Acquisitions and Sales of Other Assets (Accounting Charges) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Significant Acquisitions and Disposals [Line Items]
Severance Costs	$ 201	[1]		$ 172
FERC Mitigation	117		0	0
Community Support and Charitable Contributions and Other	169
Duke Energy Carolinas [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	63			99
FERC Mitigation	46		0	0
Community Support and Charitable Contributions and Other	79
Progress Energy [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	82
FERC Mitigation	71		0	0
Community Support and Charitable Contributions and Other	74
Progress Energy Carolinas [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	55
FERC Mitigation	71		0	0
Community Support and Charitable Contributions and Other	63
Progress Energy Florida [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	27
Community Support and Charitable Contributions and Other	11
Duke Energy Ohio [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	21			24
Community Support and Charitable Contributions and Other	7
Duke Energy Indiana [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	18			33
Community Support and Charitable Contributions and Other	6
Progress Merger [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	196
Progress Merger [Member] | Duke Energy Carolinas [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	63
Progress Merger [Member] | Progress Energy [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	82
Progress Merger [Member] | Progress Energy Carolinas [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	55
Progress Merger [Member] | Progress Energy Florida [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	27
Progress Merger [Member] | Duke Energy Ohio [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	21
Progress Merger [Member] | Duke Energy Indiana [Member]
Significant Acquisitions and Disposals [Line Items]
Severance Costs	$ 18

[1] Includes $14 million of accelerated stock award expense and $19 million of COBRA and healthcare reimbursement expenses for 2012.