Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating Revenues
Regulated electric	$ 6,091	$ 6,303	$ 16,122	$ 16,321
Regulated natural gas	247	89	1,168	355
Nonregulated electric and other	144	184	476	490
Total operating revenues	6,482	6,576	17,766	17,166
Operating Expenses
Fuel used in electric generation and purchased power	1,863	2,031	4,853	5,140
Cost of natural gas	68	6	402	64
Operation, maintenance and other	1,442	1,460	4,282	4,227
Depreciation and amortization	900	819	2,594	2,402
Property and other taxes	313	302	924	887
Impairment charges	207	10	216	14
Total operating expenses	4,793	4,628	13,271	12,734
Gains (Losses) on Sales of Other Assets and Other, net	6	6	24	21
Operating Income (Loss)	1,695	1,954	4,519	4,453
Other Income and Expenses
Equity in earnings (losses) of unconsolidated affiliates	36	(60)	101	(37)
Other income and expenses, net	88	86	255	237
Total other income and expenses	124	26	356	200
Interest Expense	498	464	1,475	1,431
Income (Loss) From Continuing Operations Before Income Taxes	1,321	1,516	3,400	3,222
Income Tax Expense (Benefit) from Continuing Operations	364	515	1,035	1,020
Income from Continuing Operations	957	1,001	2,365	2,202
(Loss) Income From Discontinued Operations, net of tax	(2)	180	(4)	190
Net income	955	1,181	2,361	2,392
Less: Net Income Attributable to Noncontrolling Interests	1	5	5	13
Net Income (Loss) Attributable to Parent	954	1,176	2,356	2,379
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	0	0	2	2
Net unrealized (losses) gains on cash flow hedges	2	6	(2)	(19)
Reclassification into earnings from cash flow hedges	(2)	1	3	3
Unrealized gains on available-for-sale securities	2	0	10	7
Other Comprehensive Income, net of tax	2	(5)	13	88
Comprehensive Income	957	1,176	2,374	2,480
Less: Comprehensive Income Attributable to Noncontrolling Interests	1	4	5	16
Comprehensive Income (Loss) Attributable to Parent	$ 956	$ 1,172	$ 2,369	$ 2,464
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 1.36	$ 1.44	$ 3.37	$ 3.19
Diluted (usd per share)	1.36	1.44	3.37	3.18
Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)		0.26	(0.01)	0.26
Diluted (usd per share)		0.26	(0.01)	0.26
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	1.36	1.70	3.36	3.45
Diluted (usd per share)	$ 1.36	$ 1.70	$ 3.36	$ 3.44
Weighted average shares outstanding
Basic (shares)	700	689	700	689
Diluted (shares)	700	691	700	690
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 2,136	$ 2,226	$ 5,581	$ 5,641
Operating Expenses
Fuel used in electric generation and purchased power	531	581	1,394	1,391
Operation, maintenance and other	480	493	1,431	1,481
Depreciation and amortization	281	268	804	802
Property and other taxes	67	68	206	206
Total operating expenses	1,359	1,410	3,835	3,880
Gains (Losses) on Sales of Other Assets and Other, net		(1)		(1)
Operating Income (Loss)	777	815	1,746	1,760
Other Income and Expenses
Other income and expenses, net	26	39	99	121
Interest Expense	108	102	314	316
Income (Loss) From Continuing Operations Before Income Taxes	695	752	1,531	1,565
Income Tax Expense (Benefit) from Continuing Operations	229	258	522	539
Net Income (Loss) Attributable to Parent	466	494	1,009	1,026
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges			1	1
Other Comprehensive Income, net of tax			1	1
Comprehensive Income (Loss) Attributable to Parent	466	494	1,010	1,027
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,864	2,965	7,435	7,645
Operating Expenses
Fuel used in electric generation and purchased power	1,031	1,120	2,588	2,832
Operation, maintenance and other	572	582	1,650	1,699
Depreciation and amortization	334	318	958	904
Property and other taxes	140	136	386	375
Impairment charges	135	1	137	4
Total operating expenses	2,212	2,157	5,719	5,814
Gains (Losses) on Sales of Other Assets and Other, net	5	6	19	18
Operating Income (Loss)	657	814	1,735	1,849
Other Income and Expenses
Other income and expenses, net	20	31	65	79
Interest Expense	193	177	595	497
Income (Loss) From Continuing Operations Before Income Taxes	484	668	1,205	1,431
Income Tax Expense (Benefit) from Continuing Operations	141	219	384	496
Net income	343	449	821	935
Less: Net Income Attributable to Noncontrolling Interests	2	3	7	8
Net Income (Loss) Attributable to Parent	341	446	814	927
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	3		5	2
Net unrealized (losses) gains on cash flow hedges	(2)		4
Reclassification into earnings from cash flow hedges		1		4
Unrealized gains on available-for-sale securities	1	1	3	2
Other Comprehensive Income, net of tax	2	2	12	8
Comprehensive Income	345	451	833	943
Less: Comprehensive Income Attributable to Noncontrolling Interests	2	3	7	8
Comprehensive Income (Loss) Attributable to Parent	343	448	826	935
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,460	1,583	3,878	4,103
Operating Expenses
Fuel used in electric generation and purchased power	475	569	1,214	1,441
Operation, maintenance and other	352	360	1,032	1,067
Depreciation and amortization	182	176	536	526
Property and other taxes	40	40	120	119
Impairment charges		1		1
Total operating expenses	1,049	1,146	2,902	3,154
Gains (Losses) on Sales of Other Assets and Other, net		1	3	2
Operating Income (Loss)	411	438	979	951
Other Income and Expenses
Other income and expenses, net	14	18	47	47
Interest Expense	65	61	217	188
Income (Loss) From Continuing Operations Before Income Taxes	360	395	809	810
Income Tax Expense (Benefit) from Continuing Operations	114	124	262	271
Net Income (Loss) Attributable to Parent	246	271	547	539
Other Comprehensive Income (Loss), net of tax
Comprehensive Income (Loss) Attributable to Parent	246	271	547	539
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,401	1,381	3,551	3,538
Operating Expenses
Fuel used in electric generation and purchased power	557	550	1,374	1,391
Operation, maintenance and other	216	219	610	623
Depreciation and amortization	154	142	423	378
Property and other taxes	99	96	265	256
Impairment charges	135	1	137	4
Total operating expenses	1,161	1,008	2,809	2,652
Operating Income (Loss)	240	373	742	886
Other Income and Expenses
Other income and expenses, net	15	11	45	30
Interest Expense	71	62	211	143
Income (Loss) From Continuing Operations Before Income Taxes	184	322	576	773
Income Tax Expense (Benefit) from Continuing Operations	64	116	208	286
Net Income (Loss) Attributable to Parent	120	206	368	487
Other Comprehensive Income (Loss), net of tax
Unrealized gains on available-for-sale securities	1	1	3	2
Other Comprehensive Income, net of tax			3	2
Comprehensive Income (Loss) Attributable to Parent	121	207	371	489
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	371	390	1,036	1,053
Regulated natural gas	90	89	360	358
Nonregulated electric and other	10	10	30	22
Total operating revenues	471	489	1,426	1,433
Operating Expenses
Fuel used in electric generation and purchased power	100	129	283	340
Fuel used in electric generation and purchased power – nonregulated	13	14	42	37
Cost of natural gas	5	6	69	64
Operation, maintenance and other	124	126	385	367
Depreciation and amortization	63	50	193	175
Property and other taxes	65	59	204	195
Impairment charges			1
Total operating expenses	370	384	1,177	1,178
Gains (Losses) on Sales of Other Assets and Other, net	1	1	1	2
Operating Income (Loss)	102	106	250	257
Other Income and Expenses
Other income and expenses, net	4	3	12	6
Interest Expense	22	22	67	63
Income (Loss) From Continuing Operations Before Income Taxes	84	87	195	200
Income Tax Expense (Benefit) from Continuing Operations	28	32	67	65
Income from Continuing Operations	56	55	128	135
(Loss) Income From Discontinued Operations, net of tax	(1)	34	(1)	36
Net Income (Loss) Attributable to Parent	55	89	127	171
Other Comprehensive Income (Loss), net of tax
Comprehensive Income (Loss) Attributable to Parent	55	89	127	171
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	802	809	2,302	2,225
Operating Expenses
Fuel used in electric generation and purchased power	259	242	744	690
Operation, maintenance and other	175	175	541	526
Depreciation and amortization	120	123	336	345
Property and other taxes	19	22	56	67
Impairment charges		8		8
Total operating expenses	573	570	1,677	1,636
Gains (Losses) on Sales of Other Assets and Other, net	1		1
Operating Income (Loss)	230	239	626	589
Other Income and Expenses
Other income and expenses, net	10	5	27	15
Interest Expense	44	45	132	136
Income (Loss) From Continuing Operations Before Income Taxes	196	199	521	468
Income Tax Expense (Benefit) from Continuing Operations	75	70	203	159
Net Income (Loss) Attributable to Parent	121	129	318	309
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges				(1)
Other Comprehensive Income, net of tax				(1)
Comprehensive Income (Loss) Attributable to Parent	121	129	318	308
Piedmont Natural Gas [Member]
Operating Revenues
Regulated natural gas	181	155	877	815
Nonregulated electric and other	2	3	7	8
Total operating revenues	183	158	884	823
Operating Expenses
Cost of natural gas	63	42	333	289
Operation, maintenance and other	73	74	226	221
Depreciation and amortization	38	35	109	103
Property and other taxes	13	11	38	33
Impairment charges			7
Total operating expenses	187	162	713	646
Operating Income (Loss)	(4)	(4)	171	177
Other Income and Expenses
Equity in earnings (losses) of unconsolidated affiliates	3	2	8	25
Other income and expenses, net		(1)	(1)	(1)
Total other income and expenses	3	1	7	24
Interest Expense	20	17	59	50
Income (Loss) From Continuing Operations Before Income Taxes	(21)	(20)	119	151
Income Tax Expense (Benefit) from Continuing Operations	(10)	(8)	43	57
Net Income (Loss) Attributable to Parent	(11)	(12)	76	94
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges		1		1
Other Comprehensive Income, net of tax				1
Comprehensive Income (Loss) Attributable to Parent	$ (11)	$ (11)	$ 76	$ 95