Segments and Geographic Area Analysis (Details 2)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Brazil [Member]
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	49.40%	36.80%	18.20%
Angola [Member]
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	9.60%	6.10%	1.80%
Australia [Member]
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	6.70%	10.00%	10.80%
INDONESIA
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	5.00%	1.30%	1.20%
United Kingdom [Member]
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	4.60%	5.60%	6.70%
Mexico [Member]
Individual countries that comprised 5% or more of our total contract drilling revenues from unaffiliated customers
Percentage of total drilling revenues from unaffiliated customers	1.90%	4.10%	8.90%