Asset Impairment Expense (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended
	Jan. 09, 2013 MW	Mar. 31, 2014	Mar. 31, 2013
Asset Impairment Expense [Line Items]
Asset impairment expense		$ 12	$ 48
Beaver Valley [Member]
Asset Impairment Expense [Line Items]
Asset impairment expense		0	46
Generation capacity mega watts	125
Lump sum payment received for termination of PPA	60
East Bend DPL [Member]
Asset Impairment Expense [Line Items]
Asset impairment expense		12	0
Generation capacity mega watts		186
Assets, fair value		2
Other Impairment [Member]
Asset Impairment Expense [Line Items]
Asset impairment expense		$ 0	$ 2