Employee Benefit Plans (Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	$ 1,111	$ 1,088
Regulatory assets	13,901	12,250
Regulatory liabilities	7,290	6,655
Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	97	107
Regulatory assets	3,397	3,071
Regulatory liabilities	3,001	2,841
Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	547	536
Regulatory assets	6,123	5,797
Regulatory liabilities	2,584	2,673
Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	252	262
Regulatory assets	3,431	2,974
Regulatory liabilities	2,104	1,963
Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	262	242
Regulatory assets	2,693	2,823
Regulatory liabilities	479	709
Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	56	56
Regulatory assets	557	533
Regulatory liabilities	257	257
Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	71	80
Regulatory assets	1,222	818
Regulatory liabilities	788	816
Pension Plan [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	518	474
Noncurrent pension liability	118	65
Net amount recognized	400	409
Regulatory assets	2,098	1,884
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(41)	(45)
Prior year service cost (credit) arising during the year	(6)	(4)
Net actuarial loss (gain)	123	130
Net amount recognized in accumulated other comprehensive income (loss)	76	81
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	147
Unrecognized prior service (credit) cost	(24)
Pension Plan [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	273	252
Noncurrent pension liability		4
Net amount recognized	273	248
Regulatory assets	476	472
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	31
Unrecognized prior service (credit) cost	(8)
Pension Plan [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	225	232
Noncurrent pension liability	62	43
Net amount recognized	163	189
Regulatory assets	805	771
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(6)	(6)
Net actuarial loss (gain)	16	17
Net amount recognized in accumulated other comprehensive income (loss)	10	11
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	52
Unrecognized prior service (credit) cost	(3)
Pension Plan [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	132	145
Noncurrent pension liability		4
Net amount recognized	132	141
Regulatory assets	378	360
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	23
Unrecognized prior service (credit) cost	(2)
Pension Plan [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	91	84
Noncurrent pension liability	62	39
Net amount recognized	29	45
Regulatory assets	426	410
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	29
Unrecognized prior service (credit) cost	(1)
Pension Plan [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension	6	1
Noncurrent pension liability	25	21
Net amount recognized	(19)	(20)
Regulatory assets	81	79
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	5
Pension Plan [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Prefunded pension		6
Noncurrent pension liability	1
Net amount recognized	(1)	6
Regulatory assets	171	162
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	8
Unrecognized prior service (credit) cost	(2)
Brazilian Retirement Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Net amount recognized in accumulated other comprehensive income (loss)		13
Non-Qualified Pension Plans [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	28	27
Noncurrent pension liability	304	314
Total accrued pension liability	332	341
Regulatory assets	73	76
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(3)	(3)
Prior year service cost (credit) arising during the year	(1)
Net actuarial loss (gain)	10	9
Net amount recognized in accumulated other comprehensive income (loss)	6	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	7
Unrecognized prior service (credit) cost	(2)
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	12	14
Total accrued pension liability	14	16
Regulatory assets	5	7
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	8	8
Noncurrent pension liability	106	104
Total accrued pension liability	114	112
Regulatory assets	18	16
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax asset	(3)	(3)
Net actuarial loss (gain)	9	9
Net amount recognized in accumulated other comprehensive income (loss)	6	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	2
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	3
Noncurrent pension liability	31	30
Total accrued pension liability	33	33
Regulatory assets	7	6
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	3	3
Noncurrent pension liability	43	43
Total accrued pension liability	46	46
Regulatory assets	11	10
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	1
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0
Noncurrent pension liability	4	4
Total accrued pension liability	4	4
Regulatory assets	1	1
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	0
Noncurrent pension liability	3	5
Total accrued pension liability	3	5
Regulatory assets	0	1
Other Post-Retirement Benefit Plans [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	38	37
Noncurrent pension liability	586	583
Total accrued pension liability	624	620
Regulatory assets	54	1
Regulatory liabilities	174	288
Accumulated Other Comprehensive Income (Loss) [Abstract]
Deferred income tax liability	5	7
Prior year service cost (credit) arising during the year	(5)	(6)
Net actuarial loss (gain)	(10)	(13)
Net amount recognized in accumulated other comprehensive income (loss)	(10)	(12)
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	10
Unrecognized prior service (credit) cost	(115)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	64	66
Total accrued pension liability	64	66
Regulatory liabilities	46	68
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(2)
Unrecognized prior service (credit) cost	(10)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	31	31
Noncurrent pension liability	325	323
Total accrued pension liability	356	354
Regulatory assets	48	1
Regulatory liabilities		51
Accumulated Other Comprehensive Income (Loss) [Abstract]
Prior year service cost (credit) arising during the year		(1)
Net amount recognized in accumulated other comprehensive income (loss)		(1)
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	21
Unrecognized prior service (credit) cost	(85)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	17	16
Noncurrent pension liability	174	172
Total accrued pension liability	191	188
Regulatory assets	38
Regulatory liabilities		25
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	12
Unrecognized prior service (credit) cost	(55)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	15	15
Noncurrent pension liability	149	149
Total accrued pension liability	164	164
Regulatory assets	10	1
Regulatory liabilities		26
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	9
Unrecognized prior service (credit) cost	(30)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Current pension liability	2	2
Noncurrent pension liability	23	25
Total accrued pension liability	25	27
Regulatory liabilities	19	21
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(2)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Amounts Recognized in Consolidated Balance Sheets [Abstract]
Noncurrent pension liability	63	68
Total accrued pension liability	63	68
Regulatory assets	51	57
Regulatory liabilities	71	$ 83
Amounts to be recognized in net periodic pension expense in the next year [Abstract]
Unrecognized net actuarial loss	(6)
Unrecognized prior service (credit) cost	$ (1)