Duke Energy Carolinas 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Jun. 30, 2017shares
Document Information [Line Items]
Entity Registrant Name	Duke Energy Corporation
Entity Central Index Key	1,326,160
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding	699,950,383
Trading Symbol	DUK
Duke Energy Carolinas [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Carolinas, LLC
Entity Central Index Key	30,371
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Progress Energy [Member]
Document Information [Line Items]
Entity Registrant Name	Progress Energy, Inc
Entity Central Index Key	1,094,093
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Progress [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Progress, LLC
Entity Central Index Key	17,797
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Florida [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Florida, LLC
Entity Central Index Key	37,637
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Ohio [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Ohio, Inc.
Entity Central Index Key	20,290
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Indiana [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Indiana, LLC
Entity Central Index Key	81,020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Piedmont Natural Gas [Member]
Document Information [Line Items]
Entity Registrant Name	Piedmont Natural Gas Company, Inc.
Entity Central Index Key	78,460
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer

Condensed Consolidated Statemen

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	$ 1.73
Diluted (usd per share)	0.98	0.90	2	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	1.74
Diluted (usd per share)	$ 0.98	$ 0.74	$ 2	$ 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

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income	$ 689	$ 512	$ 1,406	$ 1,211
Other Comprehensive Income, net of tax
Foreign currency translation adjustments	0	58	0	107
Pension and OPEB adjustments	1	2	2	2
Net unrealized losses 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

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 298	$ 392
Receivables (net of allowance for doubtful accounts)	498	751
Receivables of VIEs (net of allowance for doubtful accounts)	1,880	1,893
Inventory	3,369	3,522
Regulatory assets	1,192	1,023
Other	436	458
Total current assets	7,673	8,039
Property, Plant and Equipment
Cost	124,439	121,397
Accumulated depreciation and amortization	(40,522)	(39,406)
Generation facilities to be retired, net	487	529
Net property, plant and equipment	84,404	82,520
Other Noncurrent Assets
Goodwill	19,425	19,425
Regulatory assets	12,808	12,878
Nuclear decommissioning trust funds	6,601	6,205
Investments in equity method unconsolidated affiliates	1,267	925
Other	2,826	2,769
Total other noncurrent assets	42,927	42,202
Total Assets	135,004	132,761
Current Liabilities
Accounts payable	2,177	2,994
Notes payable and commercial paper	3,488	2,487
Taxes accrued	432	384
Interest accrued	506	503
Current maturities of long-term debt	3,472	2,319
Asset retirement obligation	397	411
Regulatory liabilities	286	409
Other	1,708	2,044
Total current liabilities	12,466	11,551
Long-Term Debt	46,043	45,576
Other Noncurrent Liabilities
Deferred income taxes	14,695	14,155
Asset retirement obligations	10,165	10,200
Regulatory liabilities	7,048	6,881
Accrued pension and other post-retirement benefit costs	1,108	1,111
Investment tax credits	534	493
Other	1,651	1,753
Total other noncurrent liabilities	35,201	34,593
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	38,758	38,741
Retained earnings	2,607	2,384
Accumulated other comprehensive loss	(82)	(93)
Total Parent stockholders' equity	41,284	41,033
Noncontrolling interests	10	8
Total equity	41,294	41,041
Total Liabilities and Equity	135,004	132,761
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	16	14
Receivables (net of allowance for doubtful accounts)	165	160
Receivables of VIEs (net of allowance for doubtful accounts)	611	645
Receivables from affiliated companies	85	163
Notes receivable from affiliated companies		66
Inventory	1,066	1,055
Regulatory assets	249	238
Other	34	37
Total current assets	2,226	2,378
Property, Plant and Equipment
Cost	41,881	41,127
Accumulated depreciation and amortization	(14,632)	(14,365)
Net property, plant and equipment	27,249	26,762
Other Noncurrent Assets
Regulatory assets	3,060	3,159
Nuclear decommissioning trust funds	3,499	3,273
Other	929	943
Total other noncurrent assets	7,488	7,375
Total Assets	36,963	36,515
Current Liabilities
Accounts payable	639	833
Accounts payable to affiliated companies	127	247
Notes payable to affiliated companies	534
Taxes accrued	162	143
Interest accrued	104	102
Current maturities of long-term debt	704	116
Asset retirement obligation	227	222
Regulatory liabilities	115	161
Other	409	468
Total current liabilities	3,021	2,292
Long-Term Debt	8,520	9,187
Long-Term Debt Payable to Affiliated Companies	300	300
Other Noncurrent Liabilities
Deferred income taxes	6,742	6,544
Asset retirement obligations	3,644	3,673
Regulatory liabilities	2,885	2,840
Accrued pension and other post-retirement benefit costs	103	97
Investment tax credits	235	203
Other	574	607
Total other noncurrent liabilities	14,183	13,964
Commitments and Contingencies
Equity
Member's equity	10,947	10,781
Accumulated other comprehensive loss	(8)	(9)
Total member's equity	10,939	10,772
Total Liabilities and Equity	36,963	36,515
Progress Energy [Member]
Current Assets
Cash and cash equivalents	39	46
Receivables (net of allowance for doubtful accounts)	95	114
Receivables of VIEs (net of allowance for doubtful accounts)	777	692
Receivables from affiliated companies	3	106
Notes receivable from affiliated companies	140	80
Inventory	1,621	1,717
Regulatory assets	533	401
Other	196	148
Total current assets	3,404	3,304
Property, Plant and Equipment
Cost	46,317	44,864
Accumulated depreciation and amortization	(15,652)	(15,212)
Generation facilities to be retired, net	487	529
Net property, plant and equipment	31,152	30,181
Other Noncurrent Assets
Goodwill	3,655	3,655
Regulatory assets	5,853	5,722
Nuclear decommissioning trust funds	3,102	2,932
Other	865	856
Total other noncurrent assets	13,475	13,165
Total Assets	48,031	46,650
Current Liabilities
Accounts payable	649	1,003
Accounts payable to affiliated companies	208	348
Notes payable to affiliated companies	1,070	729
Taxes accrued	165	83
Interest accrued	228	201
Current maturities of long-term debt	1,022	778
Asset retirement obligation	170	189
Regulatory liabilities	120	189
Other	660	745
Total current liabilities	4,292	4,265
Long-Term Debt	15,950	15,590
Long-Term Debt Payable to Affiliated Companies	1,173	1,173
Other Noncurrent Liabilities
Deferred income taxes	5,662	5,246
Asset retirement obligations	5,288	5,286
Regulatory liabilities	2,511	2,395
Accrued pension and other post-retirement benefit costs	537	547
Other	321	341
Total other noncurrent liabilities	14,319	13,815
Commitments and Contingencies
Equity
Additional paid-in capital	8,096	8,094
Retained earnings	4,237	3,764
Accumulated other comprehensive loss	(28)	(38)
Total Parent stockholders' equity	12,305	11,820
Noncontrolling interests	(8)	(13)
Total equity	12,297	11,807
Total Liabilities and Equity	48,031	46,650
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	12	11
Receivables (net of allowance for doubtful accounts)	32	51
Receivables of VIEs (net of allowance for doubtful accounts)	422	404
Receivables from affiliated companies	5	5
Notes receivable from affiliated companies		165
Inventory	1,053	1,076
Regulatory assets	212	188
Other	76	57
Total current assets	1,812	1,957
Property, Plant and Equipment
Cost	28,936	28,419
Accumulated depreciation and amortization	(10,734)	(10,561)
Generation facilities to be retired, net	487	529
Net property, plant and equipment	18,689	18,387
Other Noncurrent Assets
Regulatory assets	3,379	3,243
Nuclear decommissioning trust funds	2,380	2,217
Other	536	525
Total other noncurrent assets	6,295	5,985
Total Assets	26,796	26,329
Current Liabilities
Accounts payable	277	589
Accounts payable to affiliated companies	169	227
Notes payable to affiliated companies	633
Taxes accrued	61	104
Interest accrued	101	102
Current maturities of long-term debt	203	452
Asset retirement obligation	170	189
Regulatory liabilities	113	158
Other	308	365
Total current liabilities	2,035	2,186
Long-Term Debt	6,407	6,409
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	3,539	3,323
Asset retirement obligations	4,520	4,508
Regulatory liabilities	2,048	1,946
Accrued pension and other post-retirement benefit costs	246	252
Investment tax credits	145	146
Other	47	51
Total other noncurrent liabilities	10,545	10,226
Commitments and Contingencies
Equity
Total member's equity	7,659	7,358
Total Liabilities and Equity	26,796	26,329
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	8	16
Receivables (net of allowance for doubtful accounts)	61	61
Receivables of VIEs (net of allowance for doubtful accounts)	354	288
Receivables from affiliated companies	1	5
Notes receivable from affiliated companies	230
Inventory	568	641
Regulatory assets	321	213
Other	50	125
Total current assets	1,593	1,349
Property, Plant and Equipment
Cost	17,369	16,434
Accumulated depreciation and amortization	(4,910)	(4,644)
Net property, plant and equipment	12,459	11,790
Other Noncurrent Assets
Regulatory assets	2,474	2,480
Nuclear decommissioning trust funds	723	715
Other	279	278
Total other noncurrent assets	3,476	3,473
Total Assets	17,528	16,612
Current Liabilities
Accounts payable	372	413
Accounts payable to affiliated companies	42	125
Notes payable to affiliated companies		297
Taxes accrued	112	33
Interest accrued	58	49
Current maturities of long-term debt	819	326
Regulatory liabilities	7	31
Other	322	352
Total current liabilities	1,732	1,626
Long-Term Debt	6,160	5,799
Other Noncurrent Liabilities
Deferred income taxes	2,893	2,694
Asset retirement obligations	768	778
Regulatory liabilities	462	448
Accrued pension and other post-retirement benefit costs	258	262
Other	103	105
Total other noncurrent liabilities	4,484	4,287
Commitments and Contingencies
Equity
Member's equity	5,149	4,899
Accumulated other comprehensive loss	3	1
Total member's equity	5,152	4,900
Total Liabilities and Equity	17,528	16,612
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	9	13
Receivables (net of allowance for doubtful accounts)	61	71
Receivables from affiliated companies	74	129
Notes receivable from affiliated companies	63	94
Inventory	134	137
Regulatory assets	42	37
Other	38	37
Total current assets	421	518
Property, Plant and Equipment
Cost	8,348	8,126
Accumulated depreciation and amortization	(2,626)	(2,579)
Net property, plant and equipment	5,722	5,547
Other Noncurrent Assets
Goodwill	920	920
Regulatory assets	519	520
Other	23	23
Total other noncurrent assets	1,462	1,463
Total Assets	7,605	7,528
Current Liabilities
Accounts payable	267	282
Accounts payable to affiliated companies	47	63
Notes payable to affiliated companies	24	16
Taxes accrued	100	178
Interest accrued	19	19
Current maturities of long-term debt	1	1
Regulatory liabilities	16	21
Other	77	91
Total current liabilities	551	671
Long-Term Debt	1,951	1,858
Long-Term Debt Payable to Affiliated Companies	25	25
Other Noncurrent Liabilities
Deferred income taxes	1,506	1,443
Asset retirement obligations	76	77
Regulatory liabilities	240	236
Accrued pension and other post-retirement benefit costs	56	56
Other	157	166
Total other noncurrent liabilities	2,035	1,978
Commitments and Contingencies
Equity
Common stock	762	762
Additional paid-in capital	2,670	2,695
Retained earnings	(389)	(461)
Total Parent stockholders' equity	3,043	2,996
Total Liabilities and Equity	7,605	7,528
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	17	17
Receivables (net of allowance for doubtful accounts)	45	105
Receivables from affiliated companies	87	114
Notes receivable from affiliated companies	19	86
Inventory	470	504
Regulatory assets	159	149
Other	88	45
Total current assets	885	1,020
Property, Plant and Equipment
Cost	14,573	14,241
Accumulated depreciation and amortization	(4,484)	(4,317)
Net property, plant and equipment	10,089	9,924
Other Noncurrent Assets
Regulatory assets	1,100	1,073
Other	159	147
Total other noncurrent assets	1,259	1,220
Total Assets	12,233	12,164
Current Liabilities
Accounts payable	171	263
Accounts payable to affiliated companies	50	74
Taxes accrued	28	31
Interest accrued	59	61
Current maturities of long-term debt	3	3
Regulatory liabilities	36	40
Other	122	93
Total current liabilities	469	565
Long-Term Debt	3,631	3,633
Long-Term Debt Payable to Affiliated Companies	150	150
Other Noncurrent Liabilities
Deferred income taxes	2,011	1,900
Asset retirement obligations	865	866
Regulatory liabilities	745	748
Accrued pension and other post-retirement benefit costs	77	71
Investment tax credits	148	137
Other	23	27
Total other noncurrent liabilities	3,869	3,749
Commitments and Contingencies
Equity
Total member's equity	4,114	4,067
Total Liabilities and Equity	12,233	12,164
Piedmont Natural Gas [Member]
Current Assets
Cash and cash equivalents	14	25
Receivables (net of allowance for doubtful accounts)	80	232
Receivables from affiliated companies	8	7
Inventory	38	66
Regulatory assets	119	124
Other	87	21
Total current assets	346	475
Property, Plant and Equipment
Cost	6,430	6,174
Accumulated depreciation and amortization	(1,424)	(1,360)
Net property, plant and equipment	5,006	4,814
Other Noncurrent Assets
Goodwill	49	49
Regulatory assets	346	373
Investments in equity method unconsolidated affiliates	74	212
Other	12	21
Total other noncurrent assets	481	655
Total Assets	5,833	5,944
Current Liabilities
Accounts payable	105	155
Accounts payable to affiliated companies	50	8
Notes payable and commercial paper		330
Notes payable to affiliated companies	167
Taxes accrued	21	67
Interest accrued	30	33
Current maturities of long-term debt	35	35
Other	67	102
Total current liabilities	475	730
Long-Term Debt	1,911	1,786
Other Noncurrent Liabilities
Deferred income taxes	1,019	931
Asset retirement obligations	15	14
Regulatory liabilities	625	608
Accrued pension and other post-retirement benefit costs	14	14
Other	164	189
Total other noncurrent liabilities	1,837	1,756
Commitments and Contingencies
Equity
Common stock	860	860
Retained earnings	750	812
Total Parent stockholders' equity	1,610	1,672
Total Liabilities and Equity	$ 5,833	$ 5,944

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Allowance for doubtful accounts - receivables	$ 13	$ 14
Regulatory assets, current	1,192	1,023
Other, current assets	436	458
Regulatory assets, noncurrent	12,808	12,878
Current maturities of long-term debt	3,472	2,319
Long-Term Debt	$ 46,043	$ 45,576
Common stock, par or stated value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	700,000,000	700,000,000
Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 56	$ 54
Regulatory assets, current	52	50
Regulatory assets, noncurrent	1,121	1,142
Current maturities of long-term debt	212	260
Long-Term Debt	4,018	3,587
Duke Energy Carolinas [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	249	238
Other, current assets	34	37
Regulatory assets, noncurrent	3,060	3,159
Current maturities of long-term debt	704	116
Long-Term Debt	8,520	9,187
Duke Energy Carolinas [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	7	7
Progress Energy [Member]
Allowance for doubtful accounts - receivables	4	6
Regulatory assets, current	533	401
Other, current assets	196	148
Regulatory assets, noncurrent	5,853	5,722
Current maturities of long-term debt	1,022	778
Long-Term Debt	$ 15,950	$ 15,590
Common stock, par or stated value	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Progress Energy [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	$ 7	$ 7
Regulatory assets, current	52	50
Regulatory assets, noncurrent	1,121	1,142
Current maturities of long-term debt	55	62
Long-Term Debt	1,711	1,741
Duke Energy Progress [Member]
Allowance for doubtful accounts - receivables	1	4
Regulatory assets, current	212	188
Other, current assets	76	57
Regulatory assets, noncurrent	3,379	3,243
Current maturities of long-term debt	203	452
Long-Term Debt	6,407	6,409
Duke Energy Progress [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	5	5
Duke Energy Florida [Member]
Allowance for doubtful accounts - receivables	3	2
Regulatory assets, current	321	213
Other, current assets	50	125
Regulatory assets, noncurrent	2,474	2,480
Current maturities of long-term debt	819	326
Long-Term Debt	6,160	5,799
Duke Energy Florida [Member] | Variable Interest Entity [Member]
Allowance for doubtful accounts - receivables of VIEs	2	2
Regulatory assets, current	52	50
Other, current assets	33	53
Regulatory assets, noncurrent	1,121	1,142
Current maturities of long-term debt	55	62
Long-Term Debt	1,414	1,442
Duke Energy Ohio [Member]
Allowance for doubtful accounts - receivables	2	2
Regulatory assets, current	42	37
Other, current assets	38	37
Regulatory assets, noncurrent	519	520
Current maturities of long-term debt	1	1
Long-Term Debt	$ 1,951	$ 1,858
Common stock, par or stated value	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	90,000,000	90,000,000
Duke Energy Indiana [Member]
Allowance for doubtful accounts - receivables	$ 1	$ 1
Regulatory assets, current	159	149
Other, current assets	88	45
Regulatory assets, noncurrent	1,100	1,073
Current maturities of long-term debt	3	3
Long-Term Debt	3,631	3,633
Piedmont Natural Gas [Member]
Allowance for doubtful accounts - receivables	4	3
Regulatory assets, current	119	124
Other, current assets	87	21
Regulatory assets, noncurrent	346	373
Current maturities of long-term debt	35	35
Long-Term Debt	$ 1,911	$ 1,786
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 1,406	$ 1,211
Net income (attributable to parent)	1,402	1,203
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,953	1,868
Equity component of AFUDC	(125)	(87)
Gains on sales of other assets	(20)	(18)
Impairment charges	9	198
Deferred income taxes	669	285
Equity in earnings of unconsolidated affiliates	(65)	(23)
Accrued pension and other post-retirement benefit costs	13	8
Payments for asset retirement obligations	(272)	(263)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(12)	199
Receivables	293	(38)
Inventory	153	178
Other current assets	(148)	(51)
Increase (decrease) in
Accounts payable	(505)	(153)
Taxes accrued	41	216
Other current liabilities	(531)	(281)
Other assets	(101)	(9)
Other liabilities	(2)	(15)
Net cash provided by operating activities	2,756	3,225
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(3,931)	(3,393)
Contributions to equity method investments	(287)	(136)
Purchases of available-for-sale securities	(2,412)	(3,033)
Proceeds from sales and maturities of available-for-sale securities	2,439	3,059
Change in restricted cash	(44)	(21)
Other	(89)	(84)
Net cash used in investing activities	(4,324)	(3,608)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	2,734	3,514
Proceeds from the issuance of common stock related to employee benefit plans		7
Payments for the redemption of long-term debt	(1,009)	(795)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	230	500
Payments for the redemption of short-term debt with original maturities greater than 90 days	(32)	(492)
Notes payable and commercial paper	783	(1,349)
Dividends paid	(1,200)	(1,140)
Other	(32)	(43)
Net cash provided by financing activities	1,474	202
Changes in cash and cash equivalents associated with assets held for sale		79
Net decrease in cash and cash equivalents	(94)	(102)
Cash and cash equivalents at beginning of period	392	383
Cash and cash equivalents at end of period	298	281
Significant non-cash transactions:
Accrued capital expenditures	589	670
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	543	532
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	688	673
Equity component of AFUDC	(59)	(48)
Deferred income taxes	283	273
Accrued pension and other post-retirement benefit costs		2
Payments for asset retirement obligations	(123)	(118)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	24	3
Receivables	36	(48)
Receivable from affiliated companies	78	36
Inventory	(14)	102
Other current assets	(21)	24
Increase (decrease) in
Accounts payable	(125)	(226)
Accounts payable to affiliated companies	(120)	(56)
Taxes accrued	19	188
Other current liabilities	(140)	28
Other assets	(44)	22
Other liabilities	(15)	(14)
Net cash provided by operating activities	1,010	1,373
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,092)	(1,031)
Purchases of available-for-sale securities	(1,225)	(1,395)
Proceeds from sales and maturities of available-for-sale securities	1,228	1,395
Notes receivable from affiliated companies	66
Notes receivable from affiliated companies		(89)
Other	(29)	(41)
Net cash used in investing activities	(1,052)	(1,161)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		992
Payments for the redemption of long-term debt	(114)	(1)
Notes payable to affiliated companies	534
Distributions to parent	(375)	(1,200)
Other	(1)
Net cash provided by financing activities	44	(209)
Net decrease in cash and cash equivalents	2	3
Cash and cash equivalents at beginning of period	14	13
Cash and cash equivalents at end of period	16	16
Significant non-cash transactions:
Accrued capital expenditures	200	228
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	478	486
Net income (attributable to parent)	473	481
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	733	696
Equity component of AFUDC	(48)	(30)
Gains on sales of other assets	(15)	(15)
Impairment charges	2	3
Deferred income taxes	412	285
Accrued pension and other post-retirement benefit costs	(5)	(12)
Payments for asset retirement obligations	(128)	(126)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		32
Receivables	(64)	(66)
Receivable from affiliated companies	99	306
Inventory	95	25
Other current assets	(200)	45
Increase (decrease) in
Accounts payable	(211)	(26)
Accounts payable to affiliated companies	(140)	(79)
Taxes accrued	81	90
Other current liabilities	(148)	(162)
Other assets	(70)	(72)
Other liabilities	(18)	15
Net cash provided by operating activities	853	1,395
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,733)	(1,441)
Purchases of available-for-sale securities	(1,108)	(1,570)
Proceeds from sales and maturities of available-for-sale securities	1,123	1,594
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(60)
Change in restricted cash	5	(6)
Other	(26)	(14)
Net cash used in investing activities	(1,795)	(1,379)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	923	1,338
Payments for the redemption of long-term debt	(326)	(320)
Notes payable to affiliated companies	341	(392)
Dividends to parent		(651)
Other	(3)	(1)
Net cash provided by financing activities	935	(26)
Net decrease in cash and cash equivalents	(7)	(10)
Cash and cash equivalents at beginning of period	46	44
Cash and cash equivalents at end of period	39	34
Significant non-cash transactions:
Accrued capital expenditures	174	288
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	301	268
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	453	451
Equity component of AFUDC	(26)	(20)
Gains on sales of other assets	(4)	(3)
Deferred income taxes	224	172
Accrued pension and other post-retirement benefit costs	(10)	(16)
Payments for asset retirement obligations	(101)	(100)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(3)	(1)
Receivables	3	(19)
Receivable from affiliated companies		7
Inventory	23	20
Other current assets	(50)	131
Increase (decrease) in
Accounts payable	(218)	(28)
Accounts payable to affiliated companies	(58)	(56)
Taxes accrued	(43)	56
Other current liabilities	(111)	(12)
Other assets	(37)	(26)
Other liabilities	(9)	(6)
Net cash provided by operating activities	334	818
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(840)	(704)
Purchases of available-for-sale securities	(819)	(1,299)
Proceeds from sales and maturities of available-for-sale securities	805	1,284
Notes receivable from affiliated companies	165
Other	(22)	(19)
Net cash used in investing activities	(711)	(738)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	15	59
Payments for the redemption of long-term debt	(269)	(15)
Notes payable to affiliated companies	633	(131)
Other	(1)
Net cash provided by financing activities	378	(87)
Net decrease in cash and cash equivalents	1	(7)
Cash and cash equivalents at beginning of period	11	15
Cash and cash equivalents at end of period	12	8
Significant non-cash transactions:
Accrued capital expenditures	52	73
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	248	281
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	274	239
Equity component of AFUDC	(22)	(9)
Impairment charges	2	3
Deferred income taxes	186	113
Accrued pension and other post-retirement benefit costs	2	1
Payments for asset retirement obligations	(27)	(25)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	2	34
Receivables	(65)	(49)
Receivable from affiliated companies		23
Inventory	72	5
Other current assets	(47)	(13)
Increase (decrease) in
Accounts payable	7	3
Accounts payable to affiliated companies	(83)	(16)
Taxes accrued	78	5
Other current liabilities	(57)	(142)
Other assets	(32)	(47)
Other liabilities	(5)	20
Net cash provided by operating activities	533	426
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(893)	(737)
Purchases of available-for-sale securities	(289)	(271)
Proceeds from sales and maturities of available-for-sale securities	318	310
Proceeds from Insurance	4	58
Notes receivable from affiliated companies	(230)
Change in restricted cash		(6)
Other	(4)	5
Net cash used in investing activities	(1,094)	(641)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	908	1,278
Payments for the redemption of long-term debt	(57)	(5)
Notes payable to affiliated companies	(297)	(407)
Distributions to parent		(649)
Other	(1)	(2)
Net cash provided by financing activities	553	215
Net decrease in cash and cash equivalents	(8)
Cash and cash equivalents at beginning of period	16	8
Cash and cash equivalents at end of period	8	8
Significant non-cash transactions:
Accrued capital expenditures	122	215
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	72	82
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	132	127
Equity component of AFUDC	(5)	(2)
Gains on sales of other assets		(1)
Impairment charges	1
Deferred income taxes	64	68
Accrued pension and other post-retirement benefit costs	2	3
Payments for asset retirement obligations	(3)	(3)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		(2)
Receivables	11	3
Receivable from affiliated companies	55	49
Inventory	6	(5)
Other current assets	(11)	49
Increase (decrease) in
Accounts payable	(4)	8
Accounts payable to affiliated companies	(16)	23
Taxes accrued	(79)	(68)
Other current liabilities	(15)	(66)
Other assets	(12)	(8)
Other liabilities	(8)	(9)
Net cash provided by operating activities	190	248
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(286)	(214)
Notes receivable from affiliated companies	31
Notes receivable from affiliated companies		(186)
Other	(13)	(13)
Net cash used in investing activities	(268)	(413)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	93	341
Payments for the redemption of long-term debt	(1)	(52)
Notes payable to affiliated companies	8	(103)
Dividends to parent	(25)	(25)
Other	(1)
Net cash provided by financing activities	74	161
Net decrease in cash and cash equivalents	(4)	(4)
Cash and cash equivalents at beginning of period	13	14
Cash and cash equivalents at end of period	9	10
Significant non-cash transactions:
Accrued capital expenditures	59	30
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	197	180
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	218	223
Equity component of AFUDC	(12)	(7)
Deferred income taxes	131	36
Accrued pension and other post-retirement benefit costs	3	4
Payments for asset retirement obligations	(17)	(16)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	1
Receivables	73	12
Receivable from affiliated companies	27	11
Inventory	34	62
Other current assets	(15)	(19)
Increase (decrease) in
Accounts payable	(68)	(22)
Accounts payable to affiliated companies	(24)	4
Taxes accrued	(3)	(42)
Other current liabilities	(11)	(60)
Other assets	(13)	(29)
Other liabilities	(9)	44
Net cash provided by operating activities	512	381
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(397)	(325)
Purchases of available-for-sale securities	(10)	(7)
Proceeds from sales and maturities of available-for-sale securities	4	5
Notes receivable from affiliated companies	67
Notes receivable from affiliated companies		(64)
Other	(23)	(6)
Net cash used in investing activities	(359)	(397)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		495
Payments for the redemption of long-term debt	(2)	(326)
Distributions to parent	(150)	(149)
Other	(1)	(1)
Net cash provided by financing activities	(153)	19
Net decrease in cash and cash equivalents		3
Cash and cash equivalents at beginning of period	17	9
Cash and cash equivalents at end of period	17	12
Significant non-cash transactions:
Accrued capital expenditures	81	43
Piedmont Natural Gas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (attributable to parent)	87	106
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	74	74
Impairment charges	7
Deferred income taxes	100	70
Equity in earnings of unconsolidated affiliates	(5)	(23)
Accrued pension and other post-retirement benefit costs	6	2
Payments for asset retirement obligations		(4)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(39)	41
Receivables	155	90
Receivable from affiliated companies	(1)	48
Inventory	28
Other current assets	(64)	(93)
Increase (decrease) in
Accounts payable	(44)	(21)
Accounts payable to affiliated companies	42
Taxes accrued	(46)	8
Other current liabilities	(23)	(4)
Other assets	28	49
Other liabilities	(6)	3
Net cash provided by operating activities	299	346
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(260)	(247)
Contributions to equity method investments	(12)	(22)
Other	1	(1)
Net cash used in investing activities	(271)	(270)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	125
Proceeds from the issuance of common stock related to employee benefit plans		12
Payments for the redemption of long-term debt		(40)
Notes payable and commercial paper	(330)	(5)
Notes payable to affiliated companies	167
Dividends paid		(55)
Other	(1)
Net cash provided by financing activities	(39)	(88)
Net decrease in cash and cash equivalents	(11)	(12)
Cash and cash equivalents at beginning of period	25	33
Cash and cash equivalents at end of period	14	21
Significant non-cash transactions:
Accrued capital expenditures	45	$ 50
Transfer of Ownership Interest in Investments [Member] | Piedmont Natural Gas [Member]
Significant non-cash transactions:
Transfer of ownership interest of certain equity method investees to parent	$ 149

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]		Foreign Currency Translation Adjustments [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]	Net Unrealized Gains (Losses) on Available for Sale Securities [Member]	Pension and OPEB Adjustments [Member]	Common Stockholders' Equity [Member]		Noncontrolling Interest [Member]	Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member]Members Equity [Member]	Duke Energy Carolinas [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member]	Progress Energy [Member]Additional Paid-in Capital [Member]	Progress Energy [Member]Retained Earnings [Member]	Progress Energy [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member]Net Unrealized Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]Pension and OPEB Adjustments [Member]	Progress Energy [Member]Common Stockholders' Equity [Member]	Progress Energy [Member]Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]Members Equity [Member]	Duke Energy Florida [Member]Net Unrealized Gains (Losses) on Available for Sale Securities [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]Common Stock [Member]	Duke Energy Ohio [Member]Additional Paid-in Capital [Member]	Duke Energy Ohio [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]Common Stock [Member]	Duke Energy Indiana [Member]Additional Paid-in Capital [Member]	Duke Energy Indiana [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]Members Equity [Member]	Duke Energy Indiana [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Piedmont Natural Gas [Member]	Piedmont Natural Gas [Member]Common Stock [Member]	Piedmont Natural Gas [Member]Retained Earnings [Member]	Piedmont Natural Gas [Member]Net Gains (Losses) on Cash Flow Hedges [Member]
Beginning Balance at Dec. 31, 2015	$ 39,771		$ 1	$ 37,968	$ 2,564		$ (692)	$ (50)	$ (3)	$ (61)	$ 39,727		$ 44				$ 12,853	$ 8,092	$ 4,831	$ (31)		$ (17)	$ 12,875	$ (22)
Beginning Balance, in shares at Dec. 31, 2015			688,000,000
Beginning Balance (member's equity) at Dec. 31, 2015														$ 11,606	$ 11,617	$ (11)									$ 7,059	$ 5,121	$ 5,121
Beginning Balance (parent) at Dec. 31, 2015																													$ 2,784	$ 762	$ 2,720	$ (698)	$ 3,836	$ 1	$ 1,384	$ 2,450		$ 1	$ 1,458	$ 728	$ 731	$ (1)
Net income	1,211				1,203						1,203		8				486		481				481	5
Net income (attributable to parent)	1,203													532	532		481								268	281	281		82			82	180				$ 180		106		106
Other comprehensive income (loss)	93						103	(23)	7	2	89		4	1		1	6			3	$ 1	2	6			1		$ 1					(1)					$ (1)
Common stock issuances, including dividend reinvestment and employee benefits, shares			1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	16			16							16																												12	12
Common stock dividends	(1,140)				(1,140)						(1,140)						(651)		(651)				(651)						(25)		(25)								(55)		(55)
Distributions to parent														(1,200)	(1,200)											(649)	(649)						(149)				(149)
Distributions to noncontrolling interest in subsidiaries	(3)												(3)				(1)							(1)
Other																																		$ (1)	$ (1,384)	$ (2,450)	3,835
Ending Balance at Jun. 30, 2016	39,948		$ 1	37,984	2,627		$ (589)	(73)	4	(59)	39,895		53				12,693	8,092	4,661	(28)	1	(15)	12,711	(18)
Ending Balance, in shares at Jun. 30, 2016			689,000,000
Ending Balance (member's equity) at Jun. 30, 2016														10,939	10,949	(10)									7,327	4,754	4,753	1					3,866				3,866
Ending Balance (parent) at Jun. 30, 2016																													$ 2,841	762	2,695	(616)							$ 1,521	740	782	$ (1)
Beginning Balance at Dec. 31, 2016	$ 41,041		$ 1	38,741	2,384			(20)	(1)	(72)	41,033		8				$ 11,807	8,094	3,764	(23)	1	(16)	11,820	(13)
Beginning Balance, in shares at Dec. 31, 2016	700,000,000		700,000,000														100												90,000,000										100
Beginning Balance (member's equity) at Dec. 31, 2016														10,772	10,781	(9)									7,358	4,900	4,899	1					4,067				4,067
Beginning Balance (parent) at Dec. 31, 2016	$ 41,033																$ 11,820												$ 2,996	762	2,695	(461)							$ 1,672	860	812
Net income	1,406				1,402						1,402		4				478		473				473	5
Net income (attributable to parent)	1,402													543	543		473								301	248	248		72			72	197				197		87		87
Other comprehensive income (loss)	11							1	8	2	11			1		1	10			6	2	2	10			2		2
Common stock issuances, including dividend reinvestment and employee benefits	17			17							17
Common stock dividends	(1,200)				(1,200)						(1,200)																		$ (25)		(25)
Distributions to parent														(375)	(375)																		(150)				(150)
Distributions to noncontrolling interest in subsidiaries	(2)												(2)
Other	21	[1]			21	[1]					21	[1]		(2)	(2)		2	2					2			2	2												$ (149)		(149)
Ending Balance at Jun. 30, 2017	$ 41,294		$ 1	$ 38,758	$ 2,607			$ (19)	$ 7	$ (70)	$ 41,284		$ 10				$ 12,297	$ 8,096	$ 4,237	$ (17)	$ 3	$ (14)	$ 12,305	$ (8)
Ending Balance, in shares at Jun. 30, 2017	700,000,000		700,000,000														100												90,000,000										100
Ending Balance (member's equity) at Jun. 30, 2017														$ 10,939	$ 10,947	$ (8)									$ 7,659	$ 5,152	$ 5,149	$ 3					$ 4,114				$ 4,114
Ending Balance (parent) at Jun. 30, 2017	$ 41,284																$ 12,305												$ 3,043	$ 762	$ 2,670	$ (389)							$ 1,610	$ 860	$ 750
[1]	Cumulative-effect adjustment due to implementation of a new accounting standard related to stock-based compensation and the associated income taxes. See Note 1 for more information.

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Organization and Basis of Presentation	Index to Combined Notes to Condensed Consolidated Financial Statements The unaudited notes to the condensed consolidated financial statements that follow are a combined presentation. The following list indicates the registrants to which the footnotes apply. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Duke Energy Corporation • • • • • • • • • • • • • • • • Duke Energy Carolinas, LLC • • • • • • • • • • • • • Progress Energy, Inc. • • • • • • • • • • • • • • Duke Energy Progress, LLC • • • • • • • • • • • • • Duke Energy Florida, LLC • • • • • • • • • • • • • Duke Energy Ohio, Inc. • • • • • • • • • • • • • Duke Energy Indiana, LLC • • • • • • • • • • • • • Piedmont Natural Gas Company, Inc. • • • • • • • • • • • • • • • • Tables within the notes may not sum across due to (i) Progress Energy's consolidation of Duke Energy Progress, Duke Energy Florida and other subsidiaries that are not registrants, (ii) subsidiaries that are not registrants but included in the consolidated Duke Energy balances and (iii) the Piedmont registrant not included in the consolidated Duke Energy results for the three and six months ended June 30, 2016, as Piedmont results were not consolidated by Duke Energy until after the acquisition date of October 3, 2016. ORGANIZATION AND BASIS OF PRESENTATION NATURE OF OPERATIONS AND BASIS OF CONSOLIDATION Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) primarily through its direct and indirect subsidiaries. Certain Duke Energy subsidiaries are also subsidiary registrants, including Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, LLC (Duke Energy Progress); Duke Energy Florida, LLC (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio), Duke Energy Indiana, LLC (Duke Energy Indiana) and Piedmont Natural Gas Company, Inc. (Piedmont). When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants. On October 3, 2016, Duke Energy completed the acquisition of Piedmont. Piedmont's results of operations and cash flows are included in the accompanying condensed consolidated financial statements of Duke Energy for the three and six months ended June 30, 2017 , but not for the three and six months ended June 30, 2016 , as Piedmont's earnings and cash flows are only included in Duke Energy's consolidated results subsequent to the acquisition date. See Note 2 for additional information regarding the acquisition. In December 2016, Duke Energy completed an exit of the Latin American market to focus on its domestic regulated business, which was further bolstered by the acquisition of Piedmont. The sale of the International Energy business segment, excluding an equity method investment in National Methanol Company (NMC), was completed through two transactions including a sale of assets in Brazil to China Three Gorges (Luxembourg) Energy S.à.r.l. (China Three Gorges) and a sale of Duke Energy's remaining Latin American assets in Peru, Chile, Ecuador, Guatemala, El Salvador and Argentina to ISQ Enerlam Aggregator, L.P. and Enerlam (UK) Holding Ltd. (I Squared Capital) (collectively, the International Disposal Group). See Note 2 for additional information on the sale of International Energy. The results of operations of the International Disposal Group have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations. See Note 2 for additional information. These Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities. Substantially all of the Subsidiary Registrants' operations qualify for regulatory accounting. Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), Public Service Commission of South Carolina (PSCSC), U.S. Nuclear Regulatory Commission (NRC) and FERC. Progress Energy is a public utility holding company headquartered in Raleigh, North Carolina, subject to regulation by FERC. Progress Energy conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the Florida Public Service Commission (FPSC), NRC and FERC. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers and recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and FERC. Piedmont is a regulated public utility primarily engaged in the distribution of natural gas in portions of North Carolina, South Carolina and Tennessee. Piedmont is subject to the regulatory provisions of the NCUC, PSCSC, Tennessee Public Utility Commission (formerly the Tennessee Regulatory Authority) (TPUC) and FERC. BASIS OF PRESENTATION These Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP in the U.S. for annual financial statements. Since the interim Condensed Consolidated Financial Statements and Notes do not include all information and notes required by GAAP in the U.S. for annual financial statements, the Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the Consolidated Financial Statements and Notes in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2016 , and the Consolidated Financial Statements and Notes in the Piedmont Annual Report on Form 10‑K for the year ended October 31, 2016. Effective November 1, 2016, Piedmont's fiscal year-end was changed from October 31 to December 31, the year-end of Duke Energy. A transition report was filed on Form 10-Q (Form 10-QT) as of December 31, 2016, for the transition period from November 1, 2016 to December 31, 2016. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors. In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform to the current year presentation. UNBILLED REVENUE Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy and natural gas delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills, meter reading schedules, and the impact of weather normalization or margin decoupling mechanisms. Unbilled revenues are included within Receivables and Receivables of variable interest entities (VIEs) on the Condensed Consolidated Balance Sheets as shown in the following table. (in millions) June 30, 2017 December 31, 2016 Duke Energy $ 761 $ 831 Duke Energy Carolinas 310 313 Progress Energy 220 161 Duke Energy Progress 125 102 Duke Energy Florida 95 59 Duke Energy Ohio 1 2 Duke Energy Indiana 13 32 Piedmont 1 77 Additionally, Duke Energy Ohio and Duke Energy Indiana sell nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 for further information. These receivables for unbilled revenues are shown in the table below. (in millions) June 30, 2017 December 31, 2016 Duke Energy Ohio $ 70 $ 97 Duke Energy Indiana 118 123 AMOUNTS ATTRIBUTABLE TO CONTROLLING INTERESTS For the three and six months ended June 30, 2017 , the Loss from Discontinued Operations, net of tax on Duke Energy's Condensed Consolidated Statements of Operations is entirely attributable to controlling interests. The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations for the three and six months ended June 30, 2016 . Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Income from Continuing Operations $ 624 $ 1,201 Income from Continuing Operations Attributable to Noncontrolling Interests — 3 Income from Continuing Operations Attributable to Duke Energy Corporation $ 624 $ 1,198 (Loss) Income from Discontinued Operations, net of tax $ (112 ) $ 10 Income from Discontinued Operations Attributable to Noncontrolling Interests, net of tax 3 5 (Loss) Income from Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ (115 ) $ 5 Net Income $ 512 $ 1,211 Net Income Attributable to Noncontrolling Interests 3 8 Net Income Attributable to Duke Energy Corporation $ 509 $ 1,203 INVENTORY Inventory is used for operations and is recorded primarily using the average cost method. Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Materials and supplies are recorded as inventory when purchased and subsequently charged to expense or capitalized to property, plant and equipment when installed. Inventory, including excess or obsolete inventory, is written-down to the lower of cost or market value. Once inventory has been written-down, it creates a new cost basis for the inventory that is not subsequently written-up. Provisions for inventory write-offs were not material at June 30, 2017 , and December 31, 2016 . The components of inventory are presented in the tables below. June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,368 $ 791 $ 1,129 $ 782 $ 347 $ 85 $ 321 $ 2 Coal 665 239 262 161 101 17 147 — Natural gas, oil and other fuel 336 36 230 110 120 32 2 36 Total inventory $ 3,369 $ 1,066 $ 1,621 $ 1,053 $ 568 $ 134 $ 470 $ 38 December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,374 $ 767 $ 1,167 $ 813 $ 354 $ 84 $ 312 $ 1 Coal 774 251 314 148 166 19 190 — Natural gas, oil and other fuel 374 37 236 115 121 34 2 65 Total inventory $ 3,522 $ 1,055 $ 1,717 $ 1,076 $ 641 $ 137 $ 504 $ 66 EXCISE TAXES Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Otherwise, excise taxes are accounted for on a net basis. Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes on the Condensed Consolidated Statements of Operations were as follows. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy $ 91 $ 87 $ 182 $ 178 Duke Energy Carolinas 9 7 18 15 Progress Energy 55 50 101 96 Duke Energy Progress 4 4 9 9 Duke Energy Florida 51 46 92 87 Duke Energy Ohio 23 22 51 51 Duke Energy Indiana 3 8 10 16 Piedmont 1 — 2 1 NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2017 and 2016 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. While immaterial, adoption of the following accounting standard had the most significant impact on the Duke Energy results of operations, cash flows and financial position for the six months ended June 30, 2017. Stock-Based Compensation and Income Taxes. In first quarter 2017, Duke Energy adopted Financial Accounting Standards Board (FASB) guidance, which revised the accounting for stock-based compensation and the associated income taxes. The adopted guidance changes certain aspects of accounting for stock-based payment awards to employees including the accounting for income taxes and classification on the Condensed Consolidated Statements of Cash Flows. The primary impact to Duke Energy as a result of implementing this guidance was a cumulative-effect adjustment to retained earnings for tax benefits not previously recognized and additional income tax expense for the six months ended June 30, 2017. See the Duke Energy Condensed Consolidated Statements of Changes in Equity for further information. The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of June 30, 2017 . Retirement Benefits. In March 2017, the FASB issued revised accounting guidance for the presentation of net periodic costs related to benefit plans. Current GAAP permits the aggregation of all the components of net periodic costs on the income statement and does not require the disclosure of the location of net periodic costs on the Condensed Consolidated Statement of Operations. Under the amended guidance, the service cost component of net periodic costs must be included within Operating income within the same line as other compensation expenses. All other components of net periodic costs must be outside of Operating income. In addition, the updated guidance permits only the service cost component of net periodic costs to be capitalized to Inventory or Property, Plant and Equipment. This represents a change from current GAAP, which permits all components of net periodic costs to be capitalized. The guidance allows for a practical expedient that permits a company to use amounts disclosed in prior-period financial statements as the estimation basis for applying the retrospective presentation requirements. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2018. These amendments should be applied retrospectively for the presentation of the various components of net periodic costs and prospectively for the change in eligible costs to be capitalized. Duke Energy currently presents all of the components of net periodic costs that are not capitalized within Operation, maintenance and other on the Condensed Consolidated Statement of Operations. Under this updated guidance, Duke Energy will retrospectively reclassify all the components of net periodic costs except for the service cost component to be presented outside of Operating income. However, Duke Energy will continue to present the service cost amount not capitalized within Operation, maintenance and other as this line item includes other compensation expense. Duke Energy is currently evaluating the financial statement impact, if any, of adopting this standard and whether or not the practical expedient will be utilized. Goodwill Impairment. In January 2017, the FASB issued revised guidance for subsequent measurement of goodwill. Under the guidance, a company will recognize an impairment to goodwill for the amount by which a reporting unit's carrying value exceeds the reporting unit's fair value, not to exceed the amount of goodwill allocated to that reporting unit. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2020. However, Duke Energy expects to early adopt this guidance on a prospective basis for the next annual goodwill impairment test. Duke Energy does not expect adopting this guidance will have a material impact to its results of operations or financial position. Revenue from Contracts with Customers . In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Most of Duke Energy’s revenue is expected to be in scope of the new guidance. The majority of our sales, including energy provided to residential customers, are from tariff offerings that provide natural gas or electricity without a defined contractual term ("at-will"). For such arrangements, Duke Energy expects that the revenue from contracts with customers will be equivalent to the electricity or natural gas supplied and billed in that period (including estimated billings). As such, Duke Energy does not expect that there will be a significant shift in the timing or pattern of revenue recognition for such sales. The evaluation of other revenue streams is ongoing, including long-term contracts with industrial customers and long-term purchase power agreements (PPA). Duke Energy continues to evaluate what information would be most useful for users of the financial statements, including information already provided in disclosures outside of the financial statement footnotes. These additional disclosures could include the disaggregation of revenues by geographic location, type of service, customer class or by duration of contract ("at-will" versus contracted revenue). Revenues from contracts with customers, revenue recognized under regulated operations accounting and revenue from lease accounting will also be disclosed. Duke Energy intends to use the modified retrospective method of adoption effective January 1, 2018. This method results in a cumulative-effect adjustment that will be recorded to retained earnings as of January 1, 2018, as if the standard had always been in effect. Disclosures for 2018 will include a comparison to what would have been reported for 2018 under the current revenue recognition rules in order to assist financial statement users in understanding how revenue recognition has changed as a result of this standard and to facilitate comparability with prior year reported results, which are not restated under the modified retrospective approach. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2019, although it can be early adopted. The guidance is applied using a modified retrospective approach. Duke Energy is currently evaluating the financial statement impact of adopting this standard and is continuing to monitor industry implementation issues, including easements, pole attachments and renewable power purchase agreements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Significant system enhancements may be required to facilitate the identification, tracking and reporting of potential leases based upon requirements of the new lease standard. Statement of Cash Flows. In November 2016, the FASB issued revised accounting guidance to reduce diversity in practice for the presentation and classification of restricted cash on the statement of cash flows. Under the updated guidance, restricted cash and restricted cash equivalents will be included within beginning-of-period and end-of-period cash and cash equivalents on the statement of cash flows. For Duke Energy, this guidance is effective for the interim and annual periods beginning January 1, 2018, although it can be early adopted. The guidance will be applied using a retrospective transition method to each period presented. Upon adoption by Duke Energy, the revised guidance will result in a change to the amount of cash and cash equivalents and restricted cash explained when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Prior to adoption, the Duke Energy Registrants reflect changes in restricted cash within Cash Flows from Investing Activities on the Condensed Consolidated Statement of Cash Flows. Financial Instruments Classification and Measurement. In January 2016, the FASB issued revised accounting guidance for the classification and measurement of financial instruments. Changes in the fair value of all equity securities will be required to be recorded in net income. Current GAAP allows some changes in fair value for available-for-sale equity securities to be recorded in Accumulated other comprehensive income (AOCI). Additional disclosures will be required to present separately the financial assets and financial liabilities by measurement category and form of financial asset. An entity's equity investments that are accounted for under the equity method of accounting are not included within the scope of the new guidance. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, by recording a cumulative-effect adjustment to retained earnings as of January 1, 2018. This guidance is expected to have minimal impact on the Duke Energy Registrant's Condensed Consolidated Statements of Operations and Comprehensive Income as changes in the fair value of most of the Duke Energy Registrants' available-for-sale equity securities are deferred as regulatory assets or liabilities pursuant to accounting guidance for regulated operations.

Acquisitions and Dispositions

Acquisitions and Dispositions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS ACQUISITIONS The Duke Energy Registrants consolidate assets and liabilities from acquisitions as of the purchase date, and include earnings from acquisitions in consolidated earnings after the purchase date. Acquisition of Piedmont Natural Gas On October 3, 2016, Duke Energy acquired all outstanding common stock of Piedmont for a total cash purchase price of $5.0 billion and assumed Piedmont's existing long-term debt, which had a fair value of approximately $2.0 billion at the time of the acquisition. The acquisition provides a foundation for Duke Energy to establish a broader, long-term strategic natural gas infrastructure platform to complement its existing natural gas pipeline investments and regulated natural gas business in the Midwest. In connection with the closing of the acquisition, Piedmont became a wholly owned subsidiary of Duke Energy. Purchase Price Allocation The purchase price allocation of the Piedmont acquisition is as follows: (in millions) Current assets $ 497 Property, plant and equipment, net 4,714 Goodwill 3,353 Other long-term assets 804 Total assets 9,368 Current liabilities, including current maturities of long-term debt 576 Long-term liabilities 1,790 Long-term debt 2,002 Total liabilities 4,368 Total purchase price $ 5,000 The fair value of Piedmont's assets and liabilities were determined based on significant estimates and assumptions that are judgmental in nature, including the amount and timing of projected future cash flows, discount rates reflecting risk inherent in the future cash flows and market prices of long-term debt. The majority of Piedmont’s operations are subject to the rate-setting authority of the NCUC, the PSCSC and the TPUC and are accounted for pursuant to accounting guidance for regulated operations. The rate-setting and cost recovery provisions currently in place for Piedmont’s regulated operations provide revenues derived from costs, including a return on investment of assets and liabilities included in rate base. Thus, the fair value of Piedmont's assets and liabilities subject to these rate-setting provisions approximates the pre-acquisition carrying value and does not reflect any net valuation adjustments. The significant assets and liabilities for which valuation adjustments were reflected within the purchase price allocation include the acquired equity method investments and long-term debt. The difference between the fair value and the pre-acquisition carrying value of long-term debt for regulated operations was recorded as a regulatory asset. The excess of the purchase price over the fair value of Piedmont's assets and liabilities on the acquisition date was recorded as goodwill. The goodwill reflects the value paid by Duke Energy primarily for establishing a broader, long-term strategic natural gas infrastructure platform, an improved risk profile and expected synergies resulting from the combined entities. Under Securities and Exchange Commission (SEC) regulations, Duke Energy elected not to apply push down accounting to the stand-alone Piedmont financial statements. Other Acquisition Related Matters Duke Energy recorded unrealized losses on forward-starting interest rate swaps related to the acquisition financing of $75 million and $168 million for the three and six months ended June 30, 2016, respectively. See Note 9 for additional information. During the three months ended June 30, 2017, Piedmont recorded a $7 million software impairment resulting from planned accounting system and process integration. Pro Forma Financial Information The following unaudited pro forma financial information reflects the combined results of operations of Duke Energy and Piedmont as if the merger had occurred as of January 1, 2016. The pro forma financial information excludes potential cost savings, intercompany revenues, Piedmont’s earnings from the equity method investment in SouthStar Energy Services, LLC (SouthStar) sold immediately prior to the merger, and after-tax nonrecurring transaction and integration costs incurred by Duke Energy and Piedmont of $57 million and $120 million for the three and six months ended June 30, 2016, respectively. See Note 3 for additional information on Piedmont's sale of SouthStar. This information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Duke Energy. Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Operating Revenues $ 5,374 $ 11,214 Net Income Attributable to Duke Energy Corporation 540 1,372 DISPOSITIONS Sale of International Energy In December 2016, Duke Energy sold its International Energy businesses, excluding the equity method investment in NMC (the International Disposal Group), in two separate transactions. Duke Energy sold its Brazilian business to China Three Gorges for approximately $1.2 billion , including the assumption of debt, and its remaining Central and South American businesses to I Squared Capital in a deal also valued at approximately $1.2 billion , including the assumption of debt. The transactions generated cash proceeds of $1.9 billion , excluding transaction costs, which were primarily used to reduce Duke Energy holding company debt. The following table presents the results of the International Disposal Group, which are included in Income from Discontinued Operations, net of tax in Duke Energy's Condensed Consolidated Statements of Operations. Interest expense directly associated with the International Disposal Group was allocated to discontinued operations. No interest from corporate level debt was allocated to discontinued operations. Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Operating Revenues $ 270 $ 516 Fuel used in electric generation and purchased power 70 117 Cost of natural gas 12 23 Operation, maintenance and other 84 155 Depreciation and amortization 22 44 Property and other taxes 2 5 Impairment charges (a) 194 194 Gains on Sales of Other Assets and Other, net 1 1 Other Income and Expenses, net 11 21 Interest Expense 22 44 Loss before income taxes (124 ) (44 ) Income tax benefit (b) (13 ) (52 ) (Loss) Income from discontinued operations of the International Disposal Group (111 ) 8 (Loss) Income from discontinued operations of other businesses (1 ) 2 (Loss) Income from Discontinued Operations, net of tax $ (112 ) $ 10 (a) In conjunction with the advancements of marketing efforts during 2016, Duke Energy performed recoverability tests of the long-lived asset groups of International Energy. As a result, Duke Energy determined the carrying value of certain assets in Central America was not fully recoverable and recorded a pretax impairment charge of $194 million . The charge represents the excess carrying value over the estimated fair value of the assets, which was based on a Level 3 Fair Value measurement that was primarily determined from the income approach using discounted cash flows but also considered market information obtained in 2016. (b) Includes an income tax benefit of $95 million for the six months ended June 30, 2016 related to historical undistributed foreign earnings. See Note 16 for additional information. Duke Energy has elected not to separately disclose discontinued operations on the Condensed Consolidated Statements of Cash Flows. The following table summarizes Duke Energy's cash flows from discontinued operations related to the International Disposal Group. Six Months Ended (in millions) June 30, 2016 Cash flows provided by (used in): Operating activities $ 144 Investing activities (24 ) Other Sale Related Matters Duke Energy will provide certain transition services to China Three Gorges and I Squared Capital for a period not to extend beyond November 2017 and December 2017, respectively. Cash flows related to providing the transition services are not material. In addition, Duke Energy will reimburse China Three Gorges and I Squared Capital for all tax obligations arising from the period preceding consummation on the transactions, totaling approximately $78 million . Duke Energy has not recorded any other liabilities, contingent liabilities or indemnifications related to the International Disposal Group.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Operating segments are determined based on information used by the chief operating decision-maker in deciding how to allocate resources and evaluate the performance of the business. Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income includes intercompany revenues and expenses that are eliminated on the Condensed Consolidated Financial Statements. Duke Energy Due to the Piedmont acquisition and the sale of International Energy in the fourth quarter of 2016, Duke Energy's segment structure has been realigned to include the following segments: Electric Utilities and Infrastructure, Gas Utilities and Infrastructure and Commercial Renewables. Prior period information has been recast to conform to the current segment structure. See Note 2 for further information on the Piedmont and International Energy transactions. The Electric Utilities and Infrastructure segment includes Duke Energy's regulated electric utilities in the Carolinas, Florida and the Midwest. The regulated electric utilities conduct operations through the Subsidiary Registrants that are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. Electric Utilities and Infrastructure also includes Duke Energy's electric transmission infrastructure investments. The Gas Utilities and Infrastructure segment includes Piedmont, Duke Energy's natural gas local distribution companies in Ohio and Kentucky, and Duke Energy's natural gas storage and midstream pipeline investments. Gas Utilities and Infrastructure's operations are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. Commercial Renewables is primarily comprised of nonregulated utility scale wind and solar generation assets located throughout the U.S. The remainder of Duke Energy’s operations is presented as Other, which is primarily comprised of unallocated corporate interest expense, unallocated corporate costs, contributions to the Duke Energy Foundation and the operations of Duke Energy’s wholly owned captive insurance subsidiary, Bison Insurance Company Limited (Bison). Other also includes Duke Energy's 25 percent interest in NMC, a large regional producer of methyl tertiary butyl ether (MTBE) located in Saudi Arabia. The investment in NMC is accounted for under the equity method of accounting. Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Three Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,150 $ 279 $ 110 $ 5,539 $ 16 $ — $ 5,555 Intersegment revenues 8 22 — 30 19 (49 ) — Total revenues $ 5,158 $ 301 $ 110 $ 5,569 $ 35 $ (49 ) $ 5,555 Segment income (loss) (a) $ 729 $ 27 $ 26 $ 782 $ (94 ) $ — $ 688 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (2 ) Net income $ 689 Segment assets $ 117,009 $ 11,073 $ 4,306 $ 132,388 $ 2,435 $ 181 $ 135,004 Three Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 4,993 $ 97 $ 112 $ 5,202 $ 11 $ — $ 5,213 Intersegment revenues 8 2 — 10 19 (29 ) — Total revenues $ 5,001 $ 99 $ 112 $ 5,212 $ 30 $ (29 ) $ 5,213 Segment income (loss) (a) $ 704 $ 16 $ 11 $ 731 $ (107 ) $ — $ 624 Loss from discontinued operations, net of tax (112 ) Net income $ 512 Six Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 10,090 $ 927 $ 238 $ 11,255 $ 29 $ — $ 11,284 Intersegment revenues 15 44 — 59 39 (98 ) — Total revenues $ 10,105 $ 971 $ 238 $ 11,314 $ 68 $ (98 ) $ 11,284 Segment income (loss) (a) $ 1,364 $ 160 $ 51 $ 1,575 $ (171 ) $ — $ 1,404 Add back noncontrolling interests 4 Loss from discontinued operations, net of tax (2 ) Net income $ 1,406 Six Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 10,074 $ 266 $ 226 $ 10,566 $ 24 $ — $ 10,590 Intersegment revenues 16 3 — 19 35 (54 ) — Total revenues $ 10,090 $ 269 $ 226 $ 10,585 $ 59 $ (54 ) $ 10,590 Segment income (loss) (a) $ 1,368 $ 48 $ 37 $ 1,453 $ (255 ) $ — $ 1,198 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 10 Net income $ 1,211 (a) Other includes costs to achieve the Piedmont acquisition. See Notes 2 and 9 for additional information. Duke Energy Ohio Duke Energy Ohio has two reportable operating segments, Electric Utilities and Infrastructure and Gas Utilities and Infrastructure. Electric Utilities and Infrastructure transmits and distributes electricity in portions of Ohio and generates, distributes and sells electricity in portions of northern Kentucky. Gas Utilities and Infrastructure transports and sells natural gas in portions of Ohio and northern Kentucky. It conducts operations primarily through Duke Energy Ohio and its wholly owned subsidiary, Duke Energy Kentucky. The remainder of Duke Energy Ohio's operations is presented as Other, which is primarily comprised of governance costs allocated by its parent, Duke Energy, and revenues and expenses related to Duke Energy Ohio's contractual arrangement to buy power from the Ohio Valley Electric Corporation's (OVEC) power plants. See Note 8 for additional information on related party transactions. Three Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 329 $ 100 $ 429 $ 8 $ 437 Segment income (loss)/Net Income 22 17 39 (9 ) 30 Segment assets 4,879 2,672 7,551 54 7,605 Three Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 323 $ 98 $ 421 $ 7 $ 428 Segment income (loss)/Net Income 19 14 33 (10 ) 23 Six Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 665 $ 270 $ 935 $ 20 $ 955 Segment income (loss)/Net Income 46 42 88 (16 ) 72 Six Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 663 $ 269 $ 932 $ 12 $ 944 Segment income (loss) $ 55 $ 45 $ 100 $ (20 ) $ 80 Income from discontinued operations, net of tax 2 Net income 82 DUKE ENERGY CAROLINAS, PROGRESS ENERGY, DUKE ENERGY PROGRESS, DUKE ENERGY FLORIDA, DUKE ENERGY INDIANA AND PIEDMONT Piedmont has one reportable segment, Gas Utilities and Infrastructure, which transports and sells natural gas. The remainder of Piedmont's operations is presented as Other, which is comprised of certain unallocated corporate costs, including acquisition-related expenses, and earnings from Piedmont's equity method investment in SouthStar prior to its sale. Piedmont sold its 15 percent membership interest in SouthStar on October 3, 2016. Piedmont's income, net of tax, from SouthStar for the three and six months ended June 30, 2016 , was $3 million and $10 million , respectively. The remaining Subsidiary Registrants each have one reportable operating segment, Electric Utilities and Infrastructure, which generates, transmits, distributes and sells electricity. The remainder of each company's operations is presented as Other, which is comprised of certain unallocated corporate costs. Other for Progress Energy also includes interest expense on corporate debt instruments of $56 million and $111 million for the three and six months ended June 30, 2017 , respectively, and $55 million and $111 million for the three and six months ended June 30, 2016 , respectively. The following table summarizes the net (loss) income of Other for each of these entities. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas $ (6 ) $ (17 ) $ (12 ) $ (34 ) Progress Energy (45 ) (45 ) (88 ) (94 ) Duke Energy Progress (4 ) (8 ) (7 ) (16 ) Duke Energy Florida (3 ) (5 ) (5 ) (9 ) Duke Energy Indiana (1 ) (5 ) (3 ) (7 ) Piedmont (9 ) 1 (13 ) 7 The assets at Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana are substantially all included within the Electric Utilities and Infrastructure segment at June 30, 2017 . The assets at Piedmont are substantially all included within the Gas Utilities and Infrastructure segment at June 30, 2017 .

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2017
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS RATE RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO, TPUC and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects. Duke Energy Carolinas and Duke Energy Progress Ash Basin Closure Costs Deferral On December 30, 2016, Duke Energy Carolinas and Duke Energy Progress filed a joint petition with the NCUC seeking an accounting order authorizing deferral of certain costs incurred in connection with federal and state environmental remediation requirements related to the permanent closure of ash basins and other ash storage units at coal-fired generating facilities that have provided or are providing generation to customers located in North Carolina. Initial comments were received in March 2017, and reply comments were filed on April 19, 2017. On July 10, 2017, the NCUC consolidated Duke Energy Progress’ coal ash deferral request into the Duke Energy Progress rate case docket for decision. See "2017 North Carolina Rate Case" section below for additional discussion. The NCUC also indicated that the Duke Energy Carolinas coal ash deferral request will be consolidated into Duke Energy Carolinas' next base rate case proceeding . Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. Duke Energy Carolinas Lincoln County Combustion Turbine Addition On June 12, 2017, Duke Energy Carolinas filed an application with the NCUC for a Certificate of Public Convenience and Necessity (CPCN) to construct and operate a new 402-megawatt (MW) simple cycle advanced combustion turbine natural gas-fueled electric generating unit at its existing Lincoln County site. The request also included construction of related transmission and natural gas pipeline interconnection facilities. If approved, construction would begin in 2018 with an estimated commercial operation date in 2024. An evidentiary hearing is scheduled for August 30, 2017. Duke Energy Carolinas cannot predict the outcome of this matter. William States Lee Combined Cycle Facility On April 9, 2014, the PSCSC granted Duke Energy Carolinas and North Carolina Electric Membership Corporation (NCEMC) a Certificate of Environmental Compatibility and Public Convenience and Necessity (CECPCN) for the construction and operation of a 750-MW combined-cycle natural gas-fired generating plant at Duke Energy Carolinas' existing William States Lee Generating Station in Anderson, South Carolina. Duke Energy Carolinas began construction in July 2015 and estimates a cost to build of $600 million for its share of the facility, including allowance for funds used during construction (AFUDC). The project is expected to be commercially available in late 2017. NCEMC will own approximately 13 percent of the project. On July 3, 2014, the South Carolina Coastal Conservation League (SCCL) and Southern Alliance for Clean Energy (SACE) jointly filed a Notice of Appeal with the Court of Appeals of South Carolina (S.C. Court of Appeals) seeking the court's review of the PSCSC's decision, claiming the PSCSC did not properly consider a request related to a proposed solar facility prior to granting approval of the CECPCN. The S.C. Court of Appeals affirmed the PSCSC's decision on February 10, 2016, and on March 24, 2016, denied a request for rehearing filed by SCCL and SACE. On April 21, 2016, SCCL and SACE petitioned the South Carolina Supreme Court for review of the S.C. Court of Appeals decision. On March 24, 2017, the South Carolina Supreme Court denied the request for review, thus concluding the matter. William States Lee III Nuclear Station In December 2007, Duke Energy Carolinas applied to the NRC for combined operating licenses (COLs) for two Westinghouse Electric Company (Westinghouse) AP1000 reactors for the proposed William States Lee III Nuclear Station (Lee Nuclear Station) to be located at a site in Cherokee County, South Carolina. The NCUC and PSCSC have concurred with the prudency of Duke Energy Carolinas decisions to incur certain project development and preconstruction costs through several separately issued orders through 2011, although full cost recovery is not guaranteed. In December 2016, the NRC issued a COL for each reactor. Duke Energy Carolinas is not required to build the nuclear reactors as a result of the COLs being issued. On March 29, 2017, Westinghouse filed for voluntary Chapter 11 bankruptcy in the U.S. Bankruptcy Court for the Southern District of New York. Duke Energy Carolinas is monitoring the bankruptcy proceedings to assess the impact it will have on the future construction of nuclear plants. On May 15, 2017, the NCUC issued an order requiring Duke Energy Carolinas to provide information regarding potential impacts of the Westinghouse bankruptcy on the Lee Nuclear Station, as well as Duke Energy Carolinas' plans for cost recovery and additional financial information regarding the project. The NCUC granted an extension until August 30, 2017, to provide that information. Duke Energy Carolinas cannot predict the outcome of this matter. Duke Energy Progress 2017 North Carolina Rate Case On June 1, 2017, Duke Energy Progress filed an application with the NCUC for a rate increase for retail customers of approximately $477 million , which represents an approximate 14.9 percent increase in annual revenues. The rate increase is driven by capital investments subsequent to the previous base rate case, costs of complying with coal combustion residuals (CCR) regulations and the North Carolina Coal Ash Management Act of 2014 (Coal Ash Act), costs relating to storm recovery, investments in customer service technologies and recovery of costs associated with renewable purchased power. An evidentiary hearing is scheduled to begin November 20, 2017. Duke Energy Progress cannot predict the outcome of this matter. Storm Cost Deferral Filing On December 16, 2016, Duke Energy Progress filed a petition with the NCUC requesting an accounting order to defer certain costs incurred in connection with response to Hurricane Matthew and other significant storms in 2016. Duke Energy Progress proposed in the filing to true-up the total costs quarterly through August 2017. The current estimate of incremental operation and maintenance and capital costs is $116 million . On March 15, 2017, the North Carolina Utilities Commission Public Staff filed comments supporting deferral of a portion of Duke Energy Progress’ requested amount. Duke Energy Progress filed reply comments on April 12, 2017. On July 10, 2017, the NCUC consolidated Duke Energy Progress' storm deferral request into the Duke Energy Progress rate case docket for decision. See "2017 North Carolina Rate Case" for additional discussion. Duke Energy Progress cannot predict the outcome of this matter. Western Carolinas Modernization Plan On November 4, 2015, Duke Energy Progress announced a Western Carolinas Modernization Plan, which included retirement of the existing Asheville coal-fired plant, the construction of two 280‑MW combined-cycle natural gas plants having dual fuel capability, with the option to build a third natural gas simple cycle unit in 2023 based upon the outcome of initiatives to reduce the region's power demand. The plan also included upgrades to existing transmission lines and substations, installation of solar generation and a pilot battery storage project. These investments will be made within the next seven years. Duke Energy Progress is also working with the local natural gas distribution company to upgrade an existing natural gas pipeline to serve the natural gas plant. On March 28, 2016, the NCUC issued an order approving a CPCN for the new combined-cycle natural gas plants, but denying the CPCN for the contingent simple cycle unit without prejudice to Duke Energy Progress to refile for approval in the future. On March 28, 2017, Duke Energy Progress filed an annual progress report for the construction of the combined-cycle plants with the NCUC, with an estimated cost of $893 million . Site preparation activities for the combined-cycle plants are underway and construction of these plants is scheduled to begin in fall 2017, with an expected in-service date in late 2019. Duke Energy Progress plans to file for future approvals related to the proposed solar generation and pilot battery storage project. The carrying value of the 376 -MW Asheville coal-fired plant, including associated ash basin closure costs, of $450 million and $492 million are included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheet as of June 30, 2017 and December 31, 2016 , respectively. Duke Energy Florida Hines Chiller Uprate Project On February 2, 2017, Duke Energy Florida filed a petition seeking approval to include in base rates the revenue requirement for a Chiller Uprate Project (Uprate Project) at the Hines Energy Complex. The Uprate Project was placed into service in March 2017 at a cost of approximately $150 million . The annual retail revenue requirement is approximately $19 million . On March 28, 2017, the FPSC issued an order approving the revenue requirement, which was included in base rates for the first billing cycle of April 2017. Levy Nuclear Project On July 28, 2008, Duke Energy Florida applied to the NRC for COLs for two Westinghouse AP1000 reactors at Levy. In 2008, the FPSC granted Duke Energy Florida’s petition for an affirmative Determination of Need and related orders requesting cost recovery under Florida’s nuclear cost-recovery rule, together with the associated facilities, including transmission lines and substation facilities. In October 2016, the NRC issued COLs for the proposed Levy Nuclear Plant Units 1 and 2. Duke Energy Florida is not required to build the nuclear reactors as a result of the COLs being issued. On January 28, 2014, Duke Energy Florida terminated the Levy engineering, procurement and construction agreement (EPC). Duke Energy Florida may be required to pay for work performed under the EPC. Duke Energy Florida recorded an exit obligation in 2014 for the termination of the EPC. This liability was recorded within Other in Other Noncurrent Liabilities with an offset primarily to Regulatory assets on the Condensed Consolidated Balance Sheets. Duke Energy Florida is allowed to recover reasonable and prudent EPC cancellation costs from its retail customers. On May 1, 2017, Duke Energy Florida filed a request with the FPSC to recover approximately $82 million of Levy Nuclear Project costs from retail customers in 2018. A hearing is scheduled in October 2017. Duke Energy Florida cannot predict the outcome of this matter. On March 29, 2017, Westinghouse filed for voluntary Chapter 11 bankruptcy in the U.S. Bankruptcy Court for the Southern District of New York. Duke Energy Florida is monitoring the bankruptcy proceedings to assess the impact it will have on the future construction of nuclear plants. Duke Energy Ohio Electric Security Plan Filing On June 1, 2017, Duke Energy Ohio filed with the PUCO a request for a standard service offer in the form of an electric security plan (ESP). If approved by the PUCO, the term of the ESP would be from June 1, 2018, to May 31, 2024. Terms of the ESP included continuation of market-based customer rates through competitive procurement processes for generation, continuation of existing rider mechanisms and proposed new rider mechanisms relating to regulatory mandates, costs incurred to enhance the customer experience and transform the grid and a service reliability rider for vegetation management. Duke Energy Ohio cannot predict the outcome of this matter. Woodsdale Station Fuel System Filing On June 9, 2015, the FERC ruled in favor of PJM Interconnection, LLC (PJM) on a revised Tariff and Reliability Assurance Agreement including implementation of a Capacity Performance (CP) proposal and to amend sections of the Operating Agreement related to generation non-performance. The CP proposal includes performance-based penalties for non-compliance. Duke Energy Kentucky is a Fixed Resource Requirement (FRR) entity, and therefore is subject to the compliance standards through its FRR plans. A partial CP obligation will apply to Duke Energy Kentucky in the delivery year beginning June 1, 2019, with full compliance beginning June 1, 2020. Duke Energy Kentucky has developed strategies for CP compliance investments. On May 31, 2017, Duke Energy Kentucky filed an application with the KPSC requesting authority to construct an ultra-low sulfur diesel backup fuel system for the Woodsdale Station. The back-up fuel system is projected to cost approximately $55 million and, if approved, is anticipated to be in service prior to the CP compliance deadline of April 2019. Duke Energy Kentucky cannot predict the outcome of this proceeding at this time. Ohio Valley Electric Corporation On March 31, 2017, Duke Energy Ohio filed for approval to adjust its existing price stabilization rider (Rider PSR) to pass through net costs related to its contractual entitlement to capacity and energy from the generating assets owned by OVEC. The PUCO approved Rider PSR, but set it at zero dollars in connection with the most recent ESP. The application seeks to adjust Rider PSR as of April 1, 2017. Duke Energy Ohio is seeking deferral authority for net costs incurred from April 1, 2017, until the new rates under Rider PSR are put into effect. Various intervenors have filed motions to dismiss or stay the proceeding and Duke Energy Ohio has opposed these filings. See Note 12 for additional discussion of Duke Energy Ohio's ownership interest in OVEC. Duke Energy Ohio cannot predict the outcome of this proceeding. East Bend Coal Ash Basin Filing On December 2, 2016, Duke Energy Kentucky filed with the KPSC a request for a CPCN for construction projects necessary to close and repurpose an ash basin at the East Bend facility as a result of current and proposed U.S. Environmental Protection Agency (EPA) regulations. Duke Energy Kentucky estimated a total cost of approximately $93 million in the filing and expects in-service date in the fourth quarter of 2018. On June 6, 2017, the KPSC approved the CPCN request. Base Rate Case Duke Energy Ohio filed with the PUCO an electric distribution base rate case application and supporting testimony in March 2017. Duke Energy Ohio has requested an estimated annual increase of approximately $15 million and a return on equity of 10.4 percent . The application also includes requests to continue certain current riders and establish new riders related to LED Outdoor Lighting Service and regulatory mandates. Duke Energy Ohio cannot predict the outcome of this matter. Natural Gas Pipeline Extension Duke Energy Ohio is proposing to install a new natural gas pipeline in its Ohio service territory to increase system reliability and enable the retirement of older infrastructure. On January 20, 2017, Duke Energy Ohio filed an amended application with the Ohio Power Siting Board for approval of one of two proposed routes. If approved, construction of the pipeline extension is expected to be completed before the 2019/2020 winter season. A public hearing was held on June 15, 2017, and an adjudicatory hearing is scheduled to begin September 11, 2017. The proposed project involves the installation of a natural gas line and is estimated to cost between $86 million and $110 million , excluding AFUDC. Advanced Metering Infrastructure On April 25, 2016, Duke Energy Kentucky filed with the KPSC an application for approval of a CPCN for the construction of advanced metering infrastructure. Duke Energy Kentucky estimates the $49 million project will take two years to complete. Duke Energy Kentucky also requested approval to establish a regulatory asset of approximately $10 million for the remaining book value of existing meter equipment and inventory to be replaced. Duke Energy Kentucky and the Kentucky Attorney General entered into a stipulation to settle matters related to the application. On May 25, 2017, the KPSC issued an order to approve the stipulation with certain modifications. On June 1, 2017, Duke Energy Kentucky filed its acceptance of the modifications. Accelerated Natural Gas Service Line Replacement Rider On January 20, 2015, Duke Energy Ohio filed an application for approval of an accelerated natural gas service line replacement program (ASRP). Under the ASRP, Duke Energy Ohio proposed to replace certain natural gas service lines on an accelerated basis over a 10-year period. Duke Energy Ohio also proposed to complete preliminary survey and investigation work related to natural gas service lines that are customer owned and for which it does not have valid records and, further, to relocate interior natural gas meters to suitable exterior locations where such relocation can be accomplished. Duke Energy Ohio's projected total capital and operations and maintenance expenditures under the ASRP were approximately $240 million . The filing also sought approval of a rider mechanism (Rider ASRP) to recover related expenditures. Duke Energy Ohio proposed to update Rider ASRP on an annual basis. Intervenors opposed the ASRP, primarily because they believe the program is neither required nor necessary under federal pipeline regulation. On October 26, 2016, the PUCO issued an order denying the proposed ASRP. Duke Energy Ohio's application for rehearing of the PUCO decision was denied on May 17, 2017. Energy Efficiency Cost Recovery On March 28, 2014, Duke Energy Ohio filed an application for recovery of program costs, lost distribution revenue and performance incentives related to its energy efficiency and peak demand reduction programs. These programs are undertaken to comply with environmental mandates set forth in Ohio law. The PUCO approved Duke Energy Ohio’s application, but found that Duke Energy Ohio was not permitted to use banked energy savings from previous years in order to calculate the amount of allowed incentive. This conclusion represented a change to the cost recovery mechanism that had been agreed upon by intervenors and approved by the PUCO in previous cases. The PUCO granted the applications for rehearing filed by Duke Energy Ohio and an intervenor. On January 6, 2016, Duke Energy Ohio and the PUCO Staff entered into a stipulation, pending the PUCO's approval, to resolve issues related to performance incentives and the PUCO Staff audit of 2013 costs, among other issues. In December 2015, based upon the stipulation, Duke Energy Ohio re-established approximately $20 million of the revenues that had been previously reversed. On October 26, 2016, the PUCO issued an order approving the stipulation without modification. Intervenors requested a rehearing of the PUCO decision. In December 2016, the PUCO granted a rehearing for the purpose of further review. Duke Energy Ohio cannot predict the outcome of this matter. 2012 Natural Gas Rate Case/Manufactured Gas Plant Cost Recovery On November 13, 2013, the PUCO issued an order approving a settlement of Duke Energy Ohio’s natural gas base rate case and authorizing the recovery of costs incurred between 2008 and 2012 for environmental investigation and remediation of two former manufactured gas plant (MGP) sites. The PUCO order also authorized Duke Energy Ohio to continue deferring MGP environmental investigation and remediation costs incurred subsequent to 2012 and to submit annual filings to adjust the MGP rider for future costs. Intervening parties appealed this decision to the Ohio Supreme Court and on June 29, 2017, the Ohio Supreme Court issued its decision affirming the PUCO order. Appellants have filed a request for reconsideration with the court. Duke Energy Ohio and the PUCO opposed the request. Incurred and projected investigation and remediation expenses at these MGP sites that have not been collected through the MGP rider are approximately $95 million and are recorded as Regulatory assets on Duke Energy Ohio's Condensed Consolidated Balance Sheet as of June 30, 2017 . Duke Energy Ohio cannot predict the outcome of this matter. Regional Transmission Organization Realignment Duke Energy Ohio, including Duke Energy Kentucky, transferred control of its transmission assets from Midcontinent Independent System Operator, Inc. (MISO) to PJM, effective December 31, 2011. The PUCO approved a settlement related to Duke Energy Ohio’s recovery of certain costs of the Regional Transmission Organization (RTO) realignment via a non-bypassable rider. Duke Energy Ohio is allowed to recover all MISO Transmission Expansion Planning (MTEP) costs, including but not limited to Multi Value Project (MVP) costs, directly or indirectly charged to Ohio customers. Duke Energy Ohio also agreed to vigorously defend against any charges for MVP projects from MISO. The KPSC also approved a request to effect the RTO realignment, subject to a commitment not to seek double recovery in a future rate case of the transmission expansion fees that may be charged by MISO and PJM in the same period or overlapping periods. Duke Energy Ohio had a recorded liability for its exit obligation and share of MTEP costs, excluding MVP, of $90 million at June 30, 2017 , and December 31, 2016 , recorded within Other in Current liabilities and Other in Other Noncurrent Liabilities on the Condensed Consolidated Balance Sheets. The retail portions of MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. As of June 30, 2017 , and December 31, 2016 , Duke Energy Ohio had $71 million recorded in Regulatory assets on the Condensed Consolidated Balance Sheets. MVP. MISO approved 17 MVP proposals prior to Duke Energy Ohio’s exit from MISO on December 31, 2011. Construction of these projects is expected to continue through 2020. Costs of these projects, including operating and maintenance costs, property and income taxes, depreciation and an allowed return, are allocated and billed to MISO transmission owners. On December 29, 2011, MISO filed a tariff with the FERC providing for the allocation of MVP costs to a withdrawing owner based on monthly energy usage. The FERC set for hearing (i) whether MISO’s proposed cost allocation methodology to transmission owners who withdrew from MISO prior to January 1, 2012, is consistent with the tariff at the time of their withdrawal from MISO and, (ii) if not, what the amount of and methodology for calculating any MVP cost responsibility should be. In 2012, MISO estimated Duke Energy Ohio’s MVP obligation over the period from 2012 to 2071 at $2.7 billion , on an undiscounted basis. On July 16, 2013, a FERC Administrative Law Judge (ALJ) issued an initial decision. Under this Initial Decision, Duke Energy Ohio would be liable for MVP costs. Duke Energy Ohio filed exceptions to the initial decision, requesting FERC to overturn the ALJ’s decision. On October 29, 2015, the FERC issued an order reversing the ALJ's decision. The FERC ruled the cost allocation methodology is not consistent with the MISO tariff and that Duke Energy Ohio has no liability for MVP costs after its withdrawal from MISO. On May 19, 2016, the FERC denied the request for rehearing filed by MISO and the MISO Transmission Owners. On July 15, 2016, the MISO Transmission Owners filed a petition for review with the U.S. Court of Appeals for the Sixth Circuit. On June 21, 2017, a three-judge panel affirmed FERC's 2015 decision holding that Duke Energy Ohio has no liability for the cost of the MVP projects constructed after Duke Energy Ohio's withdrawal from MISO. MISO has the right to file a petition for rehearing by all the Sixth Circuit judges or to file a petition with the U.S. Supreme Court seeking a review of the decision. Duke Energy Ohio cannot predict the outcome of this matter. Duke Energy Indiana Coal Combustion Residual Plan On March 17, 2016, Duke Energy Indiana filed with the IURC a request for approval of its first group of federally mandated CCR rule compliance projects (Phase I CCR Compliance Projects) to comply with the EPA's CCR rule. The projects in this Phase I filing are CCR compliance projects, including the conversion of Cayuga and Gibson stations to dry bottom ash handling and related water treatment. Duke Energy Indiana has requested timely recovery of approximately $380 million in retail capital costs, including AFUDC, and recovery of incremental operating and maintenance costs under a federal mandate tracker that provides for timely recovery of 80 percent of such costs and deferral with carrying costs of 20 percent of such costs for recovery in a subsequent retail base rate case. On January 24, 2017, Duke Energy Indiana and various Intervenors filed a settlement agreement with the IURC. Terms of the settlement include recovery of 60 percent of the estimated CCR compliance construction project capital costs through existing rider mechanisms and deferral of 40 percent of these costs until Duke Energy Indiana's next general retail rate case. The deferred costs will earn a return based on Duke Energy Indiana's long-term debt rate of 4.73 percent until costs are included in retail rates, at which time the deferred costs will earn a full return. Costs are to be capped at $365 million , plus actual AFUDC. Costs above the cap would be considered for recovery in the next rate case. Terms of the settlement agreement also require Duke Energy Indiana to perform certain reporting and groundwater monitoring. An evidentiary hearing was held on February 23, 2017, and Duke Energy Indiana filed a proposed order with the IURC on March 30, 2017. On May 24, 2017, the IURC approved the settlement agreement. FERC Transmission Return on Equity Complaints Customer groups have filed with the FERC complaints against MISO and its transmission-owning members, including Duke Energy Indiana, alleging, among other things, that the current base rate of return on equity earned by MISO transmission owners of 12.38 percent is unjust and unreasonable. The complaints, among other things, claim that the current base rate of return on equity earned by MISO transmission owners should be reduced to 8.67 percent . On January 5, 2015, the FERC issued an order accepting the MISO transmission owners' adder of 0.50 percent to the base rate of return on equity based on participation in an RTO subject to it being applied to a return on equity that is shown to be just and reasonable in the pending return on equity complaints. On December 22, 2015, the presiding FERC ALJ in the first complaint issued an Initial Decision in which the base rate of return on equity was set at 10.32 percent . On September 28, 2016, the Initial Decision in the first complaint was affirmed by FERC, but is subject to rehearing requests. On June 30, 2016, the presiding FERC ALJ in the second complaint issued an Initial Decision setting the base rate of return on equity at 9.70 percent . The Initial Decision in the second complaint is pending FERC review. On April 14, 2017, the U.S. Court of Appeals for the District of Columbia Circuit, in Emera Maine v. FERC , reversed and remanded certain aspects of the methodology employed by FERC to establish rates of return on equity. This decision may affect the outcome of the complaints against Duke Energy Indiana. Duke Energy Indiana currently believes these matters will not have a material impact on its results of operations, cash flows and financial position. Piedmont South Carolina Rate Stabilization Adjustment Filing In June 2017, Piedmont filed with the PSCSC under the South Carolina Rate Stabilization Act its quarterly monitoring report for the 12-month period ending March 31, 2017. The filing includes a revenue deficiency calculation and tariff rates in order to permit Piedmont the opportunity to earn the rate of return on common equity established in its last general rate case. This filing is currently under review and audit by the South Carolina Office of Regulatory Staff. Piedmont cannot predict the outcome of this matter. North Carolina Integrity Management Rider Filings In May 2017, Piedmont filed, and the NCUC approved, a petition under the Integrity Management Rider mechanism to collect an additional $11.6 million in annual revenues, effective June 2017, based on the eligible capital investments closed to integrity and safety projects over the six-month period ending March 31, 2017. OTHER REGULATORY MATTERS Atlantic Coast Pipeline On September 2, 2014, Duke Energy, Dominion Resources (Dominion), Piedmont and Southern Company Gas announced the formation of Atlantic Coast Pipeline, LLC (ACP) to build and own the proposed Atlantic Coast Pipeline (ACP pipeline), an approximately 600-mile interstate natural gas pipeline running from West Virginia to North Carolina. The ACP pipeline is designed to meet the needs identified in RFPs by Duke Energy Carolinas, Duke Energy Progress and Piedmont. The ACP pipeline development costs are estimated between $5.0 billion to $5.5 billion . Dominion will build and operate the ACP pipeline and holds a leading ownership percentage in ACP of 48 percent . Duke Energy owns a 47 percent interest through its Gas Utilities and Infrastructure segment. Southern Company Gas maintains a 5 percent interest. See Note 12 for additional information related to Duke Energy's ownership interest. Duke Energy Carolinas, Duke Energy Progress and Piedmont, among others, will be customers of the pipeline. Purchases will be made under several 20 -year supply contracts, subject to state regulatory approval. On September 18, 2015, ACP filed an application with the FERC requesting a CPCN authorizing ACP to construct the pipeline. ACP executed a construction agreement in September 2016. ACP also requested approval of an open access tariff and the precedent agreements it entered into with future pipeline customers. In December 2016, FERC issued a draft Environmental Impact Statement (EIS) indicating that the proposed pipeline would not cause significant harm to the environment or protected populations. The FERC issued the final EIS in July 2017. FERC approval of the application is expected in the fall of 2017 if the FERC reaches a quorum. Construction is projected to begin in the fourth quarter of 2017, with a targeted in-service date in the second half of 2019. Sabal Trail Transmission, LLC Pipeline On May 4, 2015, Duke Energy acquired a 7.5 percent ownership interest in Sabal Trail Transmission, LLC (Sabal Trail) from Spectra Energy Partners, LP, a master limited partnership, formed by Enbridge Inc. (formerly Spectra Energy Corp.). Spectra Energy Partners, LP holds a 50 percent ownership interest in Sabal Trail and NextEra Energy has a 42.5 percent ownership interest. Sabal Trail is a joint venture to construct a 515-mile natural gas pipeline (Sabal Trail pipeline) to transport natural gas to Florida. Total estimated project costs are approximately $3.2 billion . The Sabal Trail pipeline traverses Alabama, Georgia and Florida. The primary customers of the Sabal Trail pipeline, Duke Energy Florida and Florida Power & Light Company (FP&L), have each contracted to buy pipeline capacity for 25 -year initial terms. On February 3, 2016, the FERC issued an order granting the request for a CPCN to construct and operate the pipeline. On September 7, 2016, FERC denied the intervenors' rehearing requests. On September 21, 2016, intervenors filed an appeal of FERC's CPCN orders to the U.S. Court of Appeals for the District of Columbia Circuit. Oral argument on the appeal was held on April 18, 2017, and a decision is expected in the summer of 2017. The Sabal Trail pipeline has received other required regulatory approvals and the phase one mainline was placed in service in July 2017. Completion of a lateral line to Citrus County is expected in October 2017. See Note 12 for additional information related to Duke Energy's ownership interest. Constitution Pipeline Company, LLC Duke Energy has a 24 percent ownership interest in Constitution Pipeline Company, LLC (Constitution). Constitution is a natural gas pipeline project slated to transport natural gas supplies from the Marcellus supply region in northern Pennsylvania to major northeastern markets. The pipeline will be constructed and operated by Williams Partners L.P., which has a 41 percent ownership share. The remaining interest is held by Cabot Oil and Gas Corporation and WGL Holdings, Inc. Duke Energy's total anticipated contributions are app

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES ENVIRONMENTAL The Duke Energy Registrants are subject to federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. These regulations can be changed from time to time, imposing new obligations on the Duke Energy Registrants. The following environmental matters impact all of the Duke Energy Registrants. Remediation Activities In addition to asset retirement obligations recorded as a result of various environmental regulations, the Duke Energy Registrants are responsible for environmental remediation at various sites. These include certain properties that are part of ongoing operations and sites formerly owned or used by Duke Energy entities. These sites are in various stages of investigation, remediation and monitoring. Managed in conjunction with relevant federal, state and local agencies, remediation activities vary based upon site conditions and location, remediation requirements, complexity and sharing of responsibility. If remediation activities involve joint and several liability provisions, strict liability, or cost recovery or contribution actions, the Duke Energy Registrants could potentially be held responsible for environmental impacts caused by other potentially responsible parties and may also benefit from insurance policies or contractual indemnities that cover some or all cleanup costs. Liabilities are recorded when losses become probable and are reasonably estimable. The total costs that may be incurred cannot be estimated because the extent of environmental impact, allocation among potentially responsible parties, remediation alternatives and/or regulatory decisions have not yet been determined at all sites. Additional costs associated with remediation activities are likely to be incurred in the future and could be significant. Costs are typically expensed as Operation, maintenance and other on the Condensed Consolidated Statements of Operations unless regulatory recovery of the costs is deemed probable. The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Other within Other Noncurrent Liabilities on the Condensed Consolidated Balance Sheets. Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10 $ 1 Provisions/adjustments — 1 — — 1 (2 ) — — Cash reductions (8 ) (1 ) (2 ) — (2 ) (4 ) (1 ) — Balance at end of period $ 90 $ 10 $ 16 $ 3 $ 13 $ 53 $ 9 $ 1 Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 94 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 $ 1 Provisions/adjustments 27 3 4 1 3 1 21 — Cash reductions (7 ) (2 ) (4 ) (1 ) (3 ) (1 ) (1 ) — Balance at end of period $ 114 $ 11 $ 17 $ 3 $ 14 $ 54 $ 32 $ 1 Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 70 Duke Energy Carolinas 23 Duke Energy Ohio 35 Duke Energy Indiana 7 Piedmont 2 North Carolina and South Carolina Ash Basins In February 2014, a break in a stormwater pipe beneath an ash basin at Duke Energy Carolinas’ retired Dan River Steam Station caused a release of ash basin water and ash into the Dan River. Duke Energy Carolinas estimates 30,000 to 39,000 tons of ash and 24 million to 27 million gallons of basin water were released into the river. In July 2014, Duke Energy completed remediation work identified by the EPA. Future costs related to the Dan River release, including future civil enforcement, future regulatory directives, natural resources damages, future claims or litigation and long-term environmental impact costs, cannot be reasonably estimated at this time. The North Carolina Department of Environmental Quality (NCDEQ) has historically assessed Duke Energy Carolinas and Duke Energy Progress with Notice of Violations (NOV) for violations that were most often resolved through satisfactory corrective actions and minor, if any, fines or penalties. Subsequent to the Dan River ash release, Duke Energy Carolinas and Duke Energy Progress have been served with a higher level of NOVs, including assessed penalties for violations at L.V. Sutton Combined Cycle Plant (Sutton) and Dan River Steam Station. Duke Energy Carolinas and Duke Energy Progress cannot predict whether the NCDEQ will assess future penalties related to existing unresolved NOVs and if such penalties would be material. See "NCDEQ Notices of Violation" section below for additional discussion. LITIGATION Duke Energy Duke Energy no longer has exposure to litigation matters related to the International Disposal Group as a result of the divestiture of the business in December 2016. See Note 2 for additional information related to the sale of International Energy. Ash Basin Shareholder Derivative Litigation Five shareholder derivative lawsuits were filed in Delaware Chancery Court relating to the release at Dan River and to the management of Duke Energy’s ash basins. On October 31, 2014, the five lawsuits were consolidated in a single proceeding titled In Re Duke Energy Corporation Coal Ash Derivative Litigation . On December 2, 2014, plaintiffs filed a Corrected Verified Consolidated Shareholder Derivative Complaint (Consolidated Complaint). The Consolidated Complaint names as defendants several current and former Duke Energy officers and directors (collectively, the Duke Energy Defendants). Duke Energy is named as a nominal defendant. The Consolidated Complaint alleges the Duke Energy Defendants breached their fiduciary duties by failing to adequately oversee Duke Energy’s ash basins and that these breaches of fiduciary duty may have contributed to the incident at Dan River and continued thereafter. The lawsuit also asserts claims against the Duke Energy Defendants for corporate waste (relating to the money Duke Energy has spent and will spend as a result of the fines, penalties and coal ash removal) and unjust enrichment (relating to the compensation and director remuneration that was received despite these alleged breaches of fiduciary duty). The lawsuit seeks both injunctive relief against Duke Energy and restitution from the Duke Energy Defendants. On April 22, 2016, plaintiffs filed an Amended Verified Consolidated Shareholder Derivative Complaint (Amended Complaint) making the same allegations as in the Consolidated Complaint. The Duke Energy Defendants filed a motion to dismiss the Amended Complaint on June 21, 2016. On December 14, 2016, the Delaware Chancery Court entered an order dismissing the Amended Complaint. Plaintiffs filed an appeal to the Delaware Supreme Court on January 9, 2017. The parties have completed briefing in the case and oral argument is scheduled for September 27, 2017. On October 30, 2015, shareholder Saul Bresalier filed a shareholder derivative complaint (Bresalier Complaint) in the U.S. District Court for the District of Delaware. The lawsuit alleges that several current and former Duke Energy officers and directors (Bresalier Defendants) breached their fiduciary duties in connection with coal ash environmental issues, the post-merger change in Chief Executive Officer (CEO) and oversight of political contributions. Duke Energy is named as a nominal defendant. The Bresalier Complaint contends that the appointed Demand Review Committee failed to appropriately consider the shareholder’s earlier demand for litigation and improperly decided not to pursue claims against the Bresalier Defendants. On March 30, 2017, the court granted Defendants’ Motion to Dismiss on the claims relating to coal ash environmental issues and political contributions. A notice of appeal has not been filed. As discussed below, an agreement-in-principle has been reached to settle the merger related claims in the Bresalier Complaint, and those claims were also dismissed subject to that agreement. It is not possible to predict whether Duke Energy will incur any liability or to estimate the damages, if any, it might incur in connection with these matters. Progress Energy Merger Shareholder Litigation On May 31, 2013, the Delaware Chancery Court consolidated four shareholder derivative lawsuits filed in 2012. The Court also appointed a lead plaintiff and counsel for plaintiffs and designated the case as In Re Duke Energy Corporation Derivative Litigation (Merger Chancery Litigation). The lawsuit names as defendants the Legacy Duke Energy Directors. Duke Energy is named as a nominal defendant. The case alleges claims for breach of fiduciary duties of loyalty and care in connection with the post-merger change in CEO. Two shareholder Derivative Complaints, filed in 2012 in federal district court in Delaware, were consolidated as Tansey v. Rogers, et al. The case alleges claims against the Legacy Duke Energy Directors for breach of fiduciary duty and waste of corporate assets, as well as claims under Section 14(a) and 20(a) of the Exchange Act. Duke Energy is named as a nominal defendant. On December 21, 2015, Plaintiff filed a Consolidated Amended Complaint asserting the same claims contained in the original complaints. The Legacy Duke Energy Directors reached an agreement-in-principle to settle the Merger Chancery Litigation, conditioned on dismissal as well, of the Tansey v. Rogers, et al case and the merger related claims in the Bresalier Complaint discussed above, for a total of $27 million , which was approved by the Delaware Chancery Court on July 13, 2017. The entire settlement amount is to be funded by insurance. The settlement amount, less court-approved attorney fees, will be payable to Duke Energy. Price Reporting Cases Duke Energy Trading and Marketing, LLC (DETM), a non-operating Duke Energy affiliate, was a defendant, along with numerous other energy companies, in four class-action lawsuits and a fifth single-plaintiff lawsuit in a consolidated federal court proceeding in Nevada. Each of these lawsuits contained similar claims that defendants allegedly manipulated natural gas markets by various means, including providing false information to natural gas trade publications and entering into unlawful arrangements and agreements in violation of the antitrust laws of the respective states. Plaintiffs sought damages in unspecified amounts. In February 2016, DETM reached agreements in principle to settle all of the pending lawsuits. Settlement of the single-plaintiff settlement was finalized and paid in March 2016. The proposed settlement of the class action lawsuits was approved by the Court and all settlement amounts, which are not material to Duke Energy, have been paid. Duke Energy Carolinas and Duke Energy Progress Coal Ash Insurance Coverage Litigation In March 2017, Duke Energy Carolinas and Duke Energy Progress filed a civil action in North Carolina Superior Court against various insurance providers. The lawsuit seeks payment for coal ash related liabilities covered by third-party liability insurance policies. The insurance policies were issued between 1971 and 1986 and provide third-party liability insurance for property damage. The civil action seeks damages for breach of contract and indemnification for costs arising from the Coal Ash Act and the EPA CCR rule at 15 coal-fired plants in North Carolina and South Carolina. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter. NCDEQ State Enforcement Actions In the first quarter of 2013, the Southern Environmental Law Center (SELC) sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged Clean Water Act (CWA) violations from coal ash basins at two of their coal-fired power plants in North Carolina. The NCDEQ filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The cases have been consolidated and are being heard before a single judge. On August 16, 2013, the NCDEQ filed an enforcement action against Duke Energy Carolinas and Duke Energy Progress related to their remaining plants in North Carolina, alleging violations of the CWA and violations of the North Carolina groundwater standards. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. SELC is representing several environmental groups who have been permitted to intervene in these cases. The court issued orders in 2016 granting Motions' for Partial Summary Judgment for seven of the 14 North Carolina plants named in the enforcement actions. The litigation is concluded for these seven plants. Litigation continues for the remaining seven plants. In response to a motion for partial summary judgment on the groundwater claims filed by the environmental groups, on October 17, 2016, Duke Energy Carolinas and Duke Energy Progress filed a cross-motion for partial summary judgment on the groundwater claims. On February 13, 2017, the court issued an order denying both the environmental groups' motion for partial summary judgment and Duke Energy Carolinas and Duke Energy Progress' cross-motion for partial summary judgment. On March 15, 2017, Duke Energy Carolinas and Duke Energy Progress filed a Notice of Appeal to challenge the trial court’s denial of their cross-motion for partial summary judgment. The parties were unable to reach an agreement at mediation on April 18, 2017. The court has requested the parties to make submissions on what issues remain to be tried. It is not possible to predict any liability or estimate any damages Duke Energy Carolinas or Duke Energy Progress might incur in connection with these matters. Federal Citizens Suits On June 13, 2016, the Roanoke River Basin Association (RRBA) filed a federal citizen suit in the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Mayo Plant. On August 19, 2016, Duke Energy Progress filed a Motion to Dismiss. On April 26, 2017, the court entered an order dismissing four of the claims in the federal citizen suit. Two claims relating to alleged violations of National Pollutant Discharge Elimination System permit provisions survived the motion to dismiss, and Duke Energy Progress filed its response on May 10, 2017. The parties are engaged in pre-trial discovery. On March 16, 2017, RRBA served Duke Energy Progress with a Notice of Intent to Sue under the CWA for alleged violations of effluent standards and limitations at the Roxboro Plant. In anticipation of litigation, Duke Energy Progress filed a Complaint for Declaratory Relief in the U.S. District Court for the Western District of Virginia on May 11, 2017, disputing RRBA's claims and requesting declaratory judgment in its favor. RRBA then filed a motion to dismiss or transfer venue of the declaratory action filed by Duke Energy Progress in the Western District of Virginia. Duke Energy Progress' motion of opposition was heard on July 24, 2017, and a ruling is pending. On May 16, 2017, RRBA filed a federal citizen suit in the U.S. District Court for the Middle District of North Carolina. On July 17, 2017, Duke Energy Progress filed a motion to dismiss that action in favor of the pending action in the Western District of Virginia. On June 20, 2017, RRBA filed a federal citizen suit in the U.S. District Court for the Middle District of North Carolina challenging the closure plans at the Mayo Plant under the EPA CCR Rule. Duke Energy Progress' response is due by August 21, 2017. On August 2, 2017, RRBA filed a federal citizen suit in the U.S. District Court for the Middle District of North Carolina challenging the closure plans at the Roxboro Plant under the EPA CCR Rule. Duke Energy Progress' response is due by October 2, 2017. It is not possible to predict whether Duke Energy Progress will incur any liability or to estimate the damages, if any, it might incur in connection with these matters. Five previously filed cases involving the Riverbend, Cape Fear, H.F. Lee, Sutton and Buck plants were dismissed or settled in 2016. Potential Groundwater Contamination Claims Beginning in May 2015, a number of residents living in the vicinity of the North Carolina facilities with ash basins received letters from the NCDEQ advising them not to drink water from the private wells on their land tested by the NCDEQ as the samples were found to have certain substances at levels higher than the criteria set by the North Carolina Department of Health and Human Services (DHHS). The criteria, in some cases, are considerably more stringent than federal drinking water standards established to protect human health and welfare. The Coal Ash Act requires additional groundwater monitoring and assessments for each of the 14 coal-fired plants in North Carolina, including sampling of private water supply wells. The data gathered through these Comprehensive Site Assessments (CSAs) will be used by NCDEQ to determine whether the water quality of these private water supply wells has been adversely impacted by the ash basins. Duke Energy has submitted CSAs documenting the results of extensive groundwater monitoring around coal ash basins at all 14 of the plants with coal ash basins. Generally, the data gathered through the installation of new monitoring wells and soil and water samples across the state have been consistent with historical data provided to state regulators over many years. The DHHS and NCDEQ sent follow-up letters on October 15, 2015, to residents near coal ash basins who have had their wells tested, stating that private well samplings at a considerable distance from coal ash basins, as well as some municipal water supplies, contain similar levels of vanadium and hexavalent chromium, which leads investigators to believe these constituents are naturally occurring. In March 2016, DHHS rescinded the advisories. Duke Energy Carolinas and Duke Energy Progress have received formal demand letters from residents near Duke Energy Carolinas' and Duke Energy Progress' coal ash basins. The residents claim damages for nuisance and diminution in property value, among other things. The parties held three days of mediation discussions that ended at impasse. On January 6, 2017, Duke Energy Carolinas and Duke Energy Progress received the plaintiffs' notice of their intent to file suits should the matter not settle. The NCDEQ preliminarily approved Duke Energy’s permanent water solution plans on January 13, 2017, and as a result shortly thereafter, Duke Energy issued a press release, providing additional details regarding the homeowner compensation package. This package consists of three components: (i) a $5,000 goodwill payment to each eligible well owner to support the transition to a new water supply, (ii) where a public water supply is available and selected by the eligible well owner, a stipend to cover 25 years of water bills and (iii) the Property Value Protection Plan. The Property Value Protection Plan is a program offered by Duke Energy designed to guarantee eligible plant neighbors the fair market value of their residential property should they decide to sell their property during the time that the plan is offered. Duke Energy received a letter from Plaintiffs' counsel indicating their intent to file suit on February 2, 2017, should a settlement not be reached by that date. Plaintiff’s counsel did not file suit upon the expiration of the tolling agreement on February 2, 2017, and no suit has been filed to date. Duke Energy Carolinas and Duke Energy Progress have recognized reserves of $18 million and $4 million , respectively. It is not possible to estimate the maximum exposure of loss, if any, that may occur in connection with claims, which might be made by these residents. Asbestos-related Injuries and Damages Claims Duke Energy Carolinas has experienced numerous claims for indemnification and medical cost reimbursement related to asbestos exposure. These claims relate to damages for bodily injuries alleged to have arisen from exposure to or use of asbestos in connection with construction and maintenance activities conducted on its electric generation plants prior to 1985. As of June 30, 2017 , there were 87 asserted claims for non-malignant cases with cumulative relief sought of up to $23 million , and 58 asserted claims for malignant cases with cumulative relief sought of up to $16 million . Based on Duke Energy Carolinas’ experience, it is expected that the ultimate resolution of most of these claims likely will be less than the amount claimed. Duke Energy Carolinas has recognized asbestos-related reserves of $497 million at June 30, 2017 and $512 million at December 31, 2016 . These reserves are classified in Other within Other Noncurrent Liabilities and Other within Current Liabilities on the Condensed Consolidated Balance Sheets. These reserves are based upon the minimum amount of the range of loss for current and future asbestos claims through 2036, are recorded on an undiscounted basis and incorporate anticipated inflation. In light of the uncertainties inherent in a longer-term forecast, management does not believe they can reasonably estimate the indemnity and medical costs that might be incurred after 2036 related to such potential claims. It is possible Duke Energy Carolinas may incur asbestos liabilities in excess of the recorded reserves. Duke Energy Carolinas has third-party insurance to cover certain losses related to asbestos-related injuries and damages above an aggregate self-insured retention. Duke Energy Carolinas’ cumulative payments began to exceed the self-insurance retention in 2008. Future payments up to the policy limit will be reimbursed by the third-party insurance carrier. The insurance policy limit for potential future insurance recoveries indemnification and medical cost claim payments is $814 million in excess of the self-insured retention. Receivables for insurance recoveries were $587 million at June 30, 2017 and December 31, 2016 . These amounts are classified in Other within Other Noncurrent Assets and Receivables within Current Assets on the Condensed Consolidated Balance Sheets. Duke Energy Carolinas is not aware of any uncertainties regarding the legal sufficiency of insurance claims. Duke Energy Carolinas believes the insurance recovery asset is probable of recovery as the insurance carrier continues to have a strong financial strength rating. Duke Energy Florida Class Action Lawsuit On February 22, 2016, a lawsuit was filed in the U.S. District Court for the Southern District of Florida on behalf of a putative class of Duke Energy Florida and FP&L’s customers in Florida. The suit alleges the State of Florida’s nuclear power plant cost recovery statutes (NCRS) are unconstitutional and pre-empted by federal law. Plaintiffs claim they are entitled to repayment of all money paid by customers of Duke Energy Florida and FP&L as a result of the NCRS, as well as an injunction against any future charges under those statutes. The constitutionality of the NCRS has been challenged unsuccessfully in a number of prior cases on alternative grounds. Duke Energy Florida and FP&L filed motions to dismiss the complaint on May 5, 2016. On September 21, 2016, the Court granted the motions to dismiss with prejudice. Plaintiffs filed a motion for reconsideration, which was denied. On January 4, 2017, plaintiffs filed a notice of appeal to the Eleventh Circuit U.S. Court of Appeals. Plaintiffs filed an appellate brief on March 16, 2017, and Duke Energy Florida filed responses on April 17, 2017. Oral argument is scheduled for August 22, 2017. Duke Energy Florida cannot predict the outcome of this appeal. Westinghouse Contract Litigation On March 28, 2014, Duke Energy Florida filed a lawsuit against Westinghouse in the U.S. District Court for the Western District of North Carolina. The lawsuit seeks recovery of $54 million in milestone payments in excess of work performed under an EPC for Levy as well as a determination by the court of the amounts due to Westinghouse as a result of the termination of the EPC. Duke Energy Florida recognized an exit obligation as a result of the termination of the EPC. On March 31, 2014, Westinghouse filed a lawsuit against Duke Energy Florida in U.S. District Court for the Western District of Pennsylvania. The Pennsylvania lawsuit alleged damages under the EPC in excess of $510 million for engineering and design work, costs to end supplier contracts and an alleged termination fee. On June 9, 2014, the judge in the North Carolina case ruled that the litigation will proceed in the Western District of North Carolina. On July 11, 2016, Duke Energy Florida and Westinghouse filed separate Motions for Summary Judgment. On September 29, 2016, the court issued its ruling on the parties' respective Motions for Summary Judgment, ruling in favor of Westinghouse on a $30 million termination fee claim and dismissing Duke Energy Florida's $54 million refund claim, but stating that Duke Energy Florida could use the refund claim to offset any damages for termination costs. Westinghouse's claim for termination costs was unaffected by this ruling and continued to trial. At trial, Westinghouse reduced its claim for termination costs from $482 million to $424 million . Following a trial on the matter, the court issued its final order in December 2016 denying Westinghouse’s claim for termination costs and re-affirming its earlier ruling in favor of Westinghouse on the $30 million termination fee and Duke Energy Florida’s refund claim. Judgment was entered against Duke Energy Florida in the amount of approximately $34 million , which includes prejudgment interest. Westinghouse has appealed the trial court's order and Duke Energy Florida has cross-appealed. Duke Energy Florida cannot predict the ultimate outcome of the appeal of the trial court's order. On March 29, 2017, Westinghouse filed Chapter 11 bankruptcy in the Southern District of New York, which automatically stayed the appeal. On May 23, 2017, the bankruptcy court entered an order lifting the stay with respect to the appeal. The Fourth Circuit has issued a revised briefing schedule that provides for completion of briefing by October 20, 2017. Ultimate resolution of these matters could have a material effect on the results of operations, financial position or cash flows of Duke Energy Florida. However, appropriate regulatory recovery will be pursued for the retail portion of any costs incurred in connection with such resolution. MGP Cost Recovery Action On December 30, 2011, Duke Energy Florida filed a lawsuit against FirstEnergy Corp. (FirstEnergy) to recover investigation and remediation costs incurred by Duke Energy Florida in connection with the restoration of two former MGP sites in Florida. Duke Energy Florida alleged that FirstEnergy, as the successor to Associated Gas & Electric Co., owes past and future contribution and response costs of up to $43 million for the investigation and remediation of MGP sites. On December 6, 2016, the trial court entered judgment against Duke Energy Florida in the case. In January 2017, Duke Energy Florida appealed the decision to the U.S. Court of Appeals for the 6th Circuit and briefing has been completed. Duke Energy Florida cannot predict the outcome of this appeal. Duke Energy Indiana Benton County Wind Farm Dispute On December 16, 2013, Benton County Wind Farm LLC (BCWF) filed a lawsuit against Duke Energy Indiana seeking damages for past generation losses totaling approximately $16 million alleging Duke Energy Indiana violated its obligations under a 2006 PPA by refusing to offer electricity to the market at negative prices. Damage claims continue to increase during times that BCWF is not dispatched. Under 2013 revised MISO market rules, Duke Energy Indiana is required to make a price offer to MISO for the power it proposes to sell into MISO markets and MISO determines whether BCWF is dispatched. Because market prices would have been negative due to increased market participation, Duke Energy Indiana determined it would not bid at negative prices in order to balance customer needs against BCWF's need to run. BCWF contends Duke Energy Indiana must bid at the lowest negative price to ensure dispatch, while Duke Energy Indiana contends it is not obligated to bid at any particular price, that it cannot ensure dispatch with any bid and that it has reasonably balanced the parties' interests. On July 6, 2015, the U.S. District Court for the Southern District of Indiana entered judgment against BCWF on all claims. BCWF appealed the decision and on December 9, 2016, the appeals court ruled in favor of BCWF. On June 30, 2017, the parties finalized a settlement agreement. Terms of the settlement included Duke Energy Indiana paying $29 million for back damages. Additionally, the parties agreed on the method by which the contract will be bid into the market in the future. Duke Energy Indiana recorded an obligation and a regulatory asset related to the settlement amount in fourth quarter 2016. The settlement amount was paid in June 2017. Other Litigation and Legal Proceedings The Duke Energy Registrants are involved in other legal, tax and regulatory proceedings arising in the ordinary course of business, some of which involve significant amounts. The Duke Energy Registrants believe the final disposition of these proceedings will not have a material effect on their results of operations, cash flows or financial position. The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves and the exit obligation discussed above related to the termination of an EPC contract. Reserves are classified on the Condensed Consolidated Balance Sheets in Other within Other Noncurrent Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. (in millions) June 30, 2017 December 31, 2016 Reserves for Legal Matters Duke Energy $ 82 $ 98 Duke Energy Carolinas 23 23 Progress Energy 57 59 Duke Energy Progress 12 14 Duke Energy Florida 28 28 Duke Energy Ohio — 4 Piedmont 2 2 OTHER COMMITMENTS AND CONTINGENCIES General As part of their normal business, the Duke Energy Registrants are party to various financial guarantees, performance guarantees and other contractual commitments to extend guarantees of credit and other assistance to various subsidiaries, investees and other third parties. These guarantees involve elements of performance and credit risk, which are not fully recognized on the Condensed Consolidated Balance Sheets and have unlimited maximum potential payments. However, the Duke Energy Registrants do not believe these guarantees will have a material effect on their results of operations, cash flows or financial position. In addition, the Duke Energy Registrants enter into various fixed-price, noncancelable commitments to purchase or sell power or natural gas, take-or-pay arrangements, transportation, or throughput agreements and other contracts that may or may not be recognized on their respective Condensed Consolidated Balance Sheets. Some of these arrangements may be recognized at fair value on their respective Condensed Consolidated Balance Sheets if such contracts meet the definition of a derivative and the normal purchase/normal sale (NPNS) exception does not apply. In most cases, the Duke Energy Registrants’ purchase obligation contracts contain provisions for price adjustments, minimum purchase levels and other financial commitments.

Debt and Credit Facilities

Debt and Credit Facilities	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Debt And Credit Facilities	DEBT AND CREDIT FACILITIES SUMMARY OF SIGNIFICANT DEBT ISSUANCES The following table summarizes significant debt issuances (in millions). Refer to the "Available Credit Facilities" section below regarding amounts issued under the Three Year Revolver and the Piedmont Term Loan facilities. Six Months Ended June 30, 2017 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Florida Ohio Unsecured Debt April 2017 (a) April 2025 3.364 % $ 420 $ 420 $ — $ — June 2017 (b) June 2020 2.100 % 330 330 — — Secured Debt February 2017 (c) June 2034 4.120 % 587 — — — First Mortgage Bonds January 2017 (d) January 2020 1.850 % 250 — 250 — January 2017 (d) January 2027 3.200 % 650 — 650 — March 2017 (e) June 2046 3.700 % 100 — — 100 Total issuances $ 2,337 $ 750 $ 900 $ 100 (a) Proceeds were used to refinance $ 400 million of unsecured debt at maturity and to repay a portion of outstanding commercial paper. (b) Debt issued to repay a portion of outstanding commercial paper. (c) Portfolio financing of four Texas and Oklahoma wind facilities. Secured by substantially all of the assets of these wind facilities and nonrecourse to Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures. (d) Debt issued to fund capital expenditures for ongoing construction and capital maintenance, to repay at maturity a $250 million aggregate principal amount of bonds due September 2017 and for general corporate purposes. (e) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. CURRENT MATURITIES OF LONG-TERM DEBT The following table shows the significant components of Current Maturities of Long-Term Debt on the Condensed Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate June 30, 2017 Unsecured Debt Duke Energy (Parent) August 2017 1.625 % $ 700 Piedmont September 2017 8.510 % 35 Duke Energy (Parent) June 2018 6.250 % 250 Duke Energy (Parent) June 2018 2.100 % 500 First Mortgage Bonds Duke Energy Florida September 2017 5.800 % 250 Duke Energy Progress November 2017 1.372 % 200 Duke Energy Carolinas January 2018 5.250 % 400 Duke Energy Carolinas April 2018 5.100 % 300 Duke Energy Florida June 2018 5.650 % 500 Other (a) 337 Current maturities of long-term debt $ 3,472 (a) Includes capital lease obligations, amortizing debt and small bullet maturities. AVAILABLE CREDIT FACILITIES Master Credit Facility In March 2017, Duke Energy amended its Master Credit Facility to increase its capacity from $7.5 billion to $8 billion , and to extend the termination date of the facility from January 30, 2020, to March 16, 2022. The amendment also added Piedmont as a borrower within the Master Credit Facility. Piedmont's separate $850 million credit facility was terminated in connection with the amendment. With the amendment, the Duke Energy Registrants, excluding Progress Energy (Parent), have borrowing capacity under the Master Credit Facility up to a specified sublimit for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower. The amount available under the Master Credit Facility has been reduced to backstop issuances of commercial paper, certain letters of credit and variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder. Duke Energy Carolinas and Duke Energy Progress are also required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet obligations under plea agreements reached with the U.S. Department of Justice in 2015 related to violations at North Carolina facilities with ash basins. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. June 30, 2017 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 3,150 $ 1,350 $ 1,250 $ 700 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (3,115 ) (1,392 ) (732 ) (661 ) — (45 ) (150 ) (135 ) Outstanding letters of credit (68 ) (59 ) (4 ) (2 ) (1 ) — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 4,236 $ 1,699 $ 364 $ 337 $ 699 $ 405 $ 369 $ 363 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies on the Condensed Consolidated Balance Sheets. Three Year Revolving Credit Facility In June 2017, Duke Energy (Parent) entered into a three -year $1.0 billion revolving credit facility (the Three Year Revolver). Borrowings under this facility will be used for general corporate purposes. As of June 30, 2017, $270 million has been drawn under the Three Year Revolver. This balance is classified as Long-Term Debt on Duke Energy's Condensed Consolidated Balance Sheets. Any undrawn commitments can be drawn, and borrowings can be prepaid, at any time throughout the term of the facility. The terms and conditions of the Three Year Revolver are generally consistent with those governing Duke Energy's Master Credit Facility. Piedmont Term Loan Facility In June 2017, Piedmont entered into an 18 -month term loan facility with commitments totaling $250 million (the Piedmont Term Loan). Borrowings under the facility will be used for general corporate purposes. As of June 30, 2017, $125 million has been drawn under the Piedmont Term Loan. This balance is classified as Long-Term Debt on Piedmont's Condensed Consolidated Balance Sheets. The remaining $125 million can be drawn in one additional borrowing, which must occur within 90 days of the closing date of the facility. Piedmont anticipates borrowing the remaining $125 million in the third quarter of 2017. The terms and conditions of the Piedmont Term Loan are generally consistent with those governing Duke Energy's Master Credit Facility.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS GOODWILL Duke Energy The following table presents the goodwill by reportable operating segment on Duke Energy's Condensed Consolidated Balance Sheets at June 30, 2017 and December 31, 2016 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill $ 17,379 $ 1,924 $ 122 $ 19,425 Duke Energy Ohio Duke Energy Ohio's Goodwill balance of $920 million , allocated $596 million to Electric Utilities and Infrastructure and $324 million to Gas Utilities and Infrastructure, is presented net of accumulated impairment charges of $216 million on the Condensed Consolidated Balance Sheets at June 30, 2017 and December 31, 2016 . Progress Energy Progress Energy's Goodwill is included in the Electric Utilities and Infrastructure operating segment and there are no accumulated impairment charges. Piedmont Piedmont's Goodwill is included in the Gas Utilities and Infrastructure operating segment and there are no accumulated impairment charges. Effective November 1, 2016, Piedmont's fiscal year was changed from October 31 to December 31. Effective with this change, Piedmont changed the date of their annual impairment testing of goodwill from October 31 to August 31 to align with the other Duke Energy Registrants.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with applicable state and federal commission regulations. Refer to the Condensed Consolidated Balance Sheets of the Subsidiary Registrants for balances due to or due from related parties. Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas. In addition to the amounts presented above, the Subsidiary Registrants have other affiliate transactions, including rental of office space, participation in a money pool arrangement, other operational transactions and their proportionate share of certain charged expenses. See Note 6 to the Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2016, for more information regarding the money pool. These transactions of the Subsidiary Registrants were not material for the three and six months ended June 30, 2017 and 2016 . As discussed in Note 12 , certain trade receivables have been sold by Duke Energy Ohio and Duke Energy Indiana to CRC, an affiliate formed by a subsidiary of Duke Energy. The proceeds obtained from the sales of receivables are largely cash but also include a subordinated note from the affiliate for a portion of the purchase price. Equity Method Investments Piedmont has related party transactions as a customer of its equity method investments in natural gas storage and transportation facilities. The following table presents expenses for the three and six months ended June 30, 2017 and 2016 , which are included in Cost of natural gas on Piedmont's Condensed Consolidated Statement of Operations and Comprehensive Income. Three Months Ended June 30, Six Months Ended June 30, (in millions) Type of expense 2017 2016 2017 2016 Cardinal Transportation Costs $ 2 $ 2 $ 4 $ 4 Pine Needle Gas Storage Costs 2 2 4 5 Hardy Storage Gas Storage Costs 3 3 5 5 Total $ 7 $ 7 $ 13 $ 14 Piedmont had accounts payable to its equity method investments of $2 million at June 30, 2017 , and December 31, 2016 , related to these transactions. These amounts are included in Accounts payable on the Condensed Consolidated Balance Sheets. Intercompany Income Taxes Duke Energy and the Subsidiary Registrants file a consolidated federal income tax return and other state and jurisdictional returns. The Subsidiary Registrants have a tax sharing agreement with Duke Energy for the allocation of consolidated tax liabilities and benefits. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38

Derivatives and Hedging

Derivatives and Hedging	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price risk and interest rate risk. The primary use of commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Piedmont enters into gas supply contracts to provide diversification, reliability and gas cost benefits to their customers. Interest rate swaps are used to manage interest rate risk associated with borrowings. All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the Condensed Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting arrangements is offset against the collateralized derivatives on the Condensed Consolidated Balance Sheets. The cash impacts of settled derivatives are recorded as operating activities on the Condensed Consolidated Statements of Cash Flows. INTEREST RATE RISK The Duke Energy Registrants are exposed to changes in interest rates as a result of their issuance or anticipated issuance of variable-rate and fixed-rate debt and commercial paper. Interest rate risk is managed by limiting variable-rate exposures to a percentage of total debt and by monitoring changes in interest rates. To manage risk associated with changes in interest rates, the Duke Energy Registrants may enter into interest rate swaps, U.S. Treasury lock agreements and other financial contracts. In anticipation of certain fixed-rate debt issuances, a series of forward-starting interest rate swaps or Treasury locks may be executed to lock in components of current market interest rates. These instruments are later terminated prior to or upon the issuance of the corresponding debt. Cash Flow Hedges For a derivative designated as hedging the exposure to variable cash flows of a future transaction, referred to as a cash flow hedge, the effective portion of the derivative's gain or loss is initially reported as a component of other comprehensive income and subsequently reclassified into earnings once the future transaction impacts earnings. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. Gains and losses reclassified out of AOCI for the three and six months ended June 30, 2017 , were not material. Duke Energy's interest rate derivatives designated as hedges include interest rate swaps used to hedge existing debt within the Commercial Renewables business. In July and August 2017, Duke Energy entered into $200 million notional amount of Treasury locks that were designated as hedges of debt anticipated to be issued in 2017. Undesignated Contracts Undesignated contracts include contracts not designated as a hedge because they are accounted for under regulatory accounting and contracts that do not qualify for hedge accounting. Duke Energy’s interest rate swaps for its regulated operations employ regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the swaps are deferred as regulatory liabilities or regulatory assets, respectively. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The accrual of interest on the swaps is recorded as Interest Expense. As of June 30, 2016 , Duke Energy entered into $1.4 billion of forward-starting interest rate swaps to manage interest rate exposure related to the Piedmont acquisition financing. The swaps did not qualify for hedge accounting and were marked-to-market, with any gains or losses included within earnings. For the three and six months ended June 30, 2016 , unrealized losses on the swaps of $75 million and $168 million , respectively, were included within Interest Expense on Duke Energy's Condensed Consolidated Statements of Operations. The swaps were unwound in August 2016 in conjunction with the acquisition financing. See Note 2 for additional information related to the Piedmont acquisition. The following table shows notional amounts of outstanding derivatives related to interest rate risk. June 30, 2017 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 703 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,630 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 750 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,677 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $703 million and $750 million as of June 30, 2017 and December 31, 2016 , respectively. COMMODITY PRICE RISK The Duke Energy Registrants are exposed to the impact of changes in the prices of electricity purchased and sold in bulk power markets and coal and natural gas purchases, including Piedmont's gas supply contracts. Exposure to commodity price risk is influenced by a number of factors including the term of contracts, the liquidity of markets and delivery locations. For the Subsidiary Registrants, bulk power electricity and coal and natural gas purchases flow through fuel adjustment clauses, formula based contracts or other cost sharing mechanisms. Differences between the costs included in rates and the incurred costs, including undesignated derivative contracts, are largely deferred as regulatory assets or regulatory liabilities. Piedmont policies allow for the use of financial instruments to hedge commodity price risks. The strategy and objective of these hedging programs are to use the financial instruments to reduce gas costs volatility for customers. Volumes The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. June 30, 2017 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Carolinas Energy Progress Florida Indiana Piedmont Electricity (gigawatt-hours) 178 — — — — 178 — Natural gas (millions of dekatherms) 791 92 202 106 96 2 495 December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Carolinas Energy Progress Florida Indiana Piedmont Electricity (gigawatt-hours) 147 — — — — 147 — Natural gas (millions of dekatherms) 890 91 269 118 151 1 529 LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED ON THE CONDENSED CONSOLIDATED BALANCE SHEETS The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 76 $ 7 $ 11 $ 7 $ 4 $ 3 $ 54 $ 2 Noncurrent 3 1 2 1 1 — — — Total Derivative Assets – Commodity Contracts $ 79 $ 8 $ 13 $ 8 $ 5 $ 3 $ 54 $ 2 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 14 $ — $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 2 — 2 — 1 — — — Total Derivative Assets – Interest Rate Contracts $ 16 $ — $ 2 $ — $ 1 $ — $ — $ — Total Derivative Assets $ 95 $ 8 $ 15 $ 8 $ 6 $ 3 $ 54 $ 2 Derivative Liabilities June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 40 $ 1 $ 21 $ 2 $ 19 $ — $ — $ 18 Noncurrent 140 3 10 3 1 — — 127 Total Derivative Liabilities – Commodity Contracts $ 180 $ 4 $ 31 $ 5 $ 20 $ — $ — $ 145 Interest Rate Contracts Designated as Hedging Instruments Current $ 6 $ — $ — $ — $ — $ — $ — $ — Noncurrent 9 — — — — — — — Not Designated as Hedging Instruments Current 23 22 — — — 1 — — Noncurrent 9 — 4 3 — 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 47 $ 22 $ 4 $ 3 $ — $ 5 $ — $ — Total Derivative Liabilities $ 227 $ 26 $ 35 $ 8 $ 20 $ 5 $ — $ 145 Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 108 $ 23 $ 61 $ 35 $ 26 $ 4 $ 16 $ 3 Noncurrent 32 10 21 10 11 1 — — Total Derivative Assets – Commodity Contracts $ 140 $ 33 $ 82 $ 45 $ 37 $ 5 $ 16 $ 3 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 19 $ — $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 3 — 3 1 2 — — — Total Derivative Assets – Interest Rate Contracts $ 22 $ — $ 3 $ 1 $ 2 $ — $ — $ — Total Derivative Assets $ 162 $ 33 $ 85 $ 46 $ 39 $ 5 $ 16 $ 3 Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 43 $ — $ 12 $ — $ 12 $ — $ 2 $ 35 Noncurrent 166 1 7 1 — — — 152 Total Derivative Liabilities – Commodity Contracts $ 209 $ 1 $ 19 $ 1 $ 12 $ — $ 2 $ 187 Interest Rate Contracts Designated as Hedging Instruments Current $ 8 $ — $ — $ — $ — $ — $ — $ — Noncurrent 8 — — — — — — — Not Designated as Hedging Instruments — Current 1 — — — — 1 — — Noncurrent 26 15 6 6 — 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 43 $ 15 $ 6 $ 6 $ — $ 6 $ — $ — Total Derivative Liabilities $ 252 $ 16 $ 25 $ 7 $ 12 $ 6 $ 2 $ 187 OFFSETTING ASSETS AND LIABILITIES The following tables present the line items on the Condensed Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position, and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 78 $ 7 $ 13 $ 7 $ 5 $ 3 $ 54 $ 2 Gross amounts offset (3 ) — (4 ) — (3 ) — — — Net amounts presented in Current Assets: Other $ 75 $ 7 $ 9 $ 7 $ 2 $ 3 $ 54 $ 2 Noncurrent Gross amounts recognized $ 17 $ 1 $ 2 $ 1 $ 1 $ — $ — $ — Gross amounts offset (1 ) — (1 ) — (1 ) — — — Net amounts presented in Other Noncurrent Assets: Other $ 16 $ 1 $ 1 $ 1 $ — $ — $ — $ — Derivative Liabilities June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 69 $ 23 $ 21 $ 2 $ 19 $ 1 $ — $ 18 Gross amounts offset (4 ) (1 ) (4 ) (1 ) (3 ) — — — Net amounts presented in Current Liabilities: Other $ 65 $ 22 $ 17 $ 1 $ 16 $ 1 $ — $ 18 Noncurrent Gross amounts recognized $ 158 $ 3 $ 14 $ 6 $ 1 $ 4 $ — $ 127 Gross amounts offset (2 ) (1 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 156 $ 2 $ 13 $ 5 $ — $ 4 $ — $ 127 Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 111 $ 23 $ 64 $ 36 $ 28 $ 4 $ 16 $ 3 Gross amounts offset (11 ) — (11 ) — (11 ) — — — Net amounts presented in Current Assets: Other $ 100 $ 23 $ 53 $ 36 $ 17 $ 4 $ 16 $ 3 Noncurrent Gross amounts recognized $ 51 $ 10 $ 21 $ 10 $ 11 $ 1 $ — $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 49 $ 9 $ 20 $ 9 $ 11 $ 1 $ — $ — Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 52 $ — $ 12 $ — $ 12 $ 1 $ 2 $ 35 Gross amounts offset (11 ) — (11 ) — (11 ) — — — Net amounts presented in Current Liabilities: Other $ 41 $ — $ 1 $ — $ 1 $ 1 $ 2 $ 35 Noncurrent Gross amounts recognized $ 200 $ 16 $ 13 $ 7 $ — $ 5 $ — $ 152 Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 198 $ 15 $ 12 $ 6 $ — $ 5 $ — $ 152 OBJECTIVE CREDIT CONTINGENT FEATURES Certain derivative contracts contain objective credit contingent features. These features include the requirement to post cash collateral or letters of credit if specific events occur, such as a credit rating downgrade below investment grade. The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio, Duke Energy Indiana and Piedmont were not material. June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 51 $ 25 $ 26 $ 7 $ 19 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 51 25 26 7 19 December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 34 $ 16 $ 18 $ 6 $ 12 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 34 16 18 6 12 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement.

Investments in Debt and Equity

Investments in Debt and Equity Securities	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investments In Debt And Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES The Duke Energy Registrants classify their investments in debt and equity securities as either trading or available-for-sale. TRADING SECURITIES Piedmont's investments in debt and equity securities held in rabbi trusts associated with certain deferred compensation plans are classified as trading securities. The fair value of these investments was $2 million and $5 million as of June 30, 2017 and December 31, 2016 , respectively. AVAILABLE-FOR-SALE (AFS) SECURITIES All other investments in debt and equity securities are classified as AFS. Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the nuclear decommissioning trust fund (NDTF) at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to Other Post-Retirement Benefit Obligations (OPEB) plans and (iii) Bison. Duke Energy classifies all other investments in debt and equity securities as long term, unless otherwise noted. Investment Trusts The investments within the NDTF investments and the Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana grantor trusts (Investment Trusts) are managed by independent investment managers with discretion to buy, sell, and invest pursuant to the objectives set forth by the trust agreements. The Duke Energy Registrants have limited oversight of the day-to-day management of these investments. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt and equity securities within the Investment Trusts are considered other-than-temporary impairments (OTTIs) and are recognized immediately. Investments within the Investment Trusts generally qualify for regulatory accounting, and accordingly realized and unrealized gains and losses are deferred as a regulatory asset or liability. Substantially all amounts of the Duke Energy Registrants' gross unrealized holding losses as of June 30, 2017 and December 31, 2016 , are considered OTTIs on investments within Investment Trusts that have been recognized immediately as a regulatory asset. Other AFS Securities Unrealized gains and losses on all other AFS securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. The Duke Energy Registrants analyze all investment holdings each reporting period to determine whether a decline in fair value should be considered other-than-temporary. If an OTTI exists, the unrealized credit loss is included in earnings. There were no material credit losses as of June 30, 2017 and December 31, 2016 . Other Investments amounts are recorded in Other within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets. DUKE ENERGY The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 116 $ — $ — $ 111 Equity securities 2,373 29 4,422 2,092 54 4,106 Corporate debt securities 15 2 611 10 8 528 Municipal bonds 4 3 340 3 10 331 U.S. government bonds 12 6 961 10 8 984 Other debt securities — 1 142 — 3 124 Total NDTF $ 2,404 $ 41 $ 6,592 $ 2,115 $ 83 $ 6,184 Other Investments Cash and cash equivalents $ — $ — $ 15 $ — $ — $ 25 Equity securities 47 — 110 38 — 104 Corporate debt securities 1 — 63 1 1 66 Municipal bonds 3 1 82 2 1 82 U.S. government bonds — — 49 — 1 51 Other debt securities — — 36 — 2 42 Total Other Investments $ 51 $ 1 $ 355 $ 41 $ 5 $ 370 Total Investments $ 2,455 $ 42 $ 6,947 $ 2,156 $ 88 $ 6,554 The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 86 Due after one through five years 631 Due after five through 10 years 503 Due after 10 years 1,064 Total $ 2,284 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 40 $ 64 $ 133 $ 118 Realized losses 37 42 99 92 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 33 $ — $ — $ 18 Equity securities 1,299 14 2,441 1,157 28 2,245 Corporate debt securities 9 2 407 5 6 354 Municipal bonds 1 1 60 1 2 67 U.S. government bonds 3 3 417 2 5 458 Other debt securities — 1 132 — 3 116 Total NDTF $ 1,312 $ 21 $ 3,490 $ 1,165 $ 44 $ 3,258 Other Investments Other debt securities — — — — 1 3 Total Investments $ 1,312 $ 21 $ 3,490 $ 1,165 $ 45 $ 3,261 The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 4 Due after one through five years 224 Due after five through 10 years 245 Due after 10 years 543 Total $ 1,016 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 24 $ 33 $ 90 $ 67 Realized losses 23 19 63 56 PROGRESS ENERGY The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 83 $ — $ — $ 93 Equity securities 1,074 15 1,981 935 26 1,861 Corporate debt securities 6 — 204 5 2 174 Municipal bonds 3 2 280 2 8 264 U.S. government bonds 9 3 544 8 3 526 Other debt securities — — 10 — — 8 Total NDTF $ 1,092 $ 20 $ 3,102 $ 950 $ 39 $ 2,926 Other Investments Cash and cash equivalents $ — $ — $ 12 $ — $ — $ 21 Municipal bonds 3 — 47 2 — 44 Total Other Investments $ 3 $ — $ 59 $ 2 $ — $ 65 Total Investments $ 1,095 $ 20 $ 3,161 $ 952 $ 39 $ 2,991 The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 72 Due after one through five years 347 Due after five through 10 years 196 Due after 10 years 470 Total $ 1,085 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 15 $ 31 $ 42 $ 50 Realized losses 14 23 35 36 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 31 $ — $ — $ 45 Equity securities 816 12 1,607 704 21 1,505 Corporate debt securities 5 — 142 4 1 120 Municipal bonds 3 2 279 2 8 263 U.S. government bonds 6 2 314 5 2 275 Other debt securities — — 6 — — 5 Total NDTF $ 830 $ 16 $ 2,379 $ 715 $ 32 $ 2,213 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 830 $ 16 $ 2,380 $ 715 $ 32 $ 2,214 The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 18 Due after one through five years 220 Due after five through 10 years 144 Due after 10 years 359 Total $ 741 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 11 $ 27 $ 35 $ 42 Realized losses 11 20 30 31 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 48 Equity securities 258 3 374 231 5 356 Corporate debt securities 1 — 62 1 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 3 1 230 3 1 251 Other debt securities — — 4 — — 3 Total NDTF (a) $ 262 $ 4 $ 723 $ 235 $ 7 $ 713 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 4 Municipal bonds 3 — 47 2 — 44 Total Other Investments $ 3 $ — $ 48 $ 2 $ — $ 48 Total Investments $ 265 $ 4 $ 771 $ 237 $ 7 $ 761 (a) During the six months ended June 30, 2017 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant. The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 54 Due after one through five years 127 Due after five through 10 years 52 Due after 10 years 111 Total $ 344 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 4 $ 4 $ 7 $ 8 Realized losses 3 3 5 5 DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value Investments Equity securities $ 40 $ — $ 87 $ 33 $ — $ 79 Corporate debt securities — — 3 — — 2 Municipal bonds — 1 27 — 1 28 U.S. government bonds — — 1 — — 1 Total Investments $ 40 $ 1 $ 118 $ 33 $ 1 $ 110 The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 3 Due after one through five years 14 Due after five through 10 years 8 Due after 10 years 6 Total $ 31 Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were insignificant for the three and six months ended June 30, 2017 and 2016 .

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data, or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient. Fair value measurements are classified in three levels based on the fair value hierarchy: Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. An active market is one in which transactions for an asset or liability occur with sufficient frequency and volume to provide ongoing pricing information. Level 2 – A fair value measurement utilizing inputs other than quoted prices included in Level 1 that are observable, either directly or indirectly, for an asset or liability. Inputs include (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active, (iii) and inputs other than quoted market prices that are observable for the asset or liability, such as interest rate curves and yield curves observable at commonly quoted intervals, volatilities and credit spreads. A Level 2 measurement cannot have more than an insignificant portion of its valuation based on unobservable inputs. Instruments in this category include non-exchange-traded derivatives, such as over-the-counter forwards, swaps and options; certain marketable debt securities; and financial instruments traded in less-than-active markets. Level 3 – Any fair value measurement that includes unobservable inputs for more than an insignificant portion of the valuation. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value. Level 3 measurements may include longer-term instruments that extend into periods in which observable inputs are not available. Not Categorized – Certain investments are not categorized within the Fair Value hierarchy. These investments are measured based on the fair value of the underlying investments but may not be readily redeemable at that fair value. Fair value accounting guidance permits entities to elect to measure certain financial instruments that are not required to be accounted for at fair value, such as equity method investments or the company’s own debt, at fair value. The Duke Energy Registrants have not elected to record any of these items at fair value. Transfers between levels represent assets or liabilities that were previously (i) categorized at a higher level for which the inputs to the estimate became less observable or (ii) classified at a lower level for which the inputs became more observable during the period. The Duke Energy Registrant’s policy is to recognize transfers between levels of the fair value hierarchy at the end of the period. There were no transfers between levels during the three and six months ended June 30, 2017 and 2016 . Valuation methods of the primary fair value measurements disclosed below are as follows. Investments in equity securities The majority of investments in equity securities are valued using Level 1 measurements. Investments in equity securities are typically valued at the closing price in the principal active market as of the last business day of the quarter. Principal active markets for equity prices include published exchanges such as New York Stock Exchange (NYSE) and Nasdaq Stock Market. Foreign equity prices are translated from their trading currency using the currency exchange rate in effect at the close of the principal active market. There was no after-hours market activity that was required to be reflected in the reported fair value measurements. Investments in debt securities Most investments in debt securities are valued using Level 2 measurements because the valuations use interest rate curves and credit spreads applied to the terms of the debt instrument (maturity and coupon interest rate) and consider the counterparty credit rating. If the market for a particular fixed-income security is relatively inactive or illiquid, the measurement is Level 3. Commodity derivatives Commodity derivatives with clearinghouses are classified as Level 1. Other commodity derivatives, including Piedmont's gas supply contracts, are primarily valued using internally developed discounted cash flow models that incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or non-performance risk (after reflecting credit enhancements such as collateral), and are discounted to present value. Pricing inputs are derived from published exchange transaction prices and other observable data sources. In the absence of an active market, the last available price may be used. If forward price curves are not observable for the full term of the contract and the unobservable period had more than an insignificant impact on the valuation, the commodity derivative is classified as Level 3. In isolation, increases (decreases) in natural gas forward prices result in favorable (unfavorable) fair value adjustments for gas purchase contracts; and increases (decreases) in electricity forward prices result in unfavorable (favorable) fair value adjustments for electricity sales contracts. Duke Energy regularly evaluates and validates pricing inputs used to estimate the fair value of gas commodity contracts by a market participant price verification procedure. This procedure provides a comparison of internal forward commodity curves to market participant generated curves. Interest rate derivatives Most over-the-counter interest rate contract derivatives are valued using financial models that utilize observable inputs for similar instruments and are classified as Level 2. Inputs include forward interest rate curves, notional amounts, interest rates and credit quality of the counterparties. Other fair value considerations See Note 2 related to the acquisition of Piedmont in 2016. See Note 11 in Duke Energy's Annual Report on Form 10-K for the year ended December 31, 2016, for a discussion of the valuation of goodwill and intangible assets. DUKE ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type for the Duke Energy Registrants. June 30, 2017 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 4,422 $ 4,345 $ — $ — $ 77 NDTF debt securities 2,170 593 1,577 — — Other trading and AFS equity securities 112 112 — — — Other trading and AFS debt securities 245 63 182 — — Derivative assets 95 4 37 54 — Total assets 7,044 5,117 1,796 54 77 Derivative liabilities (227 ) (1 ) (81 ) (145 ) — Net assets (liabilities) $ 6,817 $ 5,116 $ 1,715 $ (91 ) $ 77 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 4,106 $ 4,029 $ — $ — $ 77 NDTF debt securities 2,078 632 1,446 — — Other trading and AFS equity securities 104 104 — — — Other trading and AFS debt securities 266 75 186 5 — Derivative assets 162 5 136 21 — Total assets 6,716 4,845 1,768 26 77 Derivative liabilities (252 ) (2 ) (63 ) (187 ) — Net assets (liabilities) $ 6,464 $ 4,843 $ 1,705 $ (161 ) $ 77 The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Cost of natural gas on the Duke Energy Registrants' Condensed Consolidated Statements of Operations and Comprehensive Income. Amounts included in changes of net assets on the Duke Energy Registrants' Condensed Consolidated Balance Sheets are included in regulatory assets or liabilities. All derivative assets and liabilities are presented on a net basis. Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 (in millions) Investments Derivatives (net) Total Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (135 ) $ (130 ) $ 4 $ 2 $ 6 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — — — Purchases, sales, issuances and settlements: Purchases — 55 55 — 34 34 Sales (6 ) — (6 ) — — — Settlements — (9 ) (9 ) — (6 ) (6 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet — (2 ) (2 ) — 4 4 Balance at end of period $ — $ (91 ) $ (91 ) $ 4 $ 34 $ 38 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 (in millions) Investments Derivatives (net) Total Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (166 ) $ (161 ) $ 5 $ 10 $ 15 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — — — Purchases, sales, issuances and settlements: Purchases — 55 55 — 34 34 Sales (6 ) — (6 ) (1 ) — (1 ) Settlements — (18 ) (18 ) — (13 ) (13 ) Total gains included on the Condensed Consolidated Balance Sheet — 38 38 — 3 3 Balance at end of period $ — $ (91 ) $ (91 ) $ 4 $ 34 $ 38 DUKE ENERGY CAROLINAS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 2,441 $ 2,364 $ — $ — $ 77 NDTF debt securities 1,049 141 908 — — Derivative assets 8 — 8 — — Total assets 3,498 2,505 916 — 77 Derivative liabilities (26 ) — (26 ) — — Net assets $ 3,472 $ 2,505 $ 890 $ — $ 77 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 2,245 $ 2,168 $ — $ — $ 77 NDTF debt securities 1,013 178 835 — — Other AFS debt securities 3 — — 3 — Derivative assets 33 — 33 — — Total assets 3,294 2,346 868 3 77 Derivative liabilities (16 ) — (16 ) — — Net assets $ 3,278 $ 2,346 $ 852 $ 3 $ 77 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Investments Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period 3 $ 3 $ 3 3 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — Purchases, sales, issuances and settlements: Sales (4 ) — (4 ) — Balance at end of period $ — $ 3 $ — $ 3 PROGRESS ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,981 $ 1,981 $ — $ 1,861 $ 1,861 $ — NDTF debt securities 1,121 452 669 1,065 454 611 Other AFS debt securities 59 12 47 65 21 44 Derivative assets 15 — 15 85 — 85 Total assets 3,176 2,445 731 3,076 2,336 740 Derivative liabilities (35 ) — (35 ) (25 ) — (25 ) Net assets $ 3,141 $ 2,445 $ 696 $ 3,051 $ 2,336 $ 715 DUKE ENERGY PROGRESS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,607 $ 1,607 $ — $ 1,505 $ 1,505 $ — NDTF debt securities and other 772 226 546 708 207 501 Other AFS debt securities and other 1 1 — 1 1 — Derivative assets 8 — 8 46 — 46 Total assets 2,388 1,834 554 2,260 1,713 547 Derivative liabilities (8 ) — (8 ) (7 ) — (7 ) Net assets $ 2,380 $ 1,834 $ 546 $ 2,253 $ 1,713 $ 540 DUKE ENERGY FLORIDA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 374 $ 374 $ — $ 356 $ 356 $ — NDTF debt securities and other 349 226 123 357 247 110 Other AFS debt securities and other 48 1 47 48 4 44 Derivative assets 6 — 6 39 — 39 Total assets 777 601 176 800 607 193 Derivative liabilities (20 ) — (20 ) (12 ) — (12 ) Net assets $ 757 $ 601 $ 156 $ 788 $ 607 $ 181 DUKE ENERGY OHIO The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 2 Level 3 Total Fair Value Level 2 Level 3 Derivative assets $ 3 $ — $ 3 $ 5 $ — $ 5 Derivative liabilities (5 ) (5 ) — (6 ) (6 ) — Net (liabilities) assets $ (2 ) $ (5 ) $ 3 $ (1 ) $ (6 ) $ 5 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 1 $ — $ 5 $ 3 Purchases, sales, issuances and settlements: Purchases 3 5 3 5 Settlements (1 ) — (2 ) (2 ) Total losses included on the Condensed Consolidated Balance Sheet — — (3 ) (1 ) Balance at end of period $ 3 $ 5 $ 3 $ 5 DUKE ENERGY INDIANA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other AFS equity securities $ 87 $ 87 $ — $ — $ 79 $ 79 $ — $ — Other AFS debt securities and other 31 — 31 — 31 — 31 — Derivative assets 54 3 — 51 16 — — 16 Total assets 172 90 31 51 126 79 31 16 Derivative liabilities — — — — (2 ) (2 ) — — Net assets $ 172 $ 90 $ 31 $ 51 $ 124 $ 77 $ 31 $ 16 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 9 $ 2 $ 16 $ 7 Purchases, sales, issuances and settlements: Purchases 52 29 52 29 Settlements (9 ) (6 ) (16 ) (11 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet (1 ) 4 (1 ) 4 Balance at end of period $ 51 $ 29 $ 51 $ 29 PIEDMONT The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Other trading equity securities 2 2 — $ 4 $ 4 $ — Other trading debt securities — — — 1 1 — Derivative assets 2 2 — 3 3 — Total assets 4 4 — 8 8 — Derivative liabilities (145 ) — (145 ) (187 ) — (187 ) Net (liabilities) assets $ (141 ) $ 4 $ (145 ) $ (179 ) $ 8 $ (187 ) The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ (145 ) $ (126 ) $ (187 ) $ (149 ) Total (losses) gains and settlements — (64 ) 42 (41 ) Balance at end of period $ (145 ) $ (190 ) $ (145 ) $ (190 ) QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. June 30, 2017 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio Financial Transmission Rights (FTRs) $ 3 RTO auction pricing FTR price – per megawatt-hour (MWh) $ (5.24 ) - $ 1.82 Duke Energy Indiana FTRs 51 RTO auction pricing FTR price – per MWh (1.65 ) - 6.66 Piedmont Natural gas contracts (145 ) Discounted cash flow Forward natural gas curves – price per million British thermal unit (MMBtu) 2.21 - 3.78 Duke Energy Total Level 3 derivatives $ (91 ) December 31, 2016 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 5 RTO auction pricing FTR price – per MWh $ 0.77 - $ 3.52 Duke Energy Indiana FTRs 16 RTO auction pricing FTR price – per MWh (0.83 ) - 9.32 Piedmont Natural gas contracts (187 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.31 - 4.18 Duke Energy Total Level 3 derivatives $ (166 ) OTHER FAIR VALUE DISCLOSURES The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. June 30, 2017 December 31, 2016 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 49,515 $ 51,947 $ 47,895 $ 49,161 Duke Energy Carolinas 9,524 10,657 9,603 10,494 Progress Energy 18,145 20,101 17,541 19,107 Duke Energy Progress 6,760 7,266 7,011 7,357 Duke Energy Florida 6,979 7,753 6,125 6,728 Duke Energy Ohio 1,977 2,155 1,884 2,020 Duke Energy Indiana 3,784 4,379 3,786 4,260 Piedmont 1,946 2,107 1,821 1,933 At both June 30, 2017 and December 31, 2016 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and nonrecourse notes payable of VIEs are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2017
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES A VIE is an entity that is evaluated for consolidation using more than a simple analysis of voting control. The analysis to determine whether an entity is a VIE considers contracts with an entity, credit support for an entity, the adequacy of the equity investment of an entity and the relationship of voting power to the amount of equity invested in an entity. This analysis is performed either upon the creation of a legal entity or upon the occurrence of an event requiring reevaluation, such as a significant change in an entity’s assets or activities. A qualitative analysis of control determines the party that consolidates a VIE. This assessment is based on (i) what party has the power to direct the activities of the VIE that most significantly impact its economic performance and (ii) what party has rights to receive benefits or is obligated to absorb losses that could potentially be significant to the VIE. The analysis of the party that consolidates a VIE is a continual reassessment. CONSOLIDATED VIEs The obligations of the consolidated VIEs discussed in the following paragraphs are nonrecourse to the Duke Energy registrants. The registrants have no requirement to provide liquidity to, purchase assets of or guarantee performance of these VIEs unless noted in the following paragraphs. No financial support was provided to any of the consolidated VIEs during the six months ended June 30, 2017 and the year ended December 31, 2016 , or is expected to be provided in the future, that was not previously contractually required. Receivables Financing – DERF / DEPR / DEFR Duke Energy Receivables Finance Company, LLC (DERF), Duke Energy Progress Receivables, LLC (DEPR) and Duke Energy Florida Receivables, LLC (DEFR) are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. DERF, DEPR and DEFR are wholly owned limited liability companies with separate legal existence from their parent companies, and their assets are not generally available to creditors of their parent companies. On a revolving basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and related services from their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy these receivables. Borrowing availability from the credit facilities is limited to the amount of qualified receivables purchased. The sole source of funds to satisfy the related debt obligations is cash collections from the receivables. Amounts borrowed under the credit facilities are reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. The most significant activity that impacts the economic performance of DERF, DEPR and DEFR are the decisions made to manage delinquent receivables. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida consolidate DERF, DEPR and DEFR, respectively, as they make those decisions. Receivables Financing – CRC CRC is a bankruptcy remote, special purpose entity indirectly owned by Duke Energy. On a revolving basis, CRC buys certain accounts receivable arising from the sale of electricity, natural gas and related services from Duke Energy Ohio and Duke Energy Indiana. CRC borrows amounts under a credit facility to buy the receivables from Duke Energy Ohio and Duke Energy Indiana. Borrowing availability from the credit facility is limited to the amount of qualified receivables sold to CRC. The sole source of funds to satisfy the related debt obligation is cash collections from the receivables. Amounts borrowed under the credit facility are reflected on Duke Energy's Condensed Consolidated Balance Sheets as Long-Term Debt. The proceeds Duke Energy Ohio and Duke Energy Indiana receive from the sale of receivables to CRC are typically 75 percent cash and 25 percent in the form of a subordinated note from CRC. The subordinated note is a retained interest in the receivables sold. Depending on collection experience, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million . CRC is considered a VIE because (i) equity capitalization is insufficient to support its operations, (ii) power to direct the activities that most significantly impact the economic performance of the entity are not performed by the equity holder, and (iii) deficiencies in net worth of CRC are funded by Duke Energy. The most significant activities that impact the economic performance of CRC are decisions made to manage delinquent receivables. Duke Energy consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC. Receivables Financing – Credit Facilities The following table summarizes the amounts and expiration dates of the credit facilities described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida (in millions) CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount $ 325 $ 425 $ 300 $ 225 Amounts borrowed at June 30, 2017 325 425 297 225 Amounts borrowed at December 31, 2016 325 425 300 225 Nuclear Asset-Recovery Bonds – DEFPF Duke Energy Florida Project Finance, LLC (DEFPF) is a bankruptcy remote, wholly owned special purpose subsidiary of Duke Energy Florida. DEFPF was formed in 2016 for the sole purpose of issuing nuclear asset-recovery bonds to finance Duke Energy Florida's unrecovered regulatory asset related to Crystal River Unit 3. In June 2016, DEFPF issued $ 1,294 million of senior secured bonds and used the proceeds to acquire nuclear asset-recovery property from Duke Energy Florida. The nuclear asset-recovery property acquired includes the right to impose, bill, collect and adjust a non-bypassable nuclear asset-recovery charge from all Duke Energy Florida retail customers until the bonds are paid in full and all financing costs have been recovered. The nuclear asset-recovery bonds are secured by the nuclear asset-recovery property, and cash collections from the nuclear asset-recovery charges are the sole source of funds to satisfy the debt obligation. The bondholders have no recourse to Duke Energy Florida. DEFPF is considered a VIE primarily because the equity capitalization is insufficient to support its operations. Duke Energy Florida has the power to direct the significant activities of the VIE as described above, and therefore Duke Energy Florida is considered the primary beneficiary and consolidates DEFPF. The following table summarizes the impact of DEFPF on Duke Energy Florida's Condensed Consolidated Balance Sheets. (in millions) June 30, 2017 December 31, 2016 Receivables of VIEs $ 5 $ 6 Current Assets: Regulatory assets 52 50 Current Assets: Other 33 53 Other Noncurrent Assets: Regulatory assets 1,121 1,142 Current Liabilities: Other 10 17 Current maturities of long-term debt 55 62 Long-Term Debt 1,189 1,217 Commercial Renewables Certain of Duke Energy’s renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Assets are restricted and cannot be pledged as collateral or sold to third parties without prior approval of debt holders. The activities that most significantly impact the economic performance of these renewable energy facilities were decisions associated with siting, negotiating PPAs, engineering, procurement and construction and decisions associated with ongoing operations and maintenance-related activities. Duke Energy consolidates the entities as it is responsible for all of these decisions. The table below presents material balances reported on Duke Energy's Condensed Consolidated Balance Sheets related to renewables VIEs. (in millions) June 30, 2017 December 31, 2016 Current Assets: Other $ 293 $ 223 Property, plant and equipment, cost 3,695 3,419 Accumulated depreciation and amortization (518 ) (453 ) Current maturities of long-term debt 157 198 Long-Term Debt 1,557 1,097 Deferred income taxes 300 275 Other Noncurrent Liabilities: Other 249 252 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. June 30, 2017 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 44 $ 72 Investments in equity method unconsolidated affiliates 800 176 92 1,068 — — Other noncurrent assets 12 — — 12 — — Total assets $ 812 $ 176 $ 92 $ 1,080 $ 44 $ 72 Other current liabilities 10 — — 10 — — Other noncurrent liabilities — — 13 13 — — Total liabilities $ 10 $ — $ 13 $ 23 $ — $ — Net assets $ 802 $ 176 $ 79 $ 1,057 $ 44 $ 72 December 31, 2016 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Piedmont (a) Receivables from affiliated companies $ — $ — $ — $ — $ 82 $ 101 $ — Investments in equity method unconsolidated affiliates 487 174 90 751 — — 139 Other noncurrent assets 12 — — 12 — — — Total assets $ 499 $ 174 $ 90 $ 763 $ 82 $ 101 $ 139 Other current liabilities — — 3 3 — — — Other noncurrent liabilities — — 13 13 — — 4 Total liabilities $ — $ — $ 16 $ 16 $ — $ — 4 Net assets $ 499 $ 174 $ 74 $ 747 $ 82 $ 101 $ 135 (a) In April 2017, Piedmont transferred its non-consolidated VIE investments to a wholly owned subsidiary of Duke Energy. See "Pipeline Investments" section below for additional detail. The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the power purchase agreement with OVEC, which is discussed below, and various guarantees, some of which are reflected in the table above as Other noncurrent liabilities. For more information on various guarantees, refer to Note 5 . Pipeline Investments Duke Energy has investments in various joint ventures with pipeline projects currently under construction. These entities are considered VIEs due to having insufficient equity to finance their own activities without subordinated financial support. Duke Energy does not have the power to direct the activities that most significantly impact the economic performance, the obligation to absorb losses or the right to receive benefits of these VIEs and therefore does not consolidate these entities. The table below presents the ownership interest and investment balances in these joint ventures. Duke Energy VIE Investment Amount (in millions) Ownership June 30, December 31, Entity Name Interest 2017 2016 ACP 47 % $ 507 $ 265 Sabal Trail 7.5 % 211 140 Constitution 24 % 82 82 Total $ 800 $ 487 At December 31, 2016, Piedmont had a 7 percent ownership interest in ACP and a 24 percent ownership interest in Constitution. In April 2017, Piedmont transferred its ownership interests in ACP and Constitution to a wholly owned subsidiary of Duke Energy at book value. Commercial Renewables Duke Energy has investments in various renewable energy project entities. Some of these entities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. Duke Energy does not consolidate these VIEs because power to direct and control key activities is shared jointly by Duke Energy and other owners. Other VIEs Duke Energy holds a 50 percent equity interest in Duke-American Transmission Company, LLC (DATC). DATC is considered a VIE due to having insufficient equity to finance their own activities without subordinated financial support. The activities that most significantly impact DATC's economic performance are decisions related to investing in existing and development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner, American Transmission Company, LLC, therefore Duke Energy does not consolidate DATC. Duke Energy holds a 50 percent equity interest in Pioneer Transmission, LLC (Pioneer). Pioneer is considered a VIE due to having insufficient equity to finance their own activities without subordinated financial support. The activities that most significantly impact Pioneer's economic performance are decisions related to the development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner, American Electric Power, therefore Duke Energy does not consolidate Pioneer. OVEC Duke Energy Ohio’s 9 percent ownership interest in OVEC is considered a non-consolidated VIE due to OVEC having insufficient equity to finance their activities without subordinated financial support. As a counterparty to an inter-company power agreement (ICPA), Duke Energy Ohio has a contractual arrangement to receive entitlements to capacity and energy from OVEC’s power plants through June 2040 commensurate with its power participation ratio, which is equivalent to Duke Energy Ohio's ownership interest. Costs, including fuel, operating expenses, fixed costs, debt amortization, and interest expense are allocated to counterparties to the ICPA based on their power participation ratio. The value of the ICPA is subject to variability due to fluctuation in power prices and changes in OVEC's cost of business, including costs associated with its 2,256 MW of coal-fired generation capacity. Deterioration in the credit quality, or bankruptcy of one or more parties to the ICPA could increase the costs of OVEC. In addition, certain proposed environmental rulemaking could result in future increased cost allocations. CRC See discussion under Consolidated VIEs for additional information related to CRC. Amounts included in Receivables from affiliated companies in the above table for Duke Energy Ohio and Duke Energy Indiana reflect their retained interest in receivables sold to CRC. These subordinated notes held by Duke Energy Ohio and Duke Energy Indiana are stated at fair value. Carrying values of retained interests are determined by allocating carrying value of the receivables between assets sold and interests retained based on relative fair value. The allocated bases of the subordinated notes are not materially different than their face value because (i) the receivables generally turn over in less than two months, (ii) credit losses are reasonably predictable due to the broad customer base and lack of significant concentration, and (iii) the equity in CRC is subordinate to all retained interests and thus would absorb losses first. The hypothetical effect on fair value of the retained interests assuming both a 10 percent and a 20 percent unfavorable variation in credit losses or discount rates is not material due to the short turnover of receivables and historically low credit loss history. Interest accrues to Duke Energy Ohio and Duke Energy Indiana on the retained interests using the acceptable yield method. This method generally approximates the stated rate on the notes since the allocated basis and the face value are nearly equivalent. An impairment charge is recorded against the carrying value of both retained interests and purchased beneficial interest whenever it is determined that an OTTI has occurred. Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2017 2016 2017 2016 Anticipated credit loss ratio 0.5 % 0.5 % 0.3 % 0.3 % Discount rate 1.9 % 1.5 % 1.9 % 1.5 % Receivable turnover rate 13.4 % 13.3 % 10.7 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Receivables sold $ 210 $ 267 $ 299 $ 306 Less: Retained interests 44 82 72 101 Net receivables sold $ 166 $ 185 $ 227 $ 205 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Six Months Ended Three Months Ended Six Months Ended June 30, June 30, June 30, June 30, (in millions) 2017 2016 2017 2016 2017 2016 2017 2016 Sales Receivables sold $ 421 $ 429 $ 954 $ 961 $ 663 $ 623 $ 1,327 $ 1,258 Loss recognized on sale 3 2 5 5 3 2 6 5 Cash flows Cash proceeds from receivables sold $ 428 $ 427 $ 987 $ 964 $ 658 $ 612 $ 1,351 $ 1,255 Collection fees received — — — — 1 1 1 1 Return received on retained interests 1 — 2 1 1 1 3 2 Cash flows from sales of receivables are reflected within Operating Activities on Duke Energy Ohio’s and Duke Energy Indiana’s Condensed Consolidated Statements of Cash Flows. Collection fees received in connection with servicing transferred accounts receivable are included in Operation, maintenance and other on Duke Energy Ohio’s and Duke Energy Indiana’s Condensed Consolidated Statements of Operations and Comprehensive Income. The loss recognized on sales of receivables is calculated monthly by multiplying receivables sold during the month by the required discount. The required discount is derived monthly utilizing a three-year weighted average formula that considers charge-off history, late charge history and turnover history on the sold receivables, as well as a component for the time value of money. The discount rate, or component for the time value of money, is the prior month-end LIBOR plus a fixed rate of 1.00 percent .

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Common Stock	COMMON STOCK Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options and equity forward sale agreements, were exercised or settled. Duke Energy’s participating securities are restricted stock units that are entitled to dividends declared on Duke Energy common stock during the restricted stock unit’s vesting periods. The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common shares outstanding to the diluted weighted average number of common shares outstanding. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per-share amounts) 2017 2016 2017 2016 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 687 $ 621 $ 1,402 $ 1,195 Weighted average shares outstanding – basic 700 689 700 689 Equity Forwards — 1 — — Weighted average shares outstanding – diluted 700 690 700 689 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 0.98 $ 0.90 $ 2.00 $ 1.73 Diluted $ 0.98 $ 0.90 $ 2.00 $ 1.73 Potentially dilutive items excluded from the calculation (a) 2 2 2 2 Dividends declared per common share $ 0.855 $ 0.825 $ 1.71 $ 1.65 (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met. Equity Forwards In March 2016, Duke Energy marketed an equity offering of 10.6 million shares of common stock. In lieu of issuing equity at the time of the offering, Duke Energy entered into equity forward sale agreements with Barclays (the Equity Forwards). The Equity Forwards required Duke Energy to either physically settle the transactions by issuing 10.6 million shares, or net settle in whole or in part through the delivery or receipt of cash or shares. As of June 30, 2016, share dilution resulting from the agreements was determined under the treasury stock method. Duke Energy physically settled the Equity Forwards in full in October 2016 following the close of the Piedmont acquisition. See Note 2 for additional information related to the Piedmont acquisition.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION For employee awards, equity classified stock-based compensation cost is measured at the service inception date or the grant date, based on the estimated achievement of certain performance metrics or the fair value of the award, and is recognized as expense or capitalized as a component of property, plant and equipment over the requisite service period. Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Restricted stock unit awards $ 12 $ 10 $ 20 $ 17 Performance awards 6 5 13 10 Pretax stock-based compensation cost $ 18 $ 15 $ 33 $ 27 Tax benefit associated with stock-based compensation expense $ 7 $ 5 $ 12 $ 9 Stock-based compensation costs capitalized — 1 1 2 Prior to Duke Energy acquiring Piedmont, Piedmont had an incentive compensation plan for eligible officers and other participants. Piedmont's total pretax stock-based compensation costs were approximately $2 million and $3 million for the three and six months ended June 30, 2016 , respectively. The tax benefit associated with Piedmont's stock based compensation expense for the three and six months ended June 30, 2016, was immaterial.

Employee Benefit Plans

Employee Benefit Plans	6 Months Ended
	Jun. 30, 2017
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy maintains, and the Subsidiary Registrants participate in, qualified and non-qualified, non-contributory defined benefit retirement plans. Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the six months ended June 30, 2017 and 2016 . Net periodic benefit costs disclosed in the tables below represent the cost of the respective benefit plan for the periods presented. However, portions of the net periodic benefit costs disclosed in the tables below have been capitalized as a component of property, plant and equipment. Amounts presented in the tables below for the Subsidiary Registrants represent the amounts of pension and other post-retirement benefit costs allocated by Duke Energy for employees of the Subsidiary Registrants. Additionally, the Subsidiary Registrants are allocated their proportionate share of pension and post-retirement benefit costs for employees of Duke Energy’s shared services affiliate that provides support to the Subsidiary Registrants. These allocated amounts are included in the governance and shared service costs discussed in Note 8 . Duke Energy uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 40 $ 12 $ 12 $ 6 $ 5 $ 1 $ 2 $ 3 Interest cost on projected benefit obligation 82 20 25 12 13 5 7 3 Expected return on plan assets (136 ) (36 ) (43 ) (21 ) (21 ) (7 ) (11 ) (6 ) Amortization of actuarial loss 36 8 14 6 7 1 3 3 Amortization of prior service credit (6 ) (2 ) (1 ) — — — — (1 ) Other 2 — 1 1 — — — 1 Net periodic pension costs $ 18 $ 2 $ 8 $ 4 $ 4 $ — $ 1 $ 3 Three Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 37 $ 12 $ 10 $ 6 $ 5 $ 1 $ 2 $ 2 Interest cost on projected benefit obligation 83 22 27 13 14 5 7 3 Expected return on plan assets (129 ) (36 ) (42 ) (20 ) (21 ) (7 ) (11 ) (6 ) Amortization of actuarial loss 33 8 13 5 7 1 3 2 Amortization of prior service credit (4 ) (2 ) (1 ) (1 ) — — — (1 ) Other 1 — — 1 — — — — Net periodic pension costs $ 21 $ 4 $ 7 $ 4 $ 5 $ — $ 1 $ — Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 80 $ 24 $ 24 $ 12 $ 10 $ 2 $ 4 $ 6 Interest cost on projected benefit obligation 164 40 50 24 26 10 14 6 Expected return on plan assets (272 ) (71 ) (86 ) (42 ) (42 ) (14 ) (22 ) (12 ) Amortization of actuarial loss 72 16 28 12 14 2 6 6 Amortization of prior service credit (12 ) (4 ) (2 ) — — — — (2 ) Other 4 — 2 1 — — — 1 Net periodic pension costs $ 36 $ 5 $ 16 $ 7 $ 8 $ — $ 2 $ 5 Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 73 $ 24 $ 21 $ 12 $ 10 $ 2 $ 4 $ 5 Interest cost on projected benefit obligation 166 43 53 25 28 10 14 5 Expected return on plan assets (258 ) (71 ) (84 ) (41 ) (42 ) (14 ) (21 ) (12 ) Amortization of actuarial loss 66 16 27 11 14 2 6 4 Amortization of prior service credit (8 ) (4 ) (2 ) (1 ) — — — (1 ) Other 4 1 1 1 — — — — Net periodic pension costs $ 43 $ 9 $ 16 $ 7 $ 10 $ — $ 3 $ 1 NON-QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for non-qualified pension plans for registrants with non-qualified pension costs. Three Months Ended June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 3 1 1 — — Amortization of actuarial loss 2 — 1 — — Net periodic pension costs $ 5 $ 1 $ 2 $ — $ — Three Months Ended June 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 3 1 1 1 1 Amortization of actuarial loss 2 — — — — Net periodic pension costs $ 6 $ 1 $ 1 $ 1 $ 1 Six Months Ended June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 6 1 2 1 1 Amortization of actuarial loss 4 — 2 — — Net periodic pension costs $ 10 $ 1 $ 4 $ 1 $ 1 Six Months Ended June 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 7 1 2 1 1 Amortization of actuarial loss 4 — 1 — — Net periodic pension costs $ 12 $ 1 $ 3 $ 1 $ 1 OTHER POST-RETIREMENT BENEFIT PLANS Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 1 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 3 2 2 — — — Expected return on plan assets (4 ) (2 ) — — — — — — Amortization of actuarial loss (gain) 2 (1 ) 5 3 2 (1 ) — — Amortization of prior service credit (29 ) (2 ) (21 ) (13 ) (7 ) — — — Net periodic other post-retirement benefit costs $ (21 ) $ (3 ) $ (13 ) $ (8 ) $ (3 ) $ (1 ) $ — $ — Three Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 1 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 3 2 1 1 1 — Expected return on plan assets (4 ) (2 ) — — — — (1 ) — Amortization of actuarial loss (gain) 2 (1 ) 6 3 3 (1 ) — — Amortization of prior service credit (36 ) (3 ) (25 ) (17 ) (9 ) — — — Net periodic other post-retirement benefit costs $ (28 ) $ (4 ) $ (16 ) $ (12 ) $ (5 ) $ — $ — $ — Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 2 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 18 4 7 4 4 — — — Expected return on plan assets (7 ) (4 ) — — — — — — Amortization of actuarial loss (gain) 4 (2 ) 10 6 4 (1 ) — — Amortization of prior service credit (58 ) (4 ) (42 ) (27 ) (15 ) — — — Net periodic other post-retirement benefit costs $ (41 ) $ (6 ) $ (25 ) $ (17 ) $ (7 ) $ (1 ) $ — $ — Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 2 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 17 4 7 4 3 1 2 1 Expected return on plan assets (7 ) (4 ) — — — — (1 ) (1 ) Amortization of actuarial loss (gain) 3 (2 ) 11 6 5 (1 ) (1 ) — Amortization of prior service credit (71 ) (6 ) (51 ) (34 ) (18 ) — — — Net periodic other post-retirement benefit costs $ (56 ) $ (8 ) $ (33 ) $ (24 ) $ (10 ) $ — $ — $ — DEFINED CONTRIBUTION RETIREMENT PLANS EMPLOYEE SAVINGS PLANS Duke Energy sponsors, and the Subsidiary Registrants participate in, employee savings plans that cover substantially all U.S. employees. The following table presents employer contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Three Months Ended June 30, 2017 $ 39 $ 13 $ 12 $ 8 $ 4 $ 1 $ 2 $ 1 2016 39 13 12 8 4 1 2 1 Six Months Ended June 30, 2017 $ 104 $ 35 $ 30 $ 21 $ 9 $ 2 $ 5 $ 3 2016 91 31 27 19 8 2 4 3 MONEY PURCHASE PENSION PLAN Duke Energy provides, and Piedmont participates in, the Money Purchase Pension (MPP) plan, which is a defined contribution pension plan that allows certain employees to direct investments and assume risk of investment returns. In January 2017, a $2 million contribution was made to the MPP plan.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES EFFECTIVE TAX RATES The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended Six Months Ended June 30, June 30, 2017 2016 2017 2016 Duke Energy 32.1 % 28.8 % 32.3 % 29.6 % Duke Energy Carolinas 34.7 % 35.1 % 35.0 % 34.6 % Progress Energy 33.4 % 36.0 % 33.7 % 36.3 % Duke Energy Progress 31.9 % 35.5 % 33.0 % 35.4 % Duke Energy Florida 36.8 % 37.6 % 36.7 % 37.7 % Duke Energy Ohio 34.8 % 34.3 % 35.1 % 29.2 % Duke Energy Indiana 39.4 % 36.1 % 39.4 % 33.1 % Piedmont 38.5 % 40.0 % 37.9 % 38.0 % The increase in the effective tax rate (ETR) for Duke Energy for the three and six months ended June 30, 2017 , is primarily due to favorable impacts in the prior year of finalizing federal tax audits and unfavorable tax levelization in the current year, partially offset by higher production tax credits related to wind projects placed in service. The decrease in the ETR for Progress Energy for the three and six months ended June 30, 2017 , is primarily due to lower North Carolina corporate tax rates. The decrease in the ETR for Duke Energy Progress for the three and six months ended June 30, 2017 , is primarily due to lower North Carolina corporate tax rates. The increase in the ETR for Duke Energy Ohio for the six months ended June 30, 2017 , is primarily due to an immaterial out of period adjustment in the prior year related to deferred tax balances associated with property, plant and equipment. The increase in the ETR for Duke Energy Indiana for the three months ended June 30, 2017, is primarily due to favorable state tax credits recorded in the prior year. The increase in the ETR for Duke Energy Indiana for the six months ended June 30, 2017 , is primarily due to an immaterial out of period adjustment in the prior year related to deferred tax balances associated with property, plant and equipment. The decrease in the ETR for Piedmont for the three months ended June 30, 2017, is primarily due to lower North Carolina corporate tax rates. TAXES ON FOREIGN EARNINGS As of December 31, 2015, Duke Energy's intention was to indefinitely reinvest any future undistributed foreign earnings earned after December 31, 2014. In February 2016, Duke Energy announced it had initiated a process to divest the International Disposal Group and, accordingly, no longer intended to indefinitely reinvest post-2014 undistributed foreign earnings. This change in the company's intent, combined with the extension of bonus depreciation by Congress in late 2015, allowed Duke Energy to more efficiently utilize foreign tax credits and reduce U.S. deferred tax liabilities associated with historical unremitted foreign earnings by approximately $95 million for the six months ended June 30, 2016 . Due to the classification of the International Disposal Group as discontinued operations, income tax amounts related to the International Disposal Group's foreign earnings are presented within (Loss) Income from Discontinued Operations, net of tax on the Condensed Consolidated Statements of Operations. See Note 2 for additional information related to the sale of the International Disposal Group.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on additional subsequent events related to regulatory matters, commitments and contingencies and derivatives and hedging see Notes 4, 5 and 9.

Organization and Basis of Pre25

Organization and Basis of Presentation (Policy)	6 Months Ended
	Jun. 30, 2017
Policy Text Block [Line Items]
Basis of Accounting	The results of operations of the International Disposal Group have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations. Piedmont's results of operations and cash flows are included in the accompanying condensed consolidated financial statements of Duke Energy for the three and six months ended June 30, 2017 , but not for the three and six months ended June 30, 2016 , as Piedmont's earnings and cash flows are only included in Duke Energy's consolidated results subsequent to the acquisition date. BASIS OF PRESENTATION These Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP in the U.S. for annual financial statements. Since the interim Condensed Consolidated Financial Statements and Notes do not include all information and notes required by GAAP in the U.S. for annual financial statements, the Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the Consolidated Financial Statements and Notes in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2016 , and the Consolidated Financial Statements and Notes in the Piedmont Annual Report on Form 10‑K for the year ended October 31, 2016. Effective November 1, 2016, Piedmont's fiscal year-end was changed from October 31 to December 31, the year-end of Duke Energy. A transition report was filed on Form 10-Q (Form 10-QT) as of December 31, 2016, for the transition period from November 1, 2016 to December 31, 2016. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors.
Consolidation	These Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities.
Use of Estimates	In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Unbilled Revenue	UNBILLED REVENUE Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy and natural gas delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills, meter reading schedules, and the impact of weather normalization or margin decoupling mechanisms.
Inventory	INVENTORY Inventory is used for operations and is recorded primarily using the average cost method. Inventory related to regulated operations is valued at historical cost. Inventory related to nonregulated operations is valued at the lower of cost or market. Materials and supplies are recorded as inventory when purchased and subsequently charged to expense or capitalized to property, plant and equipment when installed. Inventory, including excess or obsolete inventory, is written-down to the lower of cost or market value. Once inventory has been written-down, it creates a new cost basis for the inventory that is not subsequently written-up.
Excise Taxes	EXCISE TAXES Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Otherwise, excise taxes are accounted for on a net basis.
New Accounting Standards	NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2017 and 2016 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. While immaterial, adoption of the following accounting standard had the most significant impact on the Duke Energy results of operations, cash flows and financial position for the six months ended June 30, 2017. Stock-Based Compensation and Income Taxes. In first quarter 2017, Duke Energy adopted Financial Accounting Standards Board (FASB) guidance, which revised the accounting for stock-based compensation and the associated income taxes. The adopted guidance changes certain aspects of accounting for stock-based payment awards to employees including the accounting for income taxes and classification on the Condensed Consolidated Statements of Cash Flows. The primary impact to Duke Energy as a result of implementing this guidance was a cumulative-effect adjustment to retained earnings for tax benefits not previously recognized and additional income tax expense for the six months ended June 30, 2017. See the Duke Energy Condensed Consolidated Statements of Changes in Equity for further information. The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of June 30, 2017 . Retirement Benefits. In March 2017, the FASB issued revised accounting guidance for the presentation of net periodic costs related to benefit plans. Current GAAP permits the aggregation of all the components of net periodic costs on the income statement and does not require the disclosure of the location of net periodic costs on the Condensed Consolidated Statement of Operations. Under the amended guidance, the service cost component of net periodic costs must be included within Operating income within the same line as other compensation expenses. All other components of net periodic costs must be outside of Operating income. In addition, the updated guidance permits only the service cost component of net periodic costs to be capitalized to Inventory or Property, Plant and Equipment. This represents a change from current GAAP, which permits all components of net periodic costs to be capitalized. The guidance allows for a practical expedient that permits a company to use amounts disclosed in prior-period financial statements as the estimation basis for applying the retrospective presentation requirements. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2018. These amendments should be applied retrospectively for the presentation of the various components of net periodic costs and prospectively for the change in eligible costs to be capitalized. Duke Energy currently presents all of the components of net periodic costs that are not capitalized within Operation, maintenance and other on the Condensed Consolidated Statement of Operations. Under this updated guidance, Duke Energy will retrospectively reclassify all the components of net periodic costs except for the service cost component to be presented outside of Operating income. However, Duke Energy will continue to present the service cost amount not capitalized within Operation, maintenance and other as this line item includes other compensation expense. Duke Energy is currently evaluating the financial statement impact, if any, of adopting this standard and whether or not the practical expedient will be utilized. Goodwill Impairment. In January 2017, the FASB issued revised guidance for subsequent measurement of goodwill. Under the guidance, a company will recognize an impairment to goodwill for the amount by which a reporting unit's carrying value exceeds the reporting unit's fair value, not to exceed the amount of goodwill allocated to that reporting unit. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2020. However, Duke Energy expects to early adopt this guidance on a prospective basis for the next annual goodwill impairment test. Duke Energy does not expect adopting this guidance will have a material impact to its results of operations or financial position. Revenue from Contracts with Customers . In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Most of Duke Energy’s revenue is expected to be in scope of the new guidance. The majority of our sales, including energy provided to residential customers, are from tariff offerings that provide natural gas or electricity without a defined contractual term ("at-will"). For such arrangements, Duke Energy expects that the revenue from contracts with customers will be equivalent to the electricity or natural gas supplied and billed in that period (including estimated billings). As such, Duke Energy does not expect that there will be a significant shift in the timing or pattern of revenue recognition for such sales. The evaluation of other revenue streams is ongoing, including long-term contracts with industrial customers and long-term purchase power agreements (PPA). Duke Energy continues to evaluate what information would be most useful for users of the financial statements, including information already provided in disclosures outside of the financial statement footnotes. These additional disclosures could include the disaggregation of revenues by geographic location, type of service, customer class or by duration of contract ("at-will" versus contracted revenue). Revenues from contracts with customers, revenue recognized under regulated operations accounting and revenue from lease accounting will also be disclosed. Duke Energy intends to use the modified retrospective method of adoption effective January 1, 2018. This method results in a cumulative-effect adjustment that will be recorded to retained earnings as of January 1, 2018, as if the standard had always been in effect. Disclosures for 2018 will include a comparison to what would have been reported for 2018 under the current revenue recognition rules in order to assist financial statement users in understanding how revenue recognition has changed as a result of this standard and to facilitate comparability with prior year reported results, which are not restated under the modified retrospective approach. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2019, although it can be early adopted. The guidance is applied using a modified retrospective approach. Duke Energy is currently evaluating the financial statement impact of adopting this standard and is continuing to monitor industry implementation issues, including easements, pole attachments and renewable power purchase agreements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Significant system enhancements may be required to facilitate the identification, tracking and reporting of potential leases based upon requirements of the new lease standard. Statement of Cash Flows. In November 2016, the FASB issued revised accounting guidance to reduce diversity in practice for the presentation and classification of restricted cash on the statement of cash flows. Under the updated guidance, restricted cash and restricted cash equivalents will be included within beginning-of-period and end-of-period cash and cash equivalents on the statement of cash flows. For Duke Energy, this guidance is effective for the interim and annual periods beginning January 1, 2018, although it can be early adopted. The guidance will be applied using a retrospective transition method to each period presented. Upon adoption by Duke Energy, the revised guidance will result in a change to the amount of cash and cash equivalents and restricted cash explained when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Prior to adoption, the Duke Energy Registrants reflect changes in restricted cash within Cash Flows from Investing Activities on the Condensed Consolidated Statement of Cash Flows. Financial Instruments Classification and Measurement. In January 2016, the FASB issued revised accounting guidance for the classification and measurement of financial instruments. Changes in the fair value of all equity securities will be required to be recorded in net income. Current GAAP allows some changes in fair value for available-for-sale equity securities to be recorded in Accumulated other comprehensive income (AOCI). Additional disclosures will be required to present separately the financial assets and financial liabilities by measurement category and form of financial asset. An entity's equity investments that are accounted for under the equity method of accounting are not included within the scope of the new guidance. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, by recording a cumulative-effect adjustment to retained earnings as of January 1, 2018. This guidance is expected to have minimal impact on the Duke Energy Registrant's Condensed Consolidated Statements of Operations and Comprehensive Income as changes in the fair value of most of the Duke Energy Registrants' available-for-sale equity securities are deferred as regulatory assets or liabilities pursuant to accounting guidance for regulated operations.
Acquisitions	The fair value of Piedmont's assets and liabilities were determined based on significant estimates and assumptions that are judgmental in nature, including the amount and timing of projected future cash flows, discount rates reflecting risk inherent in the future cash flows and market prices of long-term debt.
Environmental Costs	Liabilities are recorded when losses become probable and are reasonably estimable. Costs are typically expensed as Operation, maintenance and other on the Condensed Consolidated Statements of Operations unless regulatory recovery of the costs is deemed probable.
Derivatives	Duke Energy’s interest rate swaps for its regulated operations employ regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the swaps are deferred as regulatory liabilities or regulatory assets, respectively. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The accrual of interest on the swaps is recorded as Interest Expense. For the Subsidiary Registrants, bulk power electricity and coal and natural gas purchases flow through fuel adjustment clauses, formula based contracts or other cost sharing mechanisms. Differences between the costs included in rates and the incurred costs, including undesignated derivative contracts, are largely deferred as regulatory assets or regulatory liabilities.
Investments	Unrealized gains and losses on all other AFS securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. The Duke Energy Registrants analyze all investment holdings each reporting period to determine whether a decline in fair value should be considered other-than-temporary. If an OTTI exists, the unrealized credit loss is included in earnings. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt and equity securities within the Investment Trusts are considered other-than-temporary impairments (OTTIs) and are recognized immediately. Investments within the Investment Trusts generally qualify for regulatory accounting, and accordingly realized and unrealized gains and losses are deferred as a regulatory asset or liability.
Earnings Per Share	Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options and equity forward sale agreements, were exercised or settled.
Stock-based Compensation	For employee awards, equity classified stock-based compensation cost is measured at the service inception date or the grant date, based on the estimated achievement of certain performance metrics or the fair value of the award, and is recognized as expense or capitalized as a component of property, plant and equipment over the requisite service period.
Duke Energy Ohio [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana.
Duke Energy Indiana [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana.

Organization and Basis of Pre26

Organization and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2017
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues are included within Receivables and Receivables of variable interest entities (VIEs) on the Condensed Consolidated Balance Sheets as shown in the following table. (in millions) June 30, 2017 December 31, 2016 Duke Energy $ 761 $ 831 Duke Energy Carolinas 310 313 Progress Energy 220 161 Duke Energy Progress 125 102 Duke Energy Florida 95 59 Duke Energy Ohio 1 2 Duke Energy Indiana 13 32 Piedmont 1 77
Schedule Of Net Income Amounts Attributable To Controlling Interests	For the three and six months ended June 30, 2017 , the Loss from Discontinued Operations, net of tax on Duke Energy's Condensed Consolidated Statements of Operations is entirely attributable to controlling interests. The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations for the three and six months ended June 30, 2016 . Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Income from Continuing Operations $ 624 $ 1,201 Income from Continuing Operations Attributable to Noncontrolling Interests — 3 Income from Continuing Operations Attributable to Duke Energy Corporation $ 624 $ 1,198 (Loss) Income from Discontinued Operations, net of tax $ (112 ) $ 10 Income from Discontinued Operations Attributable to Noncontrolling Interests, net of tax 3 5 (Loss) Income from Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ (115 ) $ 5 Net Income $ 512 $ 1,211 Net Income Attributable to Noncontrolling Interests 3 8 Net Income Attributable to Duke Energy Corporation $ 509 $ 1,203
Schedule of Utility Inventory	The components of inventory are presented in the tables below. June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,368 $ 791 $ 1,129 $ 782 $ 347 $ 85 $ 321 $ 2 Coal 665 239 262 161 101 17 147 — Natural gas, oil and other fuel 336 36 230 110 120 32 2 36 Total inventory $ 3,369 $ 1,066 $ 1,621 $ 1,053 $ 568 $ 134 $ 470 $ 38 December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Materials and supplies $ 2,374 $ 767 $ 1,167 $ 813 $ 354 $ 84 $ 312 $ 1 Coal 774 251 314 148 166 19 190 — Natural gas, oil and other fuel 374 37 236 115 121 34 2 65 Total inventory $ 3,522 $ 1,055 $ 1,717 $ 1,076 $ 641 $ 137 $ 504 $ 66
Schedule of Excise Taxes	Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes on the Condensed Consolidated Statements of Operations were as follows. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy $ 91 $ 87 $ 182 $ 178 Duke Energy Carolinas 9 7 18 15 Progress Energy 55 50 101 96 Duke Energy Progress 4 4 9 9 Duke Energy Florida 51 46 92 87 Duke Energy Ohio 23 22 51 51 Duke Energy Indiana 3 8 10 16 Piedmont 1 — 2 1
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below. (in millions) June 30, 2017 December 31, 2016 Duke Energy Ohio $ 70 $ 97 Duke Energy Indiana 118 123
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below. (in millions) June 30, 2017 December 31, 2016 Duke Energy Ohio $ 70 $ 97 Duke Energy Indiana 118 123

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The purchase price allocation of the Piedmont acquisition is as follows: (in millions) Current assets $ 497 Property, plant and equipment, net 4,714 Goodwill 3,353 Other long-term assets 804 Total assets 9,368 Current liabilities, including current maturities of long-term debt 576 Long-term liabilities 1,790 Long-term debt 2,002 Total liabilities 4,368 Total purchase price $ 5,000
Business Acquisition, Pro Forma Information [Table Text Block]	This information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Duke Energy. Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Operating Revenues $ 5,374 $ 11,214 Net Income Attributable to Duke Energy Corporation 540 1,372
Financial Statement Disclosures	The following table presents the results of the International Disposal Group, which are included in Income from Discontinued Operations, net of tax in Duke Energy's Condensed Consolidated Statements of Operations. Interest expense directly associated with the International Disposal Group was allocated to discontinued operations. No interest from corporate level debt was allocated to discontinued operations. Three Months Ended Six Months Ended (in millions) June 30, 2016 June 30, 2016 Operating Revenues $ 270 $ 516 Fuel used in electric generation and purchased power 70 117 Cost of natural gas 12 23 Operation, maintenance and other 84 155 Depreciation and amortization 22 44 Property and other taxes 2 5 Impairment charges (a) 194 194 Gains on Sales of Other Assets and Other, net 1 1 Other Income and Expenses, net 11 21 Interest Expense 22 44 Loss before income taxes (124 ) (44 ) Income tax benefit (b) (13 ) (52 ) (Loss) Income from discontinued operations of the International Disposal Group (111 ) 8 (Loss) Income from discontinued operations of other businesses (1 ) 2 (Loss) Income from Discontinued Operations, net of tax $ (112 ) $ 10 (a) In conjunction with the advancements of marketing efforts during 2016, Duke Energy performed recoverability tests of the long-lived asset groups of International Energy. As a result, Duke Energy determined the carrying value of certain assets in Central America was not fully recoverable and recorded a pretax impairment charge of $194 million . The charge represents the excess carrying value over the estimated fair value of the assets, which was based on a Level 3 Fair Value measurement that was primarily determined from the income approach using discounted cash flows but also considered market information obtained in 2016. (b) Includes an income tax benefit of $95 million for the six months ended June 30, 2016 related to historical undistributed foreign earnings. See Note 16 for additional information. Duke Energy has elected not to separately disclose discontinued operations on the Condensed Consolidated Statements of Cash Flows. The following table summarizes Duke Energy's cash flows from discontinued operations related to the International Disposal Group. Six Months Ended (in millions) June 30, 2016 Cash flows provided by (used in): Operating activities $ 144 Investing activities (24 )

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting Information [Line Items]
Business Segment Data	Business segment information is presented in the following tables. Segment assets presented exclude intercompany assets. Three Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,150 $ 279 $ 110 $ 5,539 $ 16 $ — $ 5,555 Intersegment revenues 8 22 — 30 19 (49 ) — Total revenues $ 5,158 $ 301 $ 110 $ 5,569 $ 35 $ (49 ) $ 5,555 Segment income (loss) (a) $ 729 $ 27 $ 26 $ 782 $ (94 ) $ — $ 688 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (2 ) Net income $ 689 Segment assets $ 117,009 $ 11,073 $ 4,306 $ 132,388 $ 2,435 $ 181 $ 135,004 Three Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 4,993 $ 97 $ 112 $ 5,202 $ 11 $ — $ 5,213 Intersegment revenues 8 2 — 10 19 (29 ) — Total revenues $ 5,001 $ 99 $ 112 $ 5,212 $ 30 $ (29 ) $ 5,213 Segment income (loss) (a) $ 704 $ 16 $ 11 $ 731 $ (107 ) $ — $ 624 Loss from discontinued operations, net of tax (112 ) Net income $ 512 Six Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 10,090 $ 927 $ 238 $ 11,255 $ 29 $ — $ 11,284 Intersegment revenues 15 44 — 59 39 (98 ) — Total revenues $ 10,105 $ 971 $ 238 $ 11,314 $ 68 $ (98 ) $ 11,284 Segment income (loss) (a) $ 1,364 $ 160 $ 51 $ 1,575 $ (171 ) $ — $ 1,404 Add back noncontrolling interests 4 Loss from discontinued operations, net of tax (2 ) Net income $ 1,406 Six Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Commercial Reportable (in millions) Infrastructure Infrastructure Renewables Segments Other Eliminations Consolidated Unaffiliated revenues $ 10,074 $ 266 $ 226 $ 10,566 $ 24 $ — $ 10,590 Intersegment revenues 16 3 — 19 35 (54 ) — Total revenues $ 10,090 $ 269 $ 226 $ 10,585 $ 59 $ (54 ) $ 10,590 Segment income (loss) (a) $ 1,368 $ 48 $ 37 $ 1,453 $ (255 ) $ — $ 1,198 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 10 Net income $ 1,211 (a) Other includes costs to achieve the Piedmont acquisition. See Notes 2 and 9 for additional information. The following table summarizes the net (loss) income of Other for each of these entities. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas $ (6 ) $ (17 ) $ (12 ) $ (34 ) Progress Energy (45 ) (45 ) (88 ) (94 ) Duke Energy Progress (4 ) (8 ) (7 ) (16 ) Duke Energy Florida (3 ) (5 ) (5 ) (9 ) Duke Energy Indiana (1 ) (5 ) (3 ) (7 ) Piedmont (9 ) 1 (13 ) 7
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 329 $ 100 $ 429 $ 8 $ 437 Segment income (loss)/Net Income 22 17 39 (9 ) 30 Segment assets 4,879 2,672 7,551 54 7,605 Three Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 323 $ 98 $ 421 $ 7 $ 428 Segment income (loss)/Net Income 19 14 33 (10 ) 23 Six Months Ended June 30, 2017 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 665 $ 270 $ 935 $ 20 $ 955 Segment income (loss)/Net Income 46 42 88 (16 ) 72 Six Months Ended June 30, 2016 Electric Gas Total Utilities and Utilities and Reportable (in millions) Infrastructure Infrastructure Segments Other Consolidated Total revenues $ 663 $ 269 $ 932 $ 12 $ 944 Segment income (loss) $ 55 $ 45 $ 100 $ (20 ) $ 80 Income from discontinued operations, net of tax 2 Net income 82

Regulatory Matters (Tables)

Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2017
Public Utilities, General Disclosures [Line Items]
Schedule of Potential Plant Retirements	The table below contains the net carrying value of generating facilities planned for retirement or included in recent IRPs as evaluated for potential retirement. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets as of June 30, 2017 , and exclude capitalized asset retirement costs. Remaining Net Capacity Book Value (in MW) (in millions) Duke Energy Carolinas Allen Steam Station Units 1-3 (a) 585 $ 172 Progress Energy and Duke Energy Florida Crystal River Units 1 and 2 (b) 873 113 Duke Energy Indiana Gallagher Units 2 and 4 (c) 280 131 Total Duke Energy 1,738 $ 416 (a) Duke Energy Carolinas will retire Allen Steam Station Units 1 through 3 by December 31, 2024, as part of the resolution of a lawsuit involving alleged New Source Review violations. (b) Duke Energy Florida will likely retire these coal units by 2018 to comply with environmental regulations. (c) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the settlement of Edwardsport IGCC matters.

Commitments and Contingencies (

Commitments and Contingencies (Table)	6 Months Ended
	Jun. 30, 2017
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Additional Possible Losses in Excess of Recorded Environmental Reserves	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 70 Duke Energy Carolinas 23 Duke Energy Ohio 35 Duke Energy Indiana 7 Piedmont 2
Reserve for Environmental Costs [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Legal Reserves	The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Other within Other Noncurrent Liabilities on the Condensed Consolidated Balance Sheets. Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 98 $ 10 $ 18 $ 3 $ 14 $ 59 $ 10 $ 1 Provisions/adjustments — 1 — — 1 (2 ) — — Cash reductions (8 ) (1 ) (2 ) — (2 ) (4 ) (1 ) — Balance at end of period $ 90 $ 10 $ 16 $ 3 $ 13 $ 53 $ 9 $ 1 Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Balance at beginning of period $ 94 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 $ 1 Provisions/adjustments 27 3 4 1 3 1 21 — Cash reductions (7 ) (2 ) (4 ) (1 ) (3 ) (1 ) (1 ) — Balance at end of period $ 114 $ 11 $ 17 $ 3 $ 14 $ 54 $ 32 $ 1
Legal Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Legal Reserves	The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos-related reserves and the exit obligation discussed above related to the termination of an EPC contract. Reserves are classified on the Condensed Consolidated Balance Sheets in Other within Other Noncurrent Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. (in millions) June 30, 2017 December 31, 2016 Reserves for Legal Matters Duke Energy $ 82 $ 98 Duke Energy Carolinas 23 23 Progress Energy 57 59 Duke Energy Progress 12 14 Duke Energy Florida 28 28 Duke Energy Ohio — 4 Piedmont 2 2

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table summarizes significant debt issuances (in millions). Refer to the "Available Credit Facilities" section below regarding amounts issued under the Three Year Revolver and the Piedmont Term Loan facilities. Six Months Ended June 30, 2017 Duke Duke Duke Maturity Interest Duke Energy Energy Energy Issuance Date Date Rate Energy (Parent) Florida Ohio Unsecured Debt April 2017 (a) April 2025 3.364 % $ 420 $ 420 $ — $ — June 2017 (b) June 2020 2.100 % 330 330 — — Secured Debt February 2017 (c) June 2034 4.120 % 587 — — — First Mortgage Bonds January 2017 (d) January 2020 1.850 % 250 — 250 — January 2017 (d) January 2027 3.200 % 650 — 650 — March 2017 (e) June 2046 3.700 % 100 — — 100 Total issuances $ 2,337 $ 750 $ 900 $ 100 (a) Proceeds were used to refinance $ 400 million of unsecured debt at maturity and to repay a portion of outstanding commercial paper. (b) Debt issued to repay a portion of outstanding commercial paper. (c) Portfolio financing of four Texas and Oklahoma wind facilities. Secured by substantially all of the assets of these wind facilities and nonrecourse to Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures. (d) Debt issued to fund capital expenditures for ongoing construction and capital maintenance, to repay at maturity a $250 million aggregate principal amount of bonds due September 2017 and for general corporate purposes. (e) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes.
Schedule Of Debt	The following table shows the significant components of Current Maturities of Long-Term Debt on the Condensed Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate June 30, 2017 Unsecured Debt Duke Energy (Parent) August 2017 1.625 % $ 700 Piedmont September 2017 8.510 % 35 Duke Energy (Parent) June 2018 6.250 % 250 Duke Energy (Parent) June 2018 2.100 % 500 First Mortgage Bonds Duke Energy Florida September 2017 5.800 % 250 Duke Energy Progress November 2017 1.372 % 200 Duke Energy Carolinas January 2018 5.250 % 400 Duke Energy Carolinas April 2018 5.100 % 300 Duke Energy Florida June 2018 5.650 % 500 Other (a) 337 Current maturities of long-term debt $ 3,472 (a) Includes capital lease obligations, amortizing debt and small bullet maturities.
Schedule Of Line Of Credit Facilities	The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. June 30, 2017 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Piedmont Facility size (a) $ 8,000 $ 3,150 $ 1,350 $ 1,250 $ 700 $ 450 $ 600 $ 500 Reduction to backstop issuances Commercial paper (b) (3,115 ) (1,392 ) (732 ) (661 ) — (45 ) (150 ) (135 ) Outstanding letters of credit (68 ) (59 ) (4 ) (2 ) (1 ) — — (2 ) Tax-exempt bonds (81 ) — — — — — (81 ) — Coal ash set-aside (500 ) — (250 ) (250 ) — — — — Available capacity under the Master Credit Facility $ 4,236 $ 1,699 $ 364 $ 337 $ 699 $ 405 $ 369 $ 363 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies on the Condensed Consolidated Balance Sheets.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill By Reportable Operating Segment	Duke Energy The following table presents the goodwill by reportable operating segment on Duke Energy's Condensed Consolidated Balance Sheets at June 30, 2017 and December 31, 2016 . Electric Utilities Gas Utilities Commercial (in millions) and Infrastructure and Infrastructure Renewables Total Goodwill $ 17,379 $ 1,924 $ 122 $ 19,425

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2017
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38
Progress Energy [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38 Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas.
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38 Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas.
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38 Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas.
Piedmont Natural Gas [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana Piedmont June 30, 2017 Intercompany income tax receivable $ — $ 102 $ 35 $ — $ 19 $ 25 $ 56 Intercompany income tax payable 20 — — 3 — — — December 31, 2016 Intercompany income tax receivable $ 1 $ — $ — $ 37 $ — $ — $ — Intercompany income tax payable — 37 90 — 1 3 38 The following table presents expenses for the three and six months ended June 30, 2017 and 2016 , which are included in Cost of natural gas on Piedmont's Condensed Consolidated Statement of Operations and Comprehensive Income. Three Months Ended June 30, Six Months Ended June 30, (in millions) Type of expense 2017 2016 2017 2016 Cardinal Transportation Costs $ 2 $ 2 $ 4 $ 4 Pine Needle Gas Storage Costs 2 2 4 5 Hardy Storage Gas Storage Costs 3 3 5 5 Total $ 7 $ 7 $ 13 $ 14 Material amounts related to transactions with related parties included on the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 178 $ 199 $ 377 $ 416 Indemnification coverages (b) 6 5 12 11 JDA revenue (c) 17 2 33 11 JDA expense (c) 21 50 52 91 Intercompany natural gas purchases (d) 1 — 2 — Progress Energy Corporate governance and shared service expenses (a) $ 173 $ 160 $ 342 $ 334 Indemnification coverages (b) 9 9 19 17 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Progress Corporate governance and shared service expenses (a) $ 102 $ 89 $ 205 $ 189 Indemnification coverages (b) 3 4 7 7 JDA revenue (c) 21 50 52 91 JDA expense (c) 17 2 33 11 Intercompany natural gas purchases (d) 19 — 38 — Duke Energy Florida Corporate governance and shared service expenses (a) $ 71 $ 71 $ 137 $ 145 Indemnification coverages (b) 6 5 12 10 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 84 $ 87 $ 174 $ 172 Indemnification coverages (b) 1 1 2 2 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 89 $ 177 $ 183 Indemnification coverages (b) 2 2 4 4 Piedmont Corporate governance and shared service expenses (a) $ 8 $ — $ 14 $ — Indemnification coverages (b) — — 1 — Intercompany natural gas sales (d) 20 — 40 — (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are primarily recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a Joint Dispatch Agreement (JDA), which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power and expenses from the purchase of power under the JDA are recorded in Operating Revenues and Fuel used in electric generation and purchased power, respectively, on the Condensed Consolidated Statements of Operations and Comprehensive Income. (d) Piedmont provides long-term natural gas delivery service to certain Duke Energy Carolinas and Duke Energy Progress' natural gas-fired generation facilities. Piedmont records the sales in Regulated natural gas revenues, and Duke Energy Carolinas and Duke Energy Progress record the related purchases in Fuel used in electric generation and purchased power on their respective Condensed Consolidated Statements of Operations and Comprehensive Income. The amounts are not eliminated in accordance with rate-based accounting regulations. For the three and six months ended June 30, 2016, which was prior to the Piedmont acquisition, Piedmont recorded $19 million and $38 million , respectively, of natural gas sales with Duke Energy Progress and $1 million and 2 million , respectively, with Duke Energy Carolinas.

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The following table shows notional amounts of outstanding derivatives related to interest rate risk. June 30, 2017 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 703 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,630 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 750 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,677 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $703 million and $750 million as of June 30, 2017 and December 31, 2016 , respectively. The tables below include volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. The Duke Energy Registrants have netted contractual amounts where offsetting purchase and sale contracts exist with identical delivery locations and times of delivery. Where all commodity positions are perfectly offset, no quantities are shown. June 30, 2017 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Carolinas Energy Progress Florida Indiana Piedmont Electricity (gigawatt-hours) 178 — — — — 178 — Natural gas (millions of dekatherms) 791 92 202 106 96 2 495 December 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Carolinas Energy Progress Florida Indiana Piedmont Electricity (gigawatt-hours) 147 — — — — 147 — Natural gas (millions of dekatherms) 890 91 269 118 151 1 529
Location And Fair Value Of Derivatives Recognized in the Condensed Consolidated Balance Sheets	The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 76 $ 7 $ 11 $ 7 $ 4 $ 3 $ 54 $ 2 Noncurrent 3 1 2 1 1 — — — Total Derivative Assets – Commodity Contracts $ 79 $ 8 $ 13 $ 8 $ 5 $ 3 $ 54 $ 2 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 14 $ — $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 2 — 2 — 1 — — — Total Derivative Assets – Interest Rate Contracts $ 16 $ — $ 2 $ — $ 1 $ — $ — $ — Total Derivative Assets $ 95 $ 8 $ 15 $ 8 $ 6 $ 3 $ 54 $ 2 Derivative Liabilities June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 40 $ 1 $ 21 $ 2 $ 19 $ — $ — $ 18 Noncurrent 140 3 10 3 1 — — 127 Total Derivative Liabilities – Commodity Contracts $ 180 $ 4 $ 31 $ 5 $ 20 $ — $ — $ 145 Interest Rate Contracts Designated as Hedging Instruments Current $ 6 $ — $ — $ — $ — $ — $ — $ — Noncurrent 9 — — — — — — — Not Designated as Hedging Instruments Current 23 22 — — — 1 — — Noncurrent 9 — 4 3 — 4 — — Total Derivative Liabilities – Interest Rate Contracts $ 47 $ 22 $ 4 $ 3 $ — $ 5 $ — $ — Total Derivative Liabilities $ 227 $ 26 $ 35 $ 8 $ 20 $ 5 $ — $ 145 Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 108 $ 23 $ 61 $ 35 $ 26 $ 4 $ 16 $ 3 Noncurrent 32 10 21 10 11 1 — — Total Derivative Assets – Commodity Contracts $ 140 $ 33 $ 82 $ 45 $ 37 $ 5 $ 16 $ 3 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 19 $ — $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 3 — 3 1 2 — — — Total Derivative Assets – Interest Rate Contracts $ 22 $ — $ 3 $ 1 $ 2 $ — $ — $ — Total Derivative Assets $ 162 $ 33 $ 85 $ 46 $ 39 $ 5 $ 16 $ 3 Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Commodity Contracts Not Designated as Hedging Instruments Current $ 43 $ — $ 12 $ — $ 12 $ — $ 2 $ 35 Noncurrent 166 1 7 1 — — — 152 Total Derivative Liabilities – Commodity Contracts $ 209 $ 1 $ 19 $ 1 $ 12 $ — $ 2 $ 187 Interest Rate Contracts Designated as Hedging Instruments Current $ 8 $ — $ — $ — $ — $ — $ — $ — Noncurrent 8 — — — — — — — Not Designated as Hedging Instruments — Current 1 — — — — 1 — — Noncurrent 26 15 6 6 — 5 — — Total Derivative Liabilities – Interest Rate Contracts $ 43 $ 15 $ 6 $ 6 $ — $ 6 $ — $ — Total Derivative Liabilities $ 252 $ 16 $ 25 $ 7 $ 12 $ 6 $ 2 $ 187
Offsetting Assets	The following tables present the line items on the Condensed Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position, and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 78 $ 7 $ 13 $ 7 $ 5 $ 3 $ 54 $ 2 Gross amounts offset (3 ) — (4 ) — (3 ) — — — Net amounts presented in Current Assets: Other $ 75 $ 7 $ 9 $ 7 $ 2 $ 3 $ 54 $ 2 Noncurrent Gross amounts recognized $ 17 $ 1 $ 2 $ 1 $ 1 $ — $ — $ — Gross amounts offset (1 ) — (1 ) — (1 ) — — — Net amounts presented in Other Noncurrent Assets: Other $ 16 $ 1 $ 1 $ 1 $ — $ — $ — $ — Derivative Assets December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 111 $ 23 $ 64 $ 36 $ 28 $ 4 $ 16 $ 3 Gross amounts offset (11 ) — (11 ) — (11 ) — — — Net amounts presented in Current Assets: Other $ 100 $ 23 $ 53 $ 36 $ 17 $ 4 $ 16 $ 3 Noncurrent Gross amounts recognized $ 51 $ 10 $ 21 $ 10 $ 11 $ 1 $ — $ — Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — — Net amounts presented in Other Noncurrent Assets: Other $ 49 $ 9 $ 20 $ 9 $ 11 $ 1 $ — $ —
Offsetting Liabilities	Derivative Liabilities December 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 52 $ — $ 12 $ — $ 12 $ 1 $ 2 $ 35 Gross amounts offset (11 ) — (11 ) — (11 ) — — — Net amounts presented in Current Liabilities: Other $ 41 $ — $ 1 $ — $ 1 $ 1 $ 2 $ 35 Noncurrent Gross amounts recognized $ 200 $ 16 $ 13 $ 7 $ — $ 5 $ — $ 152 Gross amounts offset (2 ) (1 ) (1 ) (1 ) — — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 198 $ 15 $ 12 $ 6 $ — $ 5 $ — $ 152 Derivative Liabilities June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Current Gross amounts recognized $ 69 $ 23 $ 21 $ 2 $ 19 $ 1 $ — $ 18 Gross amounts offset (4 ) (1 ) (4 ) (1 ) (3 ) — — — Net amounts presented in Current Liabilities: Other $ 65 $ 22 $ 17 $ 1 $ 16 $ 1 $ — $ 18 Noncurrent Gross amounts recognized $ 158 $ 3 $ 14 $ 6 $ 1 $ 4 $ — $ 127 Gross amounts offset (2 ) (1 ) (1 ) (1 ) (1 ) — — — Net amounts presented in Other Noncurrent Liabilities: Other $ 156 $ 2 $ 13 $ 5 $ — $ 4 $ — $ 127 The following tables present the line items on the Condensed Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position, and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below.
Derivative Contracts with Contingent Credit Features	The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio, Duke Energy Indiana and Piedmont were not material. June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 51 $ 25 $ 26 $ 7 $ 19 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 51 25 26 7 19 December 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 34 $ 16 $ 18 $ 6 $ 12 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 34 16 18 6 12 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative and cash collateral must be executed with the same counterparty under the same master netting arrangement.

Investments in Debt and Equit35

Investments in Debt and Equity Securities (Tables)	6 Months Ended
	Jun. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 116 $ — $ — $ 111 Equity securities 2,373 29 4,422 2,092 54 4,106 Corporate debt securities 15 2 611 10 8 528 Municipal bonds 4 3 340 3 10 331 U.S. government bonds 12 6 961 10 8 984 Other debt securities — 1 142 — 3 124 Total NDTF $ 2,404 $ 41 $ 6,592 $ 2,115 $ 83 $ 6,184 Other Investments Cash and cash equivalents $ — $ — $ 15 $ — $ — $ 25 Equity securities 47 — 110 38 — 104 Corporate debt securities 1 — 63 1 1 66 Municipal bonds 3 1 82 2 1 82 U.S. government bonds — — 49 — 1 51 Other debt securities — — 36 — 2 42 Total Other Investments $ 51 $ 1 $ 355 $ 41 $ 5 $ 370 Total Investments $ 2,455 $ 42 $ 6,947 $ 2,156 $ 88 $ 6,554
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 86 Due after one through five years 631 Due after five through 10 years 503 Due after 10 years 1,064 Total $ 2,284
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 40 $ 64 $ 133 $ 118 Realized losses 37 42 99 92
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 33 $ — $ — $ 18 Equity securities 1,299 14 2,441 1,157 28 2,245 Corporate debt securities 9 2 407 5 6 354 Municipal bonds 1 1 60 1 2 67 U.S. government bonds 3 3 417 2 5 458 Other debt securities — 1 132 — 3 116 Total NDTF $ 1,312 $ 21 $ 3,490 $ 1,165 $ 44 $ 3,258 Other Investments Other debt securities — — — — 1 3 Total Investments $ 1,312 $ 21 $ 3,490 $ 1,165 $ 45 $ 3,261
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 4 Due after one through five years 224 Due after five through 10 years 245 Due after 10 years 543 Total $ 1,016
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 24 $ 33 $ 90 $ 67 Realized losses 23 19 63 56
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 83 $ — $ — $ 93 Equity securities 1,074 15 1,981 935 26 1,861 Corporate debt securities 6 — 204 5 2 174 Municipal bonds 3 2 280 2 8 264 U.S. government bonds 9 3 544 8 3 526 Other debt securities — — 10 — — 8 Total NDTF $ 1,092 $ 20 $ 3,102 $ 950 $ 39 $ 2,926 Other Investments Cash and cash equivalents $ — $ — $ 12 $ — $ — $ 21 Municipal bonds 3 — 47 2 — 44 Total Other Investments $ 3 $ — $ 59 $ 2 $ — $ 65 Total Investments $ 1,095 $ 20 $ 3,161 $ 952 $ 39 $ 2,991
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 72 Due after one through five years 347 Due after five through 10 years 196 Due after 10 years 470 Total $ 1,085
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 15 $ 31 $ 42 $ 50 Realized losses 14 23 35 36
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 31 $ — $ — $ 45 Equity securities 816 12 1,607 704 21 1,505 Corporate debt securities 5 — 142 4 1 120 Municipal bonds 3 2 279 2 8 263 U.S. government bonds 6 2 314 5 2 275 Other debt securities — — 6 — — 5 Total NDTF $ 830 $ 16 $ 2,379 $ 715 $ 32 $ 2,213 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 830 $ 16 $ 2,380 $ 715 $ 32 $ 2,214
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 18 Due after one through five years 220 Due after five through 10 years 144 Due after 10 years 359 Total $ 741
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 11 $ 27 $ 35 $ 42 Realized losses 11 20 30 31
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 48 Equity securities 258 3 374 231 5 356 Corporate debt securities 1 — 62 1 1 54 Municipal bonds — — 1 — — 1 U.S. government bonds 3 1 230 3 1 251 Other debt securities — — 4 — — 3 Total NDTF (a) $ 262 $ 4 $ 723 $ 235 $ 7 $ 713 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 4 Municipal bonds 3 — 47 2 — 44 Total Other Investments $ 3 $ — $ 48 $ 2 $ — $ 48 Total Investments $ 265 $ 4 $ 771 $ 237 $ 7 $ 761 (a) During the six months ended June 30, 2017 , Duke Energy Florida continued to receive reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 nuclear plant.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 54 Due after one through five years 127 Due after five through 10 years 52 Due after 10 years 111 Total $ 344
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of AFS securities were as follows. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Realized gains $ 4 $ 4 $ 7 $ 8 Realized losses 3 3 5 5
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in AFS securities. June 30, 2017 December 31, 2016 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses Value Gains Losses Value Investments Equity securities $ 40 $ — $ 87 $ 33 $ — $ 79 Corporate debt securities — — 3 — — 2 Municipal bonds — 1 27 — 1 28 U.S. government bonds — — 1 — — 1 Total Investments $ 40 $ 1 $ 118 $ 33 $ 1 $ 110
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) June 30, 2017 Due in one year or less $ 3 Due after one through five years 14 Due after five through 10 years 8 Due after 10 years 6 Total $ 31

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the tables below for all Duke Energy Registrants exclude cash collateral, which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type for the Duke Energy Registrants. June 30, 2017 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 4,422 $ 4,345 $ — $ — $ 77 NDTF debt securities 2,170 593 1,577 — — Other trading and AFS equity securities 112 112 — — — Other trading and AFS debt securities 245 63 182 — — Derivative assets 95 4 37 54 — Total assets 7,044 5,117 1,796 54 77 Derivative liabilities (227 ) (1 ) (81 ) (145 ) — Net assets (liabilities) $ 6,817 $ 5,116 $ 1,715 $ (91 ) $ 77 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 4,106 $ 4,029 $ — $ — $ 77 NDTF debt securities 2,078 632 1,446 — — Other trading and AFS equity securities 104 104 — — — Other trading and AFS debt securities 266 75 186 5 — Derivative assets 162 5 136 21 — Total assets 6,716 4,845 1,768 26 77 Derivative liabilities (252 ) (2 ) (63 ) (187 ) — Net assets (liabilities) $ 6,464 $ 4,843 $ 1,705 $ (161 ) $ 77
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Cost of natural gas on the Duke Energy Registrants' Condensed Consolidated Statements of Operations and Comprehensive Income. Amounts included in changes of net assets on the Duke Energy Registrants' Condensed Consolidated Balance Sheets are included in regulatory assets or liabilities. All derivative assets and liabilities are presented on a net basis. Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 (in millions) Investments Derivatives (net) Total Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (135 ) $ (130 ) $ 4 $ 2 $ 6 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — — — Purchases, sales, issuances and settlements: Purchases — 55 55 — 34 34 Sales (6 ) — (6 ) — — — Settlements — (9 ) (9 ) — (6 ) (6 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet — (2 ) (2 ) — 4 4 Balance at end of period $ — $ (91 ) $ (91 ) $ 4 $ 34 $ 38 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 (in millions) Investments Derivatives (net) Total Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (166 ) $ (161 ) $ 5 $ 10 $ 15 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — — — Purchases, sales, issuances and settlements: Purchases — 55 55 — 34 34 Sales (6 ) — (6 ) (1 ) — (1 ) Settlements — (18 ) (18 ) — (13 ) (13 ) Total gains included on the Condensed Consolidated Balance Sheet — 38 38 — 3 3 Balance at end of period $ — $ (91 ) $ (91 ) $ 4 $ 34 $ 38
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. June 30, 2017 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio Financial Transmission Rights (FTRs) $ 3 RTO auction pricing FTR price – per megawatt-hour (MWh) $ (5.24 ) - $ 1.82 Duke Energy Indiana FTRs 51 RTO auction pricing FTR price – per MWh (1.65 ) - 6.66 Piedmont Natural gas contracts (145 ) Discounted cash flow Forward natural gas curves – price per million British thermal unit (MMBtu) 2.21 - 3.78 Duke Energy Total Level 3 derivatives $ (91 ) December 31, 2016 Fair Value Investment Type (in millions) Valuation Technique Unobservable Input Range Duke Energy Ohio FTRs $ 5 RTO auction pricing FTR price – per MWh $ 0.77 - $ 3.52 Duke Energy Indiana FTRs 16 RTO auction pricing FTR price – per MWh (0.83 ) - 9.32 Piedmont Natural gas contracts (187 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.31 - 4.18 Duke Energy Total Level 3 derivatives $ (166 )
Schedule Of Long Term Debt Fair Value	The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. June 30, 2017 December 31, 2016 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 49,515 $ 51,947 $ 47,895 $ 49,161 Duke Energy Carolinas 9,524 10,657 9,603 10,494 Progress Energy 18,145 20,101 17,541 19,107 Duke Energy Progress 6,760 7,266 7,011 7,357 Duke Energy Florida 6,979 7,753 6,125 6,728 Duke Energy Ohio 1,977 2,155 1,884 2,020 Duke Energy Indiana 3,784 4,379 3,786 4,260 Piedmont 1,946 2,107 1,821 1,933
Duke Energy Carolinas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 2,441 $ 2,364 $ — $ — $ 77 NDTF debt securities 1,049 141 908 — — Derivative assets 8 — 8 — — Total assets 3,498 2,505 916 — 77 Derivative liabilities (26 ) — (26 ) — — Net assets $ 3,472 $ 2,505 $ 890 $ — $ 77 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized NDTF equity securities $ 2,245 $ 2,168 $ — $ — $ 77 NDTF debt securities 1,013 178 835 — — Other AFS debt securities 3 — — 3 — Derivative assets 33 — 33 — — Total assets 3,294 2,346 868 3 77 Derivative liabilities (16 ) — (16 ) — — Net assets $ 3,278 $ 2,346 $ 852 $ 3 $ 77
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Investments Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period 3 $ 3 $ 3 3 Total pretax realized or unrealized gains included in comprehensive income 1 — 1 — Purchases, sales, issuances and settlements: Sales (4 ) — (4 ) — Balance at end of period $ — $ 3 $ — $ 3
Progress Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,981 $ 1,981 $ — $ 1,861 $ 1,861 $ — NDTF debt securities 1,121 452 669 1,065 454 611 Other AFS debt securities 59 12 47 65 21 44 Derivative assets 15 — 15 85 — 85 Total assets 3,176 2,445 731 3,076 2,336 740 Derivative liabilities (35 ) — (35 ) (25 ) — (25 ) Net assets $ 3,141 $ 2,445 $ 696 $ 3,051 $ 2,336 $ 715
Duke Energy Progress [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 1,607 $ 1,607 $ — $ 1,505 $ 1,505 $ — NDTF debt securities and other 772 226 546 708 207 501 Other AFS debt securities and other 1 1 — 1 1 — Derivative assets 8 — 8 46 — 46 Total assets 2,388 1,834 554 2,260 1,713 547 Derivative liabilities (8 ) — (8 ) (7 ) — (7 ) Net assets $ 2,380 $ 1,834 $ 546 $ 2,253 $ 1,713 $ 540
Duke Energy Florida [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Total Fair Value Level 1 Level 2 NDTF equity securities $ 374 $ 374 $ — $ 356 $ 356 $ — NDTF debt securities and other 349 226 123 357 247 110 Other AFS debt securities and other 48 1 47 48 4 44 Derivative assets 6 — 6 39 — 39 Total assets 777 601 176 800 607 193 Derivative liabilities (20 ) — (20 ) (12 ) — (12 ) Net assets $ 757 $ 601 $ 156 $ 788 $ 607 $ 181
Duke Energy Ohio [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 2 Level 3 Total Fair Value Level 2 Level 3 Derivative assets $ 3 $ — $ 3 $ 5 $ — $ 5 Derivative liabilities (5 ) (5 ) — (6 ) (6 ) — Net (liabilities) assets $ (2 ) $ (5 ) $ 3 $ (1 ) $ (6 ) $ 5
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 1 $ — $ 5 $ 3 Purchases, sales, issuances and settlements: Purchases 3 5 3 5 Settlements (1 ) — (2 ) (2 ) Total losses included on the Condensed Consolidated Balance Sheet — — (3 ) (1 ) Balance at end of period $ 3 $ 5 $ 3 $ 5
Duke Energy Indiana [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Other AFS equity securities $ 87 $ 87 $ — $ — $ 79 $ 79 $ — $ — Other AFS debt securities and other 31 — 31 — 31 — 31 — Derivative assets 54 3 — 51 16 — — 16 Total assets 172 90 31 51 126 79 31 16 Derivative liabilities — — — — (2 ) (2 ) — — Net assets $ 172 $ 90 $ 31 $ 51 $ 124 $ 77 $ 31 $ 16
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 9 $ 2 $ 16 $ 7 Purchases, sales, issuances and settlements: Purchases 52 29 52 29 Settlements (9 ) (6 ) (16 ) (11 ) Total (losses) gains included on the Condensed Consolidated Balance Sheet (1 ) 4 (1 ) 4 Balance at end of period $ 51 $ 29 $ 51 $ 29
Piedmont Natural Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. June 30, 2017 December 31, 2016 (in millions) Total Fair Value Level 1 Level 3 Total Fair Value Level 1 Level 3 Other trading equity securities 2 2 — $ 4 $ 4 $ — Other trading debt securities — — — 1 1 — Derivative assets 2 2 — 3 3 — Total assets 4 4 — 8 8 — Derivative liabilities (145 ) — (145 ) (187 ) — (187 ) Net (liabilities) assets $ (141 ) $ 4 $ (145 ) $ (179 ) $ 8 $ (187 )
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended June 30, Six Months Ended June 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ (145 ) $ (126 ) $ (187 ) $ (149 ) Total (losses) gains and settlements — (64 ) 42 (41 ) Balance at end of period $ (145 ) $ (190 ) $ (145 ) $ (190 )

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 2017
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the amounts and expiration dates of the credit facilities described above. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida (in millions) CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount $ 325 $ 425 $ 300 $ 225 Amounts borrowed at June 30, 2017 325 425 297 225 Amounts borrowed at December 31, 2016 325 425 300 225
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. June 30, 2017 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ — $ 44 $ 72 Investments in equity method unconsolidated affiliates 800 176 92 1,068 — — Other noncurrent assets 12 — — 12 — — Total assets $ 812 $ 176 $ 92 $ 1,080 $ 44 $ 72 Other current liabilities 10 — — 10 — — Other noncurrent liabilities — — 13 13 — — Total liabilities $ 10 $ — $ 13 $ 23 $ — $ — Net assets $ 802 $ 176 $ 79 $ 1,057 $ 44 $ 72 December 31, 2016 Duke Energy Duke Duke Pipeline Commercial Other Energy Energy (in millions) Investments Renewables VIEs Total Ohio Indiana Piedmont (a) Receivables from affiliated companies $ — $ — $ — $ — $ 82 $ 101 $ — Investments in equity method unconsolidated affiliates 487 174 90 751 — — 139 Other noncurrent assets 12 — — 12 — — — Total assets $ 499 $ 174 $ 90 $ 763 $ 82 $ 101 $ 139 Other current liabilities — — 3 3 — — — Other noncurrent liabilities — — 13 13 — — 4 Total liabilities $ — $ — $ 16 $ 16 $ — $ — 4 Net assets $ 499 $ 174 $ 74 $ 747 $ 82 $ 101 $ 135 (a) In April 2017, Piedmont transferred its non-consolidated VIE investments to a wholly owned subsidiary of Duke Energy. See "Pipeline Investments" section below for additional detail.
DEFPF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following table summarizes the impact of DEFPF on Duke Energy Florida's Condensed Consolidated Balance Sheets. (in millions) June 30, 2017 December 31, 2016 Receivables of VIEs $ 5 $ 6 Current Assets: Regulatory assets 52 50 Current Assets: Other 33 53 Other Noncurrent Assets: Regulatory assets 1,121 1,142 Current Liabilities: Other 10 17 Current maturities of long-term debt 55 62 Long-Term Debt 1,189 1,217
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The table below presents material balances reported on Duke Energy's Condensed Consolidated Balance Sheets related to renewables VIEs. (in millions) June 30, 2017 December 31, 2016 Current Assets: Other $ 293 $ 223 Property, plant and equipment, cost 3,695 3,419 Accumulated depreciation and amortization (518 ) (453 ) Current maturities of long-term debt 157 198 Long-Term Debt 1,557 1,097 Deferred income taxes 300 275 Other Noncurrent Liabilities: Other 249 252
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The table below presents the ownership interest and investment balances in these joint ventures. Duke Energy VIE Investment Amount (in millions) Ownership June 30, December 31, Entity Name Interest 2017 2016 ACP 47 % $ 507 $ 265 Sabal Trail 7.5 % 211 140 Constitution 24 % 82 82 Total $ 800 $ 487
Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2017 2016 2017 2016 Anticipated credit loss ratio 0.5 % 0.5 % 0.3 % 0.3 % Discount rate 1.9 % 1.5 % 1.9 % 1.5 % Receivable turnover rate 13.4 % 13.3 % 10.7 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Receivables sold $ 210 $ 267 $ 299 $ 306 Less: Retained interests 44 82 72 101 Net receivables sold $ 166 $ 185 $ 227 $ 205 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Six Months Ended Three Months Ended Six Months Ended June 30, June 30, June 30, June 30, (in millions) 2017 2016 2017 2016 2017 2016 2017 2016 Sales Receivables sold $ 421 $ 429 $ 954 $ 961 $ 663 $ 623 $ 1,327 $ 1,258 Loss recognized on sale 3 2 5 5 3 2 6 5 Cash flows Cash proceeds from receivables sold $ 428 $ 427 $ 987 $ 964 $ 658 $ 612 $ 1,351 $ 1,255 Collection fees received — — — — 1 1 1 1 Return received on retained interests 1 — 2 1 1 1 3 2

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common shares outstanding to the diluted weighted average number of common shares outstanding. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per-share amounts) 2017 2016 2017 2016 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 687 $ 621 $ 1,402 $ 1,195 Weighted average shares outstanding – basic 700 689 700 689 Equity Forwards — 1 — — Weighted average shares outstanding – diluted 700 690 700 689 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 0.98 $ 0.90 $ 2.00 $ 1.73 Diluted $ 0.98 $ 0.90 $ 2.00 $ 1.73 Potentially dilutive items excluded from the calculation (a) 2 2 2 2 Dividends declared per common share $ 0.855 $ 0.825 $ 1.71 $ 1.65 (a) Performance stock awards were not included in the dilutive securities calculation because the performance measures related to the awards had not been met.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule Of Stock-Based Compensation Expense	Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table. Three Months Ended Six Months Ended June 30, June 30, (in millions) 2017 2016 2017 2016 Restricted stock unit awards $ 12 $ 10 $ 20 $ 17 Performance awards 6 5 13 10 Pretax stock-based compensation cost $ 18 $ 15 $ 33 $ 27 Tax benefit associated with stock-based compensation expense $ 7 $ 5 $ 12 $ 9 Stock-based compensation costs capitalized — 1 1 2

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan Disclosures	The following table presents employer contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Three Months Ended June 30, 2017 $ 39 $ 13 $ 12 $ 8 $ 4 $ 1 $ 2 $ 1 2016 39 13 12 8 4 1 2 1 Six Months Ended June 30, 2017 $ 104 $ 35 $ 30 $ 21 $ 9 $ 2 $ 5 $ 3 2016 91 31 27 19 8 2 4 3
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 40 $ 12 $ 12 $ 6 $ 5 $ 1 $ 2 $ 3 Interest cost on projected benefit obligation 82 20 25 12 13 5 7 3 Expected return on plan assets (136 ) (36 ) (43 ) (21 ) (21 ) (7 ) (11 ) (6 ) Amortization of actuarial loss 36 8 14 6 7 1 3 3 Amortization of prior service credit (6 ) (2 ) (1 ) — — — — (1 ) Other 2 — 1 1 — — — 1 Net periodic pension costs $ 18 $ 2 $ 8 $ 4 $ 4 $ — $ 1 $ 3 Three Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 37 $ 12 $ 10 $ 6 $ 5 $ 1 $ 2 $ 2 Interest cost on projected benefit obligation 83 22 27 13 14 5 7 3 Expected return on plan assets (129 ) (36 ) (42 ) (20 ) (21 ) (7 ) (11 ) (6 ) Amortization of actuarial loss 33 8 13 5 7 1 3 2 Amortization of prior service credit (4 ) (2 ) (1 ) (1 ) — — — (1 ) Other 1 — — 1 — — — — Net periodic pension costs $ 21 $ 4 $ 7 $ 4 $ 5 $ — $ 1 $ — Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 80 $ 24 $ 24 $ 12 $ 10 $ 2 $ 4 $ 6 Interest cost on projected benefit obligation 164 40 50 24 26 10 14 6 Expected return on plan assets (272 ) (71 ) (86 ) (42 ) (42 ) (14 ) (22 ) (12 ) Amortization of actuarial loss 72 16 28 12 14 2 6 6 Amortization of prior service credit (12 ) (4 ) (2 ) — — — — (2 ) Other 4 — 2 1 — — — 1 Net periodic pension costs $ 36 $ 5 $ 16 $ 7 $ 8 $ — $ 2 $ 5 Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 73 $ 24 $ 21 $ 12 $ 10 $ 2 $ 4 $ 5 Interest cost on projected benefit obligation 166 43 53 25 28 10 14 5 Expected return on plan assets (258 ) (71 ) (84 ) (41 ) (42 ) (14 ) (21 ) (12 ) Amortization of actuarial loss 66 16 27 11 14 2 6 4 Amortization of prior service credit (8 ) (4 ) (2 ) (1 ) — — — (1 ) Other 4 1 1 1 — — — — Net periodic pension costs $ 43 $ 9 $ 16 $ 7 $ 10 $ — $ 3 $ 1
Non-Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for non-qualified pension plans for registrants with non-qualified pension costs. Three Months Ended June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 3 1 1 — — Amortization of actuarial loss 2 — 1 — — Net periodic pension costs $ 5 $ 1 $ 2 $ — $ — Three Months Ended June 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 3 1 1 1 1 Amortization of actuarial loss 2 — — — — Net periodic pension costs $ 6 $ 1 $ 1 $ 1 $ 1 Six Months Ended June 30, 2017 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ — $ — $ — $ — $ — Interest cost on projected benefit obligation 6 1 2 1 1 Amortization of actuarial loss 4 — 2 — — Net periodic pension costs $ 10 $ 1 $ 4 $ 1 $ 1 Six Months Ended June 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ — $ — Interest cost on projected benefit obligation 7 1 2 1 1 Amortization of actuarial loss 4 — 1 — — Net periodic pension costs $ 12 $ 1 $ 3 $ 1 $ 1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 1 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 3 2 2 — — — Expected return on plan assets (4 ) (2 ) — — — — — — Amortization of actuarial loss (gain) 2 (1 ) 5 3 2 (1 ) — — Amortization of prior service credit (29 ) (2 ) (21 ) (13 ) (7 ) — — — Net periodic other post-retirement benefit costs $ (21 ) $ (3 ) $ (13 ) $ (8 ) $ (3 ) $ (1 ) $ — $ — Three Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 1 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 3 2 1 1 1 — Expected return on plan assets (4 ) (2 ) — — — — (1 ) — Amortization of actuarial loss (gain) 2 (1 ) 6 3 3 (1 ) — — Amortization of prior service credit (36 ) (3 ) (25 ) (17 ) (9 ) — — — Net periodic other post-retirement benefit costs $ (28 ) $ (4 ) $ (16 ) $ (12 ) $ (5 ) $ — $ — $ — Six Months Ended June 30, 2017 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 2 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 18 4 7 4 4 — — — Expected return on plan assets (7 ) (4 ) — — — — — — Amortization of actuarial loss (gain) 4 (2 ) 10 6 4 (1 ) — — Amortization of prior service credit (58 ) (4 ) (42 ) (27 ) (15 ) — — — Net periodic other post-retirement benefit costs $ (41 ) $ (6 ) $ (25 ) $ (17 ) $ (7 ) $ (1 ) $ — $ — Six Months Ended June 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Piedmont Service cost $ 2 $ — $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 17 4 7 4 3 1 2 1 Expected return on plan assets (7 ) (4 ) — — — — (1 ) (1 ) Amortization of actuarial loss (gain) 3 (2 ) 11 6 5 (1 ) (1 ) — Amortization of prior service credit (71 ) (6 ) (51 ) (34 ) (18 ) — — — Net periodic other post-retirement benefit costs $ (56 ) $ (8 ) $ (33 ) $ (24 ) $ (10 ) $ — $ — $ —

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rates	The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended Six Months Ended June 30, June 30, 2017 2016 2017 2016 Duke Energy 32.1 % 28.8 % 32.3 % 29.6 % Duke Energy Carolinas 34.7 % 35.1 % 35.0 % 34.6 % Progress Energy 33.4 % 36.0 % 33.7 % 36.3 % Duke Energy Progress 31.9 % 35.5 % 33.0 % 35.4 % Duke Energy Florida 36.8 % 37.6 % 36.7 % 37.7 % Duke Energy Ohio 34.8 % 34.3 % 35.1 % 29.2 % Duke Energy Indiana 39.4 % 36.1 % 39.4 % 33.1 % Piedmont 38.5 % 40.0 % 37.9 % 38.0 %

Organization and Basis of Pre42

Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 761	$ 831
Duke Energy Carolinas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	310	313
Progress Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	220	161
Duke Energy Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	125	102
Duke Energy Florida [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	95	59
Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	1	2
Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	13	32
Piedmont Natural Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	1	77
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	70	97
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 118	$ 123

Organization and Basis of Pre43

Organization and Basis of Presentation (Schedule of Net Income Attributable to Noncontrolling Interest) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Net Income Attributable to Noncontrolling Interest [Abstract]
Income From Continuing Operations	$ 691	$ 624	$ 1,408	$ 1,201
Income From Continuing Operations Attributable to Noncontrolling Interests	3		4	3
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	688	624	1,404	1,198
(Loss) Income From Discontinued Operations, net of tax	(2)	(112)	(2)	10
Income From Discontinued Operations Attributable to Noncontrolling Interests, net of tax		3		5
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		(115)		5
Net Income	689	512	1,406	1,211
Net Income (Loss) Attributable to Noncontrolling Interests	3	3	4	8
Net Income Attributable to Parent	$ 686	$ 509	$ 1,402	$ 1,203

Organization and Basis of Pre44

Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Public Utilities, Inventory [Line Items]
Inventory	$ 3,369	$ 3,522
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,368	2,374
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	665	774
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	336	374
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,066	1,055
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	791	767
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	239	251
Duke Energy Carolinas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	36	37
Progress Energy [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,621	1,717
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,129	1,167
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	262	314
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	230	236
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,053	1,076
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	782	813
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	161	148
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	110	115
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	568	641
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	347	354
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	101	166
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	120	121
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	134	137
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	85	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	17	19
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	32	34
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	470	504
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	321	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	147	190
Duke Energy Indiana [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	2
Piedmont Natural Gas [Member]
Public Utilities, Inventory [Line Items]
Inventory	38	66
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	1
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 36	$ 65

Organization and Basis of Pre45

Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 91	$ 87	$ 182	$ 178
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	9	7	18	15
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	55	50	101	96
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4	4	9	9
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	51	46	92	87
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	23	22	51	51
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	3	$ 8	10	16
Piedmont Natural Gas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 1		$ 2	$ 1

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisitions (Narrative) (Details) - USD ($) $ in Millions	Oct. 03, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Business Acquisition [Line Items]
Asset Impairment Charges		$ 9	$ 1	$ 9	$ 4
Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Payments to acquire businesses	$ 5,000
Long-term debt assumed	$ 2,002
Unrealized Losses on Forward-Starting Interest Rate Swaps			75		168
Asset Impairment Charges		$ 7
Business Combination, After Tax Integration Related Costs			$ 57		$ 120

Acquisitions and Dispositions47

Acquisitions and Dispositions - Dispositions (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
DEI Brazil Holdings [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Enterprise Value	$ 1,200
DEI Latin American [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Enterprise Value	1,200
International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	1,900
Obligations [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tax obligations	$ 78

Acquisitions and Dispositions48

Acquisitions and Dispositions (Purchase Price Allocation) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Oct. 03, 2016
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill	$ 19,425	$ 19,425
Piedmont Natural Gas [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Current assets			$ 497
Property, plant and equipment, net			4,714
Goodwill			3,353
Other long-term assets			804
Total assets			9,368
Current liabilities, including current maturities of long-term debt			576
Long-term liabilities			1,790
Long-term debt			2,002
Total liabilities			4,368
Total purchase price			$ 5,000

Acquisitions and Dispositions49

Acquisitions and Dispositions (Pro Forma Information) (Details) - Piedmont Natural Gas [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Operating Revenues	$ 5,374	$ 11,214
Net income attributable to Duke Energy Corporation	$ 540	$ 1,372

Acquisitions and Dispositions50

Acquisitions and Dispositions (Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income From Discontinued Operations, net of tax	$ (2)	$ (112)	$ (2)	$ 10
International Energy [Member] | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues		270		516
Fuel used in electric generation and purchased power		70		117
Cost of natural gas		12		23
Operation, maintenance and other		84		155
Deprecation and amortization		22		44
Property and other taxes		2		5
Impairment Charges		194		194
Gains on Sales of Other Assets and Other, net		1		1
Other Income and Expenses, net		11		21
Interest Expense		22		44
Income before income taxes		(124)		(44)
Income tax benefit		(13)		(52)
Income From Discontinued Operations, net of tax		(111)		8
Other Disposal Groups [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income From Discontinued Operations, net of tax		$ (1)		2
Previously Remitted Earnings [Member] | International Energy [Member] | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit				$ (95)

Acquisitions and Dispositions51

Acquisitions and Dispositions (Cash Flow Statement) (Details) - International Energy [Member] $ in Millions	6 Months Ended
	Jun. 30, 2016USD ($)
Operating Activities	$ 144
Investing Activities	$ (24)

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)segment	Jun. 30, 2016USD ($)	Oct. 02, 2016
Segment Reporting Information [Line Items]
Net income	$ 686	$ 509	$ 1,402	$ 1,203
Interest Expense	486	478	$ 977	967
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	273	261	$ 543	532
Interest Expense	103	107	$ 206	214
Progress Energy [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	274	272	$ 473	481
Interest Expense	196	160	$ 402	320
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	154	131	$ 301	268
Interest Expense	70	64	$ 152	127
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	158	171	$ 248	281
Interest Expense	70	40	$ 140	81
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			2
Net income	30	23	$ 72	82
Interest Expense	23	21	$ 45	41
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	106	85	$ 197	180
Interest Expense	44	47	$ 88	91
Piedmont Natural Gas [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Net income	(8)	3	$ 87	106
Interest Expense	19	16	39	33
Other [Member] | Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	$ 56	55	$ 111	111
National Methanol Company [Member] | Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	25.00%		25.00%
SouthStar [Member] | Piedmont Natural Gas [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage					15.00%
Net income		$ 3		$ 10

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Unaffiliated revenues	$ 5,555	$ 5,213	$ 11,284	$ 10,590
Operating revenues	5,555	5,213	11,284	10,590
Segment income	688	624	1,404	1,198
Add back noncontrolling interests	3		4	3
(Loss) Income From Discontinued Operations, net of tax	(2)	(112)	(2)	10
Net income	689	512	1,406	1,211
Net income	686	509	1,402	1,203
Segment assets	135,004		135,004		$ 132,761
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	5,150	4,993	10,090	10,074
Operating revenues	5,158	5,001	10,105	10,090
Segment income	729	704	1,364	1,368
Segment assets	117,009		117,009
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	279	97	927	266
Operating revenues	301	99	971	269
Segment income	27	16	160	48
Segment assets	11,073		11,073
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	110	112	238	226
Operating revenues	110	112	238	226
Segment income	26	11	51	37
Segment assets	4,306		4,306
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	5,539	5,202	11,255	10,566
Operating revenues	5,569	5,212	11,314	10,585
Segment income	782	731	1,575	1,453
Segment assets	132,388		132,388
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(29)	(98)	(54)
Segment assets	181		181
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	8	15	16
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	22	2	44	3
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	19	19	39	35
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	30	10	59	19
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	16	11	29	24
Operating revenues	35	30	68	59
Segment income	(94)	(107)	(171)	(255)
Segment assets	2,435		2,435
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	437	428	955	944
Segment income	30	23	72	80
(Loss) Income From Discontinued Operations, net of tax				2
Net income	30	23	72	82
Segment assets	7,605		7,605		$ 7,528
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	329	323	665	663
Segment income	22	19	46	55
Segment assets	4,879		4,879
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	100	98	270	269
Segment income	17	14	42	45
Segment assets	2,672		2,672
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	429	421	935	932
Segment income	39	33	88	100
Segment assets	7,551		7,551
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	7	20	12
Segment income	(9)	$ (10)	(16)	$ (20)
Segment assets	$ 54		$ 54

Business Segments (Schedule of

Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Segment income	$ 688	$ 624	$ 1,404	$ 1,198
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(6)	(17)	(12)	(34)
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(45)	(45)	(88)	(94)
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(4)	(8)	(7)	(16)
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(3)	(5)	(5)	(9)
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(1)	(5)	(3)	(7)
Piedmont Natural Gas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (9)	$ 1	$ (13)	$ 7

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2015USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		$ 84,404		$ 84,404		$ 82,520
Generation Facilities To Be Retired Net		487		487		529
Electric Domestic Regulated Revenue		5,118	$ 4,965	$ 10,031	$ 10,018
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				1,738
Public Utilities, Property, Plant and Equipment, Net		$ 416		$ 416
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		47.00%		47.00%
Long-term Purchase Commitment, Period				20 years
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		7.50%		7.50%
Estimated capital cost		$ 3,200		$ 3,200
Long-term Purchase Commitment, Period				25 years
Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		24.00%		24.00%
Estimated Contributions		$ 229		$ 229
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		5,000		5,000
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		$ 5,500		$ 5,500
Dominion Resources [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		48.00%		48.00%
Southern Company Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		5.00%		5.00%
Spectra Energy [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		50.00%		50.00%
NextEra [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		42.50%		42.50%
Williams Partners L.P. [Member] | Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		41.00%		41.00%
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		$ 27,249		$ 27,249		26,762
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member] | NCEMC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		$ 600		$ 600
Joint owner ownership percentage		13.00%		13.00%
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		$ 31,152		$ 31,152		30,181
Generation Facilities To Be Retired Net		487		487		529
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		18,689		18,689		18,387
Generation Facilities To Be Retired Net		487		$ 487		529
Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				376
Generation Facilities To Be Retired Net		450		$ 450		492
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		12,459		12,459		11,790
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		5,722		5,722		5,547
Electric Domestic Regulated Revenue		328	$ 323	665	$ 663
Duke Energy Ohio [Member] | Regional Transmission Organization Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Exit obligation		90		90		90
Regulatory Assets		$ 71		$ 71		71
Approved MVP Proposals		17		17
MISO estimate of Duke Energy Ohio's MVP obligation				$ 2,700
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		$ 10,089		10,089		9,924
Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net		5,006		5,006		$ 4,814
2017 Base Rate Case [Member] | NCUC [Member] | Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount				$ 477
Requested Rate Increase, Percentage				14.90%
2017 Base Rate Case [Member] | PUCO [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount				$ 15
Requested Return on Equity, Percentage				10.40%
Storm Cost Deferrals [Member] | NCUC [Member] | Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved		116		$ 116
Western Carolinas Modernization Plan [Member] | NCUC [Member] | Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		893		893
Hines Chiller Uprate Project [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		150		150
Hines Chiller Uprate Project [Member] | FPSC [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Approved Rate Increase (Decrease), Amount				19
Levy Nuclear Project [Member] | FPSC [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount				82
Woodsdale Station Fuel System [Member] | KPSC [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		55		55
East Bend Coal Ash Basin Filing [Member] | KPSC [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		93		93
Natural Gas Pipeline Extension [Member] | PUCO [Member] | Duke Energy Ohio [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC		86		86
Natural Gas Pipeline Extension [Member] | PUCO [Member] | Duke Energy Ohio [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC		110		110
Advanced Metering Infrastructure Project [Member] | KPSC [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved		10		10
Estimated capital cost		49		49
Accelerated Natural Gas Service Line Replacement Rider [Member] | PUCO [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved		240		240
Energy Efficiency and Peak Demand Reduction Program [Member] | PUCO [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue	$ 20
MGP Remediation [Member] | PUCO [Member] | Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets		$ 95		95
Coal Combustion Residual Plan [Member] | IURC [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Approved Rate Increase (Decrease), Amount				365
Requested Rate Increase (Decrease), Amount				$ 380
Federal Mandate Costs Recovered Through Tracker Mechanism				80.00%
Federally Mandated Costs Recovered In Future Rate Case				20.00%
Percentage of Costs Recovered through Existing Rider				60.00%
Percentage Recovered Through Future Rate Case				40.00%
Interest Rate on Intermediary Debt for Electric Utility Plant Construction				4.73%
FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage				12.38%
Approved Return on Equity Percentage Adder				0.50%
FERC Complaint [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage				8.67%
FERC Complaint 1 [Member] | Federal Energy Regulatory Commission [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage				10.32%
FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage				9.70%
NCUC IMR Petition Filed May 2017 [Member] | NCUC [Member] | Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Approved Rate Increase (Decrease), Amount				$ 11.6

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017USD ($)MW	Dec. 31, 2016USD ($)
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net	$ 84,404	$ 82,520
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net	27,249	26,762
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net	31,152	30,181
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net	12,459	11,790
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net	$ 10,089	$ 9,924
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,738
Public Utilities, Property, Plant and Equipment, Net	$ 416
Allen Steam Station Units 1-3 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Public Utilities, Property, Plant and Equipment, Net	$ 172
Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member] | Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Public Utilities, Property, Plant and Equipment, Net	$ 113
Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Public Utilities, Property, Plant and Equipment, Net	$ 113
Gallagher Units 2 and 4 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Public Utilities, Property, Plant and Equipment, Net	$ 131

Commitments and Contingencies57

Commitments and Contingencies (Narrative) (Details) gal in Millions	1 Months Ended	6 Months Ended
	Feb. 28, 2014Tgal	Jun. 30, 2017USD ($)plantclaim	Dec. 31, 2016USD ($)	Mar. 31, 2014USD ($)
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		$ 82,000,000	$ 98,000,000
Progress Energy Merger Shareholder Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount		$ 27,000,000
Coal Ash Insurance Coverage Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Number of NC and SC Plants with Ash Basins | plant		15
NCDEQ State Enforcement Actions [Member]
Valuation and Qualifying Accounts [Abstract]
Number of Plants with No Disputed Facts | plant		7
Number of NC Plants with Ash Basins | plant		14
Number of Plants with Disputed Facts | plant		7
Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Number of NC Plants with Ash Basins | plant		14
Goodwill Payment		$ 5,000
Water Bill Stipend Period		25 years
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		$ 23,000,000	23,000,000
Duke Energy Carolinas [Member] | Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		18,000,000
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves		497,000,000	512,000,000
Reinsurance retention policy, excess retention, amount reinsured		814,000,000
Probable insurance recoveries		$ 587,000,000	587,000,000
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member] | Non-Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim		87
Asbestos-related injuries and damages reserves		$ 23,000,000
Duke Energy Carolinas [Member] | Asbestos-related Injuries and Damages Claims [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | claim		58
Asbestos-related injuries and damages reserves		$ 16,000,000
Duke Energy Carolinas [Member] | Minimum [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Coal ash released, in tons | T	30,000
Basin water released, in gallons | gal	24
Duke Energy Carolinas [Member] | Maximum [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Coal ash released, in tons | T	39,000
Basin water released, in gallons | gal	27
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		57,000,000	59,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		12,000,000	14,000,000
Duke Energy Progress [Member] | Potential Groundwater Claims [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		4,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual		28,000,000	28,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount		54,000,000
Loss Contingency, Damages Sought, Original Amount		482,000,000		$ 510,000,000
Loss Contingency, Damages Awarded, Value		30,000,000
Gain Contingency, Dismissed Amount		54,000,000
Loss contingency, damages sought, value		424,000,000
Loss Contingency Damages Awarded and Interest, Value		34,000,000
Duke Energy Florida [Member] | MGP Cost Recovery Action [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount		43,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			$ 4,000,000
Duke Energy Indiana [Member] | Benton County Wind Farm Dispute [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, damages sought, value		16,000,000
Litigation Settlement, Amount Awarded to Other Party		$ 29,000,000

Commitments and Contingencies58

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 70
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	98	$ 94
Provisions/adjustments		27
Cash reductions	(8)	(7)
Ending balance	90	114
Duke Energy Carolinas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	23
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	10
Provisions/adjustments	1	3
Cash reductions	(1)	(2)
Ending balance	10	11
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	18	17
Provisions/adjustments		4
Cash reductions	(2)	(4)
Ending balance	16	17
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	3	3
Provisions/adjustments		1
Cash reductions	0	(1)
Ending balance	3	3
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	14	14
Provisions/adjustments	1	3
Cash reductions	(2)	(3)
Ending balance	13	14
Duke Energy Ohio [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	35
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	59	54
Provisions/adjustments	(2)	1
Cash reductions	(4)	(1)
Ending balance	53	54
Duke Energy Indiana [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	7
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	12
Provisions/adjustments		21
Cash reductions	(1)	(1)
Ending balance	9	32
Piedmont Natural Gas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	2
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	1	1
Cash reductions	0
Ending balance	$ 1	$ 1

Commitments and Contingencies59

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Reserves for legal matters	$ 82	$ 98
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	23	23
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	57	59
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	12	14
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	28	28
Duke Energy Ohio [Member]
Loss Contingencies [Line Items]
Reserves for legal matters		4
Piedmont Natural Gas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 2	$ 2

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2017USD ($)Integer	Jun. 30, 2017USD ($)Integer	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Debt issuances	$ 2,337,000,000	$ 2,337,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	8,000,000,000	8,000,000,000	$ 7,500,000,000
Line of Credit Facility, Remaining Borrowing Capacity	4,236,000,000	4,236,000,000
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	750,000,000	750,000,000
Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	3,150,000,000	3,150,000,000
Line of Credit Facility, Remaining Borrowing Capacity	1,699,000,000	1,699,000,000
Parent Company [Member] | June 2017 Three Year Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	1,000,000,000	1,000,000,000
Long-term Line of Credit	270,000,000	$ 270,000,000
Debt Instrument, Term		3 years
Piedmont Natural Gas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	500,000,000	$ 500,000,000	$ 850,000,000
Line of Credit Facility, Remaining Borrowing Capacity	363,000,000	363,000,000
Piedmont Natural Gas [Member] | June 2017 Piedmont Term Loan Facility [Member]
Debt Instrument [Line Items]
Facility size	250,000,000	250,000,000
Long-term Line of Credit	125,000,000	125,000,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 125,000,000	$ 125,000,000
Line Of Credit Facility, Remaining Available Borrowings | Integer	1	1
Line Of Credit Facility, Remaining Available Borrowing Period		90 days
Debt Instrument, Term		18 months
Line Of Credit Facility, Expected Borrowings	$ 125,000,000	$ 125,000,000
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	1,350,000,000	1,350,000,000
Line of Credit Facility, Remaining Borrowing Capacity	364,000,000	364,000,000
Duke Energy Carolinas [Member] | USDOJ [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required	250,000,000	250,000,000
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size	1,250,000,000	1,250,000,000
Line of Credit Facility, Remaining Borrowing Capacity	337,000,000	337,000,000
Duke Energy Progress [Member] | USDOJ [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required	250,000,000	250,000,000
April 2017 Debt Issuance, 3.364% Coupon [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 420,000,000	$ 420,000,000
Interest rate	3.364%	3.364%
April 2017 Debt Issuance, 3.364% Coupon [Member] | Parent Company [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 420,000,000	$ 420,000,000
Interest rate	3.364%	3.364%
April 2017 Maturity [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 400,000,000
April 2017 Maturity [Member] | Parent Company [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 400,000,000

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Debt issuances	$ 2,337
Current maturities of long-term debt	3,472	$ 2,319
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	750
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	704	116
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	203	452
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances	900
Current maturities of long-term debt	819	326
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances	100
Current maturities of long-term debt	1	1
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	3	$ 3
Unsecured Debt [Member] | April 2017 Debt Issuance, 3.364% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 420
Interest rate	3.364%
Unsecured Debt [Member] | June 2017 Debt Issuance, 2.100% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 330
Interest rate	2.10%
Unsecured Debt [Member] | April 2017 Maturity [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 400
Unsecured Debt [Member] | Parent Company [Member] | April 2017 Debt Issuance, 3.364% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 420
Interest rate	3.364%
Unsecured Debt [Member] | Parent Company [Member] | June 2017 Debt Issuance, 2.100% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 330
Interest rate	2.10%
Unsecured Debt [Member] | Parent Company [Member] | April 2017 Maturity [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 400
Secured Debt [Member] | February 2017 Debt Issuance, 4.120% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 587
Interest rate	4.12%
First Mortgage [Member] | January 2017 Debt Issuance, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	1.85%
First Mortgage [Member] | January 2017 Debt Issuance, 3.200% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 650
Interest rate	3.20%
First Mortgage [Member] | March 2017 Debt Issuance, 3.700% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 100
Interest rate	3.70%
First Mortgage [Member] | Duke Energy Florida [Member] | January 2017 Debt Issuance, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	1.85%
First Mortgage [Member] | Duke Energy Florida [Member] | January 2017 Debt Issuance, 3.200% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 650
Interest rate	3.20%
First Mortgage [Member] | Duke Energy Florida [Member] | First Mortgage Bonds Maturing September 2017, 5.800% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.80%
Current maturities of long-term debt	$ 250
First Mortgage [Member] | Duke Energy Ohio [Member] | March 2017 Debt Issuance, 3.700% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 100
Interest rate	3.70%

Debt and Credit Facilities (S62

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 3,472	$ 2,319
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 337
Parent Company [Member] | Unsecured Debt [Member] | Unsecured Debt Maturing August 2017, 1.625% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	1.625%
Current maturities of long-term debt	$ 700
Parent Company [Member] | Unsecured Debt [Member] | Unsecured Debt Maturing June 2018, 6.250% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	6.25%
Current maturities of long-term debt	$ 250
Parent Company [Member] | Unsecured Debt [Member] | Unsecured Debt Maturing June 2018, 2.100% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	2.10%
Current maturities of long-term debt	$ 500
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 704	116
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | First Mortgage Bonds Maturing January 2018, 5.250% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.25%
Current maturities of long-term debt	$ 400
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | First Mortgage Bonds Maturing April 2018, 5.100% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.10%
Current maturities of long-term debt	$ 300
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 203	452
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | First Mortgage Bonds Maturing November 2017, 1.252% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	1.372%
Current maturities of long-term debt	$ 200
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 819	326
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | First Mortgage Bonds Maturing September 2017, 5.800% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.80%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | First Mortgage Bonds Maturing June 2018, 5.650% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.65%
Current maturities of long-term debt	$ 500
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	1	1
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	3	3
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 35	$ 35
Piedmont Natural Gas [Member] | Unsecured Debt [Member] | Unsecured Debt Maturing September 2017, 8.510% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	8.51%
Current maturities of long-term debt	$ 35

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member] - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Facility size	$ 8,000,000,000	$ 7,500,000,000
Commercial paper	(3,115,000,000)
Outstanding letters of credit	(68,000,000)
Tax exempt bonds	(81,000,000)
Coal ash set-aside	(500,000,000)
Available capacity	4,236,000,000
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	3,150,000,000
Commercial paper	(1,392,000,000)
Outstanding letters of credit	(59,000,000)
Available capacity	1,699,000,000
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,350,000,000
Commercial paper	(732,000,000)
Outstanding letters of credit	(4,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	364,000,000
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,250,000,000
Commercial paper	(661,000,000)
Outstanding letters of credit	(2,000,000)
Coal ash set-aside	(250,000,000)
Available capacity	337,000,000
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	700,000,000
Outstanding letters of credit	(1,000,000)
Available capacity	699,000,000
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	450,000,000
Commercial paper	(45,000,000)
Available capacity	405,000,000
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600,000,000
Commercial paper	(150,000,000)
Tax exempt bonds	(81,000,000)
Available capacity	369,000,000
Piedmont Natural Gas [Member]
Line of Credit Facility [Line Items]
Facility size	500,000,000	$ 850,000,000
Commercial paper	(135,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	363,000,000
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member]
Line of Credit Facility [Line Items]
Commercial paper	$ (625,000,000)

Goodwill and Intangible Asset64

Goodwill and Intangible Assets (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill	$ 19,425,000,000	$ 19,425,000,000
Electric Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill	17,379,000,000	17,379,000,000
Gas Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill	1,924,000,000	1,924,000,000
Commercial Renewables [Member]
Goodwill [Roll Forward]
Goodwill	122,000,000	122,000,000
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	920,000,000	920,000,000
Accumulated impairment charges	216,000,000	216,000,000
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill	596,000,000	596,000,000
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Goodwill [Roll Forward]
Goodwill	324,000,000	324,000,000
Progress Energy [Member]
Goodwill [Roll Forward]
Goodwill	3,655,000,000	3,655,000,000
Accumulated impairment charges	0	0
Piedmont Natural Gas [Member]
Goodwill [Roll Forward]
Goodwill	49,000,000	49,000,000
Accumulated impairment charges	$ 0	$ 0

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 178	$ 199	$ 377	$ 416
Duke Energy Carolinas [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	5	12	11
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member] | Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	17	2	33	11
Related party transaction, expenses from transactions with related party	21	50	52	91
Duke Energy Carolinas [Member] | Intercompany Natural Gas Transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1		2
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	173	160	342	334
Progress Energy [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	9	19	17
Progress Energy [Member] | Joint Dispatch Agreement [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	21	50	52	91
Related party transaction, expenses from transactions with related party	17	2	33	11
Progress Energy [Member] | Intercompany Natural Gas Transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19		38
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	102	89	205	189
Duke Energy Progress [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	3	4	7	7
Duke Energy Progress [Member] | Joint Dispatch Agreement [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	21	50	52	91
Related party transaction, expenses from transactions with related party	17	2	33	11
Duke Energy Progress [Member] | Intercompany Natural Gas Transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19		38
Duke Energy Florida [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	71	71	137	145
Duke Energy Florida [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	5	12	10
Duke Energy Ohio [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	84	87	174	172
Duke Energy Ohio [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	1	2	2
Duke Energy Indiana [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	87	89	177	183
Duke Energy Indiana [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	2	2	4	4
Piedmont Natural Gas [Member] | Corporate Governance And Shared Service Expenses [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	8		14
Piedmont Natural Gas [Member] | Indemnification Coverages [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party			1
Piedmont Natural Gas [Member] | Intercompany Natural Gas Transactions [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	$ 20		$ 40
Piedmont Natural Gas [Member] | Intercompany Natural Gas Transactions [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party		1		2
Piedmont Natural Gas [Member] | Intercompany Natural Gas Transactions [Member] | Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party		$ 19		$ 38

Related Party Transactions (Equ

Related Party Transactions (Equity Method Investments) (Details) - Piedmont Natural Gas [Member] - Equity Method Investee [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 7	$ 7	$ 13	$ 14
Accounts Payable, Related Parties, Current	2		2		$ 2
Cardinal Pipeline Company, LLC [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	2	2	4	4
Pine Needle LNG Company, LLC [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	2	2	4	5
Hardy Storage Company, LLC [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 3	$ 3	$ 5	$ 5

Related Party Transactions (Int

Related Party Transactions (Intercompany Income Taxes) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	$ 85	$ 163
Intercompany income tax payable	127	247
Progress Energy [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	3	106
Intercompany income tax payable	208	348
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	5	5
Intercompany income tax payable	169	227
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	1	5
Intercompany income tax payable	42	125
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	74	129
Intercompany income tax payable	47	63
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	87	114
Intercompany income tax payable	50	74
Piedmont Natural Gas [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	8	7
Intercompany income tax payable	50	8
Income Taxes [Member] | Affiliated Entity [Member] | Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable		1
Intercompany income tax payable	20
Income Taxes [Member] | Affiliated Entity [Member] | Progress Energy [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	102
Intercompany income tax payable		37
Income Taxes [Member] | Affiliated Entity [Member] | Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	35
Intercompany income tax payable		90
Income Taxes [Member] | Affiliated Entity [Member] | Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable		37
Intercompany income tax payable	3
Income Taxes [Member] | Affiliated Entity [Member] | Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	19
Intercompany income tax payable		1
Income Taxes [Member] | Affiliated Entity [Member] | Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	25
Intercompany income tax payable		3
Income Taxes [Member] | Affiliated Entity [Member] | Piedmont Natural Gas [Member]
Related Party Transaction [Line Items]
Intercompany income tax receivable	$ 56
Intercompany income tax payable		$ 38

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)GWhMcf	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)GWhMcf	Aug. 03, 2017USD ($)
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh		178		147
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		791		890
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 1,630		$ 1,677
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		703		750
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		927		927
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional amount		$ 703		$ 750
Piedmont Natural Gas [Member]
Derivative [Line Items]
Notional amount	$ 1,400		$ 1,400
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ 75		$ 168
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		92		91
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 400		$ 400
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 400		$ 400
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		202		269
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 500		$ 500
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 500		$ 500
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		106		118
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 250		$ 250
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 250		$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		96		151
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 250		$ 250
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		250		250
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		27		27
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount		$ 27		$ 27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh		178		147
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		2		1
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Mcf		495		529
Subsequent Event [Member] | Designated as Hedging Instrument [Member] | Treasury Lock [Member]
Derivative [Line Items]
Notional amount					$ 200

Derivatives and Hedging (Locati

Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 95	$ 162
Location and fair value amounts of derivatives (Liability)	227	252
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	78	111
Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	51
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	69	52
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	158	200
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	79	140
Location and fair value amounts of derivatives (Liability)	180	209
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	22
Location and fair value amounts of derivatives (Liability)	47	43
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14	19
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	8
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	8
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	76	108
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	32
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	40	43
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	140	166
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	23	1
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	26
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	33
Location and fair value amounts of derivatives (Liability)	26	16
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	23
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	10
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	23
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	16
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	33
Location and fair value amounts of derivatives (Liability)	4	1
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	15
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	23
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	10
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	1
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		15
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	15	85
Location and fair value amounts of derivatives (Liability)	35	25
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	64
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	21
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	21	12
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	14	13
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	82
Location and fair value amounts of derivatives (Liability)	31	19
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Location and fair value amounts of derivatives (Liability)	4	6
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	61
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	21
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	21	12
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10	7
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	6
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	46
Location and fair value amounts of derivatives (Liability)	8	7
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	36
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	10
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	7
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	45
Location and fair value amounts of derivatives (Liability)	5	1
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Location and fair value amounts of derivatives (Liability)	3	6
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	35
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	10
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	1
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	6
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	39
Location and fair value amounts of derivatives (Liability)	20	12
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	28
Duke Energy Florida [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	11
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	12
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	37
Location and fair value amounts of derivatives (Liability)	20	12
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	26
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	11
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	12
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	5
Location and fair value amounts of derivatives (Liability)	5	6
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	4
Duke Energy Ohio [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	5
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	5
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	6
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	5
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	54	16
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	54	16
Duke Energy Indiana [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	54	16
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	54	16
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Piedmont Natural Gas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Location and fair value amounts of derivatives (Liability)	145	187
Piedmont Natural Gas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Piedmont Natural Gas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	35
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	127	152
Piedmont Natural Gas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Location and fair value amounts of derivatives (Liability)	145	187
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	3
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	35
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 127	$ 152

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 95	$ 162
Net amounts recognized on the Condensed Consolidated Balance Sheet	95	162
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	78	111
Gross amounts offset	(3)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	75	100
Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	17	51
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	49
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	33
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	23
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	10
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	9
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	85
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	85
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	64
Gross amounts offset	(4)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	53
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	21
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	20
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	46
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	46
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	36
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	36
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	10
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	9
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6	39
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	39
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	28
Gross amounts offset	(3)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	17
Duke Energy Florida [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	11
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet		11
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	5
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	4
Duke Energy Ohio [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		1
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	54	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	16
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	54	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	16
Piedmont Natural Gas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	3
Piedmont Natural Gas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 2	$ 3

Derivatives and Hedging (Sche71

Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 227	$ 252
Net amounts recognized on the Condensed Consolidated Balance Sheet	227	252
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	69	52
Gross amounts offset	(4)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	65	41
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	158	200
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	156	198
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	26	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	26	16
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	23
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	22
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	3	16
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	15
Progress Energy [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	35	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	35	25
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	21	12
Gross amounts offset	(4)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	1
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	14	13
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	13	12
Duke Energy Progress [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	7
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	2
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	7
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	6
Duke Energy Florida [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	20	12
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	12
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	12
Gross amounts offset	(3)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	1
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1
Gross amounts offset	(1)
Duke Energy Ohio [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	6
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	4	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	5
Duke Energy Indiana [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Piedmont Natural Gas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	145	187
Net amounts recognized on the Condensed Consolidated Balance Sheet	145	187
Piedmont Natural Gas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	35
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	35
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	127	152
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 127	$ 152

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	$ 51	$ 34
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	51	34
Duke Energy Carolinas [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	25	16
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	25	16
Progress Energy [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	26	18
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	26	18
Duke Energy Progress [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	7	6
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	7	6
Duke Energy Florida [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	19	12
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 19	$ 12

Investments in Debt and Equit73

Investments in Debt and Equity Securities (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 2	$ 5
Piedmont Natural Gas [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 2	$ 5

Investments in Debt and Equit74

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 2,455	$ 2,156
Gross Unrealized Holding Losses	42	88
Estimated Fair Value	6,947	6,554
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2,404	2,115
Gross Unrealized Holding Losses	41	83
Estimated Fair Value	6,592	6,184
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	116	111
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2,373	2,092
Gross Unrealized Holding Losses	29	54
Estimated Fair Value	4,422	4,106
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	15	10
Gross Unrealized Holding Losses	2	8
Estimated Fair Value	611	528
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Gross Unrealized Holding Losses	3	10
Estimated Fair Value	340	331
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12	10
Gross Unrealized Holding Losses	6	8
Estimated Fair Value	961	984
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	3
Estimated Fair Value	142	124
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	51	41
Gross Unrealized Holding Losses	1	5
Estimated Fair Value	355	370
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	15	25
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	47	38
Estimated Fair Value	110	104
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses		1
Estimated Fair Value	63	66
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	82	82
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses		1
Estimated Fair Value	49	51
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses		2
Estimated Fair Value	36	42
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,312	1,165
Gross Unrealized Holding Losses	21	45
Estimated Fair Value	3,490	3,261
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,312	1,165
Gross Unrealized Holding Losses	21	44
Estimated Fair Value	3,490	3,258
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	33	18
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,299	1,157
Gross Unrealized Holding Losses	14	28
Estimated Fair Value	2,441	2,245
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	9	5
Gross Unrealized Holding Losses	2	6
Estimated Fair Value	407	354
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	60	67
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	3	5
Estimated Fair Value	417	458
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	3
Estimated Fair Value	132	116
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses		1
Estimated Fair Value		3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,095	952
Gross Unrealized Holding Losses	20	39
Estimated Fair Value	3,161	2,991
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,092	950
Gross Unrealized Holding Losses	20	39
Estimated Fair Value	3,102	2,926
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	83	93
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,074	935
Gross Unrealized Holding Losses	15	26
Estimated Fair Value	1,981	1,861
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6	5
Gross Unrealized Holding Losses		2
Estimated Fair Value	204	174
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	2	8
Estimated Fair Value	280	264
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	9	8
Gross Unrealized Holding Losses	3	3
Estimated Fair Value	544	526
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	10	8
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Estimated Fair Value	59	65
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	12	21
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Estimated Fair Value	47	44
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	830	715
Gross Unrealized Holding Losses	16	32
Estimated Fair Value	2,380	2,214
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	830	715
Gross Unrealized Holding Losses	16	32
Estimated Fair Value	2,379	2,213
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	31	45
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	816	704
Gross Unrealized Holding Losses	12	21
Estimated Fair Value	1,607	1,505
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	4
Gross Unrealized Holding Losses		1
Estimated Fair Value	142	120
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	2	8
Estimated Fair Value	279	263
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6	5
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	314	275
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	6	5
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	265	237
Gross Unrealized Holding Losses	4	7
Estimated Fair Value	771	761
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	262	235
Gross Unrealized Holding Losses	4	7
Estimated Fair Value	723	713
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	52	48
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	258	231
Gross Unrealized Holding Losses	3	5
Estimated Fair Value	374	356
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses		1
Estimated Fair Value	62	54
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	230	251
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	4	3
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Estimated Fair Value	48	48
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	4
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	2
Estimated Fair Value	47	44
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	40	33
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	118	110
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	40	33
Estimated Fair Value	87	79
Duke Energy Indiana [Member] | Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3	2
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	27	28
Duke Energy Indiana [Member] | Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 1	$ 1

Investments in Debt and Equit75

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Jun. 30, 2017USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 86
Due after one through five years	631
Due after five through 10 years	503
Due after 10 years	1,064
Total	2,284
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	4
Due after one through five years	224
Due after five through 10 years	245
Due after 10 years	543
Total	1,016
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	72
Due after one through five years	347
Due after five through 10 years	196
Due after 10 years	470
Total	1,085
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	18
Due after one through five years	220
Due after five through 10 years	144
Due after 10 years	359
Total	741
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	54
Due after one through five years	127
Due after five through 10 years	52
Due after 10 years	111
Total	344
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	3
Due after one through five years	14
Due after five through 10 years	8
Due after 10 years	6
Total	$ 31

Investments in Debt and Equit76

Investments in Debt and Equity Securities (Realized Gains and Losses)(Details) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$ 40	$ 64	$ 133	$ 118
Realized losses	37	42	99	92
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	24	33	90	67
Realized losses	23	19	63	56
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	15	31	42	50
Realized losses	14	23	35	36
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	11	27	35	42
Realized losses	11	20	30	31
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	4	4	7	8
Realized losses	$ 3	$ 3	$ 5	$ 5

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investment, Fair Value Disclosure	$ 77	$ 77
Derivative assets	95	162
Total assets	7,044	6,716
Derivative liabilities	(227)	(252)
Net assets (liabilities)	6,817	6,464
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	5
Total assets	5,117	4,845
Derivative liabilities	(1)	(2)
Net assets (liabilities)	5,116	4,843
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	37	136
Total assets	1,796	1,768
Derivative liabilities	(81)	(63)
Net assets (liabilities)	1,715	1,705
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	54	21
Total assets	54	26
Derivative liabilities	(145)	(187)
Net assets (liabilities)	(91)	(161)
Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investment, Fair Value Disclosure	77	77
Investments	4,422	4,106
Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	4,345	4,029
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	112	104
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	112	104
Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,170	2,078
Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	593	632
Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,577	1,446
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	245	266
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	63	75
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	182	186
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investment, Fair Value Disclosure	77	77
Derivative assets	8	33
Total assets	3,498	3,294
Derivative liabilities	(26)	(16)
Net assets (liabilities)	3,472	3,278
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,505	2,346
Derivative liabilities	0
Net assets (liabilities)	2,505	2,346
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	33
Total assets	916	868
Derivative liabilities	(26)	(16)
Net assets (liabilities)	890	852
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets		3
Net assets (liabilities)		3
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investment, Fair Value Disclosure	77	77
Investments	2,441	2,245
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,364	2,168
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,049	1,013
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	141	178
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	908	835
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		3
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		3
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15	85
Total assets	3,176	3,076
Derivative liabilities	(35)	(25)
Net assets (liabilities)	3,141	3,051
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,445	2,336
Derivative liabilities	0
Net assets (liabilities)	2,445	2,336
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15	85
Total assets	731	740
Derivative liabilities	(35)	(25)
Net assets (liabilities)	696	715
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,981	1,861
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,981	1,861
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,121	1,065
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	452	454
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	669	611
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	59	65
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	12	21
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	47	44
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	46
Total assets	2,388	2,260
Derivative liabilities	(8)	(7)
Net assets (liabilities)	2,380	2,253
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	1,834	1,713
Derivative liabilities	0
Net assets (liabilities)	1,834	1,713
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	46
Total assets	554	547
Derivative liabilities	(8)	(7)
Net assets (liabilities)	546	540
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,607	1,505
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,607	1,505
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	772	708
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	226	207
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	546	501
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	6	39
Total assets	777	800
Derivative liabilities	(20)	(12)
Net assets (liabilities)	757	788
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	601	607
Net assets (liabilities)	601	607
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	6	39
Total assets	176	193
Derivative liabilities	(20)	(12)
Net assets (liabilities)	156	181
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	374	356
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	374	356
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	349	357
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	226	247
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	123	110
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	48	48
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	4
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	47	44
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	5
Derivative liabilities	(5)	(6)
Net assets (liabilities)	(2)	(1)
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(5)	(6)
Net assets (liabilities)	(5)	(6)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	5
Net assets (liabilities)	3	5
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	54	16
Total assets	172	126
Derivative liabilities		(2)
Net assets (liabilities)	172	124
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3
Total assets	90	79
Derivative liabilities	0	(2)
Net assets (liabilities)	90	77
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	31	31
Net assets (liabilities)	31	31
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	51	16
Total assets	51	16
Net assets (liabilities)	51	16
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	87	79
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	87	79
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	31	31
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	31	31
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	3
Total assets	4	8
Derivative liabilities	(145)	(187)
Net assets (liabilities)	(141)	(179)
Piedmont Natural Gas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	3
Total assets	4	8
Net assets (liabilities)	4	8
Piedmont Natural Gas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(145)	(187)
Net assets (liabilities)	(145)	(187)
Piedmont Natural Gas [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2	4
Piedmont Natural Gas [Member] | Equity Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 2	4
Piedmont Natural Gas [Member] | Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		1
Piedmont Natural Gas [Member] | Debt Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		$ 1

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Transfers Between Activity Levels	$ 0	$ 0	$ 0	$ 0
Derivatives (net)
Beginning balance	(135,000,000)	2,000,000	(166,000,000)	10,000,000
Purchases	55,000,000	34,000,000	55,000,000	34,000,000
Settlements	(9,000,000)	(6,000,000)	(18,000,000)	(13,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(2,000,000)	4,000,000	38,000,000	3,000,000
Ending balance	(91,000,000)	34,000,000	(91,000,000)	34,000,000
Investments and Derivatives, Net
Beginning balance	(130,000,000)	6,000,000	(161,000,000)	15,000,000
Total pretax realized or unrealized gains included in comprehensive income	1,000,000		1,000,000
Purchases	55,000,000	34,000,000	55,000,000	34,000,000
Sales	(6,000,000)		(6,000,000)	(1,000,000)
Settlements	(9,000,000)	(6,000,000)	(18,000,000)	(13,000,000)
Total amount included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(2,000,000)	4,000,000	38,000,000	3,000,000
Ending balance	(91,000,000)	38,000,000	(91,000,000)	38,000,000
Investments [Member]
Investments
Beginning balance	5,000,000	4,000,000	5,000,000	5,000,000
Total pretax realized or unrealized gains included in comprehensive income	1,000,000		1,000,000
Sales	(6,000,000)		(6,000,000)	(1,000,000)
Ending balance		4,000,000		4,000,000
Duke Energy Carolinas [Member] | Investments [Member]
Investments
Beginning balance	3,000,000	3,000,000	3,000,000	3,000,000
Total pretax realized or unrealized gains included in comprehensive income	1,000,000		1,000,000
Sales	(4,000,000)		(4,000,000)
Ending balance		3,000,000		3,000,000
Duke Energy Ohio [Member]
Derivatives (net)
Beginning balance	1,000,000		5,000,000	3,000,000
Purchases	3,000,000	5,000,000	3,000,000	5,000,000
Settlements	(1,000,000)		(2,000,000)	(2,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet			(3,000,000)	(1,000,000)
Ending balance	3,000,000	5,000,000	3,000,000	5,000,000
Duke Energy Indiana [Member]
Derivatives (net)
Beginning balance	9,000,000	2,000,000	16,000,000	7,000,000
Purchases	52,000,000	29,000,000	52,000,000	29,000,000
Settlements	(9,000,000)	(6,000,000)	(16,000,000)	(11,000,000)
Total (losses) gains included on the Condensed Consolidated Balance Sheet	(1,000,000)	4,000,000	(1,000,000)	4,000,000
Ending balance	51,000,000	29,000,000	51,000,000	29,000,000
Piedmont Natural Gas [Member]
Derivatives (net)
Beginning balance	(145,000,000)	(126,000,000)	(187,000,000)	(149,000,000)
Total gains and settlements		(64,000,000)	42,000,000	(41,000,000)
Ending balance	$ (145,000,000)	$ (190,000,000)	$ (145,000,000)	$ (190,000,000)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure - Assets) (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)$ / MWh	Dec. 31, 2016USD ($)$ / MWh	Mar. 31, 2017USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net derivative asset (liability)	$ (91)	$ (166)	$ (135)	$ 34	$ 2	$ 10
Duke Energy Ohio [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net derivative asset (liability)	3	5	1	5		3
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net derivative asset (liability)	$ 3	$ 5
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Minimum [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MWh	(5.24)	0.77
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Maximum [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MWh	1.82	3.52
Duke Energy Indiana [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net derivative asset (liability)	$ 51	$ 16	$ 9	$ 29	$ 2	$ 7
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net derivative asset (liability)	$ 51	$ 16
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MWh	(1.65)	(0.83)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MWh	6.66	9.32

Fair Value Measurements (Quan80

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure - Liabilities) (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)$ / MMBTU	Dec. 31, 2016USD ($)$ / MMBTU	Mar. 31, 2017USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Net derivative asset (liability)	$ (91)	$ (166)	$ (135)	$ 34	$ 2	$ 10
Duke Energy Indiana [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Net derivative asset (liability)	51	16	9	29	2	7
Duke Energy Ohio [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Net derivative asset (liability)	3	5	1	5		3
Piedmont Natural Gas [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Net derivative asset (liability)	(145)	(187)	$ (145)	$ (190)	$ (126)	$ (149)
Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member] | Piedmont Natural Gas [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Net derivative asset (liability)	$ (145)	$ (187)
Derivative Financial Instruments, Liabilities [Member] | Minimum [Member] | Discounted Cash Flow [Member] | Piedmont Natural Gas [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MMBTU	2.21	2.31
Derivative Financial Instruments, Liabilities [Member] | Maximum [Member] | Discounted Cash Flow [Member] | Piedmont Natural Gas [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Input Price Per Unit | $ / MMBTU	3.78	4.18

Fair Value Measurements (Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 49,515	$ 47,895
Long-term debt, fair value	51,947	49,161
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	9,524	9,603
Long-term debt, fair value	10,657	10,494
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	18,145	17,541
Long-term debt, fair value	20,101	19,107
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	6,760	7,011
Long-term debt, fair value	7,266	7,357
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	6,979	6,125
Long-term debt, fair value	7,753	6,728
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	1,977	1,884
Long-term debt, fair value	2,155	2,020
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	3,784	3,786
Long-term debt, fair value	4,379	4,260
Piedmont Natural Gas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	1,946	1,821
Long-term debt, fair value	$ 2,107	$ 1,933

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 2,337,000,000
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity, Financial or Other Support, Amount	$ 0	$ 0
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Percent of proceeds received as cash	75.00%
Percent of proceeds received as subordinated note	25.00%
Minimum equity balance required by Cinergy Receivables	$ 3,000,000
Duke American Transmission Company [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest	50.00%
Pioneer Transmission [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest	50.00%
OVEC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest	9.00%
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 900,000,000
Duke Energy Florida [Member] | DEFPF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	1,294,000,000
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 100,000,000
Duke Energy Ohio [Member] | Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Duke Energy Indiana [Member] | Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%

Variable Interest Entities (Sch

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Long-Term Debt	$ 46,043	$ 45,576
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,520	9,187
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	6,407	6,409
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 6,160	5,799
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of Credit Facility, Expiration Date	Dec. 1, 2018
Facility size	$ 325
Long-Term Debt	$ 325	325
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of Credit Facility, Expiration Date	Dec. 1, 2018
Facility size	$ 425
Long-Term Debt	$ 425	425
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of Credit Facility, Expiration Date	Feb. 1, 2019
Facility size	$ 300
Long-Term Debt	$ 297	300
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of Credit Facility, Expiration Date	Apr. 1, 2019
Facility size	$ 225
Long-Term Debt	$ 225	$ 225

Variable Interest Entities (S84

Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	$ 1,192	$ 1,023
Other, current assets	436	458
Regulatory assets, noncurrent	12,808	12,878
Property, plant and equipment, cost	124,439	121,397
Accumulated depreciation and amortization	(40,522)	(39,406)
Current Liabilities: Other	1,708	2,044
Current maturities of long-term debt	3,472	2,319
Long-Term Debt	46,043	45,576
Deferred income taxes	14,695	14,155
Noncurrent Liabilities: Other	1,651	1,753
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	249	238
Other, current assets	34	37
Regulatory assets, noncurrent	3,060	3,159
Property, plant and equipment, cost	41,881	41,127
Accumulated depreciation and amortization	(14,632)	(14,365)
Current Liabilities: Other	409	468
Current maturities of long-term debt	704	116
Long-Term Debt	8,520	9,187
Deferred income taxes	6,742	6,544
Noncurrent Liabilities: Other	574	607
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	212	188
Other, current assets	76	57
Regulatory assets, noncurrent	3,379	3,243
Property, plant and equipment, cost	28,936	28,419
Accumulated depreciation and amortization	(10,734)	(10,561)
Current Liabilities: Other	308	365
Current maturities of long-term debt	203	452
Long-Term Debt	6,407	6,409
Deferred income taxes	3,539	3,323
Noncurrent Liabilities: Other	47	51
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	321	213
Other, current assets	50	125
Regulatory assets, noncurrent	2,474	2,480
Property, plant and equipment, cost	17,369	16,434
Accumulated depreciation and amortization	(4,910)	(4,644)
Current Liabilities: Other	322	352
Current maturities of long-term debt	819	326
Long-Term Debt	6,160	5,799
Deferred income taxes	2,893	2,694
Noncurrent Liabilities: Other	103	105
DEFPF [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	5	6
Regulatory assets, current	52	50
Other, current assets	33	53
Regulatory assets, noncurrent	1,121	1,142
Current Liabilities: Other	10	17
Current maturities of long-term debt	55	62
Long-Term Debt	1,189	1,217
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	425	425
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	297	300
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	225	225
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	325	325
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Other, current assets	293	223
Property, plant and equipment, cost	3,695	3,419
Accumulated depreciation and amortization	(518)	(453)
Current maturities of long-term debt	157	198
Long-Term Debt	1,557	1,097
Deferred income taxes	300	275
Noncurrent Liabilities: Other	$ 249	$ 252

Variable Interest Entities (S85

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Other noncurrent assets	$ 2,826	$ 2,769
Taxes accrued	432	384
Current Liabilities: Other	1,708	2,044
Deferred income taxes	14,695	14,155
Noncurrent Liabilities: Other	1,651	1,753
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1,068	751
Other noncurrent assets	12	12
Total assets	1,080	763
Current Liabilities: Other	10	3
Noncurrent Liabilities: Other	13	13
Total liabilities	23	16
Net assets	1,057	747
Pipeline Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	800	487
Other noncurrent assets	12	12
Total assets	812	499
Current Liabilities: Other	10
Total liabilities	10
Net assets	802	499
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	176	174
Total assets	176	174
Net assets	176	174
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	92	90
Total assets	92	90
Current Liabilities: Other		3
Noncurrent Liabilities: Other	13	13
Total liabilities	13	16
Net assets	79	74
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	74	129
Other noncurrent assets	23	23
Taxes accrued	100	178
Current Liabilities: Other	77	91
Deferred income taxes	1,506	1,443
Noncurrent Liabilities: Other	157	166
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	44	82
Total assets	44	82
Net assets	44	82
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	87	114
Other noncurrent assets	159	147
Taxes accrued	28	31
Current Liabilities: Other	122	93
Deferred income taxes	2,011	1,900
Noncurrent Liabilities: Other	23	27
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	72	101
Total assets	72	101
Net assets	72	101
Piedmont Natural Gas [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	8	7
Other noncurrent assets	12	21
Taxes accrued	21	67
Current Liabilities: Other	67	102
Deferred income taxes	1,019	931
Noncurrent Liabilities: Other	$ 164	189
Piedmont Natural Gas [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates		139
Total assets		139
Noncurrent Liabilities: Other		4
Total liabilities		4
Net assets		$ 135

Variable Interest Entities (Pip

Variable Interest Entities (Pipeline Investments) (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Millions	Dec. 31, 2016	Jun. 30, 2017
Variable Interest Entities [Line Items]
Investments in Joint Ventures	$ 751	$ 1,068
Atlantic Coast Pipeline [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest		47.00%
Investments in Joint Ventures	265	$ 507
Sabal Trail Transmission Pipeline [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest		7.50%
Investments in Joint Ventures	140	$ 211
Constitution Pipeline [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest		24.00%
Investments in Joint Ventures	82	$ 82
Pipeline Investments [Member]
Variable Interest Entities [Line Items]
Investments in Joint Ventures	487	$ 800
Piedmont Natural Gas [Member]
Variable Interest Entities [Line Items]
Investments in Joint Ventures	$ 139
Piedmont Natural Gas [Member] | Atlantic Coast Pipeline [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest	7.00%
Piedmont Natural Gas [Member] | Constitution Pipeline [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest	24.00%

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions)(Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member]	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.50%	0.50%
Discount rate	1.90%	1.50%
Receivable turnover rate	13.40%	13.30%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.90%	1.50%
Receivable turnover rate	10.70%	10.60%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold)(Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 210	$ 267
Less: Retained interests	44	82
Net receivables sold	166	185
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	299	306
Less: Retained interests	72	101
Net receivables sold	$ 227	$ 205

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows)(Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - Cinergy Receivables [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 421	$ 429	$ 954	$ 961
Loss recognized on sale	3	2	5	5
Cash proceeds from receivables sold	428	427	987	964
Collection fees received	0		0
Return received on retained interests	1		2	1
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	663	623	1,327	1,258
Loss recognized on sale	3	2	6	5
Cash proceeds from receivables sold	658	612	1,351	1,255
Collection fees received	1	1	1	1
Return received on retained interests	$ 1	$ 1	$ 3	$ 2

Common Stock (Earnings Per Shar

Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Common Stock [Line Items]
Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities	$ 687	$ 621	$ 1,402	$ 1,195
Average shares, basic	700	689	700	689
Incremental Common Shares Attributable to Dilutive Effect of Equity Forward Agreements		1
Average shares, diluted	700	690	700	689
EPS, basic (usd per share)	$ 0.98	$ 0.90	$ 2	$ 1.73
EPS, diluted (usd per share)	$ 0.98	$ 0.90	$ 2	$ 1.73
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation	2	2	2	2
Dividends declared per share (usd per share)	$ 0.855	$ 0.825	$ 1.71	$ 1.65

Common Stock (Equity Securities

Common Stock (Equity Securities Offering) (Details) - Piedmont Natural Gas [Member] - shares shares in Millions	Jun. 30, 2016	Mar. 31, 2016
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered		10.6
Settlement Alternatives, Shares	10.6

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	$ 18	$ 15	$ 33	$ 27
Tax benefit associated with stock-based compensation expense	7	5	12	9
Stock-based compensation costs capitalized		1	1	2
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	12	10	20	17
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	$ 6	5	$ 13	10
Piedmont Natural Gas [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost		$ 2		$ 3

Employee Benefit Plans (Plan Co

Employee Benefit Plans (Plan Contributions) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	$ 0	$ 0

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Qualified Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 40	$ 37	$ 80	$ 73
Interest cost on projected benefit obligation	82	83	164	166
Expected return on plan assets	(136)	(129)	(272)	(258)
Amortization of actuarial loss (gain)	36	33	72	66
Amortization of prior service credit	(6)	(4)	(12)	(8)
Other	2	1	4	4
Net periodic costs	18	21	36	43
Qualified Pension Plan [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	12	12	24	24
Interest cost on projected benefit obligation	20	22	40	43
Expected return on plan assets	(36)	(36)	(71)	(71)
Amortization of actuarial loss (gain)	8	8	16	16
Amortization of prior service credit	(2)	(2)	(4)	(4)
Other				1
Net periodic costs	2	4	5	9
Qualified Pension Plan [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	12	10	24	21
Interest cost on projected benefit obligation	25	27	50	53
Expected return on plan assets	(43)	(42)	(86)	(84)
Amortization of actuarial loss (gain)	14	13	28	27
Amortization of prior service credit	(1)	(1)	(2)	(2)
Other	1		2	1
Net periodic costs	8	7	16	16
Qualified Pension Plan [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	6	6	12	12
Interest cost on projected benefit obligation	12	13	24	25
Expected return on plan assets	(21)	(20)	(42)	(41)
Amortization of actuarial loss (gain)	6	5	12	11
Amortization of prior service credit		(1)		(1)
Other	1	1	1	1
Net periodic costs	4	4	7	7
Qualified Pension Plan [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	5	5	10	10
Interest cost on projected benefit obligation	13	14	26	28
Expected return on plan assets	(21)	(21)	(42)	(42)
Amortization of actuarial loss (gain)	7	7	14	14
Net periodic costs	4	5	8	10
Qualified Pension Plan [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	2	2
Interest cost on projected benefit obligation	5	5	10	10
Expected return on plan assets	(7)	(7)	(14)	(14)
Amortization of actuarial loss (gain)	1	1	2	2
Qualified Pension Plan [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	2	4	4
Interest cost on projected benefit obligation	7	7	14	14
Expected return on plan assets	(11)	(11)	(22)	(21)
Amortization of actuarial loss (gain)	3	3	6	6
Net periodic costs	1	1	2	3
Qualified Pension Plan [Member] | Piedmont Natural Gas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	3	2	6	5
Interest cost on projected benefit obligation	3	3	6	5
Expected return on plan assets	(6)	(6)	(12)	(12)
Amortization of actuarial loss (gain)	3	2	6	4
Amortization of prior service credit	(1)	(1)	(2)	(1)
Other	1		1
Net periodic costs	3		5	1
Non-Qualified Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		1		1
Interest cost on projected benefit obligation	3	3	6	7
Amortization of actuarial loss (gain)	2	2	4	4
Net periodic costs	5	6	10	12
Non-Qualified Pension Plan [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	1	1	1	1
Net periodic costs	1	1	1	1
Non-Qualified Pension Plan [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	1	1	2	2
Amortization of actuarial loss (gain)	1		2	1
Net periodic costs	2	1	4	3
Non-Qualified Pension Plan [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation		1	1	1
Net periodic costs		1	1	1
Non-Qualified Pension Plan [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation		1	1	1
Net periodic costs		1	1	1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1	2	2
Interest cost on projected benefit obligation	9	9	18	17
Expected return on plan assets	(4)	(4)	(7)	(7)
Amortization of actuarial loss (gain)	2	2	4	3
Amortization of prior service credit	(29)	(36)	(58)	(71)
Net periodic costs	(21)	(28)	(41)	(56)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	2	2	4	4
Expected return on plan assets	(2)	(2)	(4)	(4)
Amortization of actuarial loss (gain)	(1)	(1)	(2)	(2)
Amortization of prior service credit	(2)	(3)	(4)	(6)
Net periodic costs	(3)	(4)	(6)	(8)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	3	3	7	7
Amortization of actuarial loss (gain)	5	6	10	11
Amortization of prior service credit	(21)	(25)	(42)	(51)
Net periodic costs	(13)	(16)	(25)	(33)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	2	2	4	4
Amortization of actuarial loss (gain)	3	3	6	6
Amortization of prior service credit	(13)	(17)	(27)	(34)
Net periodic costs	(8)	(12)	(17)	(24)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation	2	1	4	3
Amortization of actuarial loss (gain)	2	3	4	5
Amortization of prior service credit	(7)	(9)	(15)	(18)
Net periodic costs	(3)	(5)	(7)	(10)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation		1		1
Amortization of actuarial loss (gain)	(1)	(1)	(1)	(1)
Net periodic costs	$ (1)		$ (1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation		1		2
Expected return on plan assets		$ (1)		(1)
Amortization of actuarial loss (gain)				(1)
Other Post-Retirement Benefit Plans [Member] | Piedmont Natural Gas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligation				1
Expected return on plan assets				$ (1)

Employee Benefit Plans (Employe

Employee Benefit Plans (Employee Savings Plans) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Employee Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		$ 39	$ 39	$ 104	$ 91
Employee Savings Plan [Member] | Duke Energy Carolinas [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		13	13	35	31
Employee Savings Plan [Member] | Progress Energy [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		12	12	30	27
Employee Savings Plan [Member] | Duke Energy Progress [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		8	8	21	19
Employee Savings Plan [Member] | Duke Energy Florida [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		4	4	9	8
Employee Savings Plan [Member] | Duke Energy Ohio [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		1	1	2	2
Employee Savings Plan [Member] | Duke Energy Indiana [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		2	2	5	4
Employee Savings Plan [Member] | Piedmont Natural Gas [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions		$ 1	$ 1	$ 3	$ 3
Pension Plan [Member] | Piedmont Natural Gas [Member]
Defined Contribution Plan Disclosure [Line Items]
Payment for Pension Benefits	$ 2

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	32.10%	28.80%	32.30%	29.60%
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	34.70%	35.10%	35.00%	34.60%
Progress Energy [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	33.40%	36.00%	33.70%	36.30%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	31.90%	35.50%	33.00%	35.40%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	36.80%	37.60%	36.70%	37.70%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	34.80%	34.30%	35.10%	29.20%
Duke Energy Indiana [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	39.40%	36.10%	39.40%	33.10%
Piedmont Natural Gas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	38.50%	40.00%	37.90%	38.00%

Income Taxes Income Taxes (Taxe

Income Taxes Income Taxes (Taxes on Foreign Earnings) (Details) - Discontinued Operations, Disposed of by Sale [Member] - International Energy [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit	$ (13)	$ (52)
Previously Remitted Earnings [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit		$ (95)