Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current state taxes	$ (15)	$ (12)	$ 56
Current foreign taxes	2	4	6
Total current income taxes	(13)	(8)	62
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	1,064	1,097	1,144
Deferred state taxes	117	181	35
Total deferred income taxes	1,181	1,278	1,179
Investment tax credit amortization	(12)	(14)	(16)
Income tax expense (benefit) from continuing operations	1,156	1,256	1,225
Tax expense (benefit) from discontinued operations	(30)	89	149
Total income tax expense included in Consolidated Statements of Operations	1,126	1,345	1,374
Net operating loss utilization			1,544
Net operating loss carry forward	648	264
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Domestic	3,689	3,831	3,637
Foreign	45	79	126
Total income from continuing operations before income taxes	3,734	3,910	3,763
Taxes on Foreign Earnings [Abstract]
Undistributed Earnings of Foreign Subsidiaries			2,700
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			373
Duke Energy Carolinas [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	139	216	161
Current state taxes	25	14	51
Total current income taxes	164	230	212
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	430	345	407
Deferred state taxes	45	57	(25)
Total deferred income taxes	475	402	382
Investment tax credit amortization	(5)	(5)	(6)
Income tax expense (benefit) from continuing operations	634	627	588
Total income tax expense included in Consolidated Statements of Operations	634	627	588
Net operating loss utilization			345
Net operating loss carry forward	4	15
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	1,800	1,708	1,660
Progress Energy [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	15	(193)	(466)
Current state taxes	(19)	1	(8)
Total current income taxes	(4)	(192)	(474)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	486	694	938
Deferred state taxes	50	27	84
Total deferred income taxes	536	721	1,022
Investment tax credit amortization	(5)	(7)	(8)
Income tax expense (benefit) from continuing operations	527	522	540
Tax expense (benefit) from discontinued operations	1	(1)	(4)
Total income tax expense included in Consolidated Statements of Operations	528	521	536
Net operating loss utilization			530
Net operating loss carry forward	190	119
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	1,566	1,587	1,420
Duke Energy Progress [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(59)	(56)	(184)
Current state taxes	(25)	(4)	14
Total current income taxes	(84)	(60)	(170)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	350	334	436
Deferred state taxes	40	27	25
Total deferred income taxes	390	361	461
Investment tax credit amortization	(5)	(7)	(6)
Income tax expense (benefit) from continuing operations	301	294	285
Total income tax expense included in Consolidated Statements of Operations	301	294	285
Net operating loss utilization			291
Net operating loss carry forward	60	21
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	900	860	752
Duke Energy Florida [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	76	1	(53)
Current state taxes	22	(7)	1
Total current income taxes	98	(6)	(52)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	199	290	350
Deferred state taxes	25	58	52
Total deferred income taxes	224	348	402
Investment tax credit amortization			(1)
Income tax expense (benefit) from continuing operations	322	342	349
Total income tax expense included in Consolidated Statements of Operations	322	342	349
Net operating loss utilization			64
Net operating loss carry forward	49	84
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	873	941	897
Duke Energy Ohio [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	(7)	(18)	(73)
Current state taxes	(13)	(1)	3
Total current income taxes	(20)	(19)	(70)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	88	96	113
Deferred state taxes	11	5	1
Total deferred income taxes	99	101	114
Investment tax credit amortization	(1)	(1)	(1)
Income tax expense (benefit) from continuing operations	78	81	43
Tax expense (benefit) from discontinued operations	(36)	22	(300)
Total income tax expense included in Consolidated Statements of Operations	42	103	(257)
Net operating loss utilization			56
Net operating loss carry forward	26	3
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	270	230	111
Duke Energy Indiana [Member]
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal taxes	7	(86)	(112)
Current state taxes	6	(12)	1
Total current income taxes	13	(98)	(111)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred federal taxes	202	245	294
Deferred state taxes	11	17	15
Total deferred income taxes	213	262	309
Investment tax credit amortization	(1)	(1)	(1)
Income tax expense (benefit) from continuing operations	225	163	197
Total income tax expense included in Consolidated Statements of Operations	225	163	197
Net operating loss utilization			141
Net operating loss carry forward	58	45
Duke Energy Income from Continuing Operations Before Income Taxes [Abstract]
Total income from continuing operations before income taxes	606	$ 479	$ 556
Previously Remitted Earnings [Member]
Taxes on Foreign Earnings [Abstract]
Foreign Income Tax Expense (Benefit)	$ (95)