Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended				0 Months Ended
	Apr. 25, 2014	Jul. 24, 2014 Subsequent event	Jul. 01, 2014 Subsequent event Oil and gas properties located on the North Slope of Alaska	Jul. 01, 2014 Subsequent event Oil and gas properties located on the North Slope of Alaska	Jul. 01, 2014 Subsequent event Oil and gas properties located on the North Slope of Alaska Proceeds in subsequent years achiveing production targets
Subsequent event
Proceeds from sale of oil and gas properties			$ 35		$ 27
Amount of total project costs up to which the working interest is fully carried				$ 600
Dividend declared (in dollars per share)	$ 0.04	$ 0.06