Commitments and Contingencies Commitments and Contingencies - Legal Matters (Details) (USA Power [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Loss Contingencies [Line Items]
Loss Contingency, Original Damages Sought, Legal Fees as a Percentage of Damages	40.00%
Loss Contingency, Damages Awarded, Value	$ 113
Loss Contingency, Damages and Attorney Fees Awarded, Value	115
Loss Contingency Accrual, at Carrying Value	117
Amount Awarded for Actual Damages [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded by Jury, Value	18
Amount Awarded for Unjust Enrichment [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded by Jury, Value	$ 113