Dispositions (Assets Held For Sale) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	$ 515	$ 0
Current liabilities	222	7
Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	442
Current liabilities	189	0
Midwest Generation Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	515
Investments and other assets	209
Property, plant and equipment	2,025
Total assets held for sale	2,749
Current liabilities	222
Deferred credits and other liabilities	56
Total liabilities associated with assets held for sale	278
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	442
Investments and other assets	179
Property, plant and equipment	1,988
Total assets held for sale	2,609
Current liabilities	189
Deferred credits and other liabilities	55
Total liabilities associated with assets held for sale	$ 244