Asset Impairment Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 8	$ 12
East Bend DPL [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	0	12
Generation capacity mega watts		186
Assets, fair value		2
Other Impairment [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 8	$ 0