Leasing Activities (Capital Lease Assets Recorded Within Property, Plant And Equipment) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Capital Leased Assets [Line Items]
Original Cost	$ 155	$ 155
Accumulated Amortization	69	61
Net Book Value	86	94
Electric Transmission Equipment [Member]
Capital Leased Assets [Line Items]
Original Cost	76	76
Accumulated Amortization	33	29
Net Book Value	43	47
Electric Distribution Equipment [Member]
Capital Leased Assets [Line Items]
Original Cost	76	76
Accumulated Amortization	33	29
Net Book Value	43	47
General Equipment [Member]
Capital Leased Assets [Line Items]
Original Cost	3	3
Accumulated Amortization	$ 3	$ 3