Commitments and Contingencies (Narrative) (Details) $ in Millions				2 Months Ended	3 Months Ended		12 Months Ended
	Feb. 11, 2020 claim	Jun. 18, 2018 USD ($)	Apr. 26, 2017 claim	Feb. 28, 2019 USD ($)	Dec. 31, 2019 USD ($) plant basin reactor claim	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) plant basin reactor claim	Jun. 13, 2019 claim	Dec. 31, 2018 USD ($)	May 16, 2017 claim
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					98		98
Insured public liability limit per nuclear incident					$ 13,900.0		$ 13,900.0
Excess nuclear liability program coverage					13,500.0		13,500.0
Pro rata assessment for each reactor owned for each incident exceeding public liability insurance					138.0		138.0
Annual payment limit to pro rata assessments					20.5		20.5
Industry aggregate limit					3,200.0		3,200.0
Sublimit for non-nuclear terrorist events					1,800.0		1,800.0
Sublimit property damage losses					1,500.0		1,500.0
Additional nuclear accident limit					$ 1,250.0		$ 1,250.0
Insurance coverage percentage initial weeks					100.00%		100.00%
Accidental outage insurance coverage initial weeks							365 days
Insurance coverage percentage additional weeks					80.00%		80.00%
Accidental outage insurance coverage additional weeks							770 days
Weeks of sublimits for accidental outage coverage							728 days
Sublimit accidental outage recovery					$ 328.0		$ 328.0
Maximum magnitude of retroactive premiums					10		10
Maximum period for retroactive premium assessment							6 years
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment					$ (14.0)	$ 25.0	$ 11.0
Reserves for legal matters					$ 62.0		$ 62.0		$ 65.0
Coal Ash Insurance Coverage Litigation
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Number of NC and SC plants with ash basins | plant					15		15
NCDEQ State Enforcement Actions
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Number of Plants with No Disputed Facts | plant					7		7
Facilities with ash basins | plant					14		14
Number of Plants with Disputed Facts | plant					7		7
Duke Energy Carolinas
Insurance [Abstract]
Primary nuclear liability program coverage					$ 450.0		$ 450.0
Max retroactive premium assessments							155.0
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					2.0		2.0		9.0
Duke Energy Carolinas | Asbestos Issue
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves					604.0		604.0		630.0
Reinsurance retention policy, excess retention, amount reinsured							747.0
Loss contingency, receivable, noncurrent					$ 742.0		$ 742.0		739.0
Duke Energy Carolinas | Asbestos Issue | Non Malignant Asbestos Claim
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim					123		123
Asbestos-related injuries and damages reserves					$ 32.0		$ 32.0
Duke Energy Carolinas | Asbestos Issue | Malignant Asbestos Claim
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim					49		49
Asbestos-related injuries and damages reserves					$ 16.0		$ 16.0
Duke Energy Carolinas | McGuire
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2		2
Accidental outage insurance coverage policy limit					$ 490.0		$ 490.0
Duke Energy Carolinas | Catawba
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2,000,000		2,000,000
Dedicated additional nuclear accident limit					$ 1,250.0		$ 1,250.0
Additional Non-nuclear accident limit					750.0		750.0
Accidental outage insurance coverage policy limit					$ 490.0		$ 490.0
Potential obligation percentage					100.00%		100.00%
Duke Energy Carolinas | Oconee
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					3		3
Additional Non-nuclear accident limit					$ 750.0		$ 750.0
Accidental outage insurance coverage policy limit					$ 406.0		$ 406.0
Duke Energy Carolinas and Duke Energy Progress
Insurance [Abstract]
Number of coal ash basins | basin					9		9
Duke Energy Carolinas and Duke Energy Progress | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					7		7
Duke Energy Carolinas and Duke Energy Progress | Allen | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Carolinas and Duke Energy Progress | Belews Creek | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Mayo | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Roxboro | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					1		1
Duke Energy Carolinas and Duke Energy Progress | Rogers | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Carolinas and Duke Energy Progress | Marshall and Roxboro | Settled agreement
Insurance [Abstract]
Number of coal ash basins | basin					2		2
Duke Energy Florida
Insurance [Abstract]
Primary nuclear liability program coverage					$ 100.0		$ 100.0
Max retroactive premium assessments							1.0
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					22.0		22.0		24.0
Duke Energy Florida | Spent Nuclear Fuel Matters
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Damages sought		$ 203.0
Duke Energy Florida | Fluor Letter Of Credit
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Drawings on credit facility				$ 67.0
Duke Energy Florida | Crystal River Unit 3
Insurance [Abstract]
Sublimit property damage losses					50.0		50.0
Duke Energy Florida | Citrus County Combined Cycle Facility
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment							36.0
Progress Energy
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reduction of prior year impairment					11.0	$ 25.0	36.0
Reserves for legal matters					55.0		55.0		54.0
Duke Energy Progress
Insurance [Abstract]
Primary nuclear liability program coverage					450.0		450.0
Max retroactive premium assessments							94.0
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					$ 12.0		$ 12.0		12.0
Duke Energy Progress | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim										1
Duke Energy Progress | Spent Nuclear Fuel Matters
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Damages sought		$ 100.0
Duke Energy Progress | Subsequent Event | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Claims Dismissed, Number | claim	3
Duke Energy Progress | Robinson
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					1		1
Accidental outage insurance coverage policy limit					$ 364.0		$ 364.0
Duke Energy Progress | Harris
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					1,000,000		1,000,000
Accidental outage insurance coverage policy limit					$ 462.0		$ 462.0
Duke Energy Progress | Brunswick
Insurance [Abstract]
Number of licensed nuclear reactors | reactor					2		2
Accidental outage insurance coverage policy limit					$ 462.0		$ 462.0
Duke Energy Progress | Mayo | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Claims Dismissed, Number | claim			4
Loss contingency, pending claims, number | claim										2
Duke Energy Progress | Roxboro | RRBA Federal Citizens Suits
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim								2
Piedmont
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Reserves for legal matters					$ 1.0		$ 1.0		$ 1.0