Fair Value (Nonrecurring Measurements) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset Impairment Charges	$ 48	$ 10
Other non-operating expense	0	49
Long Lived Assets Held And Used [Member] | Beaver Valley [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset Impairment Charges	46
Long Lived Assets Held And Used [Member] | Kelanitissa [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Asset Impairment Charges		5
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
Other non-operating expense	38
Equity Method Affiliate [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other non-operating expense		49
Carrying Amount | Long Lived Assets Held And Used [Member] | Beaver Valley [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	61
Carrying Amount | Long Lived Assets Held And Used [Member] | Kelanitissa [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		22
Carrying Amount | Long Lived Assets Held For Sale [Member] | Wind Turbines [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	25
Carrying Amount | Equity Method Affiliate [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		204
Fair Value | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	40
Fair Value | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 1
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 2
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Long Lived Assets Held And Used [Member] | Beaver Valley [Member] | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	15
Fair Value | Long Lived Assets Held And Used [Member] | Kelanitissa [Member] | Level 1
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		0
Fair Value | Long Lived Assets Held And Used [Member] | Kelanitissa [Member] | Level 2
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		0
Fair Value | Long Lived Assets Held And Used [Member] | Kelanitissa [Member] | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		17
Fair Value | Long Lived Assets Held For Sale [Member] | Wind Turbines [Member] | Level 1
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Long Lived Assets Held For Sale [Member] | Wind Turbines [Member] | Level 2
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Long Lived Assets Held For Sale [Member] | Wind Turbines [Member] | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	25
Fair Value | Discontinued operations and held for sale businesses [Member] | Ukraine Utilities [Member] | Level 1
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Discontinued operations and held for sale businesses [Member] | Ukraine Utilities [Member] | Level 2
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	109
Fair Value | Discontinued operations and held for sale businesses [Member] | Ukraine Utilities [Member] | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring	0
Fair Value | Equity Method Affiliate [Member] | Level 1
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		0
Fair Value | Equity Method Affiliate [Member] | Level 2
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		155
Fair Value | Equity Method Affiliate [Member] | Level 3
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Fair Value, Nonrecurring		$ 0