Property and Equipment (Narrative) (Details) (USD $)	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Interest capitalized	$ 9,800,000	$ 9,000,000
Construction in Progress, Newbuild Drilling Units [Member]
Property, Plant and Equipment [Line Items]
Expenditure towards construction of drilling units currently under construction	500,000,000
Number of drilling units	3
Capital Addition Purchase Commitments [Member] | Construction in Progress, Newbuild Drilling Units [Member]
Property, Plant and Equipment [Line Items]
Commitments on drilling units under construction	$ 1,200,000,000