Commitments and Contingencies (Narrative) (Details) (USD $)	12 Months Ended	0 Months Ended		24 Months Ended	0 Months Ended	1 Months Ended
	Dec. 31, 2014 reactor	Aug. 10, 2011	Aug. 09, 2011	Dec. 31, 2000	Oct. 03, 2012	Dec. 31, 2009	Feb. 08, 2014 gal T	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2015
Insurance [Abstract]
Insured public liability limit per nuclear incident	$ 13,600,000,000
Primary nuclear liability program coverage	375,000,000
Excess nuclear liability program coverage	13,200,000,000
Pro rata assessment for each reactor owned for each incident exceeding public liability insurance	127,000,000
Number of licensed nuclear reactors	104
Annual payment limit to pro rata assessments	19,000,000
Industry aggregate limit	3,200,000,000
Sublimit for non-nuclear terrorist events	1,830,000,000
Sublimit property damage losses	1,500,000,000
Additional nuclear accident limit	1,250,000,000
Insurance Coverage Percentage Initial Weeks	100.00%
Accidental Outage Insurance Coverage Initial Weeks	365 days
Insurance Coverage Percentage Additional Weeks	80.00%
Accidental Outage Insurance Coverage Additional Weeks	770 days
Sublimit accidental outage recovery	328,000,000
Maximum Magnitude of Retroactive Premiums	10
Maximum Period for Retroactive Premium Assessment	6 years
Weeks of Sublimits for Accidental Outage Coverage	728 days
Excess Property Insurance Max Retroactive Assessments	17,000,000
Potential Obligation percentage	100.00%
North Carolina Ash Basins [Member]
Valuation and Qualifying Accounts [Abstract]
Facilities with Ash Basins	14
Ash Basins Fines and Restitution [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	68,000,000
Ash Basins Community Service and Mitigation [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	34,000,000
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent		15.00%	15.00%
Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	89,000,000
Duke Energy Carolinas [Member]
Insurance [Abstract]
Maximum potentional retroactive premium assessments for primary property insurance	73,000,000
Maximum potentional retroactive premium assessments for accidental outage insurance	32,000,000
Duke Energy Carolinas [Member] | McGuire Nuclear Station [Member]
Insurance [Abstract]
Accidental outage insurance coverage policy limit	490,000,000
Duke Energy Carolinas [Member] | Oconee Nuclear Station [Member]
Insurance [Abstract]
Additional Non Nuclear Accident Limit	750,000,000
Accidental outage insurance coverage policy limit	381,000,000
Duke Energy Carolinas [Member] | Catawba Nuclear Station [Member]
Insurance [Abstract]
Additional nuclear accident limit	1,250,000,000
Additional Non Nuclear Accident Limit	750,000,000
Accidental outage insurance coverage policy limit	490,000,000
Excess Property Insurance Max Retroactive Assessments	7,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Environmental Remediation Expense	24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member] | Minimum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated amount of ash released, in tons							30,000
Estimated amount of ash basin water released, in gallons							24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member] | Maximum [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated amount of ash released, in tons							39,000
Estimated amount of ash basin water released, in gallons							27,000,000
Duke Energy Carolinas [Member] | New Source Review Provisions Of Clean Air Act [Member]
Valuation and Qualifying Accounts [Abstract]
Maximum civil penalties per day for each violation				37,500
Projects with Alleged NSR Violations	29
Number of Coal Plants with Alleged NSR Violations	25
Loss contingency, pending claims, number	13
Remaining Number of Coal Plants with Alleged NSR Violations	13
Number of Coal Plants	11
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves	575,000,000							616,000,000
Reinsurance retention policy, amount retained	476,000,000
Reinsurance retention policy, excess retention, amount reinsured	864,000,000
Probable insurance recoveries	616,000,000							649,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number	28
Asbestos-related injuries and damages reserves	7,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number	54
Asbestos-related injuries and damages reserves	11,000,000
Duke Energy Carolinas [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	25,000,000
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
Progress Energy [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	15,000,000
Duke Energy Progress [Member]
Commitments And Contingencies [Line Items]
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Insurance [Abstract]
Maximum potentional retroactive premium assessments for primary property insurance	60,000,000
Maximum potentional retroactive premium assessments for accidental outage insurance	16,000,000
Duke Energy Progress [Member] | Robinson Nuclear Station [Member]
Insurance [Abstract]
Accidental outage insurance coverage policy limit	329,000,000
Duke Energy Progress [Member] | Brunswick Nuclear Station [Member]
Insurance [Abstract]
Accidental outage insurance coverage policy limit	419,000,000
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Insurance [Abstract]
Accidental outage insurance coverage policy limit	384,000,000
Duke Energy Progress [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain related to litigation settlement	83,000,000
Duke Energy Progress [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	1,000,000
Duke Energy Florida [Member]
Commitments And Contingencies [Line Items]
Long-term contract for purchase of electric power, share of plant output being purchased	100.00%
Insurance [Abstract]
Maximum potentional retroactive premium assessments for primary property insurance	8,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Insurance [Abstract]
Sublimit property damage losses	1,100,000,000
Duke Energy Florida [Member] | Spent Nuclear Fuels [Member]
Valuation and Qualifying Accounts [Abstract]
Gain related to litigation settlement	21,000,000
Duke Energy Florida [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	14,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, damages sought, value	510,000,000
Gain contingency, unrecorded amount	54,000,000
Duke Energy Ohio [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	42,000,000
Duke Energy Indiana [Member] | Environmental Reserves [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, range of possible loss, portion not acccrued	7,000,000
Operating Expense [Member] | Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	72,000,000
Operating Expense [Member] | Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	30,000,000
Subsequent Event [Member] | Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required										250,000,000
Subsequent Event [Member] | Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required										$ 250,000,000