Income Taxes (Effective Tax Rates) (Details) (USD $)	12 Months Ended			96 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2022
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 1,447,000,000	$ 1,328,000,000	$ 782,000,000
State income tax, net of federal income tax effect	59,000,000	66,000,000	65,000,000
Tax differential on foreign earnings	(110,000,000)	(49,000,000)	(69,000,000)
AFUDC equity income	(47,000,000)	(55,000,000)	(101,000,000)
Renewable energy production tax credits	(67,000,000)	(62,000,000)	(25,000,000)
International Tax Dividend	373,000,000
Other items, net	14,000,000	(23,000,000)	(29,000,000)
Income tax expense (benefit) from continuing operations	1,669,000,000	1,205,000,000	623,000,000
Effective tax rate	40.40%	31.80%	27.90%
State [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Net reduction in deferred tax liability		145,000,000
State [Member] | Current [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.90%
State [Member] | January 2014 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.00%
State [Member] | January 2015 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		5.00%
Foreign Jurisdictions [Member] | Merger of Subsidiaries [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense (benefit) from continuing operations	(57,000,000)
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	581,000,000	549,000,000	461,000,000
State income tax, net of federal income tax effect	17,000,000	56,000,000	34,000,000
AFUDC equity income	(32,000,000)	(32,000,000)	(54,000,000)
Other items, net	22,000,000	21,000,000	12,000,000
Income tax expense (benefit) from continuing operations	588,000,000	594,000,000	453,000,000
Effective tax rate	35.40%	37.80%	34.30%
Duke Energy Carolinas [Member] | State [Member] | Current [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.90%
Duke Energy Carolinas [Member] | State [Member] | January 2014 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.00%
Duke Energy Carolinas [Member] | State [Member] | January 2015 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		5.00%
Progress Energy [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	497,000,000	361,000,000	185,000,000
State income tax, net of federal income tax effect	49,000,000	31,000,000	33,000,000
AFUDC equity income	(9,000,000)	(18,000,000)	(37,000,000)
Other items, net	3,000,000	(1,000,000)	(9,000,000)
Income tax expense (benefit) from continuing operations	540,000,000	373,000,000	172,000,000
Effective tax rate	38.00%	36.20%	32.70%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	263,000,000	276,000,000	134,000,000
State income tax, net of federal income tax effect	25,000,000	31,000,000	1,000,000
AFUDC equity income	(9,000,000)	(15,000,000)	(24,000,000)
Other items, net	6,000,000	(4,000,000)	(1,000,000)
Income tax expense (benefit) from continuing operations	285,000,000	288,000,000	110,000,000
Effective tax rate	37.90%	36.50%	28.70%
Duke Energy Progress [Member] | State [Member] | Current [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.90%
Duke Energy Progress [Member] | State [Member] | January 2014 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		6.00%
Duke Energy Progress [Member] | State [Member] | January 2015 [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Statutory tax rate		5.00%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	314,000,000	188,000,000	145,000,000
State income tax, net of federal income tax effect	34,000,000	20,000,000	14,000,000
AFUDC equity income		(3,000,000)	(13,000,000)
Other items, net	1,000,000	8,000,000	1,000,000
Income tax expense (benefit) from continuing operations	349,000,000	213,000,000	147,000,000
Effective tax rate	38.90%	39.60%	35.70%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	39,000,000	39,000,000	27,000,000
State income tax, net of federal income tax effect	3,000,000	2,000,000	2,000,000
AFUDC equity income	(1,000,000)		(2,000,000)
Other items, net	2,000,000	2,000,000	6,000,000
Income tax expense (benefit) from continuing operations	43,000,000	43,000,000	33,000,000
Effective tax rate	38.90%	39.10%	42.90%
Duke Energy Indiana [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Income tax expense, computed at the statutory rate of 35%	195,000,000	203,000,000	(43,000,000)
State income tax, net of federal income tax effect	10,000,000	23,000,000	1,000,000
AFUDC equity income	(5,000,000)	(5,000,000)	(26,000,000)
Other items, net	(3,000,000)	2,000,000	(5,000,000)
Income tax expense (benefit) from continuing operations	197,000,000	223,000,000	(73,000,000)
Effective tax rate	35.50%	38.40%	59.50%
Scenario, Forecast [Member] | International Energy [Member]
Income Tax Disclosure [Line Items]
Foreign Earnings Repatriated				$ 2,700,000,000