Acquisitions and Sales of Other Assets (Accounting Charges) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012		Sep. 30, 2012		Sep. 30, 2011
FERC Mitigation			$ 117		$ 0
Severance Costs	146	[1]	146	[1]
Community Support and Charitable Contributions and Other			149
Duke Energy Carolinas [Member]
FERC Mitigation			46		0
Severance Costs	48		48
Community Support and Charitable Contributions and Other			73
Progress Energy Carolinas [Member]
FERC Mitigation			71
Severance Costs			42
Community Support and Charitable Contributions and Other			54
Progress Energy Florida [Member]
Severance Costs			24
Community Support and Charitable Contributions and Other			9
Duke Energy Ohio [Member]
Severance Costs	15		15
Community Support and Charitable Contributions and Other			5
Duke Energy Indiana [Member]
Severance Costs	13		13
Community Support and Charitable Contributions and Other			5
Maximum [Member]
Severance Costs			110
Minimum [Member]
Severance Costs			$ 80

[1] Includes $16 million of COBRA and healthcare reimbursement expenses and $14 million of accelerated stock award expense.