Income, Sales-Based And Other Taxes (Remaining Tax Years Subject To Examination By Major Tax Jurisdiction) (Details)	12 Months Ended
	Dec. 31, 2011
Abu Dhabi [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2000 - 2011
Angola [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2007 - 2011
Australia [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2000 - 2011
Canada [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	1994 - 2011
Equatorial Guinea [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2006 - 2011
Germany [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	1999 - 2011
Japan [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2004 - 2011
Malaysia [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2005 - 2011
Nigeria [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	1998 - 2011
Norway [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2000 - 2011
United Kingdom [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2009 - 2011
United States [Member]
Income, Sales-Based and Other Taxes [Line Items]
Open Tax Years by major tax jurisdiction	2004 - 2011