Income Taxes (Effective Tax Rates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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%	$ 1,307	$ 1,369	$ 1,317
State income tax, net of federal income tax effect	64	109	59
AFUDC equity income	(70)	(58)	(47)
Renewable energy production tax credits	(97)	(72)	(67)
Audit Adjustment	5	(22)
Tax true-up	(14)	2
Other items, net	(39)	(72)	(37)
Income tax expense (benefit) from continuing operations	$ 1,156	$ 1,256	$ 1,225
Effective tax rate	31.00%	32.10%	32.60%
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%	$ 630	$ 598	$ 581
State income tax, net of federal income tax effect	46	46	17
AFUDC equity income	(36)	(34)	(32)
Audit Adjustment	3
Tax true-up	(14)	2
Other items, net	5	15	22
Income tax expense (benefit) from continuing operations	$ 634	$ 627	$ 588
Effective tax rate	35.20%	36.70%	35.40%
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%	$ 548	$ 555	$ 497
State income tax, net of federal income tax effect	20	18	49
AFUDC equity income	(26)	(19)	(9)
Renewable energy production tax credits		(1)
Audit Adjustment		(23)
Tax true-up	(11)	(3)
Other items, net	(4)	(5)	3
Income tax expense (benefit) from continuing operations	$ 527	$ 522	$ 540
Effective tax rate	33.70%	32.90%	38.00%
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%	$ 315	$ 302	$ 263
State income tax, net of federal income tax effect	10	15	25
AFUDC equity income	(17)	(17)	(9)
Audit Adjustment		1
Tax true-up	(3)	(4)
Other items, net	(4)	(3)	6
Income tax expense (benefit) from continuing operations	$ 301	$ 294	$ 285
Effective tax rate	33.40%	34.20%	37.90%
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%	$ 306	$ 330	$ 314
State income tax, net of federal income tax effect	30	33	34
AFUDC equity income	(9)	(3)
Audit Adjustment		(24)
Tax true-up	(9)	2
Other items, net	4	4	1
Income tax expense (benefit) from continuing operations	$ 322	$ 342	$ 349
Effective tax rate	36.90%	36.30%	38.90%
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%	$ 95	$ 81	$ 39
State income tax, net of federal income tax effect	(2)	2	3
AFUDC equity income	(2)	(1)	(1)
Tax true-up	(16)	(5)
Other items, net	3	4	2
Income tax expense (benefit) from continuing operations	$ 78	$ 81	$ 43
Effective tax rate	28.90%	35.20%	38.90%
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%	$ 212	$ 168	$ 195
State income tax, net of federal income tax effect	11	2	10
AFUDC equity income	(6)	(4)	(5)
Tax true-up	2	(9)
Other items, net	6	6	(3)
Income tax expense (benefit) from continuing operations	$ 225	$ 163	$ 197
Effective tax rate	37.10%	34.00%	35.50%