Acquisitions and Dispositions (Assets Held For Sale) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax	$ (1)	$ (57)	$ 2	$ 34
Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax		(65)	$ 2	25
Midwest Generation Business [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues				543
Loss on disposition		6		(37)
Income before income taxes		(80)		67
Income tax expense		(21)		30
Income From Discontinued Operations, net of tax		(59)		37
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues				412
Loss on disposition				(44)
Income before income taxes		(88)		52
Income tax expense		(23)		27
Income From Discontinued Operations, net of tax		(65)		25
Other Disposal Groups [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax		2		(3)
Antitrust Lawsuit [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation Settlement, Expense		71		81
Antitrust Lawsuit [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation Settlement, Expense		$ 71		$ 81