Acquisitions and Dispositions (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Midwest Generation Business [Member]	Jun. 30, 2014 Midwest Generation Business [Member]	Jun. 30, 2014 Duke Energy Ohio [Member]	Jun. 30, 2013 Duke Energy Ohio [Member]	Jun. 30, 2014 Duke Energy Ohio [Member]	Jun. 30, 2013 Duke Energy Ohio [Member]	Jun. 30, 2014 Duke Energy Ohio [Member] Midwest Generation Business [Member]	Jun. 30, 2014 Duke Energy Ohio [Member] Midwest Generation Business [Member]	Jun. 30, 2014 Duke Energy Progress [Member]	Jun. 30, 2013 Duke Energy Progress [Member]	Jun. 30, 2014 Duke Energy Progress [Member]	Jun. 30, 2013 Duke Energy Progress [Member]	Dec. 31, 2016 Scenario Forecast [Member] Duke Energy Progress [Member] NCEMPA Generating Assets [Member]
Significant Acquisitions and Disposals [Line Items]
Impairment charges	$ 6,000,000	$ 386,000,000	$ 1,388,000,000	$ 386,000,000		$ 1,402,000,000	$ 21,000,000		$ 1,438,000,000			$ 1,438,000,000	$ (18,000,000)	$ 22,000,000	$ (18,000,000)	$ 22,000,000
Avoided Depreciation on Assets Held for Sale					42,000,000	42,000,000					42,000,000	42,000,000
Payments to acquire businesses																	$ 1,200,000,000