Commitments and Contingencies (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013		Dec. 31, 2012		Dec. 31, 2009
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	$ 57,000,000
Probable insurance recoveries	781,000,000	[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]
Amount of claim(s)	95,000,000
Alaskan Global Warming Lawsuit [Member] | Maximum [Member]
Valuation and Qualifying Accounts [Abstract]
Amount of claim(s)	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]
Amount of claim(s)	1,200,000,000
Settlement offer, all defendants	800,000,000
Settlement offer, individually named defendants	350,000,000
Loss contingency, interest payments	252,000,000
Loss contingency, bank fee payments	15,000,000
Settlement offer to plaintiffs, partial	50,000,000
AntiTrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Amount of claim(s)	99,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	29,000,000
Probable insurance recoveries	781,000,000	[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]
Number of nonmalignant asbestos related claims	131
Cumulative relief sought for nonmalignant asbestos related claims	32,000,000
Number of malignant asbestos related claims	37
Cumulative relief sought for malignant asbestos related claims	10,000,000
Asbestos-related injuries and damages reserves	732,000,000		751,000,000
Asbestos-related injuries and damages self insured retention	476,000,000
Policy limit for potential future insurance recoveries for indemnification and medical cost claim payments in excess of self insured limit	935,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	6,000,000
Progress Energy [Member] | Synthetic Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Judgment payment					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 exposure in excess of accrual, high estimate	3,000,000
Duke Energy Progress [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency asserted damage	84,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	3,000,000
Duke Energy Florida [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency asserted damage	21,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	17,000,000
Duke Energy Indiana [Member]
Valuation and Qualifying Accounts [Abstract]
Loss exposure in excess of accrual, high estimate	$ 5,000,000

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

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