Derivatives - Open crude oil derivative positions (Details) (June 2013 - March 2015, crude oil derivative positions, USD $)	Jun. 30, 2013 bbl
June 2013 - March 2015, crude oil derivative positions
Volume	11,000
Fixed Swap Price	$ 90

The volume of a commodity or material specified in an investment contract.

No definition available.

Name:	invest_InvestmentContractVolume
Namespace Prefix:	invest_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant