Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Regulated electric	$ 5,118	$ 4,965	$ 10,031	$ 10,018
Regulated natural gas	275	97	921	266
Nonregulated electric and other	162	151	332	306
Total operating revenues	5,555	5,213	11,284	10,590
Operating Expenses
Fuel used in electric generation and purchased power	1,541	1,521	2,990	3,109
Cost of natural gas	76	9	334	58
Operation, maintenance and other	1,407	1,351	2,840	2,767
Depreciation and amortization	835	790	1,694	1,583
Property and other taxes	307	290	611	585
Impairment charges	9	1	9	4
Total operating expenses	4,175	3,962	8,478	8,106
Gains on Sales of Other Assets and Other, net	7	8	18	15
Operating Income	1,387	1,259	2,824	2,499
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	36	15	65	23
Other income and expenses, net	81	81	167	151
Total other income and expenses	117	96	232	174
Interest Expense	486	478	977	967
Income From Continuing Operations Before Income Taxes	1,018	877	2,079	1,706
Income Tax Expense from Continuing Operations	327	253	671	505
Income from Continuing Operations	691	624	1,408	1,201
Income From Discontinued Operations, net of tax	(2)	(112)	(2)	10
Net income	689	512	1,406	1,211
Less: Net Income Attributable to Noncontrolling Interests	3	3	4	8
Net Income Attributable to Parent	686	509	1,402	1,203
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	1	2	2	2
Net unrealized gains on cash flow hedges	(6)	(11)	(4)	(25)
Reclassification into earnings from cash flow hedges	4	0	5	2
Unrealized gains on available-for-sale securities	4	3	8	7
Other Comprehensive Income, net of tax	3	52	11	93
Comprehensive Income	692	564	1,417	1,304
Less: Comprehensive Income Attributable to Noncontrolling Interests	3	6	4	12
Comprehensive Income Attributable to Parent	$ 689	$ 558	$ 1,413	$ 1,292
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 0.98	$ 0.90	$ 2.00	$ 1.73
Diluted (usd per share)	0.98	0.90	2.00	1.73
(Loss) Income from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)		(0.16)		0.01
Diluted (usd per share)		(0.16)		0.01
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	0.98	0.74	2.00	1.74
Diluted (usd per share)	$ 0.98	$ 0.74	$ 2.00	$ 1.74
Weighted average shares outstanding
Basic (shares)	700	689	700	689
Diluted (shares)	700	690	700	689
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 1,729	$ 1,675	$ 3,445	$ 3,415
Operating Expenses
Fuel used in electric generation and purchased power	435	389	863	810
Operation, maintenance and other	469	476	951	988
Depreciation and amortization	269	275	523	534
Property and other taxes	71	71	139	138
Total operating expenses	1,244	1,211	2,476	2,470
Operating Income	485	464	969	945
Other Income and Expenses
Other income and expenses, net	36	45	73	82
Interest Expense	103	107	206	214
Income From Continuing Operations Before Income Taxes	418	402	836	813
Income Tax Expense from Continuing Operations	145	141	293	281
Net Income Attributable to Parent	273	261	543	532
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges	1		1	1
Other Comprehensive Income, net of tax			1	1
Comprehensive Income Attributable to Parent	274	261	544	533
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,392	2,348	4,571	4,680
Operating Expenses
Fuel used in electric generation and purchased power	831	852	1,557	1,712
Operation, maintenance and other	534	525	1,078	1,117
Depreciation and amortization	311	296	624	586
Property and other taxes	129	120	246	239
Impairment charges	2	1	2	3
Total operating expenses	1,807	1,794	3,507	3,657
Gains on Sales of Other Assets and Other, net	6	6	14	12
Operating Income	591	560	1,078	1,035
Other Income and Expenses
Other income and expenses, net	21	28	45	48
Interest Expense	196	160	402	320
Income From Continuing Operations Before Income Taxes	416	428	721	763
Income Tax Expense from Continuing Operations	139	154	243	277
Net income	277	274	478	486
Less: Net Income Attributable to Noncontrolling Interests	3	2	5	5
Net Income Attributable to Parent	274	272	473	481
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	1	1	2	2
Net unrealized gains on cash flow hedges	5		6
Reclassification into earnings from cash flow hedges		2		3
Unrealized gains on available-for-sale securities	1		2	1
Other Comprehensive Income, net of tax	7	3	10	6
Comprehensive Income	284	277	488	492
Less: Comprehensive Income Attributable to Noncontrolling Interests	3	2	5	5
Comprehensive Income Attributable to Parent	281	275	483	487
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,199	1,213	2,418	2,520
Operating Expenses
Fuel used in electric generation and purchased power	375	424	739	872
Operation, maintenance and other	330	321	680	707
Depreciation and amortization	173	175	354	350
Property and other taxes	40	38	80	79
Total operating expenses	918	958	1,853	2,008
Gains on Sales of Other Assets and Other, net	1		3	1
Operating Income	282	255	568	513
Other Income and Expenses
Other income and expenses, net	14	12	33	29
Interest Expense	70	64	152	127
Income From Continuing Operations Before Income Taxes	226	203	449	415
Income Tax Expense from Continuing Operations	72	72	148	147
Net Income Attributable to Parent	154	131	301	268
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	154	131	301	268
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,191	1,133	2,150	2,157
Operating Expenses
Fuel used in electric generation and purchased power	455	429	817	841
Operation, maintenance and other	203	199	394	404
Depreciation and amortization	137	122	269	236
Property and other taxes	89	82	166	160
Impairment charges	1	1	2	3
Total operating expenses	885	833	1,648	1,644
Operating Income	306	300	502	513
Other Income and Expenses
Other income and expenses, net	14	14	30	19
Interest Expense	70	40	140	81
Income From Continuing Operations Before Income Taxes	250	274	392	451
Income Tax Expense from Continuing Operations	92	103	144	170
Net Income Attributable to Parent	158	171	248	281
Other Comprehensive Income (Loss), net of tax
Unrealized gains on available-for-sale securities	1		2	1
Other Comprehensive Income, net of tax			2	1
Comprehensive Income Attributable to Parent	159	171	250	282
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	328	323	665	663
Regulated natural gas	100	99	270	269
Nonregulated electric and other	9	6	20	12
Total operating revenues	437	428	955	944
Operating Expenses
Fuel used in electric generation and purchased power	86	100	183	211
Fuel used in electric generation and purchased power – nonregulated	14	13	29	23
Cost of natural gas	10	9	64	58
Operation, maintenance and other	131	122	261	241
Depreciation and amortization	63	64	130	125
Property and other taxes	67	65	139	136
Impairment charges	1		1
Total operating expenses	372	373	807	794
Gains on Sales of Other Assets and Other, net				1
Operating Income	65	55	148	151
Other Income and Expenses
Other income and expenses, net	4	1	8	3
Interest Expense	23	21	45	41
Income From Continuing Operations Before Income Taxes	46	35	111	113
Income Tax Expense from Continuing Operations	16	12	39	33
Income from Continuing Operations	30	23	72	80
Income From Discontinued Operations, net of tax				2
Net Income Attributable to Parent	30	23	72	82
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	30	23	72	82
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	742	702	1,500	1,416
Operating Expenses
Fuel used in electric generation and purchased power	234	220	485	448
Operation, maintenance and other	192	189	366	351
Depreciation and amortization	91	97	216	222
Property and other taxes	15	22	37	45
Total operating expenses	532	528	1,104	1,066
Operating Income	210	174	396	350
Other Income and Expenses
Other income and expenses, net	9	6	17	10
Interest Expense	44	47	88	91
Income From Continuing Operations Before Income Taxes	175	133	325	269
Income Tax Expense from Continuing Operations	69	48	128	89
Net Income Attributable to Parent	106	85	197	180
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges				(1)
Other Comprehensive Income, net of tax				(1)
Comprehensive Income Attributable to Parent	106	85	197	179
Piedmont Natural Gas [Member]
Operating Revenues
Regulated natural gas	198	179	696	660
Nonregulated electric and other	3	3	5	5
Total operating revenues	201	182	701	665
Operating Expenses
Cost of natural gas	65	50	270	247
Operation, maintenance and other	76	73	153	147
Depreciation and amortization	36	34	71	68
Property and other taxes	12	11	25	22
Impairment charges	7		7
Total operating expenses	196	168	526	484
Operating Income	5	14	175	181
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	2	7	5	23
Other income and expenses, net	(1)		(1)
Total other income and expenses	1	7	4	23
Interest Expense	19	16	39	33
Income From Continuing Operations Before Income Taxes	(13)	5	140	171
Income Tax Expense from Continuing Operations	(5)	2	53	65
Net Income Attributable to Parent	(8)	3	87	106
Other Comprehensive Income (Loss), net of tax
Comprehensive Income Attributable to Parent	$ (8)	$ 3	$ 87	$ 106