Belgium [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Canada [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2000
Canada [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Equatorial Guinea [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2007
Equatorial Guinea [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Indonesia [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2007
Indonesia [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Iraq [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2014
Iraq [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Malaysia [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2011
Malaysia [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Nigeria [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2006
Nigeria [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Norway [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2007
Norway [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Papua New Guinea [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2008
Papua New Guinea [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
Russia [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2017
Russia [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
United Kingdom [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2015
United Kingdom [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019
United States [Member] | Earliest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2006
United States [Member] | Latest Tax Year [Member]  
Income and Other Taxes [Line Items]  
Open tax years by major tax jurisdiction 2019