Commitments and Contingencies (Narrative) (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2013		Dec. 31, 2009	Dec. 31, 2012
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	$ 75,000,000
Probable insurance recoveries	649,000,000	[1],[2]		781,000,000	[1],[2]
Minimum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated cost of complying with recently issued and proposed EPA regulations	5,000,000,000
Maximum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated cost of complying with recently issued and proposed EPA regulations	6,000,000,000
Alaskan Global Warming Lawsuit [Member] | Minimum [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Sought, Value	95,000,000
Alaskan Global Warming Lawsuit [Member] | Maximum [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Sought, Value	400,000,000
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent	15.00%
Crescent Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Sought, Value	1,200,000,000
Settlement offer to plaintiffs, partial	50,000,000
Crescent Litigation [Member] | Interest Expense [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Sought, Value	252,000,000
Crescent Litigation [Member] | Bank Fees Member [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Sought, Value	15,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	29,000,000
Probable insurance recoveries	649,000,000	[1],[2]		781,000,000	[1],[2]
Duke Energy Carolinas [Member] | New Source Review Provisions Of Clean Air Act [Member]
Valuation and Qualifying Accounts [Abstract]
New Source Review maximum civil penalties per day for each violation	37,500
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Liability for Asbestos and Environmental Claims, Gross	633,000,000			751,000,000
Reinsurance Retention Policy, Amount Retained	476,000,000
Reinsurance Retention Policy, Excess Retention, Amount Reinsured	897,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Pending Claims, Number	35
Liability for Asbestos and Environmental Claims, Gross	11,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Pending Claims, Number	157
Liability for Asbestos and Environmental Claims, Gross	30,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	6,000,000
Progress Energy [Member] | Synthetic Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Damages Paid, Value			154,000,000
Damages awarded to plaintiff	90,000,000
Gain recognized in period				63,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	3,000,000
Duke Energy Progress [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain Contingency, Unrecorded Amount	84,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	3,000,000
Duke Energy Florida [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain Contingency, Unrecorded Amount	21,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	35,000,000
Duke Energy Indiana [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Acccrued	5,000,000
Duke Energy Indiana [Member] | Edwardsport Igcc Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Gain Contingency, Unrecorded Amount	$ 560,000,000

[1] Insurance recoveries are classified on the Condensed Consolidated Balance Sheets in Other within Investments and Other Assets and Receivables.

[2] Relates to recoveries associated with asbestos-related injuries and damages claims.