Asset Impairment Expense (Tables)

12 Months Ended

Dec. 31, 2014

Impairment or Disposal of Tangible Assets Disclosure [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset

	Years Ended December 31,
	2014		2013		2012
	(in millions)
Ebute	67		—		—
UK Wind	12		—		—
East Bend (DP&L)	12		—		—
Beaver Valley	—		46		—
Conesville (DP&L)	—		26		—
Itabo (San Lorenzo)	—		16		—
U.S. wind turbines and projects	—		—		41
Kelanitissa	—		—		19
St. Patrick	—		—		11
Other	—		7		2
Total asset impairment expense	$	91	$	95	$	73