Derivatives - Open crude oil derivative positions (Details) (July 2014 - March 2015, crude oil derivative positions, USD $)	Mar. 31, 2014 bbl
July 2014 - March 2015, crude oil derivative positions
Volume	4,500
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