Asset Impairment Expense (Impairment of Long-Lived Assets Held and Used by Asset) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended							3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Beaver Valley		Dec. 31, 2012 Beaver Valley	Dec. 31, 2011 Beaver Valley	Dec. 31, 2013 DP&L (Conesville)		Dec. 31, 2012 DP&L (Conesville)	Dec. 31, 2011 DP&L (Conesville)	Dec. 31, 2013 Itabo (San Lorenzo)		Dec. 31, 2012 Itabo (San Lorenzo)	Dec. 31, 2011 Itabo (San Lorenzo)	Dec. 31, 2013 Wind Turbines And Projects	Dec. 31, 2012 Wind Turbines And Projects	Dec. 31, 2011 Wind Turbines And Projects	Dec. 31, 2013 Kelanitissa	Dec. 31, 2012 Kelanitissa	Dec. 31, 2011 Kelanitissa	Dec. 31, 2013 St. Patrick	Dec. 31, 2012 St. Patrick	Dec. 31, 2011 St. Patrick	Dec. 31, 2013 Other Impairment	Dec. 31, 2012 Other Impairment	Dec. 31, 2011 Other Impairment
Debt Instrument [Line Items]
Asset impairment expense	$ 95	$ 73	$ 173	$ 46	[1]	$ 0	$ 0	$ 26	[1]	$ 0	$ 0	$ 16	[1]	$ 0	$ 0	$ 0	$ 41	$ 116	$ 0	$ 19	$ 42	$ 0	$ 11	$ 0	$ 7	$ 2	$ 15

[1] See Note 21 — Asset Impairment Expense for further information.