Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating Revenues
Regulated electric	$ 5,178	$ 5,118	$ 10,462	$ 10,031
Regulated natural gas	291	275	991	921
Nonregulated electric and other	174	162	325	332
Total operating revenues	5,643	5,555	11,778	11,284
Operating Expenses
Operation, maintenance and other	1,544	1,441	3,008	2,909
Depreciation and amortization	973	835	1,940	1,694
Property and other taxes	315	307	631	611
Impairment charges	172	9	215	9
Total operating expenses	4,667	4,209	9,446	8,547
Gains (Losses) on Sales of Other Assets and Other, net	3	7	(97)	18
Operating Income	979	1,353	2,235	2,755
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	36	36	12	65
Other income and expenses, net	110	115	196	236
Total other income and expenses	146	151	208	301
Interest Expense	518	486	1,033	977
Income From Continuing Operations Before Income Taxes	607	1,018	1,410	2,079
Income Tax Expense From Continuing Operations	100	327	281	671
Income From Continuing Operations	507	691	1,129	1,408
Loss From Discontinued Operations, net of tax	(5)	(2)	(5)	(2)
Net income	502	689	1,124	1,406
Less: Net Income Attributable to Noncontrolling Interests	2	3	4	4
Net Income Attributable to Parent	500	686	1,120	1,402
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	1	1	2	2
Net unrealized gains on cash flow hedges	1	(6)	13	(4)
Reclassification into earnings from cash flow hedges	(2)	4	(1)	5
Unrealized (losses) gains on available-for-sale securities	(2)	4	(5)	8
Other Comprehensive (Loss) Income, net of tax	(2)	3	9	11
Comprehensive Income	500	692	1,133	1,417
Less: Comprehensive Income Attributable to Noncontrolling Interests	2	3	4	4
Comprehensive Income Attributable to Parent	$ 498	$ 689	$ 1,129	$ 1,413
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 0.72	$ 0.98	$ 1.60	$ 2.00
Diluted (usd per share)	0.72	0.98	1.60	2.00
Loss from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	(0.01)		(0.01)
Diluted (usd per share)	(0.01)		(0.01)
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	0.71	0.98	1.59	2.00
Diluted (usd per share)	$ 0.71	$ 0.98	$ 1.59	$ 2.00
Weighted average shares outstanding
Basic (shares)	703	700	702	700
Diluted (shares)	704	700	702	700
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 1,672	$ 1,729	$ 3,435	$ 3,445
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	407	435	880	863
Operation, maintenance and other	499	483	950	978
Depreciation and amortization	289	269	561	523
Property and other taxes	75	71	147	139
Impairment charges	177		190
Total operating expenses	1,447	1,258	2,728	2,503
Gains (Losses) on Sales of Other Assets and Other, net	(1)		(1)
Operating Income	224	471	706	942
Other Income and Expenses
Total other income and expenses	35	50	74	100
Interest Expense	110	103	217	206
Income From Continuing Operations Before Income Taxes	149	418	563	836
Income Tax Expense From Continuing Operations	32	145	123	293
Net Income Attributable to Parent	117	273	440	543
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges		1	1	1
Other Comprehensive (Loss) Income, net of tax			1	1
Comprehensive Income Attributable to Parent	117	274	441	544
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,498	2,392	5,074	4,571
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	895	831	1,871	1,557
Operation, maintenance and other	610	549	1,233	1,109
Depreciation and amortization	380	311	764	624
Property and other taxes	131	129	254	246
Impairment charges	4	2	33	2
Total operating expenses	2,020	1,822	4,155	3,538
Gains (Losses) on Sales of Other Assets and Other, net	6	6	12	14
Operating Income	484	576	931	1,047
Other Income and Expenses
Total other income and expenses	42	36	77	76
Interest Expense	203	196	412	402
Income From Continuing Operations Before Income Taxes	323	416	596	721
Income Tax Expense From Continuing Operations	56	139	92	243
Net income	267	277	504	478
Less: Net Income Attributable to Noncontrolling Interests	2	3	4	5
Net Income Attributable to Parent	265	274	500	473
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	2	1	2	2
Net unrealized gains on cash flow hedges	1	5	3	6
Unrealized (losses) gains on available-for-sale securities	(1)	1	(1)	2
Other Comprehensive (Loss) Income, net of tax	2	7	4	10
Comprehensive Income	269	284	508	488
Less: Comprehensive Income Attributable to Noncontrolling Interests	2	3	4	5
Comprehensive Income Attributable to Parent	267	281	504	483
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,291	1,199	2,751	2,418
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	408	375	917	739
Operation, maintenance and other	375	342	756	704
Depreciation and amortization	235	173	470	354
Property and other taxes	40	40	75	80
Impairment charges	1		33
Total operating expenses	1,059	930	2,251	1,877
Gains (Losses) on Sales of Other Assets and Other, net	1	1	2	3
Operating Income	233	270	502	544
Other Income and Expenses
Total other income and expenses	19	26	37	57
Interest Expense	78	70	159	152
Income From Continuing Operations Before Income Taxes	174	226	380	449
Income Tax Expense From Continuing Operations	35	72	64	148
Net Income Attributable to Parent	139	154	316	301
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	139	154	316	301
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,203	1,191	2,318	2,150
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	486	455	953	817
Operation, maintenance and other	237	208	474	403
Depreciation and amortization	144	137	294	269
Property and other taxes	91	89	179	166
Impairment charges		1		2
Total operating expenses	958	890	1,900	1,657
Operating Income	245	301	418	493
Other Income and Expenses
Total other income and expenses	26	19	47	39
Interest Expense	66	70	137	140
Income From Continuing Operations Before Income Taxes	205	250	328	392
Income Tax Expense From Continuing Operations	37	92	57	144
Net Income Attributable to Parent	168	158	271	248
Other Comprehensive Income (Loss), net of tax
Unrealized (losses) gains on available-for-sale securities	(1)	1	(1)	2
Other Comprehensive (Loss) Income, net of tax			(1)	2
Comprehensive Income Attributable to Parent	167	159	270	250
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	346	328	682	665
Regulated natural gas	103	100	277	270
Nonregulated electric and other	10	9	24	20
Total operating revenues	459	437	983	955
Operating Expenses
Operation, maintenance and other	130	132	261	263
Depreciation and amortization	62	63	132	130
Property and other taxes	68	67	145	139
Impairment charges		1		1
Total operating expenses	382	373	821	809
Gains (Losses) on Sales of Other Assets and Other, net			(106)
Operating Income	77	64	56	146
Other Income and Expenses
Total other income and expenses	8	5	14	10
Interest Expense	23	23	45	45
Income From Continuing Operations Before Income Taxes	62	46	25	111
Income Tax Expense From Continuing Operations	16	16	4	39
Net Income Attributable to Parent	46	30	21	72
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	46	30	21	72
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	738	742	1,469	1,500
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	226	234	458	485
Operation, maintenance and other	197	194	378	369
Depreciation and amortization	126	91	256	216
Property and other taxes	20	15	40	37
Total operating expenses	569	534	1,132	1,107
Operating Income	169	208	337	393
Other Income and Expenses
Total other income and expenses	6	11	13	20
Interest Expense	43	44	83	88
Income From Continuing Operations Before Income Taxes	132	175	267	325
Income Tax Expense From Continuing Operations	34	69	69	128
Net Income Attributable to Parent	98	106	198	197
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	98	106	198	197
Piedmont Natural Gas [Member]
Operating Revenues
Total operating revenues	215	201	768	701
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	74	65	333	270
Operation, maintenance and other	85	76	167	153
Depreciation and amortization	39	36	78	71
Property and other taxes	12	12	24	25
Impairment charges		7		7
Total operating expenses	210	196	602	526
Operating Income	5	5	166	175
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	1	2	3	5
Other income and expenses, net	3	(1)	6	(1)
Total other income and expenses	4	1	9	4
Interest Expense	20	19	41	39
Income From Continuing Operations Before Income Taxes	(11)	(13)	134	140
Income Tax Expense From Continuing Operations	(3)	(5)	32	53
Net Income Attributable to Parent	(8)	(8)	102	87
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	(8)	(8)	102	87
Electricity, US Regulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	93	86	185	183
Electricity, Nonregulated [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	14	14	29	29
Electricity [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	1,574	1,541	3,250	2,990
Natural Gas [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	89	76	402	334
Natural Gas [Member] | Duke Energy Ohio [Member]
Operating Expenses
Fuel used in electric generation and purchased power/Cost of natural gas	$ 15	$ 10	$ 69	$ 64