Fair Value (Nonrecurring Measurements) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended					9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Jun. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense	$ 81		$ 43			$ 129		$ 71
Other Nonoperating Expense	122		0			122		50
Goodwill impairment expense	58		1,850			58		1,850
Poland Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	14					14
Asset impairment expense	65		0			65		0
Itabo (San Lorenzo) [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	7	[1]				7	[1]
Asset impairment expense	15		0			15		0
Beaver Valley [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense	0		0			46		0
Wind turbines [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense			20
Ebute [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Goodwill impairment expense	58
Kelanitissa [ Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			10					10
Asset impairment expense	0		5			0		17
Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense			16
St. Patrick [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring					22
Asset impairment expense	0		0		11	0		11
DP&L [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Goodwill impairment expense			1,850
Long Lived Assets Held And Used [Member] | Poland Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						65	[1]
Long Lived Assets Held And Used [Member] | Itabo (San Lorenzo) [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						15	[1]
Long Lived Assets Held And Used [Member] | Beaver Valley [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						46	[1]
Long Lived Assets Held And Used [Member] | Kelanitissa [ Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense								12	[1]
Long Lived Assets Held And Used [Member] | Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense								16	[1]
Long Lived Assets Held For Sale [Member] | Wind turbines [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						0		20	[1]
Long Lived Assets Held For Sale [Member] | St. Patrick [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense								11	[1]
Discontinued operations and held for sale businesses [Member] | Cameroon [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						65	[2]
Discontinued operations and held for sale businesses [Member] | Saurashtra [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						12	[2]
Discontinued operations and held for sale businesses [Member] | Ukraine utilities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset impairment expense						34	[2]
Goodwill [Member] | Ebute [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Goodwill impairment expense						58	[3]
Goodwill [Member] | DP&L [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Goodwill impairment expense								1,850
Equity Method Affiliate [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other Nonoperating Expense								50
Equity Method Affiliate [Member] | Elsta [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other Nonoperating Expense						122	[3]
Carrying Amount [Member] | Long Lived Assets Held And Used [Member] | Poland Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	79	[1]				79	[1]
Carrying Amount [Member] | Long Lived Assets Held And Used [Member] | Itabo (San Lorenzo) [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	22	[1]				22	[1]
Carrying Amount [Member] | Long Lived Assets Held And Used [Member] | Beaver Valley [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	61	[1]				61	[1]
Carrying Amount [Member] | Long Lived Assets Held And Used [Member] | Kelanitissa [ Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			22	[1]				22	[1]
Carrying Amount [Member] | Long Lived Assets Held And Used [Member] | Wind Projects [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			16	[1]				16	[1]
Carrying Amount [Member] | Long Lived Assets Held For Sale [Member] | Wind turbines [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	25	[1]	45	[1]		25	[1]	45	[1]
Carrying Amount [Member] | Long Lived Assets Held For Sale [Member] | St. Patrick [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			33	[1]				33	[1]
Carrying Amount [Member] | Discontinued operations and held for sale businesses [Member] | Cameroon [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	262	[2]				262	[2]
Carrying Amount [Member] | Discontinued operations and held for sale businesses [Member] | Saurashtra [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	19	[2]				19	[2]
Carrying Amount [Member] | Discontinued operations and held for sale businesses [Member] | Ukraine utilities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	143	[2]				143	[2]
Carrying Amount [Member] | Goodwill [Member] | Ebute [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	58	[3]				58	[3]
Carrying Amount [Member] | Goodwill [Member] | DP&L [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			2,449					2,449
Carrying Amount [Member] | Equity Method Affiliate [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			205					205
Carrying Amount [Member] | Equity Method Affiliate [Member] | Elsta [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	240	[3]				240	[3]
Fair Value [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	154					154
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Poland Wind Projects [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	14	[1]				14	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Itabo (San Lorenzo) [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	7	[1]				7	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	15	[1]				15	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Kelanitissa [ Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Kelanitissa [ Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held And Used [Member] | Kelanitissa [ Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			10	[1]				10	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | Wind turbines [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | Wind turbines [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	25	[1]				25	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | Wind turbines [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[1]	25	[1]		0	[1]	25	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | St. Patrick [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0	[1]				0	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | St. Patrick [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			22	[1]				22	[1]
Fair Value [Member] | Long Lived Assets Held For Sale [Member] | St. Patrick [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0	[1]				0	[1]
Fair Value [Member] | Discontinued operations and held for sale businesses [Member] | Cameroon [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	199	[2]				199	[2]
Fair Value [Member] | Discontinued operations and held for sale businesses [Member] | Saurashtra [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	7	[2]				7	[2]
Fair Value [Member] | Discontinued operations and held for sale businesses [Member] | Ukraine utilities [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[2]				0	[2]
Fair Value [Member] | Discontinued operations and held for sale businesses [Member] | Ukraine utilities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	113	[2]				113	[2]
Fair Value [Member] | Discontinued operations and held for sale businesses [Member] | Ukraine utilities [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0	[2]				0	[2]
Fair Value [Member] | Goodwill [Member] | DP&L [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			599					599
Fair Value [Member] | Equity Method Affiliate [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0					0
Fair Value [Member] | Equity Method Affiliate [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			155					155
Fair Value [Member] | Equity Method Affiliate [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring			0					0
Fair Value [Member] | Equity Method Affiliate [Member] | Elsta [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	$ 118	[3]				$ 118	[3]

[1] See Note 14 — Asset Impairment Expense for further information.

[2] See Note 16 — Discontinued Operations and Held-For-Sale Businesses for further information. Also, the gross loss equals the carrying amount of the disposal group less its fair value less costs to sell.

[3] See Note 15 — Other Non-Operating Expense for further information.