Acquisition (Narrative) (Details) (USD $) In Millions, unless otherwise specified		1 Months Ended	0 Months Ended			1 Months Ended	0 Months Ended
	Oct. 11, 2013 Plainfield MW	Aug. 31, 2012 maxIT	Oct. 11, 2013 Minimum Plainfield	Oct. 11, 2013 Maximum Plainfield	Nov. 01, 2013 Secured Debt [Member] Plainfield note	Oct. 31, 2013 Receivable from PRE Holdings Plainfield	Oct. 11, 2013 Connecticut Light and Power Plainfield	Nov. 01, 2013 Carlyle Group Secured Debt [Member] Plainfield	Oct. 11, 2013 Achievement of milestones Plainfield	Oct. 11, 2013 January 2014 or the completion of the collateral transfer Plainfield	Oct. 11, 2013 October 2013 or the successful sale by the Company of project. Plainfield	Oct. 11, 2013 Plainfield
Business Acquisition [Line Items]
Percentage of ownership	100.00%	100.00%
Capacity of the power plant	37.5
Percentage of power to be purchased							80.00%
Term of agreement							15 years
Fuel supply agreement, term			5 years	15 years
Receivable from Plainfield												$ 138
Number of debt instruments					2
Notes, face amount								148
Eligibility for grant, amount	70
Gains (losses) on extinguishment of debt						33
Contingent consideration	6								5	2	3
Cash paid for purchase price	111	505
Business Combination, Consideration Transferred, Liabilities Incurred		$ 13