Subsequent Events (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 29, 2015
Subsequent Event [Line Items]
Proceeds from sales of property, plant and equipment	$ 1,467,046,000	$ 1,650,000	$ 99,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Percentage of interest in oil and gas property sold during period				10.00%
Proceeds from sales of property, plant and equipment				$ 417,200,000