SCHEDULE I - CONDENSED UNCONSOLIDATED BALANCE SHEETS (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current Assets
Cash and cash equivalents	$ 901,000,000	$ 1,202,000,000	$ 925,000,000	$ 801,000,000
Other current assets	49,000,000	28,000,000
Total Current Assets	5,068,000,000	6,426,000,000
Other Noncurrent Assets
Other noncurrent assets	637,000,000	790,000,000
Total Other Noncurrent Assets	7,775,000,000	8,238,000,000
Total Assets	43,634,000,000	42,648,000,000
Current Liabilities
Taxes	90,000,000	65,000,000
Other current liabilities	1,219,000,000	1,325,000,000
Total Current Liabilities	5,625,000,000	5,255,000,000
Long-term Debt
Long-term Debt	18,725,000,000	17,993,000,000
L G And E And K U Energy L L C Unconsolidated [Member]
Current Assets
Cash and cash equivalents		2,000,000
Accounts receivable from affiliates	4,000,000	11,000,000
Notes receivable from affiliates	1,560,000,000	1,520,000,000
Other current assets	1,000,000	4,000,000
Total Current Assets	1,565,000,000	1,537,000,000
Investments
Affiliated companies at equity	4,096,000,000	4,056,000,000
Other Noncurrent Assets
Deferred income taxes	184,000,000	163,000,000
Other noncurrent assets	7,000,000	8,000,000
Total Other Noncurrent Assets	191,000,000	171,000,000
Total Assets	5,852,000,000	5,764,000,000
Current Liabilities
Notes payable to affiliates	25,000,000
Accounts payable to affiliates	906,000,000	701,000,000
Taxes	8,000,000
Other current liabilities	6,000,000	6,000,000
Total Current Liabilities	945,000,000	707,000,000
Long-term Debt
Long-term Debt	1,121,000,000	1,120,000,000
Notes payable to affiliates		196,000,000
Total Long-term Debt	1,121,000,000	1,316,000,000
Members Equity	3,786,000,000	3,741,000,000
Total Liabilities and Equity	$ 5,852,000,000	$ 5,764,000,000