Duke Energy (DUK) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2016shares
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	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	688,941,372
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

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating Revenues
Regulated electric	$ 6,303	$ 6,017	$ 16,321	$ 16,564
Nonregulated electric and other	429	377	1,251	1,157
Regulated natural gas	89	89	355	416
Total operating revenues	6,821	6,483	17,927	18,137
Operating Expenses
Fuel used in electric generation and purchased power – regulated	2,016	2,113	5,102	5,775
Fuel used in electric generation and purchased power – nonregulated	75	61	215	283
Cost of natural gas	17	21	98	158
Operation, maintenance and other	1,547	1,426	4,467	4,274
Depreciation and amortization	837	774	2,464	2,341
Property and other taxes	303	293	893	836
Impairment charges	10	111	208	111
Total operating expenses	4,805	4,799	13,447	13,778
Gains (Losses) on Sales of Other Assets and Other, net	6	4	20	31
Operating Income	2,022	1,688	4,500	4,390
Other Income and Expenses
Equity in earnings (losses) of unconsolidated affiliates	(60)	17	(37)	53
Other income and expenses, net	99	57	270	203
Total other income and expenses	39	74	233	256
Interest Expense	482	402	1,493	1,208
Income From Continuing Operations Before Income Taxes	1,579	1,360	3,240	3,438
Income Tax Expense from Continuing Operations	520	420	972	1,118
Income from Continuing Operations	1,059	940	2,268	2,320
Income (Loss) From Discontinued Operations, net of tax	122	(5)	124	29
Net income	1,181	935	2,392	2,349
Less: Net Income Attributable to Noncontrolling Interests	5	3	13	10
Net Income (Loss) Attributable to Parent	1,176	932	2,379	2,339
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments		(3)	2	(1)
Reclassification into earnings from cash flow hedges	1	1	3	6
Unrealized (losses) gains on available-for-sale securities		(2)	7	(5)
Other Comprehensive Income, net of tax	(5)	(135)	88	(245)
Comprehensive Income	1,176	800	2,480	2,104
Less: Comprehensive Income Attributable to Noncontrolling Interests	4	(2)	16
Comprehensive Income Attributable to Parent	$ 1,172	$ 802	$ 2,464	$ 2,104
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 1.52	$ 1.36	$ 3.27	$ 3.31
Diluted (usd per share)	1.52	1.36	3.26	3.31
Income (Loss) from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	0.18	(0.01)	0.18	0.05
Diluted (usd per share)	0.18	(0.01)	0.18	0.05
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	1.70	1.35	3.45	3.36
Diluted (usd per share)	$ 1.70	$ 1.35	$ 3.44	$ 3.36
Weighted average shares outstanding
Basic (shares)	689	688	689	696
Diluted (shares)	691	688	690	696
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 2,226	$ 2,061	$ 5,641	$ 5,669
Operating Expenses
Fuel used in electric generation and purchased power – regulated	581	548	1,391	1,553
Operation, maintenance and other	493	511	1,481	1,469
Depreciation and amortization	268	269	802	779
Property and other taxes	68	67	206	204
Total operating expenses	1,410	1,395	3,880	4,005
Gains (Losses) on Sales of Other Assets and Other, net	(1)	0	(1)
Operating Income	815	666	1,760	1,664
Other Income and Expenses
Other income and expenses, net	39	42	121	125
Interest Expense	102	105	316	313
Income From Continuing Operations Before Income Taxes	752	603	1,565	1,476
Income Tax Expense from Continuing Operations	258	220	539	536
Net Income (Loss) Attributable to Parent	494	383	1,026	940
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges		1	1	1
Unrealized (losses) gains on available-for-sale securities		1		1
Other Comprehensive Income, net of tax		2	1	2
Comprehensive Income Attributable to Parent	494	385	1,027	942
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,965	2,929	7,645	7,941
Operating Expenses
Fuel used in electric generation and purchased power – regulated	1,120	1,238	2,832	3,273
Operation, maintenance and other	582	539	1,699	1,672
Depreciation and amortization	318	261	904	831
Property and other taxes	136	132	375	367
Impairment charges	1	7	4	7
Total operating expenses	2,157	2,177	5,814	6,150
Gains (Losses) on Sales of Other Assets and Other, net	6	4	18	18
Operating Income	814	756	1,849	1,809
Other Income and Expenses
Other income and expenses, net	31	17	79	63
Interest Expense	177	170	497	504
Income From Continuing Operations Before Income Taxes	668	603	1,431	1,368
Income Tax Expense from Continuing Operations	219	151	496	435
Income from Continuing Operations	449	452	935	933
Income (Loss) From Discontinued Operations, net of tax		(1)		(2)
Net income	449	451	935	931
Less: Net Income Attributable to Noncontrolling Interests	3	3	8	8
Net Income (Loss) Attributable to Parent	446	448	927	923
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	0	(3)	2	(1)
Reclassification into earnings from cash flow hedges	1	3	4	2
Unrealized (losses) gains on available-for-sale securities	1	0	2	(1)
Other Comprehensive Income, net of tax	2	0	8
Comprehensive Income	451	451	943	931
Less: Comprehensive Income Attributable to Noncontrolling Interests	3	3	8	8
Comprehensive Income Attributable to Parent	448	448	935	923
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,583	1,488	4,103	4,130
Operating Expenses
Fuel used in electric generation and purchased power – regulated	569	584	1,441	1,608
Operation, maintenance and other	360	329	1,067	1,066
Depreciation and amortization	176	147	526	462
Property and other taxes	40	35	119	102
Impairment charges	1		1
Total operating expenses	1,146	1,095	3,154	3,238
Gains (Losses) on Sales of Other Assets and Other, net	1	1	2	2
Operating Income	438	394	951	894
Other Income and Expenses
Other income and expenses, net	18	14	47	49
Interest Expense	61	59	188	175
Income From Continuing Operations Before Income Taxes	395	349	810	768
Income Tax Expense from Continuing Operations	124	120	271	271
Net Income (Loss) Attributable to Parent	271	229	539	497
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,381	1,436	3,538	3,803
Operating Expenses
Fuel used in electric generation and purchased power – regulated	550	654	1,391	1,665
Operation, maintenance and other	219	208	623	598
Depreciation and amortization	142	113	378	369
Property and other taxes	96	97	256	265
Impairment charges	1	7	4	7
Total operating expenses	1,008	1,079	2,652	2,904
Operating Income	373	357	886	899
Other Income and Expenses
Other income and expenses, net	11	2	30	12
Interest Expense	62	50	143	149
Income From Continuing Operations Before Income Taxes	322	309	773	762
Income Tax Expense from Continuing Operations	116	93	286	268
Net Income (Loss) Attributable to Parent	206	216	487	494
Other Comprehensive Income (Loss), net of tax
Unrealized (losses) gains on available-for-sale securities	1		2
Other Comprehensive Income, net of tax			2
Comprehensive Income Attributable to Parent	207	216	489	494
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	390	367	1,053	1,005
Nonregulated electric and other	10	6	22	29
Regulated natural gas	89	89	358	419
Total operating revenues	489	462	1,433	1,453
Operating Expenses
Fuel used in electric generation and purchased power – regulated	129	128	340	350
Fuel used in electric generation and purchased power – nonregulated	14	10	37	36
Cost of natural gas	6	7	64	116
Operation, maintenance and other	126	124	367	370
Depreciation and amortization	50	57	175	172
Property and other taxes	59	60	195	187
Total operating expenses	384	386	1,178	1,231
Gains (Losses) on Sales of Other Assets and Other, net	1		2	8
Operating Income	106	76	257	230
Other Income and Expenses
Other income and expenses, net	3		6	(2)
Interest Expense	22	20	63	58
Income From Continuing Operations Before Income Taxes	87	56	200	170
Income Tax Expense from Continuing Operations	32	22	65	64
Income from Continuing Operations	55	34	135	106
Income (Loss) From Discontinued Operations, net of tax	34	(2)	36	23
Net Income (Loss) Attributable to Parent	89	32	171	129
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	809	749	2,225	2,223
Operating Expenses
Fuel used in electric generation and purchased power – regulated	242	250	690	779
Operation, maintenance and other	175	164	526	525
Depreciation and amortization	123	109	345	320
Property and other taxes	22	23	67	41
Impairment charges	8	85	8	85
Total operating expenses	570	631	1,636	1,750
Gains (Losses) on Sales of Other Assets and Other, net		(1)
Operating Income	239	117	589	473
Other Income and Expenses
Other income and expenses, net	5		15	9
Interest Expense	45	44	136	132
Income From Continuing Operations Before Income Taxes	199	73	468	350
Income Tax Expense from Continuing Operations	70	27	159	128
Net Income (Loss) Attributable to Parent	129	46	309	222
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges		(1)	(1)	(2)
Other Comprehensive Income, net of tax			(1)	(2)
Comprehensive Income Attributable to Parent	$ 129	$ 45	$ 308	$ 220

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income (loss)	$ 1,181	$ 935	$ 2,392	$ 2,349
Other Comprehensive (Loss) Income, net of tax
Foreign currency translation adjustments	(12)	(122)	95	(238)
Pension and OPEB adjustments		(3)	2	(1)
Net unrealized gains (losses) on cash flow hedges	6	(9)	(19)	(7)
Reclassification into earnings from cash flow hedges	1	1	3	6
Unrealized (losses) gains on available-for-sale securities		(2)	7	(5)
Other Comprehensive (Loss) Income, net of tax	(5)	(135)	88	(245)
Comprehensive Income	1,176	800	2,480	2,104
Less: Comprehensive Income (Loss) Attributable to Noncontrolling Interests	4	(2)	16
Comprehensive Income Attributable to Parent	$ 1,172	$ 802	$ 2,464	$ 2,104

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 6,179	$ 857
Receivables (net of allowance for doubtful accounts)	583	703
Receivables of VIEs (net of allowance for doubtful accounts)	2,139	1,748
Inventory	3,351	3,810
Regulatory assets	853	877
Other	429	327
Total current assets	13,534	8,322
Investments and Other Assets
Investments in equity method unconsolidated affiliates	604	499
Nuclear decommissioning trust funds	6,112	5,825
Goodwill	16,354	16,343
Other	2,948	3,042
Total investments and other assets	26,018	25,709
Property, Plant and Equipment
Cost	116,376	112,826
Accumulated depreciation and amortization	(38,812)	(37,665)
Generation facilities to be retired, net	652	548
Net property, plant and equipment	78,216	75,709
Regulatory Assets and Deferred Debits
Regulatory assets	11,896	11,373
Other	22	43
Total regulatory assets and deferred debits	11,918	11,416
Total Assets	129,686	121,156
Current Liabilities
Accounts payable	2,138	2,400
Notes payable and commercial paper	3,011	3,633
Taxes accrued	636	348
Interest accrued	504	430
Current maturities of long-term debt	3,201	2,074
Asset retirement obligation	539
Regulatory liabilities	319	400
Other	1,728	2,115
Total current liabilities	12,076	11,400
Long-Term Debt	43,964	37,495
Deferred Credits and Other Liabilities
Deferred income taxes	13,201	12,705
Investment tax credits	486	472
Accrued pension and other post-retirement benefit costs	1,030	1,088
Asset retirement obligations	10,291	10,264
Regulatory liabilities	6,241	6,255
Other	1,851	1,706
Total deferred credits and other liabilities	33,100	32,490
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	37,997	37,968
Retained earnings	3,212	2,564
Accumulated other comprehensive income (loss)	(721)	(806)
Total Duke Energy Corporation stockholders' equity	40,489	39,727
Noncontrolling interests	57	44
Total equity	40,546	39,771
Total Liabilities and Equity	129,686	121,156
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	82	13
Receivables (net of allowance for doubtful accounts)	129	142
Receivables of VIEs (net of allowance for doubtful accounts)	780	596
Receivables from affiliated companies	88	107
Notes receivable from affiliated companies	32	163
Inventory	1,053	1,276
Regulatory assets	256	305
Other	22	128
Total current assets	2,442	2,730
Investments and Other Assets
Nuclear decommissioning trust funds	3,234	3,050
Other	923	999
Total investments and other assets	4,157	4,049
Property, Plant and Equipment
Cost	40,495	39,398
Accumulated depreciation and amortization	(14,125)	(13,521)
Net property, plant and equipment	26,370	25,877
Regulatory Assets and Deferred Debits
Regulatory assets	3,040	2,766
Other	3	4
Total regulatory assets and deferred debits	3,043	2,770
Total Assets	36,012	35,426
Current Liabilities
Accounts payable	582	753
Accounts payable to affiliated companies	149	229
Taxes accrued	198	25
Interest accrued	125	95
Current maturities of long-term debt	468	356
Asset retirement obligation	303
Regulatory liabilities	125	39
Other	417	519
Total current liabilities	2,367	2,016
Long-Term Debt	8,592	7,711
Long-Term Debt Payable to Affiliated Companies	300	300
Deferred Credits and Other Liabilities
Deferred income taxes	6,464	6,146
Investment tax credits	195	199
Accrued pension and other post-retirement benefit costs	93	107
Asset retirement obligations	3,622	3,918
Regulatory liabilities	2,864	2,802
Other	685	621
Total deferred credits and other liabilities	13,923	13,793
Commitments and Contingencies
Equity
Members' equity	10,840	11,617
Accumulated other comprehensive income (loss)	(10)	(11)
Total equity	10,830	11,606
Total Liabilities and Equity	36,012	35,426
Progress Energy [Member]
Current Assets
Cash and cash equivalents	165	44
Receivables (net of allowance for doubtful accounts)	109	151
Receivables of VIEs (net of allowance for doubtful accounts)	857	658
Receivables from affiliated companies	8	375
Notes receivable from affiliated companies	43
Inventory	1,653	1,751
Regulatory assets	347	362
Other	183	156
Total current assets	3,365	3,497
Investments and Other Assets
Nuclear decommissioning trust funds	2,879	2,775
Goodwill	3,655	3,655
Other	865	834
Total investments and other assets	7,399	7,264
Property, Plant and Equipment
Cost	44,151	42,666
Accumulated depreciation and amortization	(15,169)	(14,867)
Generation facilities to be retired, net	562	548
Net property, plant and equipment	29,544	28,347
Regulatory Assets and Deferred Debits
Regulatory assets	5,652	5,435
Other	4	5
Total regulatory assets and deferred debits	5,656	5,440
Total Assets	45,964	44,548
Current Liabilities
Accounts payable	673	722
Accounts payable to affiliated companies	202	311
Notes payable to affiliated companies	510	1,308
Taxes accrued	228	53
Interest accrued	186	195
Current maturities of long-term debt	578	315
Asset retirement obligation	236
Regulatory liabilities	148	286
Other	721	891
Total current liabilities	3,482	4,081
Long-Term Debt	15,792	13,999
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	5,148	4,790
Accrued pension and other post-retirement benefit costs	516	536
Asset retirement obligations	5,421	5,369
Regulatory liabilities	2,353	2,387
Other	379	383
Total deferred credits and other liabilities	13,817	13,465
Commitments and Contingencies
Equity
Additional paid-in capital	8,096	8,092
Retained earnings	4,683	4,831
Accumulated other comprehensive income (loss)	(40)	(48)
Total Duke Energy Corporation stockholders' equity	12,739	12,875
Noncontrolling interests	(16)	(22)
Total equity	12,723	12,853
Total Liabilities and Equity	45,964	44,548
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	136	15
Receivables (net of allowance for doubtful accounts)	42	87
Receivables of VIEs (net of allowance for doubtful accounts)	473	349
Receivables from affiliated companies	5	16
Notes receivable from affiliated companies	65
Inventory	998	1,088
Regulatory assets	186	264
Other	83	121
Total current assets	1,988	1,940
Investments and Other Assets
Nuclear decommissioning trust funds	2,171	2,035
Other	518	486
Total investments and other assets	2,689	2,521
Property, Plant and Equipment
Cost	28,001	27,313
Accumulated depreciation and amortization	(10,508)	(10,141)
Generation facilities to be retired, net	562	548
Net property, plant and equipment	18,055	17,720
Regulatory Assets and Deferred Debits
Regulatory assets	3,093	2,710
Other	2	3
Total regulatory assets and deferred debits	3,095	2,713
Total Assets	25,827	24,894
Current Liabilities
Accounts payable	319	399
Accounts payable to affiliated companies	143	190
Notes payable to affiliated companies		209
Taxes accrued	91	15
Interest accrued	81	96
Current maturities of long-term debt	252	2
Asset retirement obligation	236
Regulatory liabilities	129	85
Other	326	412
Total current liabilities	1,577	1,408
Long-Term Debt	6,609	6,366
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	3,279	3,027
Investment tax credits	148	132
Accrued pension and other post-retirement benefit costs	247	262
Asset retirement obligations	4,623	4,567
Regulatory liabilities	1,874	1,878
Other	23	45
Total deferred credits and other liabilities	10,194	9,911
Commitments and Contingencies
Equity
Total equity	7,297	7,059
Total Liabilities and Equity	25,827	24,894
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	10	8
Receivables (net of allowance for doubtful accounts)	65	60
Receivables of VIEs (net of allowance for doubtful accounts)	385	308
Receivables from affiliated companies	5	84
Inventory	656	663
Regulatory assets	161	98
Other	46	21
Total current assets	1,328	1,242
Investments and Other Assets
Nuclear decommissioning trust funds	708	740
Other	292	292
Total investments and other assets	1,000	1,032
Property, Plant and Equipment
Cost	16,139	15,343
Accumulated depreciation and amortization	(4,654)	(4,720)
Net property, plant and equipment	11,485	10,623
Regulatory Assets and Deferred Debits
Regulatory assets	2,559	2,725
Other	2	2
Total regulatory assets and deferred debits	2,561	2,727
Total Assets	16,374	15,624
Current Liabilities
Accounts payable	354	322
Accounts payable to affiliated companies	61	116
Notes payable to affiliated companies	63	813
Taxes accrued	209	132
Interest accrued	58	43
Current maturities of long-term debt	326	13
Regulatory liabilities	18	200
Other	367	452
Total current liabilities	1,456	2,091
Long-Term Debt	5,802	4,253
Deferred Credits and Other Liabilities
Deferred income taxes	2,597	2,460
Accrued pension and other post-retirement benefit costs	237	242
Asset retirement obligations	798	802
Regulatory liabilities	478	509
Other	167	146
Total deferred credits and other liabilities	4,277	4,159
Commitments and Contingencies
Equity
Members' equity	4,837	5,121
Accumulated other comprehensive income (loss)	2
Total equity	4,839	5,121
Total Liabilities and Equity	16,374	15,624
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	99	14
Receivables (net of allowance for doubtful accounts)	68	66
Receivables from affiliated companies	96	84
Notes receivable from affiliated companies	47
Inventory	110	105
Regulatory assets	46	36
Other	59	110
Total current assets	525	415
Investments and Other Assets
Goodwill	920	920
Other	18	20
Total investments and other assets	938	940
Property, Plant and Equipment
Cost	8,019	7,750
Accumulated depreciation and amortization	(2,566)	(2,507)
Net property, plant and equipment	5,453	5,243
Regulatory Assets and Deferred Debits
Regulatory assets	490	497
Other	2	2
Total regulatory assets and deferred debits	492	499
Total Assets	7,408	7,097
Current Liabilities
Accounts payable	250	207
Accounts payable to affiliated companies	49	53
Notes payable to affiliated companies		103
Taxes accrued	163	171
Interest accrued	32	18
Current maturities of long-term debt	54	106
Regulatory liabilities	17	12
Other	84	153
Total current liabilities	649	823
Long-Term Debt	1,808	1,467
Long-Term Debt Payable to Affiliated Companies	25	25
Deferred Credits and Other Liabilities
Deferred income taxes	1,422	1,407
Accrued pension and other post-retirement benefit costs	51	56
Asset retirement obligations	108	125
Regulatory liabilities	238	245
Other	168	165
Total deferred credits and other liabilities	1,987	1,998
Commitments and Contingencies
Equity
Common stock	762	762
Additional paid-in capital	2,695	2,720
Retained earnings	(518)	(698)
Total equity	2,939	2,784
Total Liabilities and Equity	7,408	7,097
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	94	9
Receivables (net of allowance for doubtful accounts)	84	96
Receivables from affiliated companies	74	71
Notes receivable from affiliated companies	38	83
Inventory	424	570
Regulatory assets	131	102
Other	104	15
Total current assets	949	946
Investments and Other Assets
Total investments and other assets	174	212
Property, Plant and Equipment
Cost	14,069	14,007
Accumulated depreciation and amortization	(4,225)	(4,484)
Generation facilities to be retired, net	90
Net property, plant and equipment	9,934	9,523
Regulatory Assets and Deferred Debits
Regulatory assets	909	716
Other	2	2
Total regulatory assets and deferred debits	911	718
Total Assets	11,968	11,399
Current Liabilities
Accounts payable	167	189
Accounts payable to affiliated companies	82	83
Taxes accrued	48	89
Interest accrued	54	56
Current maturities of long-term debt	71	547
Regulatory liabilities	30	62
Other	95	97
Total current liabilities	547	1,123
Long-Term Debt	3,566	3,071
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	1,822	1,657
Investment tax credits	137	138
Accrued pension and other post-retirement benefit costs	72	80
Asset retirement obligations	847	525
Regulatory liabilities	738	754
Other	94	65
Total deferred credits and other liabilities	3,710	3,219
Commitments and Contingencies
Equity
Members' equity	3,995
Common stock		1
Additional paid-in capital		1,384
Retained earnings		2,450
Accumulated other comprehensive income (loss)		1
Total equity	3,995
Total equity		3,836
Total Liabilities and Equity	$ 11,968	$ 11,399

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Receivables, allowance for doubtful accounts	$ 25	$ 18
Receivables of VIEs, allowance for doubtful accounts	54	53
Regulatory assets	853	877
Regulatory assets	11,896	11,373
Current maturities of long-term debt	3,201	2,074
Long-term Debt of VIEs	$ 43,964	$ 37,495
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	689,000,000	688,000,000
Variable Interest Entity [Member]
Regulatory assets	$ 51
Regulatory assets	1,156
Current maturities of long-term debt	258	$ 125
Long-term Debt of VIEs	3,641	2,197
Duke Energy Carolinas [Member]
Receivables, allowance for doubtful accounts	2	3
Receivables of VIEs, allowance for doubtful accounts	7	7
Regulatory assets	256	305
Regulatory assets	3,040	2,766
Current maturities of long-term debt	468	356
Long-term Debt of VIEs	8,592	7,711
Progress Energy [Member]
Receivables, allowance for doubtful accounts	6	6
Receivables of VIEs, allowance for doubtful accounts	8	8
Regulatory assets	347	362
Regulatory assets	5,652	5,435
Current maturities of long-term debt	578	315
Long-term Debt of VIEs	$ 15,792	$ 13,999
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]
Regulatory assets	$ 51
Regulatory assets	1,156
Current maturities of long-term debt	62
Long-term Debt of VIEs	1,741	$ 479
Duke Energy Progress [Member]
Receivables, allowance for doubtful accounts	4	4
Receivables of VIEs, allowance for doubtful accounts	5	5
Regulatory assets	186	264
Regulatory assets	3,093	2,710
Current maturities of long-term debt	252	2
Long-term Debt of VIEs	6,609	6,366
Duke Energy Florida [Member]
Receivables, allowance for doubtful accounts	2	2
Receivables of VIEs, allowance for doubtful accounts	3	3
Regulatory assets	161	98
Regulatory assets	2,559	2,725
Current maturities of long-term debt	326	13
Long-term Debt of VIEs	5,802	4,253
Duke Energy Florida [Member] | Variable Interest Entity [Member]
Regulatory assets	51
Regulatory assets	1,156
Current maturities of long-term debt	62
Long-term Debt of VIEs	1,441	225
Duke Energy Ohio [Member]
Receivables, allowance for doubtful accounts	2	2
Regulatory assets	46	36
Regulatory assets	490	497
Current maturities of long-term debt	54	106
Long-term Debt of VIEs	$ 1,808	$ 1,467
Common stock, par or stated value	$ 8.50	$ 8.50
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares outstanding	89,663,086	89,663,086
Duke Energy Indiana [Member]
Receivables, allowance for doubtful accounts	$ 1	$ 1
Regulatory assets	131	102
Regulatory assets	909	716
Current maturities of long-term debt	71	547
Long-term Debt of VIEs	$ 3,566	$ 3,071
Common stock, par or stated value		$ 0.01
Common stock, shares authorized		60,000,000
Common stock, shares outstanding		53,913,701

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 2,392	$ 2,349
Net Income Attributable to Parent	2,379	2,339
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	2,847	2,680
Equity component of AFUDC	(140)	(123)
(Gains) Losses on sales of other assets	(27)	(44)
Impairment charges	279	145
Deferred income taxes	648	1,104
Equity in earnings of unconsolidated affiliates	(34)	(53)
Accrued pension and other post-retirement benefit costs	12	53
Contributions to qualified pension plans		(143)
Payments for asset retirement obligations	(443)	(208)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	36	(23)
Receivables	(295)	67
Inventory	455	(13)
Other current assets	(163)	(119)
Increase (decrease) in
Accounts payable	(207)	(182)
Taxes accrued	417	41
Other current liabilities	(157)	79
Other assets	(64)	(143)
Other liabilities	36	(71)
Net cash provided by operating activities	5,592	5,396
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(5,242)	(4,642)
Investment expenditures	(198)	(209)
Acquisitions	(10)	(1,317)
Purchases of available-for-sale securities	(4,048)	(3,017)
Proceeds from sales and maturities of available-for-sale securities	4,107	3,037
Net proceeds from the sale of the Midwest Generation Disposal Group		2,792
Net proceeds from the sales of equity investments and other assets	6	124
Change in restricted cash	(34)	(49)
Other	(136)	(10)
Net cash used in investing activities	(5,555)	(3,291)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	8,647	1,780
Proceeds from the issuance of common stock related to employee benefit plans	7	16
Payments for the redemption of long-term debt	(988)	(1,264)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	1,424	287
Payments for the redemption of short-term debt with original maturities greater than 90 days	(492)	(931)
Notes payable and commercial paper	(1,579)	531
Distributions to noncontrolling interests	(3)	(7)
Dividends paid	(1,731)	(1,685)
Repurchase of common shares		(1,500)
Other		2
Net cash provided by (used in) financing activities	5,285	(2,771)
Net increase (decrease) in cash and cash equivalents	5,322	(666)
Cash and cash equivalents at beginning of period	857	2,036
Cash and cash equivalents at end of period	6,179	1,370
Significant non-cash transactions:
Accrued capital expenditures	631	610
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income Attributable to Parent	1,026	940
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,020	1,016
Equity component of AFUDC	(75)	(73)
(Gains) Losses on sales of other assets	1
Deferred income taxes	382	183
Accrued pension and other post-retirement benefit costs	3	11
Contributions to qualified pension plans		(42)
Payments for asset retirement obligations	(204)	(104)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	4
Receivables	(191)	(9)
Receivable from affiliated companies	19
Inventory	217	(48)
Other current assets	81	42
Increase (decrease) in
Accounts payable	(179)	(141)
Accounts payable to affiliated companies	(100)	(11)
Taxes accrued	248	182
Other current liabilities	51	49
Other assets	57	97
Other liabilities	(15)	(61)
Net cash provided by operating activities	2,345	2,031
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,531)	(1,372)
Purchases of available-for-sale securities	(2,070)	(1,926)
Proceeds from sales and maturities of available-for-sale securities	2,070	1,926
Notes receivable from affiliated companies payments		(549)
Notes receivable from affiliated companies	131
Other	(65)	(13)
Net cash used in investing activities	(1,465)	(1,934)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	992	496
Payments for the redemption of long-term debt	(3)	(3)
Distributions to parent	(1,800)	(401)
Other		(4)
Net cash provided by (used in) financing activities	(811)	88
Net increase (decrease) in cash and cash equivalents	69	185
Cash and cash equivalents at beginning of period	13	13
Cash and cash equivalents at end of period	82	198
Significant non-cash transactions:
Accrued capital expenditures	228	229
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	935	931
Net Income Attributable to Parent	927	923
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,071	962
Equity component of AFUDC	(51)	(40)
(Gains) Losses on sales of other assets	(23)	(24)
Impairment charges	4	7
Deferred income taxes	425	512
Accrued pension and other post-retirement benefit costs	(19)	(4)
Contributions to qualified pension plans		(42)
Payments for asset retirement obligations	(203)	(90)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	33	6
Receivables	(155)	(103)
Receivable from affiliated companies	329	(62)
Inventory	99	44
Other current assets	(30)	298
Increase (decrease) in
Accounts payable	(24)	(157)
Accounts payable to affiliated companies	(109)	35
Taxes accrued	159	75
Other current liabilities	(156)	115
Other assets	(90)	(116)
Other liabilities	(4)	(87)
Net cash provided by operating activities	2,191	2,260
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,276)	(1,816)
Acquisitions	(10)	(1,249)
Purchases of available-for-sale securities	(1,849)	(829)
Proceeds from sales and maturities of available-for-sale securities	1,899	895
Proceeds from Insurance	58
Proceeds from the sale of nuclear fuel		81
Notes receivable from affiliated companies payments	(43)	(31)
Change in restricted cash	(6)
Other	(17)	(44)
Net cash used in investing activities	(2,244)	(2,993)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	2,375	1,195
Payments for the redemption of long-term debt	(327)	(555)
Notes payable to affiliated companies	(798)	(401)
Distributions to noncontrolling interests	(1)	(4)
Capital contribution from parent		625
Dividends to parent	(1,075)
Other		(11)
Net cash provided by (used in) financing activities	174	849
Net increase (decrease) in cash and cash equivalents	121	116
Cash and cash equivalents at beginning of period	44	42
Cash and cash equivalents at end of period	165	158
Significant non-cash transactions:
Accrued capital expenditures	228	276
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income Attributable to Parent	539	497
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	679	587
Equity component of AFUDC	(34)	(35)
(Gains) Losses on sales of other assets	(4)	(5)
Impairment charges	1
Deferred income taxes	325	308
Accrued pension and other post-retirement benefit costs	(24)	(11)
Contributions to qualified pension plans		(21)
Payments for asset retirement obligations	(163)	(53)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		(3)
Receivables	(78)	(51)
Receivable from affiliated companies	11	4
Inventory	91	37
Other current assets	37	187
Increase (decrease) in
Accounts payable	(44)	(69)
Accounts payable to affiliated companies	(47)	21
Taxes accrued	76	34
Other current liabilities	37	22
Other assets	(32)	(41)
Other liabilities	(10)	(64)
Net cash provided by operating activities	1,360	1,344
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,106)	(1,120)
Acquisitions		(1,249)
Purchases of available-for-sale securities	(1,470)	(511)
Proceeds from sales and maturities of available-for-sale securities	1,448	488
Notes receivable from affiliated companies payments	(65)	(70)
Other	(27)	(35)
Net cash used in investing activities	(1,220)	(2,497)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	505	1,195
Payments for the redemption of long-term debt	(15)	(544)
Notes payable to affiliated companies	(209)
Capital contribution from parent		625
Distributions to parent	(301)
Other	1	(9)
Net cash provided by (used in) financing activities	(19)	1,267
Net increase (decrease) in cash and cash equivalents	121	114
Cash and cash equivalents at beginning of period	15	9
Cash and cash equivalents at end of period	136	123
Significant non-cash transactions:
Accrued capital expenditures	66	136
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income Attributable to Parent	487	494
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	383	373
Equity component of AFUDC	(16)	(4)
Impairment charges	4	7
Deferred income taxes	136	341
Accrued pension and other post-retirement benefit costs	2	4
Contributions to qualified pension plans		(21)
Payments for asset retirement obligations	(41)	(37)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	34	3
Receivables	(78)	(52)
Receivable from affiliated companies	41	(58)
Inventory	8	7
Other current assets	(32)	78
Increase (decrease) in
Accounts payable	20	(88)
Accounts payable to affiliated companies	(55)	10
Taxes accrued	61	43
Other current liabilities	(183)	97
Other assets	(56)	(73)
Other liabilities	1	(29)
Net cash provided by operating activities	716	1,095
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,169)	(696)
Acquisitions	(10)
Purchases of available-for-sale securities	(379)	(318)
Proceeds from sales and maturities of available-for-sale securities	450	408
Proceeds from Insurance	58
Proceeds from the sale of nuclear fuel		81
Change in restricted cash	(6)
Other	10	(12)
Net cash used in investing activities	(1,046)	(537)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,870
Payments for the redemption of long-term debt	(12)	(11)
Notes payable to affiliated companies	(750)	161
Dividends to parent		(350)
Distributions to parent	(774)	(350)
Other	(2)
Net cash provided by (used in) financing activities	332	(550)
Net increase (decrease) in cash and cash equivalents	2	8
Cash and cash equivalents at beginning of period	8	8
Cash and cash equivalents at end of period	10	16
Significant non-cash transactions:
Accrued capital expenditures	162	140
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income Attributable to Parent	171	129
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	178	175
Equity component of AFUDC	(4)	(2)
(Gains) Losses on sales of other assets	(2)	(8)
Impairment charges		40
Deferred income taxes	36	127
Accrued pension and other post-retirement benefit costs	4	7
Contributions to qualified pension plans		(4)
Payments for asset retirement obligations	(4)	(2)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		(11)
Receivables	(1)	8
Receivable from affiliated companies	(3)	46
Inventory	(5)	2
Other current assets	50	6
Increase (decrease) in
Accounts payable	13	7
Accounts payable to affiliated companies	(4)	(32)
Taxes accrued	(13)	(58)
Other current liabilities	(53)	101
Other assets	(8)	28
Other liabilities	(28)	(57)
Net cash provided by operating activities	327	502
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(334)	(266)
Notes receivable from affiliated companies payments	(47)
Notes receivable from affiliated companies		145
Other	(21)	(9)
Net cash used in investing activities	(402)	(130)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	341
Payments for the redemption of long-term debt	(53)	(153)
Notes payable to affiliated companies	(103)	(64)
Dividends to parent	(25)	(149)
Other		(2)
Net cash provided by (used in) financing activities	160	(368)
Net increase (decrease) in cash and cash equivalents	85	4
Cash and cash equivalents at beginning of period	14	20
Cash and cash equivalents at end of period	99	24
Significant non-cash transactions:
Accrued capital expenditures	56	24
Distribution of membership interest of Duke Energy SAM, LLC to parent		1,912
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income Attributable to Parent	309	222
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	347	323
Equity component of AFUDC	(11)	(9)
Impairment charges	8	85
Deferred income taxes	122	276
Accrued pension and other post-retirement benefit costs	6	10
Contributions to qualified pension plans		(9)
Payments for asset retirement obligations	(31)	(12)
(Increase) decrease in
Receivables	16	(5)
Receivable from affiliated companies	(3)	43
Inventory	146	(27)
Other current assets	(105)	67
Increase (decrease) in
Accounts payable	(14)	11
Accounts payable to affiliated companies	(1)	(8)
Taxes accrued	12	(11)
Other current liabilities	(85)	16
Other assets	(38)	(50)
Other liabilities	64	(1)
Net cash provided by operating activities	742	921
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(540)	(506)
Purchases of available-for-sale securities	(12)	(5)
Proceeds from sales and maturities of available-for-sale securities	9	8
Net proceeds from the sales of equity investments and other assets		14
Notes receivable from affiliated companies payments		(166)
Notes receivable from affiliated companies	45
Other	(28)	13
Net cash used in investing activities	(526)	(642)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	495
Payments for the redemption of long-term debt	(476)	(2)
Notes payable to affiliated companies		(71)
Dividends to parent		(150)
Distributions to parent	(149)
Other	(1)
Net cash provided by (used in) financing activities	(131)	(223)
Net increase (decrease) in cash and cash equivalents	85	56
Cash and cash equivalents at beginning of period	9	6
Cash and cash equivalents at end of period	94	62
Significant non-cash transactions:
Accrued capital expenditures	$ 56	$ 46

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 Gains (Losses) on Available for Sale Securities [Member]	Pension and OPEB Related 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]	Duke Energy Carolinas [Member]Net Gains (Losses) on Available for Sale Securities [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 Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]Pension and OPEB Related Adjustments [Member]	Progress Energy [Member]Common Stockholders' Equity [Member]	Progress Energy [Member]Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Progress [Member]Common Stock [Member]	Duke Energy Progress [Member]Retained Earnings [Member]	Duke Energy Progress [Member]Members Equity [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]Common Stock [Member]	Duke Energy Florida [Member]Retained Earnings [Member]	Duke Energy Florida [Member]Members Equity [Member]	Duke Energy Florida [Member]Net 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]
Balance at Dec. 31, 2014	$ 40,899	$ 1	$ 39,405	$ 2,012	$ (439)	$ (59)	$ 3	$ (48)	$ 40,875	$ 24						$ 11,176	$ 7,467	$ 3,782	$ (35)	$ 1	$ (7)	$ 11,208	$ (32)	$ 5,867	$ 2,159	$ 3,708		$ 5,222	$ 1,762	$ 3,460			$ 4,674	$ 762	$ 4,782	$ (870)	$ 3,848	$ 1	$ 1,384	$ 2,460		$ 3
Balance, in shares at Dec. 31, 2014		707,000,000
Beginning member's equity at Dec. 31, 2014												$ 10,924	$ 10,937	$ (12)	$ (1)
Net Income	2,349			2,339					2,339	10						931		923				923	8
Net Income Attributable to Parent	2,339											940	940			923								497		355	$ 142	494		351	$ 143		129			129	222			222
Contribution from Parent																625	625					625		625			625
Distribution of membership interest of Duke Energy SAM, LLC to parent																																	(1,912)		(1,912)
Other comprehensive (loss) income, net of tax	(245)				(228)	(1)	(5)	(1)	(235)	(10)		2		1	$ 1				2	(1)	(1)																(2)					(2)
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	48		48						48
Stock Repurchased During Period, Shares		(20,000,000)
Stock Repurchased During Period, Value	(1,500)		(1,500)						(1,500)
Common stock dividends	(1,685)			(1,685)					(1,685)																			(350)		(350)			(149)		(149)		(150)			(150)
Distributions to parent												(401)	(401)															(350)			(350)
Distributions to noncontrolling interest in subsidiaries	(7)									(7)						(4)							(4)
Other	9			(10)					(10)	19	[1]					1		(2)				(2)	3		$ (2,159)	$ (4,063)	6,222		$ (1,762)	$ (3,461)	5,223
Balance at Sep. 30, 2015	39,868	$ 1	37,953	2,656	(667)	(60)	(2)	(49)	39,832	36						12,729	8,092	4,703	(33)		(8)	12,754	(25)	6,989			6,989	5,016			5,016		2,742	762	2,721	(741)	3,918	1	1,384	2,532		1
Balance, in shares at Sep. 30, 2015		688,000,000
Ending member's equity at Sep. 30, 2015												11,465	11,476	(11)
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)										$ 2,784	762	2,720	(698)	$ 3,836	1	1,384	2,450		1
Balance, in shares at Dec. 31, 2015	688,000,000	688,000,000														100																	89,663,086				53,913,701
Beginning member's equity at Dec. 31, 2015												11,606	11,617	(11)										7,059			7,059	5,121			5,121
Net Income	$ 2,392			2,379					2,379	13						$ 935		927				927	8
Net Income Attributable to Parent	2,379											1,026	1,026			927								539			539	487			487		$ 171			171	$ 309				$ 309
Other comprehensive (loss) income, net of tax	88				92	(16)	7	2	85	3		1		1		8			4	2	2	8						2				$ 2					(1)					$ (1)
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	29		29						29
Common stock dividends	(1,731)			(1,731)					(1,731)							(1,075)		(1,075)				(1,075)											(25)		(25)
Distributions to parent												(1,800)	(1,800)											(301)			(301)	(774)			(774)						(149)				(149)
Distributions to noncontrolling interest in subsidiaries	(3)									(3)						(1)							(1)
Other												(3)	(3)			3	4					4	(1)					3			3		9			9		$ (1)	$ (1,384)	$ (2,450)	3,835
Balance at Sep. 30, 2016	$ 40,546	$ 1	$ 37,997	$ 3,212	$ (600)	$ (66)	$ 4	$ (59)	$ 40,489	$ 57						$ 12,723	$ 8,096	$ 4,683	$ (27)	$ 2	$ (15)	$ 12,739	$ (16)										$ 2,939	$ 762	$ 2,695	$ (518)
Balance, in shares at Sep. 30, 2016	689,000,000	689,000,000														100																	89,663,086
Ending member's equity at Sep. 30, 2016												$ 10,830	$ 10,840	$ (10)										$ 7,297			$ 7,297	$ 4,839			$ 4,837	$ 2					$ 3,995				$ 3,995
[1]	The $19 million change in Noncontrolling Interests for the nine months ended September 30, 2015, is primarily related to an acquisition of majority interest in a solar company.

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2016
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. Tables within the notes may not sum across due to Progress Energy's consolidation of Duke Energy Progress, Duke Energy Florida and other subsidiaries that are not registrants. In addition, the Duke Energy amounts include balances from subsidiaries that are not registrants. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 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 • • • • • • • • • • • • • • 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.) and Latin America primarily through its direct and indirect subsidiaries. See Note 2 for information on the proposed sale of International Energy. Duke Energy’s subsidiaries include its subsidiary registrants, 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) and Duke Energy Indiana, LLC (Duke Energy Indiana). When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its six separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants). 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. 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. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting. 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. Substantially all of Progress Energy’s operations qualify for regulatory accounting. 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. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting. 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. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. 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. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). See Note 2 for additional information. Substantially all of Duke Energy Ohio’s operations that remain after the sale qualify for regulatory accounting. 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. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company. See Note 2 for information regarding Duke Energy's acquisition of Piedmont Natural Gas Company, Inc. (Piedmont) that closed on October 3, 2016. For the periods presented, Duke Energy's condensed consolidated financial information does not include the results of Piedmont. Also, the Duke Energy Registrants, as defined above, do not include Piedmont, unless otherwise noted. BASIS OF PRESENTATION Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales (collectively, the Midwest Generation Disposal Group), a retail sales business owned by Duke Energy, to Dynegy on April 2, 2015. The results of operations of these businesses prior to the date of sale 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 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, 2015 . 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 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 and meter reading schedules. Unbilled revenues, which are included within Receivables and Receivables of variable interest entities (VIEs) on the Condensed Consolidated Balance Sheets, are presented in the following table. (in millions) September 30, 2016 December 31, 2015 Duke Energy $ 800 $ 748 Duke Energy Carolinas 318 283 Progress Energy 195 172 Duke Energy Progress 96 102 Duke Energy Florida 99 70 Duke Energy Ohio 2 3 Duke Energy Indiana 36 31 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 13 for further information. These receivables for unbilled revenues are shown in the table below. (in millions) September 30, 2016 December 31, 2015 Duke Energy Ohio $ 72 $ 71 Duke Energy Indiana 109 97 AMOUNTS ATTRIBUTABLE TO CONTROLLING INTERESTS Income (Loss) from Discontinued Operations, net of tax presented on the respective Condensed Consolidated Statements of Operations for Duke Energy and Progress Energy is attributable only to controlling interests for all periods presented. 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. Reserves are established for excess and obsolete inventory. Inventory reserves were not material at September 30, 2016 and December 31, 2015 . The components of inventory are presented in the tables below. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,312 $ 760 $ 1,139 $ 781 $ 358 $ 85 $ 236 Coal held for electric generation 743 256 277 101 177 18 186 Oil, gas and other fuel held for electric generation 296 37 237 116 121 7 2 Total inventory $ 3,351 $ 1,053 $ 1,653 $ 998 $ 656 $ 110 $ 424 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,389 $ 785 $ 1,133 $ 776 $ 357 $ 81 $ 301 Coal held for electric generation 1,114 451 370 192 178 16 267 Oil, gas and other fuel held for electric generation 307 40 248 120 128 8 2 Total inventory $ 3,810 $ 1,276 $ 1,751 $ 1,088 $ 663 $ 105 $ 570 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 net. 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 September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy $ 107 $ 109 $ 285 $ 308 Duke Energy Carolinas 6 9 21 27 Progress Energy 65 67 161 174 Duke Energy Progress 4 4 13 12 Duke Energy Florida 61 63 148 162 Duke Energy Ohio 26 24 77 80 Duke Energy Indiana 10 9 26 27 NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2016 and 2015 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of September 30, 2016 . Revenue from Contracts with Customers. In May 2014, the Financial Accounting Standards Board (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. The Duke Energy Registrants intend to adopt the revised accounting guidance effective for interim and annual periods beginning January 1, 2018. The guidance can be applied retrospectively to all prior reporting periods presented or retrospectively with a cumulative effect as of the initial date of application. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined. 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 the Duke Energy Registrants, 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 requirements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Stock-Based Compensation and Income Taxes. In March 2016, the FASB issued revised accounting guidance for stock-based compensation and the associated income taxes. This standard changes certain aspects of accounting for stock-based payment awards to employees including the accounting for income taxes, statutory tax withholding requirements, as well as classification on the Condensed Consolidated Statements of Cash Flows. The primary future impact to the Duke Energy Registrants is expected to be an increase in the volatility of income tax expense. This guidance will be adopted for the period beginning January 1, 2017. Cash Flow Statement. In August 2016, the FASB issued revised accounting guidance for classification of certain cash receipts and payments. Stakeholders indicated diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. For the Duke Energy Registrants, this guidance is effective for the interim and annual periods beginning January 1, 2018, although it can be early adopted. The guidance is applied using a retrospective transition method to each period presented, if practical. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2016
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 Piedmont Natural Gas is a North Carolina corporation primarily engaged in regulated natural gas distribution to residential, commercial, industrial and power generation customers in portions of North Carolina, South Carolina and Tennessee. On October 3, 2016, Duke Energy completed the acquisition contemplated by the Agreement and Plan of Merger (Merger Agreement) with Piedmont for a total cash purchase price of approximately $5.0 billion . The acquisition provides a foundation for establishing a broader strategic natural gas infrastructure platform within Duke Energy to complement the existing natural gas pipeline investments and regulated natural gas business in the Midwest. As a result of the acquisition, Piedmont became a wholly owned subsidiary of Duke Energy. Preliminary Purchase Price Allocation The preliminary purchase price allocation of the Piedmont acquisition is estimated as follows: (in millions) Current assets $ 500 Property, plant and equipment, net 4,710 Goodwill 3,380 Other long-term assets 810 Total assets 9,400 Current liabilities, including current maturities of long-term debt 590 Long-term liabilities 1,810 Long-term debt 2,000 Total liabilities 4,400 Total purchase price $ 5,000 The estimated fair value of Piedmont's assets acquired and liabilities assumed are considered preliminary as a result of the short time period between the consummation of the merger and the filing of this Form 10-Q. The fair values were determined based on significant estimates and assumptions that are judgmental in nature, including projected future cash flows (including timing); discount rates reflecting risk inherent in the future cash flows and market prices of long-term debt. The preliminary amounts are subject to revision until the valuations are completed and to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. The majority of Piedmont’s operations are subject to the rate-setting authority of the NCUC, the PSCSC and the Tennessee Regulatory Authority 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 approximate their carrying values and do not reflect any net valuation adjustments. The significant assets and liabilities for which preliminary valuation adjustments are being determined are expected to include the acquired equity method investments and long-term debt. The difference between the preliminary fair value and the pre-merger carrying amounts for long-term debt for regulated operations are expected to be recorded as Regulatory assets. The excess of the purchase price over the estimated fair value of Piedmont's assets and liabilities on the acquisition date will be recorded as goodwill. The goodwill reflects the value paid primarily for establishing a long-term natural gas infrastructure platform, an improved risk profile and expected synergies resulting from the combined entities. The allocation of estimated goodwill to Duke Energy’s reporting units has not yet been completed as a result of the short time between the closing of the merger and the filing of this Form 10-Q. None of the goodwill recognized will be deductible for income tax purposes. Accordingly, no deferred taxes will be recorded related to goodwill. Accounting Charges Related to the Acquisition Duke Energy incurred pretax transaction and integration costs of $14 million and $22 million for the three and nine months ended September 30, 2016, respectively, substantially all of which were recorded within Operation, maintenance and other in Duke Energy’s Condensed Consolidated Statements of Operations. Additionally, Duke Energy recorded interest expense of $51 million and $234 million for the three and nine months ended September 30, 2016, respectively, related to the acquisition financing. The interest expense includes realized losses on forward-starting interest rate swaps of $22 million and $190 million for the three and nine months ended September 30, 2016, respectively. See Note 10 for additional information on the swaps. Acquisition Related Financings and Other Matters Duke Energy financed the Piedmont acquisition with a combination of debt, equity issuances and other cash sources. In August 2016, Duke Energy issued $3.75 billion of long-term debt to finance a portion of the Piedmont acquisition. On September 30, 2016, Duke Energy borrowed $750 million under the $1.5 billion short-term loan facility (Term Loan Facility) to partially fund the acquisition. The $4.9 billion senior unsecured bridge financing facility (Bridge Facility) with Barclays Capital, Inc. (Barclays) was terminated following the issuance of the long-term debt. See Note 6 for additional information related to the debt issuance and Term Loan Facility. 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 (the Equity Forwards) with Barclays. On October 5, 2016, Duke Energy settled the Equity Forwards for approximately $723 million in net cash proceeds to finance a portion of the Piedmont acquisition. For additional information regarding the Equity Forwards, see Note 14 . See Note 4 for additional information regarding Duke Energy and Piedmont's joint investment in Atlantic Coast Pipeline, LLC (ACP). Pro Forma Information The following unaudited pro forma financial information reflects the combined results of operations of Duke Energy and Piedmont. The unaudited pro forma financial 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. This information is preliminary in nature and subject to change. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Revenues $ 6,958 $ 6,627 $ 18,688 $ 19,021 Net income attributable to Duke Energy Corporation 1,180 897 2,552 2,352 The pro forma financial information does not include potential cost savings, intercompany revenues, Piedmont’s earnings from a certain equity method investment sold immediately prior to the merger or non-recurring transaction and integration costs incurred by Duke Energy and Piedmont. The after-tax non-recurring transaction and integration costs incurred by Duke Energy and Piedmont were $41 million and $161 million for the three and nine months ended September 30, 2016, respectively. Purchase of NCEMPA's Generation On July 31, 2015, Duke Energy Progress completed the purchase of North Carolina Eastern Municipal Power Agency’s (NCEMPA) ownership interests in certain generating assets, fuel and spare parts inventory jointly owned with and operated by Duke Energy Progress for approximately $1.25 billion . This purchase was accounted for as an asset acquisition. The purchase resulted in the acquisition of a total of approximately 700 megawatts (MW) of generating capacity at Brunswick Nuclear Plant, Shearon Harris Nuclear Plant, Mayo Steam Plant and Roxboro Steam Plant. In connection with this transaction, Duke Energy Progress and NCEMPA entered into a 30-year wholesale power agreement, whereby Duke Energy Progress will sell power to NCEMPA to continue to meet the needs of NCEMPA customers. The purchase price exceeded the historical carrying value of the acquired assets by $350 million , which was recognized as an acquisition adjustment and recorded in property, plant and equipment. Duke Energy Progress established a rider in North Carolina to recover the costs to acquire, operate and maintain interests in the assets purchased as allocated to its North Carolina retail operations, including the purchase acquisition adjustment, and included the purchase acquisition adjustment in wholesale power formula rates. Duke Energy Progress received an order from the PSCSC to defer recovery of the South Carolina retail allocated costs of the asset purchased until Duke Energy Progress' next general rate case, which was filed in July 2016. In October 2016, Duke Energy Progress, the Office of Regulatory Staff (ORS) and intervenors entered into a settlement agreement that provides for recovery of the historical carrying value of the South Carolina allocated purchased costs of the transaction. The settlement agreement was filed with the PSCSC on the same day but has yet to be ruled upon by the PSCSC. See Note 4 for additional information on the South Carolina rate case. DISPOSITIONS Sale of International Energy In October 2016, certain indirect subsidiaries of Duke Energy entered into two separate purchase and sale agreements (PSA) whereby Duke Energy will divest the International Energy business segment, excluding the equity method investment in National Methanol Company (NMC). Brazilian Disposal Group Duke Energy will sell its indirect ownership interest in Duke Energy International Brazil Holdings S.à.r.l. (the Brazil Subsidiary), which includes 2,090 MW of owned hydroelectric generation capacity in Brazil (the Brazilian Disposal Group), to China Three Gorges (Luxembourg) Energy S.à.r.l. (CTG), a subsidiary of China Three Gorges Corporation, pursuant to a PSA dated as of October 10, 2016 (the Brazil PSA). CTG will purchase the Brazil Subsidiary for an enterprise value of approximately $1.2 billion . Closing of the transaction is subject to various conditions, including receipt of required regulatory approvals and the absence of any injunction or other orders preventing closing of the transaction. The sale of the Brazilian Disposal Group is expected to close by early 2017. The Brazil PSA contains certain termination rights and provides that CTG may be required to pay a termination fee of approximately $49 million to Duke Energy upon termination of the Brazil PSA under certain specified circumstances. Latin American Disposal Group Duke Energy will sell its indirect ownership interest in Duke Energy International Group S.à.r.l., Duke Energy International España Holdings SL and Duke Energy International Investments No. 2 Ltd (collectively, the Latin America Subsidiaries), which includes 2,230 MW of owned hydroelectric and natural gas generation capacity, transmission infrastructure and natural gas processing facilities in Argentina, Chile, Ecuador, El Salvador, Guatemala and Peru (the Latin American Disposal Group) to ISQ Enerlam Aggregator, L.P. and Enerlam (UK) Holdings Ltd. (collectively, I Squared), entities controlled by a consortium of investors led by I Squared Capital, pursuant to a PSA dated as of October 10, 2016 (the Latin America PSA). I Squared will purchase the Latin America Subsidiaries for an enterprise value of approximately $1.2 billion . Closing of the transaction is subject to various conditions, including the absence of any injunction or other orders preventing closing of the transaction and the completion of certain internal restructuring transactions by subsidiaries of Duke Energy. The sale of the Latin American Disposal Group is expected to close by early 2017. I Squared provided irrevocable letters of credit with an undrawn face value of $89 million . In the event of a termination of the Latin America PSA under certain circumstances, Duke Energy can draw on the letters of credit as a termination fee. Other Sale Related Matters Including the impact of debt to be assumed by the buyers, working capital and other adjustments as well as local in-country taxes, Duke Energy expects the transactions to generate available cash proceeds of between $1.7 billion and $1.9 billion , excluding transaction costs. The proceeds are expected to be used to reduce Duke Energy holding company debt. Existing favorable tax attributes will result in no immediate U.S. federal-level tax impacts. As a result of the transactions, both the Brazilian Disposal Group and the Latin American Disposal Group (together, the International Disposal Group) will be classified as held for sale and as discontinued operations beginning in the fourth quarter of 2016. Upon classification of the International Disposal Group as held for sale, Duke Energy expects to record an estimated pretax impairment charge of approximately $325 million to $375 million , primarily due to the cumulative foreign currency translation losses classified as accumulated other comprehensive loss. Second Quarter Asset Impairment 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, in the second quarter of 2016, 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 is included within Impairment Charges on the Condensed Consolidated Statements of Operations for the nine months ended September 30, 2016, and represents the excess of carrying value over the estimated fair value of the assets. The fair value of the assets 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. Midwest Generation Exit Duke Energy, through indirect subsidiaries, completed the sale of the Midwest Generation Disposal Group to a subsidiary of Dynegy on April 2, 2015, for approximately $2.8 billion in cash. The nonregulated Midwest generation business included generation facilities with approximately 5,900 MW of owned capacity located in Ohio, Pennsylvania and Illinois. On April 1, 2015, prior to the sale, Duke Energy Ohio distributed its indirect ownership interest in the nonregulated Midwest generation business to a subsidiary of Duke Energy Corporation. Commercial Portfolio utilized a revolving credit agreement (RCA) to support the operations of the nonregulated Midwest generation business. Interest expense associated with the RCA was allocated to discontinued operations. No other interest expense related to corporate level debt was allocated to discontinued operations. Duke Energy Ohio had a power purchase agreement with the Midwest Generation Disposal Group for a portion of its standard service offer (SSO) supply requirement. The agreement and the SSO expired in May 2015. The Midwest Generation Disposal Group's results of operations are classified as discontinued operations in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Income. The following table presents the results of discontinued operations for the three and nine months ended September 30, 2015 . Three Months Ended Nine Months Ended September 30, 2015 September 30, 2015 Duke Duke Duke Energy Duke Energy (in millions) Energy Ohio Energy Ohio Operating Revenues $ — $ — $ 543 $ 412 Loss on disposition (5 ) (4 ) (42 ) (48 ) (Loss) Income before income taxes (a) $ (5 ) $ (4 ) $ 62 $ 48 Income tax (benefit) expense (1 ) (2 ) 29 25 (Loss) Income from discontinued operations of the Midwest Generation Disposal Group (4 ) (2 ) 33 23 Other, net of tax (b) (1 ) — (4 ) — (Loss) Income From Discontinued Operations, net of tax $ (5 ) $ (2 ) $ 29 $ 23 (a) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the agreement in principle reached in a lawsuit related to the Midwest Generation Disposal Group for the nine months ended September 30, 2015 . Refer to Note 5 for further information related to the lawsuit. (b) Relates to discontinued operations of businesses not related to the Midwest Generation Disposal Group and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments. Duke Energy and Duke Energy Ohio recognized an income tax benefit of $122 million and $34 million , respectively, for the three and nine months ended September 30, 2016, within Income From Discontinued Operations, net on the Condensed Consolidated Statements of Operations. The income tax benefit resulted from immaterial out of period deferred tax liability adjustments related to the Midwest Generation Disposal Group and another previously sold business.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS 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, as discussed below, includes intercompany revenues and expenses that are eliminated in the Condensed Consolidated Financial Statements. Certain governance costs are allocated to each segment. In addition, direct interest expense and income taxes are included in segment income. 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. During the first quarter of 2016, the Duke Energy chief operating decision-maker began to evaluate interim period segment performance based on financial information that includes the impact of income tax levelization within segment income. This represents a change from the previous measure, where the interim period impacts of income tax levelization were included within Other, and therefore excluded from segment income. As a result, prior period segment results presented have been recast to conform to this change. Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets as presented in the tables that follow exclude all intercompany assets. DUKE ENERGY Duke Energy has the following reportable operating segments: Regulated Utilities, International Energy and Commercial Portfolio. Regulated Utilities conducts electric and natural gas operations that are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. These operations are primarily conducted through the Subsidiary Registrants and are subject to the rules and regulations of the FERC, NRC, NCUC, PSCSC, FPSC, PUCO, IURC and KPSC. International Energy operates and manages power generation facilities and engages in sales and marketing of electric power, natural gas and natural gas liquids outside the U.S. Its activities principally target power generation in Latin America. Additionally, International Energy owns a 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. See Note 2 for information related to the planned divestiture of International Energy, excluding the investment in NMC. Commercial Portfolio builds, develops and operates wind and solar renewable generation and storage and energy transmission projects throughout the U.S. For periods subsequent to the sale of the Midwest Generation Disposal Group, beginning in the second quarter of 2015, certain immaterial results of operations and related assets previously presented in the Commercial Portfolio segment are presented in Regulated Utilities and Other. 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). Three Months Ended September 30, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 6,421 $ 245 $ 140 $ 6,806 $ 15 $ — $ 6,821 Intersegment revenues 9 — — 9 17 (26 ) — Total revenues $ 6,430 $ 245 $ 140 $ 6,815 $ 32 $ (26 ) $ 6,821 Segment income (loss) (a)(b) $ 1,200 $ 64 $ (21 ) $ 1,243 $ (189 ) $ — $ 1,054 Add back noncontrolling interests 5 Income from discontinued operations, net of tax (c) 122 Net income $ 1,181 Segment assets $ 114,707 $ 3,153 $ 4,414 $ 122,274 $ 7,228 $ 184 $ 129,686 (a) Other includes after-tax charges for costs to achieve mergers of $52 million , primarily due to interest expense related to the Piedmont acquisition financing, and cost savings initiatives of $12 million primarily due to severance costs. (b) Commercial Portfolio includes an after-tax impairment of $45 million related to certain equity method investments in renewable energy projects. See Note 13, Variable Interest Entities, for additional information. (c) Represents an income tax benefit resulting from deferred tax liability adjustments related to previously sold businesses. See Note 2, Acquisitions and Dispositions, for further information. Three Months Ended September 30, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 6,138 $ 281 $ 66 $ 6,485 $ (2 ) $ — $ 6,483 Intersegment revenues 9 — — 9 19 (28 ) — Total revenues $ 6,147 $ 281 $ 66 $ 6,494 $ 17 $ (28 ) $ 6,483 Segment income (loss) (a)(b) $ 905 $ 69 $ 8 $ 982 $ (45 ) $ — $ 937 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (5 ) Net income $ 935 (a) Regulated Utilities includes an after-tax charge of $56 million related to the Edwardsport settlement. See Note 4 for further information. (b) Other includes $15 million of after-tax costs to achieve the 2012 Progress Energy merger. Nine Months Ended September 30, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 16,761 $ 761 $ 366 $ 17,888 $ 39 $ — $ 17,927 Intersegment revenues 27 — — 27 52 (79 ) — Total revenues $ 16,788 $ 761 $ 366 $ 17,915 $ 91 $ (79 ) $ 17,927 Segment income (loss) (a)(b)(c) $ 2,613 $ 85 $ 20 $ 2,718 $ (463 ) $ — $ 2,255 Add back noncontrolling interests 13 Income from discontinued operations, net of tax (d) 124 Net income $ 2,392 (a) Other includes after-tax charges for costs to achieve mergers of $195 million , primarily due to losses on forward-starting interest rate swaps related to the Piedmont acquisition, and cost savings initiatives of $39 million primarily due to severance costs. See Note 10 for additional information related to the swaps. (b) International Energy includes an after-tax impairment charge of $145 million . See Note 2 for additional information. (c) Commercial Portfolio includes an after-tax impairment of $45 million related to certain equity method investments in renewable energy projects. See Note 13, Variable Interest Entities, for additional information. (d) Includes income tax benefit of $122 million resulting from deferred tax liability adjustments related to previously sold businesses. See Note 2 for further information. Nine Months Ended September 30, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 17,062 $ 841 $ 214 $ 18,117 $ 20 $ — $ 18,137 Intersegment revenues 28 — — 28 58 (86 ) — Total revenues $ 17,090 $ 841 $ 214 $ 18,145 $ 78 $ (86 ) $ 18,137 Segment income (loss) (a)(b)(c) $ 2,311 $ 157 $ (15 ) $ 2,453 $ (139 ) $ (4 ) $ 2,310 Add back noncontrolling interests 10 Income from discontinued operations, net of tax (d) 29 Net income $ 2,349 (a) Regulated Utilities includes an after-tax charge of $56 million related to the Edwardsport settlement. Refer to Note 4 for further information. (b) Other includes $42 million of after-tax costs to achieve the 2012 Progress Energy merger. (c) Commercial Portfolio includes state tax expense of $41 million , resulting from changes to state apportionment factors due to the sale of the Midwest Generation Disposal Group, that does not qualify for discontinued operations. Refer to Note 2 for further information related to the sale. (d) Includes after-tax impact of $53 million for the settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information related to the lawsuit. SUBSIDIARY REGISTRANTS The Subsidiary Registrants each have one reportable operating segment, Regulated Utilities, which generates, transmits, distributes and sells electricity, and for Duke Energy Ohio, also transports and sells natural gas. The remainder of operations is primarily comprised of unallocated corporate costs and classified as Other. The following table provides the amount of Other net expense. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas $ (16 ) $ (10 ) $ (50 ) $ (28 ) Progress Energy (a) (45 ) (3 ) (139 ) (87 ) Duke Energy Progress (10 ) (4 ) (26 ) (12 ) Duke Energy Florida (5 ) (3 ) (14 ) (9 ) Duke Energy Ohio (10 ) (12 ) (29 ) (20 ) Duke Energy Indiana (3 ) (2 ) (10 ) (6 ) (a) Other for Progress Energy also includes interest expense on corporate debt instruments of $55 million and $166 million for the three and nine months ended September 30, 2016 , respectively, and $61 million and $180 million for the three and nine months ended September 30, 2015 , respectively. The assets of the Subsidiary Registrants are substantially all included within the Regulated Utilities segment at September 30, 2016 . Duke Energy Ohio Duke Energy Ohio had two reportable operating segments, Regulated Utilities and Commercial Portfolio, during 2015 prior to the sale of the nonregulated Midwest generation business. Duke Energy Ohio's Commercial Portfolio segment had total revenues of $14 million and segment loss of $9 million for the nine months ended September 30, 2015. As a result of the sale discussed in Note 2 , Commercial Portfolio no longer qualifies as a Duke Energy Ohio reportable operating segment. Therefore, beginning in the second quarter of 2015, all of the remaining assets and related results of operations previously presented in Commercial Portfolio are presented in Regulated Utilities and Other. FUTURE OPERATING SEGMENTS Due to the Piedmont acquisition and the agreements to sell the International Disposal Group, the chief operating decision maker changed how the business will be managed beginning in the fourth quarter of 2016. The financial reporting structure has been realigned to include the following segments: Electric Utilities and Infrastructure, Gas Utilities and Infrastructure, and Commercial Renewables. • Electric Utilities and Infrastructure will be comprised of the regulated electric utilities in the Carolinas, Florida and the Midwest. This segment will also include the commercial transmission infrastructure investments. • Gas Utilities and Infrastructure will contain Piedmont, Duke Energy's local distribution companies in Ohio and Kentucky, and gas storage and pipeline investments. • Commercial Renewables will primarily include the company's non-regulated utility scale wind and solar generation assets. • International Energy will remain a segment until the divestiture is complete, although results of the equity method investment in NMC will be recast to Other in the fourth quarter of 2016. See Note 2 for further information on the Piedmont and International Energy transactions.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2016
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS RATE RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO 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, Kentucky and Indiana), as well as sales of transmission service. Duke Energy Carolinas and Duke Energy Progress Ash Basin Closure Costs Deferral On July 13, 2016, in response to a joint petition of Duke Energy Carolinas and Duke Energy Progress, the PSCSC issued an accounting order for the deferment into a regulatory account 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 South Carolina. The decision allows for ash basin closure expenses to be partially offset with excess regulatory liability amounts from the deferral of nuclear decommissioning costs that are collected from South Carolina retail customers and for Duke Energy Progress to offset incurred ash basin closure costs with costs of removal amounts collected from customers. The PSCSC's ruling does not change retail rates or the tariff amounts and in no way limits the PSCSC's ability to challenge the reasonableness of expenditures in subsequent proceedings. FERC Transmission Return on Equity Complaints On January 7, 2016, a group of transmission service customers filed a complaint with FERC that the rate of return on equity of 10.2 percent in Duke Energy Carolinas' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On the same date, a similar complaint was filed with FERC claiming that the rate of return on equity of 10.8 percent in Duke Energy Progress' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On April 21, 2016, FERC issued an order which consolidated the cases, set a refund effective date of January 7, 2016, and set the consolidated case for settlement and hearing. On June 14, 2016, Duke Energy Carolinas and Duke Energy Progress reached a settlement agreement in principle to reduce the return on equity for both companies to 10 percent . On August 19, 2016, Duke Energy Carolinas and Duke Energy Progress filed for FERC approval of the settlement agreement. Duke Energy Carolinas and Duke Energy Progress do not expect the potential impact on results of operations, cash flows or financial position to be material. Duke Energy Carolinas Advanced Metering Infrastructure Deferral On July 12, 2016, the PSCSC issued an accounting order for Duke Energy Carolinas to defer the financial effects of depreciation expense incurred for the installation of advanced metering infrastructure (AMI) meters, the carrying costs on the investment at its weighted average cost of capital and the carrying costs on the deferred costs at its weighted average cost of capital not to exceed $45 million . The decision also allows Duke Energy Carolinas to continue to depreciate the non-AMI meters to be replaced. Current retail rates will not change as a result of the decision and the PSCSC's ability to challenge the reasonableness of expenditures in subsequent proceedings is not limited. 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. Duke Energy Carolinas filed its response on June 13, 2016, and SCCL and SACE filed a reply on June 23, 2016. On September 6, 2016, the Small Business Chamber of Commerce filed a motion for permission to file a brief supporting the environmental intervenors’ position. On September 22, 2016, the South Carolina Supreme Court granted permission for the brief, and allowed Duke Energy Carolinas an opportunity to file a response, which was filed on October 3, 2016. Duke Energy Carolinas cannot predict the outcome of this matter. Duke Energy Progress South Carolina Rate Case On July 1, 2016, Duke Energy Progress filed an application with the PSCSC requesting an average 14.5 percent increase in retail revenues. The requested rate change would increase annual revenues by approximately $79 million , with a rate of return on equity of 10.75 percent . The increase is designed to recover the cost of investment in new generation infrastructure, environmental expenditures including allocated historical ash basin closure costs and increased nuclear operating costs. Duke Energy Progress has requested new rates to be effective January 1, 2017. On October 19, 2016, Duke Energy Progress, the ORS and intervenors entered into a settlement agreement that was filed with the PSCSC on the same day. Terms of the settlement agreement include an approximate $56 million increase in revenues over a two-year period. An increase of approximately $38 million in revenues would be effective January 1, 2017, and an increase of approximately $18.5 million in revenues would be effective January 1, 2018. Duke Energy Progress will amortize approximately $18.5 million from the cost of removal reserve in 2017. Other settlement terms include a rate of return on equity of 10.1 percent , agreement to implement nuclear levelization accounting in South Carolina, and ongoing deferral of allocated ash basin closure costs from July 1, 2016, until the next base rate case. The settlement also provides that Duke Energy Progress will not seek an increase in rates in South Carolina to occur prior to 2019, with limited exceptions. A hearing was held on October 31, 2016. Duke Energy Progress cannot predict the outcome of this matter. Western Carolinas Modernization Plan On November 4, 2015, in response to community feedback, Duke Energy Progress announced a revised Western Carolinas Modernization Plan with an estimated cost of $1.1 billion . The revised plan includes 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 revised plan includes upgrades to existing transmission lines and substations, but eliminates the need for a new transmission line and a new substation associated with the project in South Carolina. The revised plan has the same overall project cost as the original plan and the plans to install solar generation remain unchanged. Duke Energy Progress has also proposed to add 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. The plan requires various approvals including regulatory approvals in North Carolina. Duke Energy Progress filed for a Certificate of Public Convenience and Necessity (CPCN) with the NCUC for the new natural gas units on January 15, 2016. On March 28, 2016, the NCUC issued an order approving the 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. Site preparation activities are underway and construction of these plants is scheduled to begin in early 2017. The plants are expected to be in service by late 2019. Duke Energy Progress plans to file for future approvals related to the proposed solar generation and pilot battery storage project. On May 27, 2016, N.C. Waste Awareness and Reduction Network (NC WARN) and The Climate Times filed a notice of appeal from the CPCN order to the N.C. Court of Appeals. On May 31, 2016, Duke Energy Progress filed a motion to dismiss the notice of appeal with the NCUC due to NC WARN's and The Climate Times' failure to post a required appeal bond. After a series of filings, an NCUC order, petitions to the N.C. Court of Appeals and an evidentiary hearing, on July 8, 2016, the NCUC issued an order setting NC WARN's and The Climate Times' appeal bond at $98 million . On July 28, 2016, NC WARN and The Climate Times filed a notice of appeal and exceptions from the NCUC's July 8, 2016, appeal bond order. On August 2, 2016, the NCUC granted Duke Energy Progress' motion to dismiss NC WARN's and The Climate Times' notice of appeal from the CPCN order due to failure to post the requisite bond. On August 18, 2016, NC WARN and The Climate Times filed a petition with the N.C. Court of Appeals seeking appellate review of the NCUC’s CPCN order, the July 8, 2016, appeal bond order and the August 2, 2016, order dismissing their notice of appeal, which the N.C. Court of Appeals denied on September 6, 2016. On September 19, 2016, the NCUC granted Duke Energy Progress' motion to dismiss NC WARN's and The Climate Times' subsequent appeal of the second bond order dated July 28, 2016, and NC WARN's and The Climate Times' subsequent appeal of the CPCN order and dismissal order dated August 18, 2016. On October 17, 2016, NC WARN and The Climate Times filed another petition for review with the N.C. Court of Appeals asking the court to reverse the CPCN order, the second bond order and the dismissal of their first and second notices of appeal as to the CPCN order. Duke Energy Progress cannot predict the outcome of this matter. The carrying value of the 376 MW Asheville coal-fired plant, including associated ash basin closure costs, of $562 million and $548 million are included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheet as of September 30, 2016 and December 31, 2015 , respectively. Duke Energy Florida Hines Chiller Uprate Project On May 20, 2016, 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 station. Duke Energy Florida proposed to complete the Uprate Project in two phases: Phase one to include work on Hines Units 1-3 and common equipment, to be placed in service during October 2016; and Phase two work on Hines Unit 4 to be placed in service during January 2017. The final combined construction cost estimate for both phases of approximately $150 million is below the cost estimate provided during the need determination proceeding. Duke Energy Florida estimated an annual retail revenue requirement for Phase one and Phase two of approximately $17 million and $3 million , respectively. On August 29, 2016, the FPSC approved the Phase one revenue requirement to be effective in customer rates in November 2016. However, Duke Energy Florida made filings with the FPSC in October 2016 to remove the Uprate Project from customer rates because a portion of the common equipment required for either phase to be considered in-service will not be completed as expected. Duke Energy Florida is evaluating the potential impact to cost estimates related to the delay of the project. Duke Energy Florida will file for recovery of the costs associated with the Uprate Project at a later date. Duke Energy Florida cannot predict the outcome of this matter. Purchase of Osprey Energy Center In December 2014, Duke Energy Florida and Osprey Energy Center, LLC, a wholly owned subsidiary of Calpine Corporation (Calpine), entered into an Asset Purchase and Sale Agreement for the purchase of a 599 MW combined-cycle natural gas plant in Auburndale, Florida (Osprey Plant acquisition) for approximately $166 million . In July 2015, the FERC and the FPSC issued separate orders of approval for the Osprey Plant acquisition. The Hart-Scott-Rodino waiting period expired on May 2, 2016. Closing of the acquisition is expected to occur in January 2017, upon the expiration of an existing Power Purchase Agreement between Calpine and Duke Energy Florida. In anticipation of closing, on August 29, 2016, Duke Energy Florida filed a petition seeking approval to include in base rates the revenue requirements for the Osprey Plant acquisition to be included in customer bills beginning in February 2017. Duke Energy Florida estimates the retail revenue requirements for the Osprey acquisition to be approximately $48 million . On November 1, 2016, the FPSC approved the Osprey Plant acquisition and the petition to include the revenue requirements in base rates. Crystal River Unit 3 Regulatory Asset In June 2015, the governor of Florida signed legislation to allow utilities to issue nuclear asset-recovery bonds to finance the recovery of certain retired nuclear generation assets, with approval of the FPSC. In November 2015, the FPSC issued a financing order approving Duke Energy Florida’s request to issue nuclear asset-recovery bonds to finance its unrecovered regulatory asset related to Crystal River Unit 3 (Crystal River 3) through a wholly owned special purpose entity. Nuclear asset-recovery bonds replace the base rate recovery methodology authorized by the 2013 Revised and Restated Stipulation and Settlement Agreement (2013 Agreement) and result in a lower rate impact to customers with a recovery period of approximately 20 years . Pursuant to provisions in Florida Statutes and the FPSC financing order, in 2016, Duke Energy Florida formed Duke Energy Florida Project Finance, LLC (DEFPF), a wholly owned, bankruptcy remote special purpose subsidiary for the purpose of issuing nuclear asset-recovery bonds. In June 2016, DEFPF issued $1,294 million aggregate principal amount of senior secured bonds (nuclear asset-recovery bonds) to finance the recovery of Duke Energy Florida's Crystal River 3 regulatory asset. In connection with this financing, net proceeds to DEFPF of approximately $1,287 million , after underwriting costs, were used to acquire nuclear asset-recovery property from Duke Energy Florida and to pay transaction related expenses. The nuclear asset-recovery property includes the right to impose, bill, collect and adjust a non-bypassable nuclear asset-recovery charge, to be collected on a per kilowatt-hour basis from all Duke Energy Florida retail customers until the bonds are paid in full. Duke Energy Florida began collecting the nuclear asset-recovery charge on behalf of DEFPF in customer rates in July 2016. See Notes 6 and 13 for additional information. Duke Energy Ohio Base Rate Case In connection with Duke Energy Ohio’s deployment of SmartGrid network, consisting of investments in AMI and distribution automation, a rider was established to recover these investments and return expected savings to customers. A stipulation in establishing this rider was approved by the PUCO in 2012, whereby Duke Energy Ohio committed to filing a base electric distribution case within one year of full deployment of SmartGrid. On October 22, 2015, PUCO staff concluded that full deployment had occurred thereby, absent relief by the PUCO, Duke Energy Ohio would be required to file a base electric rate case proceeding no later than October 22, 2016. A number of proceedings have been initiated by the PUCO related to continued development of retail markets in Ohio including questions related to demand-side management, time-differentiated pricing and AMI that would impact such a base rate filing. On September 15, 2016, Duke Energy Ohio requested the PUCO approve a waiver of the condition in the 2012 stipulation to file a base rate case. On September 22, 2016, the Office of the Ohio Consumers' Counsel filed an objection to the waiver request and, on October 12, 2016, PUCO Staff filed a reply proposing a filing date no later than July 21, 2017. 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. The proposed project involves the installation of a natural gas line and is estimated to cost between $86 million and $110 million , excluding AFUDC. On September 13, 2016, Duke Energy Ohio filed 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 by early 2019. 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 AMI. Duke Energy Kentucky anticipates that the estimated $49 million project, if approved, will take about 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 that will be replaced. On July 20, 2016, the Kentucky Attorney General, the only intervenor in the proceeding, moved to dismiss the application. Duke Energy Kentucky filed its opposition to the Kentucky Attorney General's motion to dismiss on July 27, 2016. On September 28, 2016, the KPSC denied the Kentucky Attorney General's motion to dismiss and granted Duke Energy Kentucky's motion to file rebuttal testimony. An evidentiary hearing is scheduled for December 1, 2016. Duke Energy Kentucky cannot predict the outcome of this matter. 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 current projected total capital and operations and maintenance expenditures under the ASRP is approximately $240 million . The filing also sought approval of 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. The PUCO did, however, encourage Duke Energy Ohio to work with the PUCO Staff and intervenors to identify a reasonable solution for the risks attributed to service line leaks caused by corrosion. Duke Energy Ohio is currently evaluating the order. 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. After a comment period, 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 to 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 July 8, 2015. On January 6, 2016, Duke Energy Ohio and PUCO Staff entered into a stipulation pending PUCO approval, resolving the issues related to, among other things, performance incentives and the PUCO Staff audit of 2013 costs. Based on the stipulation, in December 2015, Duke Energy Ohio re-established approximately $20 million of revenues that had been reversed in the second quarter of 2015. On October 26, 2016, the PUCO issued an order approving the stipulation without modification. 2012 Natural Gas Rate Case/Manufactured Gas Plant Cost Recovery On November 13, 2013, the PUCO issued an order (PUCO 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 that appeal remains pending. Oral argument is scheduled for February 28, 2017. Investigation and remediation expenses at these MGP sites that have not been collected through the MGP rider are approximately $101 million and are recorded as Regulatory assets on Duke Energy Ohio's Condensed Consolidated Balance Sheet as of September 30, 2016. The PUCO order also contained deadlines for completing the MGP environmental investigation and remediation costs at the MGP sites. For the property known as the East End site the PUCO order established a deadline of December 31, 2016. As of September 30, 2016, $46 million of the regulatory asset represents future remediation cost expected to be incurred at the East End site after 2016. The PUCO order authorized Duke Energy Ohio to seek to extend these deadlines due to certain circumstances. On May 16, 2016, Duke Energy Ohio filed an application to extend the deadline for cost recovery applicable to the East End site. The PUCO set a procedural schedule for filing comments on the application and associated replies for November 23, 2016, and December 2, 2016, respectively. 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 Interconnection, LLC (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 $91 million and $92 million , respectively, at September 30, 2016 and December 31, 2015 , within Other in Current liabilities and Other in Deferred credits and other liabilities on Duke Energy Ohio’s 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 September 30, 2016 and December 31, 2015, Duke Energy Ohio had $72 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. 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 Coal Combustion Residual (CCR) rule compliance projects (Phase I CCR Compliance Projects) to comply with the U.S. Environmental Protection Agency's (EPA) 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 and incremental operating and maintenance costs under a federal mandate tracker which 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. An evidentiary hearing is scheduled for February 2017. Duke Energy Indiana cannot predict the outcome of this matter. Edwardsport Integrated Gasification Combined Cycle Plant On November 20, 2007, the IURC granted Duke Energy Indiana a CPCN for the construction of the Edwardsport Integrated Gasification Combined Cycle (IGCC) Plant. The Citizens Action Coalition of Indiana, Inc., Sierra Club, Inc., Save the Valley, Inc., and Valley Watch, Inc. (collectively, the Joint Intervenors) were intervenors in several matters related to the Edwardsport IGCC Plant. The Edwardsport IGCC Plant was placed in commercial operation in June 2013. Costs for the Edwardsport IGCC Plant are recovered from retail electric customers via a tracking mechanism (IGCC rider). The ninth semi-annual IGCC rider order was appealed by the Joint Intervenors. The proceeding has been remanded to the IURC for further proceedings and additional findings on the tax in-service issue. An evidentiary hearing was held on September 13, 2016, and an order is expected by early 2017. Duke Energy Indiana cannot predict the outcome of this matter. The 11th through 15th semi-annual IGCC riders and a subdocket to Duke Energy Indiana's fuel adjustment clause were approved by the IURC as part of an August 2016 settlement agreement. Issues in these filings included the determination whether the IGCC plant was properly declared in-service for ratemaking purposes in June 2013 and a review of the operational performance of the plant. On September 17, 2015, Duke Energy Indiana, the Office of Utility Consumer Counselor, the Industrial Group and Nucor Steel Indiana reached a settlement agreement to resolve these pending issues. On January 15, 2016, The Citizens Action Coalition of Indiana, Inc., Sierra Club, Save the Valley and Valley Watch joined a revised settlement (IGCC settlement). The IGCC settlement resulted in customers not being billed for previously incurred operating costs of $87.5 million , and for additional Duke Energy Indiana payments and commitments of $5.5 million for attorneys’ fees and amounts to fund consumer programs. Attorneys’ fees and expenses for the new settling parties will be addressed in a separate proceeding. Duke Energy Indiana recognized pretax impairment and related charges of $93 million in 2015. Additionally, under the IGCC settlement, the recovery of operating and maintenance expenses and ongoing maintenance capital at the plant are subject to certain caps during the years of 2016 and 2017. The IGCC settlement also includes a commitment to either retire or stop burning coal by December 31, 2022, at the Gallagher Station. Pursuant to the IGCC settlement, the in-service date used for accounting and ratemaking will remain as June 2013. Remaining deferred costs will be recovered over eight years and not earn a carrying cost. On August 24, 2016, the IURC approved the settlement in full with no changes or conditions. The order was not appealed and the proceeding is concluded. As of September 30, 2016 , deferred costs related to the project are approximately $184 million . Under the IGCC settlement, future IGCC riders will be filed annually, rather than every six months, with the next filing scheduled for first quarter 2017. FERC Transmission Return on Equity Complaint Customer groups have filed with 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 latest complaint, filed on February 12, 2015, claims the base rate of return on equity should be reduced to 8.67 percent and requests a consolidation of complaints. The motion to consolidate complaints was denied. On January 5, 2015, FERC issued an order accepting the MISO transmission owners' 0.50 percent adder 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. A hearing in the base return on equity proceeding was held in August 2015. On December 22, 2015, the presiding FERC ALJ in the first complaint issued an Initial Decision in which he set the base rate of return on equity at 10.32 percent . On September 28, 2016, the Initial Decision in the first complaint was affirmed by FERC. 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. Duke Energy Indiana currently believes these matters will not have a material impact on its results of operations, cash flows and financial position. Grid Infrastructure Improvement Plan On August 29, 2014, pursuant to a new statute, Duke Energy Indiana filed a seven-year grid infrastructure improvement plan with the IURC with an estimated cost of $1.9 billion , focusing on the reliability, integrity and modernization of the transmission and distribution system. The plan also provided for cost recovery through a tra

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES ENVIRONMENTAL Duke Energy is subject to international, federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. The Subsidiary 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. Remediation Activities In addition to Asset Retirement Obligations (AROs) 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 in 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 Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 Provisions/adjustments 34 5 5 2 3 6 20 Cash reductions (12 ) (4 ) (6 ) (2 ) (4 ) (1 ) (2 ) Balance at end of period $ 119 $ 11 $ 16 $ 3 $ 13 $ 59 $ 30 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 5 $ 12 $ 54 $ 10 Provisions/adjustments 4 — 3 — 3 1 3 Cash reductions (4 ) — (2 ) (1 ) (1 ) (1 ) (1 ) Balance at end of period $ 97 $ 10 $ 18 $ 4 $ 14 $ 54 $ 12 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 $ 69 Duke Energy Carolinas 22 Duke Energy Ohio 36 Duke Energy Indiana 7 North Carolina and South Carolina Ash Basins On February 2, 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. On February 8, 2014, a permanent plug was installed in the stormwater pipe, stopping the release of materials into the 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 and continues to cooperate with the EPA's civil enforcement process. Future costs related to the Dan River release, including pending or future state or federal civil enforcement proceedings, future regulatory directives, natural resources damages, additional pending litigation, 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 Notices 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 Plant and Dan River Steam Station. These assessed penalties were unprecedented and inconsistent with historic enforcement practices of the NCDEQ. Based on historic practices, the expected liability of any existing NOVs would not be material. 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 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 (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 January 21, 2015, the Duke Energy Defendants filed a Motion to Stay and an alternative Motion to Dismiss. On August 31, 2015, the court issued an order staying the case which was lifted on March 24, 2016. 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 March 5, 2015, shareholder Judy Mesirov filed a shareholder derivative complaint (Mesirov Complaint) in North Carolina state court. The lawsuit, styled Mesirov v. Good , is similar to the consolidated derivative action pending in Delaware Chancery Court and was filed against the same current directors and former directors and officers as the Delaware litigation. Duke Energy Corporation, Duke Energy Progress and Duke Energy Carolinas are named as nominal defendants. The Mesirov Complaint alleges that the Duke Energy Board of Directors was aware of Clean Water Act (CWA) compliance issues and failures to maintain structures in ash basins, but that the Board of Directors did not require Duke Energy Carolinas and Duke Energy Progress to take action to remedy deficiencies. The Mesirov Complaint further alleges that the Board of Directors sanctioned activities to avoid compliance with the law by allowing improper influence of the NCDEQ to minimize regulation and by opposing previously anticipated citizen suit litigation. The Mesirov Complaint seeks corporate governance reforms and damages relating to costs associated with the Dan River release, remediation of ash basins that are out of compliance with the CWA and defending and payment of fines, penalties and settlements relating to criminal and civil investigations and lawsuits. The case was stayed until July 1, 2016. On July 5, 2016, the plaintiff filed a Notice of Voluntary Dismissal Without Prejudice, closing this matter. In addition to the above derivative complaints, in 2014, Duke Energy also received two shareholder litigation demand letters. The letters alleged that the members of the Board of Directors and certain officers breached their fiduciary duties by allowing the company to illegally dispose of and store coal ash pollutants. One of the letters also alleged a breach of fiduciary duty in the decision-making relating to the leadership changes following the close of the Progress Energy merger in July 2012. By letter dated September 4, 2015, attorneys for the shareholders were informed that, on the recommendation of the Demand Review Committee formed to consider such matters, the Board of Directors concluded not to pursue potential claims against individuals. One of the shareholders, Mitchell Pinsly, sent a formal demand for records and Duke Energy responded to this request. 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 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. The Bresalier Defendants filed a Motion to Dismiss the Bresalier litigation on January 15, 2016. In lieu of a response to the Motion to Dismiss, the plaintiff filed a Motion to Convert the Bresalier Defendants' Motion to Dismiss into a Motion for Summary Judgment and also for limited discovery. Following a hearing on June 15, 2016, the court denied the plaintiff's Motion to Convert and is requiring the parties to complete briefing on the Bresalier Defendants' Motion to Dismiss. On July 29, 2016, the Bresalier Defendants filed an Amended Motion to Dismiss. As discussed below, an agreement-in-principle has been reached to settle the merger related claims in the Bresalier Complaint. 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 11 members of the Board of Directors who were also members of the pre-merger Board of Directors (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 have 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 . The entire settlement amount is to be funded by insurance. The settlement amount, less court-approved attorney fees, will be payable to Duke Energy. The settlement is subject to the execution of definitive settlement documents and court approval. 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 pending in a consolidated federal court proceeding in Nevada. Each of these lawsuits contains 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 seek 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. Settlement of the class action lawsuits are currently being finalized and will be subject to court approval. The settlement amounts are not material to Duke Energy. Brazil Expansion Lawsuit On August 9, 2011, the State of São Paulo sued Duke Energy International Geracao Paranapenema S.A. (DEIGP) in Brazilian state court. The lawsuit claims DEIGP is under a continuing obligation to expand installed generation capacity in the State of São Paulo by 15 percent pursuant to a stock purchase agreement under which DEIGP purchased generation assets from the state. On August 10, 2011, a judge granted an injunction ordering DEIGP to present a detailed expansion plan in satisfaction of the 15 percent obligation. DEIGP has previously taken a position that the expansion obligation is no longer viable given changes that have occurred in the electric energy sector since privatization. DEIGP submitted its proposed expansion plan on November 11, 2011, but reserved objections regarding enforceability. In January 2013, DEIGP filed appeals in the federal courts, which are still pending, regarding various procedural issues. A decision on the merits in the first instance court is also pending. 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 this matter. In February 2008, a group of individual plaintiffs filed suit against DEIGP, the State of São Paulo and the Brazilian electricity regulatory agency claiming that DEIGP failed to comply with its alleged obligation to expand installed generation capacity in the state of São Paulo by 15 percent . The lawsuit was dismissed as procedurally defective by the first instance federal court in São Paulo. On December 15, 2010, plaintiffs filed an appeal of the first instance court dismissal order. On September 23, 2016, in a split decision, three appellate court judges voted to reverse the first instance court decision. Due to the split decision, a review by an expanded five-judge panel has been scheduled for November 10, 2016. If the first instance court decision is reversed, the case will be remanded for continuation of the originally filed proceedings. 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 this matter. Pursuant to the Brazil PSA, Duke Energy will not retain any liability for this matter after the closing of the sale. See Note 2 for additional information regarding the Brazil PSA. Brazil Generation Record drought conditions in Brazil during 2014 and 2015 negatively impacted DEIGP. A number of electric generators have filed lawsuits seeking relief in the Brazilian courts to mitigate hydrological exposure and diminishing dispatch levels. Some courts have granted injunction orders to limit the financial exposure of certain generators. The implication of these orders is that other electricity market participants not covered by the injunctions may be required to compensate for the financial impact of the liability limitations. The Independent Power Producer Association (APINE) filed one such lawsuit on behalf of DEIGP and other hydroelectric generators against the Brazilian electric regulatory agency (ANEEL). On July 2, 2015, an injunction was granted in favor of APINE limiting the financial exposure of DEIGP and the other plaintiff generators, until the merits of the lawsuit are determined. ANEEL's appeal of the injunction was denied on December 18, 2015. The outcome of these lawsuits is uncertain. It is not possible to predict the impact to Duke Energy from the outcome of these matters. Pursuant to the Brazil PSA, Duke Energy will not retain any liability for this matter after the closing of the sale. See Note 2 for additional information regarding the Brazil PSA. Duke Energy Carolinas and Duke Energy Progress NCDEQ Notices of Violation In August 2014, the NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' L.V. Sutton Plant. On March 10, 2015, the NCDEQ issued a civil penalty of approximately $25 million to Duke Energy Progress for environmental damages related to the groundwater contamination at the L.V. Sutton Plant. On April 9, 2015, Duke Energy Progress filed a Petition for Contested Case hearing in the Office of Administrative Hearings. In February 2015, the NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' Asheville Plant. Duke Energy Progress responded to the NCDEQ regarding this NOV. On September 29, 2015, Duke Energy Progress and Duke Energy Carolinas entered into a settlement agreement with the NCDEQ resolving all former, current and future groundwater penalties at all Duke Energy Carolinas and Duke Energy Progress coal facilities in North Carolina. Under the agreement, Duke Energy Progress paid approximately $6 million and Duke Energy Carolinas paid approximately $1 million . In addition to these payments, Duke Energy Progress and Duke Energy Carolinas will accelerate remediation actions at the Sutton, Asheville, Belews Creek and H.F. Lee plants. The ALJ entered a consent order resolving the contested case relating to the Sutton Plant and the NCDEQ rescinded the NOVs relating to alleged groundwater violations at both the Sutton and Asheville plants. On October 13, 2015, the Southern Environmental Law Center (SELC), representing multiple conservation groups, filed a lawsuit in North Carolina Superior Court seeking judicial review of the order approving the settlement agreement with the NCDEQ. The conservation groups contend that the ALJ exceeded his statutory authority in approving a settlement that provided for past, present, and future resolution of groundwater issues at facilities which were not at issue in the penalty appeal. On December 18, 2015, Duke Energy Carolinas and Duke Energy Progress filed a Motion to Dismiss the complaint. On February 12, 2016, the ALJ entered a new order clarifying that the dismissal of the contested case only applied to the specific issues before the ALJ in the Petition for Contested Case. On March 10, 2016, the court dismissed the SELC lawsuit based on the ALJ's entry of the new order. On February 8, 2016, the NCDEQ assessed a penalty of approximately $6.8 million , including enforcement costs, against Duke Energy Carolinas related to storm water pipes and associated discharges at the Dan River Steam Station. Duke Energy Carolinas recorded a charge in December 2015 for this penalty. In March 2016, Duke Energy Carolinas filed an appeal of this penalty. On September 23, 2016, Duke Energy Carolinas entered into a settlement agreement with the NCDEQ, without admission of liability, under which Duke Energy Carolinas agreed to a payment of $6 million to resolve allegations underlying the asserted civil penalty related to the Dan River coal ash release and a March 4, 2016, NOV alleging unpermitted discharges at the facility. NCDEQ State Enforcement Actions In the first quarter of 2013, SELC sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged 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. On July 10, 2015, Duke Energy Carolinas and Duke Energy Progress filed two Motions for Partial Summary Judgment in the case on the basis that there is no longer either a genuine controversy or disputed material facts about the relief for seven of the 14 North Carolina plants with coal ash basins. On September 14, 2015, the court granted the Motions for Partial Summary Judgment pending court approval of the terms through an order. On April 4, 2016, the court issued an order granting Duke Energy Progress' Motion for Partial Summary Judgment for cases involving the H.F. Lee, Cape Fear and Weatherspoon plants. On June 1, 2016, the court issued an order granting Duke Energy Carolinas' and Duke Energy Progress' Motion for Partial Summary Judgment for cases involving the Asheville, Dan River, Riverbend and Sutton plants. The litigation is concluded for these seven plants. Litigation continues for the remaining seven plants. 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 There are currently three cases filed in various North Carolina federal courts related to the Sutton, Buck and Mayo plants. Three other previously filed cases involving the Riverbend, Cape Fear and H.F. Lee plants were dismissed on June 7, 2016. On September 12, 2013, Cape Fear River Watch, Inc., Sierra Club and Waterkeeper Alliance filed a citizen suit in the Federal District Court for the Eastern District of North Carolina. The lawsuit alleges unpermitted discharges to surface water and groundwater violations at the Sutton Plant. On June 9, 2014, the court granted Duke Energy Progress' request to dismiss the groundwater claims but rejected its request to dismiss the surface water claims. In response to a motion filed by the SELC on August 1, 2014, the court modified the original order to dismiss only the plaintiff's federal law claim based on hydrologic connections at Sutton Lake. The claims related to the alleged state court violations of the permits are back in the case. On August 26, 2015, the court suspended the proceedings until further order from the court. The proceedings remain stayed as the parties negotiate a settlement with SELC subsequent to the court granting summary judgment in the state enforcement litigation. On September 3, 2014, three citizen suits were filed by various environmental groups: (i) a citizen suit in the United States Court for the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Cape Fear Plant; (ii) in the United States Court for the Eastern District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the H.F. Lee Plant; and (iii) in the United States Court for the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Buck Steam Station. Motions to Stay or Dismiss the proceedings were filed in each of the three cases. The proceedings related to Cape Fear and H.F. Lee were dismissed on June 8, 2016, closing these matters. On October 20, 2015, the court issued an order denying the motions to stay or dismiss in the Buck proceedings. Duke Energy Carolinas' motion seeking appellate review of the District Court's decision relating to Buck was denied on January 29, 2016. Based on Duke Energy’s announcement that it will beneficially recycle ash at the Buck Steam Station, Duke Energy Carolinas reached an agreement with the environmental groups to settle the Buck Steam Station proceeding on September 28, 2016. On June 13, 2016, the Roanoke River Basin Association 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 the complaint. It is not possible to predict whether Duke Energy Carolinas or Duke Energy Progress will incur any liability or to estimate the damages, if any, they might incur in connection with these matters. 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 North Carolina Coal Ash Management Act of 2014, as amended, (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 the 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 the 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 impoundments, 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 have agreed to a two-phased mediation. The first phase took place on October 26, 2016, with the second phase scheduled for November 17, 2016. It is not possible to estimate the maximum exposure of loss, if any, that may occur in connection with the claims made by 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 September 30, 2016 , there were 120 asserted claims for non-malignant cases with the cumulative relief sought of up to $32 million , and 78 asserted claims for malignant cases with the cumulative relief sought of up to $14 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 $512 million at September 30, 2016 and $536 million at December 31, 2015 . These reserves are classified in Other within Deferred Credits and Other 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 2033, 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 2033 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 $567 million at September 30, 2016 and $599 million at December 31, 2015 . These amounts are classified in Other within Investments and Other Assets and Receivables 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. Following a ruling on the motion for reconsideration, the plaintiffs will have 30 days to file an 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 the terminated Engineering, Procurement and Construction agreement (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 contrac

Debt and Credit Facilities

Debt and Credit Facilities	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt And Credit Facilities	DEBT AND CREDIT FACILITIES SUMMARY OF SIGNIFICANT DEBT ISSUANCES Piedmont Acquisition Financing In August 2016, Duke Energy issued $3.75 billion of senior unsecured notes in three separate series. The net proceeds were used to finance a portion of the Piedmont acquisition. The $4.9 billion Bridge Facility was terminated following the issuance of this debt. See Note 2 for additional information on the Piedmont acquisition. Solar Facilities Financing In August 2016, Emerald State Solar, LLC, an indirect wholly owned subsidiary of Duke Energy, entered into a portfolio financing of approximately 22 North Carolina Solar facilities. The $333 million term loan facility consists of Tranche A of $228 million secured by substantially all the assets of the solar facilities and Tranche B of $105 million secured by an Equity Contribution Agreement with Duke Energy. Proceeds were used to reimburse Duke Energy for a portion of previously funded construction expenditures related to the Emerald State Solar, LLC portfolio. The initial interest rate on the loans was six months London Interbank Offered Rate (LIBOR) plus an applicable margin of 1.75 percent plus a 0.125 percent increase every three years thereafter. In connection with this debt issuance, Emerald State Solar, LLC entered into two interest rate swaps to convert the substantial majority of the loan interest payments from variable rates to fixed rates of approximately 1.81 percent for Tranche A and 1.38 percent for Tranche B, plus the applicable margin. See Note 10 for further information on the notional amounts of the interest rate swaps. Nuclear Asset-Recovery Bonds In June 2016, DEFPF issued $1,294 million of nuclear asset-recovery bonds and used the proceeds to acquire nuclear asset-recovery property from its parent, Duke Energy Florida. The nuclear asset-recovery bonds are payable only from and secured by the nuclear asset-recovery property. DEFPF is consolidated for financial reporting purposes; however, the nuclear asset-recovery bonds do not constitute a debt, liability or other legal obligation of, or interest in, Duke Energy Florida or any of its affiliates other than DEFPF. The assets of DEFPF, including the nuclear asset-recovery property, are not available to pay creditors of Duke Energy Florida or any of its affiliates. Duke Energy Florida used the proceeds from the sale to repay short-term borrowings under the intercompany money pool borrowing arrangement and make an equity distribution of $649 million to the ultimate parent, Duke Energy (Parent), which repaid short-term borrowings. See Notes 4 and 13 for additional information. The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Unsecured April 2016 (a) April 2023 2.875 % $ 350 $ 350 $ — $ — $ — $ — $ — August 2016 September 2021 1.800 % 750 750 — — — — — August 2016 September 2026 2.650 % 1,500 1,500 — — — — — August 2016 September 2046 3.750 % 1,500 1,500 — — — — — First Mortgage Bonds March 2016 (b) March 2023 2.500 % 500 — 500 — — — — March 2016 (b) March 2046 3.875 % 500 — 500 — — — — May 2016 (c) May 2046 3.750 % 500 — — — — — 500 June 2016 (b) June 2046 3.700 % 250 — — — — 250 — September 2016 (d) October 2046 3.400 % 600 — — — 600 — — September 2016 (b) October 2046 3.700 % 450 — — 450 — — — Secured Debt June 2016 (e) March 2020 1.196 % 183 — — — 183 — — June 2016 (e) September 2022 1.731 % 150 — — — 150 — — June 2016 (e) September 2029 2.538 % 436 — — — 436 — — June 2016 (e) March 2033 2.858 % 250 — — — 250 — — June 2016 (e) September 2036 3.112 % 275 — — — 275 — — August 2016 June 2034 2.747 % 228 — — — — — — August 2016 June 2020 2.747 % 105 — — — — — — Total issuances $ 8,527 $ 4,100 $ 1,000 $ 450 $ 1,894 $ 250 $ 500 (a) Proceeds were used to pay down outstanding commercial paper and for general corporate purposes. (b) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. (c) Proceeds were used to repay $325 million of unsecured debt due June 2016, $150 million of first mortgage bonds due July 2016 and for general corporate purposes. (d) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance, to repay short-term borrowings under the intercompany money pool borrowing arrangement and for general corporate purposes. (e) The nuclear asset-recovery bonds are sequential pay amortizing bonds. The maturity date above represents the scheduled final maturity date for the bonds. 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 September 30, 2016 Unsecured Debt Duke Energy (Parent) November 2016 2.150 % $ 500 Duke Energy (Parent) April 2017 1.034 % 400 Duke Energy (a) May 2017 15.681 % 56 Duke Energy (Parent) August 2017 1.625 % 700 Secured Debt Duke Energy June 2017 2.155 % 45 First Mortgage Bonds Duke Energy Carolinas December 2016 1.750 % 350 Duke Energy Progress March 2017 1.035 % 250 Duke Energy Florida September 2017 5.800 % 250 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Other (b) 573 Current maturities of long-term debt $ 3,201 (a) The interest rate includes country-specific risk premiums. (b) Includes capital lease obligations, amortizing debt and small bullet maturities. AVAILABLE CREDIT FACILITIES Master Credit Facility Duke Energy has a Master Credit Facility with a capacity of $7.5 billion through January 2020. 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. September 30, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Facility size (a) $ 7,500 $ 3,400 $ 1,100 $ 1,000 $ 950 $ 450 $ 600 Reduction to backstop issuances Commercial paper (b) (1,652 ) (1,027 ) (300 ) (150 ) — (25 ) (150 ) Outstanding letters of credit (77 ) (70 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 5,155 $ 2,303 $ 511 $ 598 $ 949 $ 425 $ 369 (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 in the Condensed Consolidated Balance Sheets. Term Loan Facility On February 22, 2016, Duke Energy (Parent) entered into a six-month term loan facility with commitments totaling $1.0 billion (the Term Loan). On August 1, 2016, Duke Energy (Parent) and each of the lenders amended and restated certain terms of this facility, resulting in aggregate commitments of $1.5 billion and extending the maturity date to July 31, 2017. As of September 30, 2016 , $850 million has been drawn under the amended and restated term loan, including $750 million used to fund a portion of the Piedmont acquisition. On October 28, 2016, Duke Energy (Parent) drew the remaining $650 million available under the $1.5 billion Term Loan and used the proceeds to manage short-term liquidity and for general corporate purposes. The terms and conditions of the Term Loan are generally consistent with those governing Duke Energy’s Master Credit Facility.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2016
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS Duke Energy records an ARO when it has a legal obligation to incur retirement costs associated with the retirement of a long-lived asset and the obligation can be reasonably estimated. The following table presents the AROs recorded on the Condensed Consolidated Balance Sheets. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Decommissioning of Nuclear Power Facilities (a) $ 5,163 $ 1,808 $ 3,153 $ 2,428 $ 725 $ — $ — Closure of Ash Impoundments 5,411 2,089 2,418 2,398 20 77 828 Other 256 28 86 33 53 31 19 Total asset retirement obligation $ 10,830 $ 3,925 $ 5,657 $ 4,859 $ 798 $ 108 $ 847 Less: current portion 539 303 236 236 — — — Total noncurrent asset retirement obligation $ 10,291 $ 3,622 $ 5,421 $ 4,623 $ 798 $ 108 $ 847 (a) The Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy. North Carolina and South Carolina Ash Basins Asset retirement obligations recorded on the Duke Energy Carolinas and Duke Energy Progress Condensed Consolidated Balance Sheets at September 30, 2016 , and December 31, 2015 , include the legal obligation for closure of coal ash basins and the disposal of related ash as a result of the Coal Ash Act, the EPA CCR rule and other agreements. In January 2016, the NCDEQ published draft proposed risk classifications for sites not specifically delineated by the Coal Ash Act as high priority. These risk rankings were generally determined based on three primary criteria: structural integrity of the impoundments and impacts to both surface and groundwater. The NCDEQ's draft proposed classifications categorized 12 basins at four sites as intermediate risk and four basins at three sites as low risk. Basins at high priority sites (Dan River, Riverbend, Asheville and Sutton) require closure through excavation including a combination of transferring the ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of high-priority basins is required to be completed no later than August 1, 2019, except for Asheville which is required to be completed no later than August 1, 2022. Intermediate risk basins require closure through excavation including a combination of converting the basin to a lined industrial landfill, transferring of the ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of intermediate risk basins is required to be completed no later than December 31, 2024. Low risk basins require closure through either the combination of the installation and maintenance of a cap system and groundwater monitoring system designed to minimize infiltration and erosion or other closure options available to intermediate risk basins. Closure of low risk basins is required to be completed no later than December 31, 2029. The NCDEQ's draft proposed classifications also categorized nine basins at six sites as “low-to-intermediate” risk, thereby not assigning a definitive risk ranking at that time. On May 18, 2016, the NCDEQ issued new proposed risk classifications, proposing to rank all originally proposed low risk and "low-intermediate" risk sites as intermediate. On July 14, 2016, the governor of North Carolina signed legislation which amended the Coal Ash Act and required Duke Energy to undertake dam improvement projects and to provide access to a permanent alternative drinking water source to certain residents within a half mile of coal ash basin compliance boundaries and to certain other potentially impacted residents. The new legislation also ranks basins at the H.F. Lee, Cape Fear and Weatherspoon stations as intermediate risk consistent with Duke Energy's previously announced plans to excavate those basins. These specific intermediate basins require closure through excavation including a combination of transferring ash to an appropriate engineered landfill or conversion of the ash for beneficial use. Closure of these specific intermediate basins is required to be completed no later than August 1, 2028. Upon satisfactory completion of the dam improvement projects and installation of alternate drinking water sources by October 15, 2018, the legislation requires the NCDEQ to reclassify sites proposed as intermediate risk, excluding H.F. Lee, Cape Fear and Weatherspoon, as low risk. Additionally, the new legislation requires the installation and operation of three large-scale coal ash beneficiation projects which are expected to produce reprocessed ash for use in the concrete industry. Closure of basins at sites with these beneficiation projects are required to be completed no later than December 31, 2029 . On October 5, 2016, Duke Energy announced Buck Steam Station as a first location for one of the beneficiation projects. Per the Coal Ash Act, final proposed classifications were to be subject to Coal Ash Management Commission (Coal Ash Commission) approval. In March 2016, the Coal Ash Commission created by the Coal Ash Act was disbanded by the Governor of North Carolina based on a North Carolina Supreme Court ruling regarding the constitutionality of the body. The new legislation eliminates the Coal Ash Commission and transfers responsibility for ash basin closure oversight to the NCDEQ. Estimated asset retirement obligations have been recognized based on the assigned risk categories or a probability weighting of potential closure methods. Costs incurred have been deferred as regulatory assets and recovery will be pursued through the normal ratemaking process with federal and state utility commissions, which permit recovery of necessary and prudently incurred costs associated with Duke Energy’s regulated operations. ARO Liability Rollforward In April 2015, the EPA published a rule to regulate the disposal of CCR from electric utilities as solid waste. The federal regulation classifies CCR as nonhazardous waste and allows for beneficial use of CCR with some restrictions. Federal CCR reporting procedures require Duke Energy to make certain closure plans available to the public during the fourth quarter of 2016. In conjunction with preparing these closure plans, the Duke Energy Registrants updated coal ash ARO liability estimates based on additional site specific information about the related costs, methods and timing of work to be performed. Actual closure costs incurred could be materially different from current estimates that form the basis of the recorded asset retirement obligations. The following table presents the change in liability associated with asset retirement obligations for Duke Energy and the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2015 (a) $ 10,264 $ 3,918 $ 5,369 $ 4,567 $ 802 $ 125 $ 525 Accretion expense (b) 290 141 171 144 28 4 16 Liabilities settled (c) (443 ) (204 ) (203 ) (163 ) (41 ) (4 ) (31 ) Liabilities incurred in the current year 13 — 3 3 — — — Revisions in estimates of cash flows 706 70 317 308 9 (17 ) 337 Balance at September 30, 2016 $ 10,830 $ 3,925 $ 5,657 $ 4,859 $ 798 $ 108 $ 847 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash basins, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) For the nine months ended September 30, 2016, substantially all accretion expense relates to Duke Energy's regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (c) Primarily relates to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3. Asset retirement costs associated with the asset retirement obligations for operating plants and retired plants are included in Net property, plant and equipment, and Regulatory assets, respectively, on the Condensed Consolidated Balance Sheets.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL AND INTANGIBLE ASSETS GOODWILL The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Regulated International Commercial (in millions) Utilities Energy Portfolio Total Goodwill at December 31, 2015 $ 15,950 $ 271 $ 122 $ 16,343 Foreign exchange changes — 11 — 11 Goodwill at September 30, 2016 $ 15,950 $ 282 $ 122 $ 16,354 Duke Energy Ohio Duke Energy Ohio's Goodwill balance of $920 million is included in the Regulated Utilities operating segment and presented net of accumulated impairment charges of $216 million on the Condensed Consolidated Balance Sheets at September 30, 2016 and December 31, 2015 . Progress Energy Progress Energy's Goodwill is included in the Regulated Utilities operating segment and there are no accumulated impairment charges. Impairment Testing Duke Energy, Duke Energy Ohio and Progress Energy are required to perform an annual goodwill impairment test as of the same date each year and, accordingly, perform their annual impairment testing of goodwill as of August 31. Duke Energy, Duke Energy Ohio and Progress Energy update their test between annual tests if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. As the fair value of Duke Energy, Duke Energy Ohio and Progress Energy's reporting units exceed their respective carrying values at the date of the annual impairment analysis, no impairment charges were recorded in the third quarter of 2016.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2016
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 in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income. In addition to the amounts presented above, the Subsidiary Registrants record the impact on net income of 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 more information regarding money pool. The net impact of these transactions was not material for the three and nine months ended September 30, 2016 and 2015 for the Subsidiary Registrants. As discussed in Note 13 , 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. Duke Energy Ohio's nonregulated indirect subsidiary, Duke Energy Commercial Asset Management (DECAM), owned generating plants included in the Midwest Generation Disposal Group sold to Dynegy on April 2, 2015. On April 1, 2015, Duke Energy Ohio distributed its indirect ownership interest in DECAM to a Duke Energy subsidiary and non-cash settled DECAM's intercompany loan payable of $294 million . Refer to Note 2 for further information on the sale of the Midwest Generation Disposal Group. 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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging

Derivatives and Hedging	9 Months Ended
	Sep. 30, 2016
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. 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 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 affects 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 Accumulated other comprehensive income (AOCI) for the three and nine months ended September 30, 2016 , were not material. Duke Energy's interest rate derivatives designated as hedges include interest rate swaps used to hedge existing debt within the International Energy and Renewables' businesses. 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 Utilities 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. In August 2016, Duke Energy unwound $1.4 billion of forward-starting interest rate swaps associated with the Piedmont acquisition financing described in Note 6, Debt and Credit Facilities. The swaps were considered undesignated as they did not qualify for hedge accounting. Losses on the swaps of $22 million and $190 million are included within Interest Expense on the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2016 , respectively. 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. September 30, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 990 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,917 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,527 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $789 million and $497 million as of September 30, 2016 and December 31, 2015 , respectively. In August 2016, Duke Energy entered into $326 million of interest rate swaps related to the solar facilities financing described in Note 6 , including $103 million of 4-year swaps and $223 million of 18-year swaps. 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. 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. Volumes The tables below show 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. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 2 — — — — — 2 Natural gas (millions of decatherms) 375 83 292 116 176 — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of decatherms) 398 66 332 117 215 — — LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES 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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 40 $ 5 $ 12 $ 7 $ 5 $ 3 $ 20 Noncurrent 13 5 8 4 4 — — Total Derivative Assets – Commodity Contracts $ 53 $ 10 $ 20 $ 11 $ 9 $ 3 $ 20 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 2 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 4 — 4 1 3 — — Noncurrent 7 — 7 3 4 — — Total Derivative Assets – Interest Rate Contracts $ 13 $ — $ 11 $ 4 $ 7 $ — $ — Total Derivative Assets $ 66 $ 10 $ 31 $ 15 $ 16 $ 3 $ 20 Derivative Liabilities September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 67 $ 5 $ 62 $ 9 $ 53 $ — $ — Noncurrent 21 2 19 3 11 — — Total Derivative Liabilities – Commodity Contracts $ 88 $ 7 $ 81 $ 12 $ 64 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — Noncurrent 46 — — — — — — Not Designated as Hedging Instruments Current 1 — — — — 1 — Noncurrent 99 92 — — — 7 — Total Derivative Liabilities – Interest Rate Contracts $ 158 $ 92 $ — $ — $ — $ 8 $ — Total Derivative Liabilities $ 246 $ 99 $ 81 $ 12 $ 64 $ 8 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 4 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 10 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 26 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 11 $ — $ — $ — $ — $ — $ — Noncurrent 33 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 63 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 419 $ 45 $ 322 $ 98 $ 216 $ 7 $ — 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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 44 $ 5 $ 16 $ 8 $ 8 $ 3 $ 20 Gross amounts offset (10 ) (3 ) (7 ) (4 ) (3 ) — — Net amounts presented in Current Assets: Other $ 34 $ 2 $ 9 $ 4 $ 5 $ 3 $ 20 Noncurrent Gross amounts recognized $ 22 $ 5 $ 15 $ 7 $ 8 $ — $ — Gross amounts offset (7 ) (2 ) (5 ) (2 ) (3 ) — — Net amounts presented in Investments and Other Assets: Other $ 15 $ 3 $ 10 $ 5 $ 5 $ — $ — Derivative Liabilities September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 80 $ 5 $ 62 $ 9 $ 53 $ 1 $ — Gross amounts offset (10 ) (3 ) (7 ) (4 ) (3 ) — — Net amounts presented in Current Liabilities: Other $ 70 $ 2 $ 55 $ 5 $ 50 $ 1 $ — Noncurrent Gross amounts recognized $ 166 $ 94 $ 19 $ 3 $ 11 $ 7 $ — Gross amounts offset (7 ) (2 ) (5 ) (2 ) (3 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 159 $ 92 $ 14 $ 1 $ 8 $ 7 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 8 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 4 $ — $ — $ — $ — $ — $ — Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 271 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 249 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 148 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 132 $ 13 $ 82 $ 21 $ 56 $ 6 $ — 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 and Duke Energy Indiana were not material. September 30, 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 $ 171 $ 99 $ 72 $ 12 $ 60 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 171 99 72 12 60 December 31, 2015 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 $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting arrangement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral under master netting arrangements. All receivables presented below were offset against net derivative positions on the Condensed Consolidated Balance Sheets. September 30, 2016 December 31, 2015 (in millions) Receivables Receivables Duke Energy $ — $ 30 Progress Energy — 30 Duke Energy Florida — 30

Investments in Debt and Equity

Investments in Debt and Equity Securities	9 Months Ended
	Sep. 30, 2016
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 available-for-sale. Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the nuclear decommissioning 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 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. However, certain investments held in Duke Energy Florida's NDTF, which were acquired in a settlement with Florida Municipal Joint Owners (FMJO), do not qualify for regulatory accounting. Except for other than temporary impairments of unrealized losses, unrealized gains and losses on these assets are included in other comprehensive income until realized. The other than temporary impairments of realized amounts and unrealized losses are included within Other income and expense, net on the Condensed Consolidated Statements of Operations. The value of these assets has not materially changed since the assets were acquired from FMJO. As a result, there is no material impact on earnings of the Duke Energy Registrants. Other Available-for-Sale Securities Unrealized gains and losses on all other available-for-sale 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 other-than-temporary impairment exists, the unrealized credit loss is included in earnings. There were no material credit losses as of September 30, 2016 and December 31, 2015 . DUKE ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 151 $ — $ — $ 179 Equity securities 1,968 55 3,949 1,823 58 3,590 Corporate debt securities 25 2 551 7 8 432 Municipal bonds 9 1 341 5 1 185 U.S. government bonds 31 — 994 11 5 1,254 Other debt securities — 3 132 — 4 177 Total NDTF $ 2,033 $ 61 $ 6,118 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 24 $ — $ — $ 29 Equity securities 38 — 104 32 1 95 Corporate debt securities 2 1 91 1 3 92 Municipal bonds 5 1 78 3 1 74 U.S. government bonds 1 — 49 — — 45 Other debt securities — 1 55 — 2 62 Total Other Investments (a) $ 46 $ 3 $ 401 $ 36 $ 7 $ 397 Total Investments $ 2,079 $ 64 $ 6,519 $ 1,882 $ 83 $ 6,214 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts are considered other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 92 Due after one through five years 655 Due after five through 10 years 529 Due after 10 years 1,015 Total $ 2,291 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 82 $ 30 $ 200 $ 160 Realized losses 42 28 134 59 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 43 $ — $ — $ 34 Equity securities 1,091 29 2,170 1,021 27 2,094 Corporate debt securities 14 2 374 3 5 292 Municipal bonds 2 — 66 1 — 33 U.S. government bonds 12 — 454 3 3 438 Other debt securities — 3 123 — 4 147 Total NDTF $ 1,119 $ 34 $ 3,230 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,119 $ 35 $ 3,233 $ 1,028 $ 40 $ 3,041 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 3 Due after one through five years 206 Due after five through 10 years 268 Due after 10 years 543 Total $ 1,020 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 58 $ 25 $ 125 $ 132 Realized losses 28 24 84 47 PROGRESS ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 108 $ — $ — $ 145 Equity securities 877 26 1,779 802 31 1,496 Corporate debt securities 11 — 177 4 3 140 Municipal bonds 7 1 275 4 1 152 U.S. government bonds 19 — 540 8 2 816 Other debt securities — — 9 — — 30 Total NDTF $ 914 $ 27 $ 2,888 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 20 $ — $ — $ 18 Municipal bonds 4 — 47 3 — 45 Total Other Investments (a) $ 4 $ — $ 67 $ 3 $ — $ 63 Total Investments $ 918 $ 27 $ 2,955 $ 821 $ 37 $ 2,842 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 67 Due after one through five years 372 Due after five through 10 years 187 Due after 10 years 422 Total $ 1,048 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 21 $ 5 $ 71 $ 26 Realized losses 13 4 49 10 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 56 $ — $ — $ 110 Equity securities 657 21 1,438 596 25 1,178 Corporate debt securities 8 — 123 3 2 96 Municipal bonds 7 1 275 4 1 150 U.S. government bonds 12 — 279 6 2 486 Other debt securities — — 6 — — 18 Total NDTF $ 684 $ 22 $ 2,177 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (a) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 684 $ 22 $ 2,178 $ 609 $ 30 $ 2,039 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 21 Due after one through five years 200 Due after five through 10 years 142 Due after 10 years 320 Total $ 683 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 18 $ 4 $ 60 $ 21 Realized losses 11 3 42 8 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 35 Equity securities 220 5 341 206 6 318 Corporate debt securities 3 — 54 1 1 44 Municipal bonds — — — — — 2 U.S. government bonds 7 — 261 2 — 330 Other debt securities — — 3 — — 12 Total NDTF (c) $ 230 $ 5 $ 711 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Municipal bonds 4 — 47 3 — 45 Total Other Investments (a) $ 4 $ — $ 49 $ 3 $ — $ 51 Total Investments $ 234 $ 5 $ 760 $ 212 $ 7 $ 792 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (c) The decrease in estimated fair value of the NDTF as of September 30, 2016, is due to reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal Unit 3 Nuclear Plant. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 46 Due after one through five years 172 Due after five through 10 years 45 Due after 10 years 102 Total $ 365 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 3 $ 1 $ 11 $ 5 Realized losses 2 1 7 2 DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value Other Investments Cash and cash equivalents $ — $ — $ — $ — $ — $ 2 Equity securities 31 — 77 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds 1 1 28 — 1 26 Total Other Investments (a) $ 32 $ 1 $ 107 $ 27 $ 1 $ 101 Total Investments $ 32 $ 1 $ 107 $ 27 $ 1 $ 101 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 3 Due after one through five years 9 Due after five through 10 years 13 Due after 10 years 5 Total $ 30 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were insignificant for the three and nine months ended September 30, 2016 and 2015 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
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 which 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 nine months ended September 30, 2016 and 2015 . 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 Nasdaq Composite (NASDAQ) and New York Stock Exchange (NYSE). 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 are primarily valued using internally developed discounted cash flow models which 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 natural 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 natural 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 which 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. 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 table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,949 $ 3,871 $ — $ — $ 78 Nuclear decommissioning trust fund debt securities 2,169 664 1,505 — — Other available-for-sale equity securities 104 104 — — — Other available-for-sale debt securities 297 74 219 4 — Derivative assets 66 — 43 23 — Total assets 6,585 4,713 1,767 27 78 Derivative liabilities (246 ) — (246 ) — — Net assets $ 6,339 $ 4,713 $ 1,521 $ 27 $ 78 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 — Derivative assets 26 — 16 10 — Total assets 6,240 4,260 1,793 15 172 Derivative liabilities (419 ) — (419 ) — — Net assets $ 5,821 $ 4,260 $ 1,374 $ 15 $ 172 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 Operating Revenues. Three Months Ended September 30, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 4 $ 34 $ 38 Purchases, sales, issuances and settlements: Settlements — (9 ) (9 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (2 ) (2 ) Balance at end of period $ 4 $ 23 $ 27 Three Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 23 $ 28 Purchases, sales, issuances and settlements: Settlements — (6 ) (6 ) Balance at end of period $ 5 $ 17 $ 22 Nine Months Ended September 30, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Purchases, sales, issuances and settlements: Purchases — 34 34 Sales (1 ) — (1 ) Settlements — (22 ) (22 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 1 Balance at end of period $ 4 $ 23 $ 27 Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains included in earnings — 18 18 Purchases, sales, issuances and settlements: Purchases — 24 24 Settlements — (28 ) (28 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 4 4 Balance at end of period $ 5 $ 17 $ 22 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. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,170 $ 2,092 $ — $ — $ 78 Nuclear decommissioning trust fund debt securities 1,060 184 876 — — Other available-for-sale debt securities 3 — — 3 — Derivative assets 10 — 10 — — Total assets 3,243 2,276 886 3 78 Derivative liabilities (99 ) — (99 ) — — Net assets $ 3,144 $ 2,276 $ 787 $ 3 $ 78 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — — Other available-for-sale debt securities 3 — — 3 — Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172 There was no change to the Level 3 balance during the three and nine months ended September 30, 2016 and September 30, 2015 . 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. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,779 $ 1,779 $ — Nuclear decommissioning trust fund debt securities 1,109 480 629 Other available-for-sale debt securities 67 20 47 Derivative assets 31 — 31 Total assets 2,986 2,279 707 Derivative liabilities (81 ) — (81 ) Net assets $ 2,905 $ 2,279 $ 626 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591 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. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,438 $ 1,438 $ — Nuclear decommissioning trust fund debt securities and other 739 220 519 Other available-for-sale debt securities and other 1 1 — Derivative assets 15 — 15 Total assets 2,193 1,659 534 Derivative liabilities (12 ) — (12 ) Net assets $ 2,181 $ 1,659 $ 522 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623 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. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 341 $ 341 $ — Nuclear decommissioning trust fund debt securities and other 370 260 110 Other available-for-sale debt securities and other 49 2 47 Derivative assets 16 — 16 Total assets 776 603 173 Derivative liabilities (64 ) — (64 ) Net assets $ 712 $ 603 $ 109 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 ) 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. Derivative amounts in the table below exclude cash collateral, which are disclosed in Note 10 . September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (8 ) — (8 ) — Net (liabilities) assets $ (5 ) $ — $ (8 ) $ 3 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3 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 September 30, (in millions) 2016 2015 Balance at beginning of period $ 5 $ 5 Purchases, sales, issuances and settlements: Purchases — 5 Sales — (5 ) Settlements (2 ) (1 ) Balance at end of period $ 3 $ 4 Derivatives (net) Nine Months Ended September 30, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains included in earnings — 21 Purchases, sales, issuances and settlements: Purchases 5 5 Settlements (4 ) (4 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (1 ) — Balance at end of period $ 3 $ 4 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. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 77 $ 77 $ — $ — Other available-for-sale debt securities and other 30 — 30 — Derivative assets 20 — — 20 Net assets $ 127 $ 77 $ 30 $ 20 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7 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 September 30, (in millions) 2016 2015 Balance at beginning of period $ 29 $ 17 Purchases, sales, issuances and settlements: Purchases — 1 Settlements (7 ) (6 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (2 ) — Balance at end of period $ 20 $ 12 Derivatives (net) Nine Months Ended September 30, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Purchases, sales, issuances and settlements: Purchases 29 19 Settlements (18 ) (25 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 2 4 Balance at end of period $ 20 $ 12 QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. As of September 30, 2016 and December 31, 2015 , all Level 3 derivatives were financial transmission rights (FTRs). September 30, 2016 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 23 RTO auction pricing FTR price – per Megawatt-Hour (MWh) $ (2.59 ) - $ 8.16 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.45 - 2.01 Duke Energy Indiana 20 RTO auction pricing FTR price – per MWh (2.59 ) - 8.16 December 31, 2015 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29 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. September 30, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 47,165 $ 50,997 $ 39,569 $ 42,537 Duke Energy Carolinas 9,360 10,799 8,367 9,156 Progress Energy 16,520 19,060 14,464 15,856 Duke Energy Progress 7,011 7,787 6,518 6,757 Duke Energy Florida 6,128 7,127 4,266 4,908 Duke Energy Ohio 1,887 2,128 1,598 1,724 Duke Energy Indiana 3,787 4,538 3,768 4,219 At both September 30, 2016 and December 31, 2015 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and non-recourse 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	9 Months Ended
	Sep. 30, 2016
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 nine months ended September 30, 2016 and the year ended December 31, 2015 , 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 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. Amounts borrowed under the credit facilities are reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount (in millions) $ 325 $ 425 $ 300 $ 225 Amounts borrowed at September 30, 2016 325 425 300 225 Amounts borrowed at December 31, 2015 325 425 254 225 Nuclear Asset-Recovery Bonds – DEFPF 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. For additional information see Notes 4 and 6 . 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) September 30, 2016 Receivables of VIEs $ 7 Regulatory Assets: Current 51 Current Assets: Other 29 Regulatory Assets and Deferred Debits: Regulatory assets 1,156 Interest accrued 9 Current maturities of long-term debt 62 Long-Term Debt 1,216 Renewables Certain Duke Energy renewable energy facilities are VIEs due to long-term, fixed-price power purchase agreements. These fixed-price agreements effectively transfer commodity price risk to the buyer of the power. Certain other Duke Energy renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. For certain VIEs, 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 purchase power agreements, 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) September 30, 2016 December 31, 2015 Current Assets: Other $ 252 $ 138 Property, plant and equipment, cost 2,583 2,015 Accumulated depreciation and amortization (400 ) (321 ) Current maturities of long-term debt 193 108 Long-Term Debt 1,151 968 Deferred Credits and Other Liabilities: Deferred income taxes 50 289 Deferred Credits and Other Liabilities: Other 270 33 NON-CONSOLIDATED VIEs The following tables summarize the impact of non-consolidated VIEs on the Condensed Consolidated Balance Sheets. September 30, 2016 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 50 $ 74 Investments in equity method unconsolidated affiliates 168 317 485 — — Investments and Other Assets: Other — 12 12 — — Total assets $ 168 $ 329 $ 497 $ 50 $ 74 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 13 13 — — Total liabilities $ — $ 15 $ 15 $ — $ — Net assets $ 168 $ 314 $ 482 $ 50 $ 74 December 31, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 235 152 387 — — Total assets $ 235 $ 152 $ 387 $ 47 $ 60 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 235 $ 135 $ 370 $ 47 $ 60 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 Ohio Valley Electric Corporation (OVEC), which is discussed below, and various guarantees, reflected in the table above as Deferred credits and other liabilities. For more information on various guarantees, refer to Note 5 . Renewables Duke Energy has investments in various renewable energy project entities. Some of these entities are VIEs due to long-term fixed-price power purchase agreements. These fixed-price agreements effectively transfer commodity price risk to the buyer of the power. Duke Energy does not consolidate these VIEs because power to direct and control key activities is shared jointly by Duke Energy and other owners. Impairment of Equity Method Investments During the three and nine months ended September 30, 2016, Duke Energy recorded an other than temporary impairment of certain wind project investments. The $71 million pretax impairment was recorded within Equity in earnings (losses) of unconsolidated affiliates on Duke Energy's Condensed Consolidated Statements of Operations. The other than temporary decline in value of these investments was primarily attributable to a sustained decline in market pricing where the wind investments are located, the continued projected net losses for the projects and a reduction in the projected cash distributions to the class of investment owned by Duke Energy. Other Duke Energy holds a 50 percent equity interest in Duke-American Transmission Company, LLC (DATC). DATC is considered a VIE due to insufficient equity at risk to permit DATC to finance its own activities without additional subordinated financial support. The activities that most significantly impact DATC’s economic performance are the 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, and therefore Duke Energy does not consolidate DATC. Duke Energy has a 40 percent equity interest and a 7.5 percent equity interest in ACP and Sabal Trail Transmission, LLC (Sabal Trail), respectively. These entities are considered VIEs as their equity is not sufficient to permit the entities to finance their activities without additional subordinated financial support. The activity that most significantly impacts the economic performance of both ACP and Sabal Trail is construction. Duke Energy does not control these activities and therefore does not consolidate ACP or Sabal Trail. See Note 4, Regulatory Matters, for information related to Duke Energy's additional ownership interest in ACP following the Piedmont acquisition. OVEC Duke Energy Ohio’s 9 percent ownership interest in OVEC is considered a non-consolidated VIE. Through its ownership interest in OVEC, Duke Energy Ohio has a contractual arrangement to buy power from OVEC’s power plants through June 2040. Proceeds from the sale of power by OVEC to its power purchase agreement counterparties are designed to be sufficient to meet its operating expenses, fixed costs, debt amortization and interest expense, as well as earn a return on equity. Accordingly, the value of this contract is subject to variability due to fluctuations in power prices and changes in OVEC’s costs of business, including costs associated with its 2,256 MW of coal-fired generation capacity. Proposed environmental rulemaking could increase the costs of OVEC, which would be passed through to Duke Energy Ohio. 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 other-than-temporary impairment has occurred. Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2016 2015 2016 2015 Anticipated credit loss ratio 0.5 % 0.6 % 0.3 % 0.3 % Discount rate 1.5 % 1.2 % 1.5 % 1.2 % Receivable turnover rate 13.3 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Receivables sold $ 217 $ 233 $ 296 $ 260 Less: Retained interests 50 47 74 60 Net receivables sold $ 167 $ 186 $ 222 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (in millions) 2016 2015 2016 2015 2016 2015 2016 2015 Sales Receivables sold $ 481 $ 449 $ 1,442 $ 1,518 $ 722 $ 679 $ 1,980 $ 2,032 Loss recognized on sale 2 2 7 7 3 3 8 8 Cash flows Cash proceeds from receivables sold $ 468 $ 461 $ 1,432 $ 1,568 $ 703 $ 692 $ 1,958 $ 2,074 Collection fees received 1 — 1 1 — — 1 1 Return received on retained interests 1 — 2 2 2 1 4 4 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	9 Months Ended
	Sep. 30, 2016
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, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common stock 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 stock 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 the Equity Forwards, 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 September 30, Nine Months Ended September 30, (in millions, except per-share amounts) 2016 2015 2016 2015 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 1,053 $ 935 $ 2,252 $ 2,307 Weighted average shares outstanding – basic 689 688 689 696 Equity Forwards 2 — 1 — Weighted average shares outstanding – diluted 691 688 690 696 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 1.52 $ 1.36 $ 3.27 $ 3.31 Diluted $ 1.52 $ 1.36 $ 3.26 $ 3.31 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 0.855 $ 0.825 $ 2.505 $ 2.42 (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 Forwards with Barclays. 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 September 30, 2016, share dilution resulting from the agreements was determined under the treasury stock method. On October 5, 2016, following the close of the Piedmont acquisition, Duke Energy physically settled the Equity Forwards in full by delivering 10.6 million shares of common stock in exchange for net cash proceeds of approximately $723 million . The net proceeds were used to finance a portion of the Piedmont acquisition. Accelerated Stock Repurchase Program On April 6, 2015, Duke Energy entered into agreements with each of Goldman, Sachs & Co. and JPMorgan Chase Bank, National Association (the Dealers) to repurchase a total of $1.5 billion of Duke Energy common stock under an accelerated stock repurchase program (the ASR). Duke Energy made payments of $750 million to each of the Dealers and was delivered 16.6 million shares, with a total fair value of $1.275 billion , which represented approximately 85 percent of the total number of shares of Duke Energy common stock expected to be repurchased under the ASR. The company recorded the $1.5 billion payment as a reduction to common stock as of April 6, 2015. In June 2015, the Dealers delivered 3.2 million additional shares to Duke Energy to complete the ASR. Approximately 19.8 million shares, in total, were delivered to Duke Energy and retired under the ASR at an average price of $75.75 per share. The final number of shares repurchased was based upon the average of the daily volume weighted average stock prices of Duke Energy’s common stock during the term of the program, less a discount.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2016
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 Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Restricted stock unit awards $ 8 $ 9 $ 25 $ 29 Performance awards 4 5 14 18 Pretax stock-based compensation cost $ 12 $ 14 $ 39 $ 47 Tax benefit associated with stock-based compensation expense $ 5 $ 6 $ 14 $ 18 Stock-based compensation costs capitalized — 1 2 3

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy maintains, and the Subsidiary Registrants participate in, qualified, non-contributory defined benefit retirement plans. The plans cover most U.S. employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits equal to a percentage of current eligible earnings based on age or the combination of age and years of service and interest credits. Certain employees are covered under plans that use a final average earnings formula. Under these average earnings formulas, a plan participant generally accumulates a retirement benefit based on their (i) highest three-year or four-year average earnings, (ii) years of participation or credited service, and (iii) various plan formula provisions (e.g., caps on years of participation or credited service). Duke Energy also maintains, and the Subsidiary Registrants participate in, non-qualified, non-contributory defined benefit retirement plans which cover certain executives. The qualified and non-qualified, non-contributory defined benefit plans are closed to new and rehired non-union and certain unionized employees. 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. The following table includes information related to Duke Energy's contributions to its U.S. qualified defined benefit pension plans. Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the nine months ended September 30, 2016 . Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Contributions $ 143 $ 42 $ 42 $ 21 $ 21 $ 4 $ 9 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 9 . 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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 36 $ 12 $ 11 $ 6 $ 4 $ 1 $ 2 Interest cost on projected benefit obligation 83 21 27 12 14 5 7 Expected return on plan assets (128 ) (35 ) (42 ) (21 ) (21 ) (6 ) (10 ) Amortization of actuarial loss 33 8 14 6 7 1 3 Amortization of prior service credit (4 ) (2 ) (1 ) — (1 ) — — Other 2 1 1 — 1 — — Net periodic pension costs $ 22 $ 5 $ 10 $ 3 $ 4 $ 1 $ 2 Three Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 40 $ 13 $ 11 $ 6 $ 5 $ 1 $ 3 Interest cost on projected benefit obligation 81 21 26 12 14 5 7 Expected return on plan assets (129 ) (35 ) (43 ) (20 ) (22 ) (7 ) (10 ) Amortization of actuarial loss 44 10 17 8 8 3 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 2 1 1 — — — — Net periodic pension costs $ 34 $ 8 $ 11 $ 6 $ 5 $ 2 $ 3 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 109 $ 36 $ 32 $ 18 $ 14 $ 3 $ 6 Interest cost on projected benefit obligation 249 64 80 37 42 15 21 Expected return on plan assets (386 ) (106 ) (126 ) (62 ) (63 ) (20 ) (31 ) Amortization of actuarial loss 99 24 41 17 21 3 9 Amortization of prior service credit (12 ) (6 ) (3 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 65 $ 14 $ 26 $ 10 $ 14 $ 1 $ 5 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 119 $ 38 $ 33 $ 18 $ 15 $ 3 $ 8 Interest cost on projected benefit obligation 244 62 78 36 41 14 21 Expected return on plan assets (387 ) (104 ) (127 ) (61 ) (66 ) (20 ) (31 ) Amortization of actuarial loss 131 30 51 25 24 8 10 Amortization of prior service credit (11 ) (6 ) (3 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 102 $ 22 $ 34 $ 18 $ 14 $ 5 $ 8 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 September 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 4 — 2 — — Amortization of actuarial loss 2 — 1 1 1 Amortization of prior service credit (1 ) — — — — Net periodic pension costs $ 6 $ — $ 3 $ 1 $ 1 Three Months Ended September 30, 2015 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 Amortization of actuarial loss 2 — 1 — — Net periodic pension costs $ 6 $ — $ 2 $ — $ 1 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ — $ — $ — Interest cost on projected benefit obligation 11 1 4 1 1 Amortization of actuarial loss 6 — 2 1 1 Amortization of prior service credit (1 ) — — — — Net periodic pension costs $ 18 $ 1 $ 6 $ 2 $ 2 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ 1 $ — $ — Interest cost on projected benefit obligation 10 1 3 1 2 Amortization of actuarial loss 5 — 2 — 1 Net periodic pension costs $ 17 $ 1 $ 6 $ 1 $ 3 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. Employees are eligible for these benefits if they have met age and service requirements at retirement, as set forth in the plans. The health care benefits include medical, dental, vision and prescription drug coverage and are subject to certain limitations, such as deductibles and co-payments. The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ — $ — $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 3 — 1 Expected return on plan assets (2 ) (2 ) (1 ) — — — — Amortization of actuarial loss (gain) 2 — 5 3 2 (1 ) — Amortization of prior service credit (35 ) (4 ) (26 ) (16 ) (8 ) — (1 ) Net periodic other post-retirement benefit costs $ (26 ) $ (4 ) $ (17 ) $ (11 ) $ (3 ) $ (1 ) $ — Three Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 1 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 2 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss 6 — 7 5 3 — — Amortization of prior service credit (35 ) (4 ) (26 ) (17 ) (9 ) — — Net periodic other post-retirement benefit costs $ (22 ) $ (4 ) $ (15 ) $ (10 ) $ (4 ) $ — $ 1 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 26 6 11 6 6 1 3 Expected return on plan assets (9 ) (6 ) (1 ) — — — (1 ) Amortization of actuarial loss (gain) 5 (2 ) 16 9 7 (2 ) (1 ) Amortization of prior service credit (106 ) (10 ) (77 ) (50 ) (26 ) — (1 ) Net periodic other post-retirement benefit costs $ (82 ) $ (12 ) $ (50 ) $ (35 ) $ (13 ) $ (1 ) $ — Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 4 $ 1 $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 27 6 11 6 5 1 3 Expected return on plan assets (9 ) (6 ) — — — — — Amortization of actuarial loss (gain) 19 (1 ) 21 14 8 — (1 ) Amortization of prior service credit (105 ) (11 ) (77 ) (50 ) (25 ) — — Net periodic other post-retirement benefit costs $ (64 ) $ (11 ) $ (44 ) $ (30 ) $ (12 ) $ 1 $ 2 EMPLOYEE SAVINGS PLAN Duke Energy sponsors, and the Subsidiary Registrants participate in, an employee savings plan that covers substantially all U.S. employees. Most employees participate in a matching contribution formula where Duke Energy provides a matching contribution generally equal to 100 percent of employee before-tax and Roth 401(k) contributions of up to 6 percent of eligible pay per pay period. Dividends on Duke Energy shares held by the savings plan are charged to retained earnings when declared and shares held in the plan are considered outstanding in the calculation of basic and diluted earnings per share. For new and rehired non-union and certain unionized employees who are not eligible to participate in Duke Energy’s defined benefit plans, an additional employer contribution of 4 percent of eligible pay per pay period, subject to a three-year vesting requirement, is provided to the employee’s savings plan account. 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 Three Months Ended September 30, 2016 $ 39 $ 13 $ 12 $ 8 $ 3 $ 1 $ 2 2015 34 11 10 7 3 — 1 Nine Months Ended September 30, 2016 $ 130 $ 44 $ 39 $ 27 $ 11 $ 3 $ 6 2015 120 40 36 26 10 2 5

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES TAXES ON FOREIGN EARNINGS As of December 31, 2015, Duke Energy's intention was to indefinitely reinvest foreign earnings of International Energy earned after December 31, 2014. In February 2016, Duke Energy announced it had initiated a process to divest the International Energy business segment, excluding the investment in NMC, and in October 2016 Duke Energy entered sales agreements to complete the divestiture. Accordingly, Duke Energy no longer intends to indefinitely reinvest the undistributed earnings of International Energy. See Note 2 for additional information on the sale. This change in the Company's intent, combined with the extension of bonus depreciation by Congress in late 2015, allows Duke Energy to more efficiently utilize foreign tax credits and reduce U.S. deferred tax liabilities associated with historic unremitted foreign earnings by approximately $ 95 million for the nine months ended September 30, 2016. 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 Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Duke Energy 32.9 % 30.9 % 30.0 % 32.5 % Duke Energy Carolinas 34.3 % 36.5 % 34.4 % 36.3 % Progress Energy 32.8 % 25.0 % 34.7 % 31.8 % Duke Energy Progress 31.4 % 34.4 % 33.5 % 35.3 % Duke Energy Florida 36.0 % 30.1 % 37.0 % 35.2 % Duke Energy Ohio 36.8 % 39.3 % 32.5 % 37.6 % Duke Energy Indiana 35.2 % 37.0 % 34.0 % 36.6 % The increase in the effective tax rate for Duke Energy for the three months ended September 30, 2016 , is primarily due to audit adjustments and the tax benefit related to a manufacturing deduction in 2015 which is now limited due to taxable income. The decrease in the effective tax rate for Duke Energy for the nine months ended September 30, 2016 , is primarily due to lower income taxes on foreign earnings due to a more efficient utilization of foreign tax credits. Refer to "Taxes on Foreign Earnings" above for additional information. The decrease in the effective tax rate for Duke Energy Carolinas for the three months ended September 30, 2016 , is primarily due to favorable tax return true-ups and a favorable change to the manufacturing deduction. The decrease in the effective tax rate for Duke Energy Carolinas for the nine months ended September 30, 2016, is primarily due to a favorable state resolution related to prior year tax returns and favorable tax return true-ups. The increase in the effective tax rate for Progress Energy for the three and nine months ended September 30, 2016 , is primarily due to state tax benefits from legal entity restructuring in 2015 and the release of tax reserves in 2015 due to expired statutes. The decrease in the effective tax rate for Duke Energy Progress for the three and nine months ended September 30, 2016 , is primarily due to the impact of tax return true-ups. The increase in the effective tax rate for Duke Energy Florida for the three and nine months ended September 30, 2016 , is primarily due to a release of tax reserves in 2015 due to expired tax statutes. The decrease in the effective tax rate for Duke Energy Ohio for the three months ended September 30, 2016 , is primarily due to an increase in AFUDC equity. The decrease in the effective tax rate for the nine months ended September 30, 2016, is primarily due to a favorable adjustment related to prior period depreciation and other property, plant and equipment. The decrease in the effective tax rate for Duke Energy Indiana for the three months ended September 30, 2016 , is primarily due to income tax levelization. The decrease in the effective tax rate for Duke Energy Indiana for the nine months ended September 30, 2016, is primarily due to a favorable adjustment related to prior period depreciation and other property, plant and equipment.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS In the fourth quarter of 2016, Hurricane Matthew caused historic flooding, extensive damage and widespread power outages across Florida and the Carolinas. Duke Energy has not completed the final accumulation of total estimated incremental storm restoration costs incurred. Duke Energy Florida intends to charge storm restoration costs to an FPSC approved storm reserve. Duke Energy Progress, given the magnitude of the storm, intends to request approval to defer the incremental costs incurred to a regulatory asset for recovery in its next base rate cases. For information on additional subsequent events related to acquisitions and dispositions, regulatory matters, commitments and contingencies, debt and credit facilities, asset retirement obligations and common stock see Notes 2, 4, 5, 6, 7 and 14, respectively.

Organization and Basis of Pre26

Organization and Basis of Presentation (Policy)	9 Months Ended
	Sep. 30, 2016
Policy Text Block [Line Items]
Nature of Operations and Basis of Consolidation	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.) and Latin America primarily through its direct and indirect subsidiaries. See Note 2 for information on the proposed sale of International Energy. Duke Energy’s subsidiaries include its subsidiary registrants, 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) and Duke Energy Indiana, LLC (Duke Energy Indiana). When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its six separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants). 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. 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. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting. 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. Substantially all of Progress Energy’s operations qualify for regulatory accounting. 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. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting. 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. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. 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. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). See Note 2 for additional information. Substantially all of Duke Energy Ohio’s operations that remain after the sale qualify for regulatory accounting. 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. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company. See Note 2 for information regarding Duke Energy's acquisition of Piedmont Natural Gas Company, Inc. (Piedmont) that closed on October 3, 2016. For the periods presented, Duke Energy's condensed consolidated financial information does not include the results of Piedmont. Also, the Duke Energy Registrants, as defined above, do not include Piedmont, unless otherwise noted.
Basis of Accounting	BASIS OF PRESENTATION Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales (collectively, the Midwest Generation Disposal Group), a retail sales business owned by Duke Energy, to Dynegy on April 2, 2015. The results of operations of these businesses prior to the date of sale 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 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, 2015 . 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.
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 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 and meter reading schedules.
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. Reserves are established for excess and obsolete inventory. Inventory reserves were not material at September 30, 2016 and December 31, 2015 .
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 net. 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.
New Accounting Standards	NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2016 and 2015 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of September 30, 2016 . Revenue from Contracts with Customers. In May 2014, the Financial Accounting Standards Board (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. The Duke Energy Registrants intend to adopt the revised accounting guidance effective for interim and annual periods beginning January 1, 2018. The guidance can be applied retrospectively to all prior reporting periods presented or retrospectively with a cumulative effect as of the initial date of application. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined. 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 the Duke Energy Registrants, 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 requirements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Stock-Based Compensation and Income Taxes. In March 2016, the FASB issued revised accounting guidance for stock-based compensation and the associated income taxes. This standard changes certain aspects of accounting for stock-based payment awards to employees including the accounting for income taxes, statutory tax withholding requirements, as well as classification on the Condensed Consolidated Statements of Cash Flows. The primary future impact to the Duke Energy Registrants is expected to be an increase in the volatility of income tax expense. This guidance will be adopted for the period beginning January 1, 2017. Cash Flow Statement. In August 2016, the FASB issued revised accounting guidance for classification of certain cash receipts and payments. Stakeholders indicated diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. For the Duke Energy Registrants, this guidance is effective for the interim and annual periods beginning January 1, 2018, although it can be early adopted. The guidance is applied using a retrospective transition method to each period presented, if practical. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined.
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. See Note 13 for further information.
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. See Note 13 for further information.

Organization and Basis of Pre27

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2016
Organization And Basis Of Presentation [Line Items]
Schedule of Utility Inventory	The components of inventory are presented in the tables below. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,312 $ 760 $ 1,139 $ 781 $ 358 $ 85 $ 236 Coal held for electric generation 743 256 277 101 177 18 186 Oil, gas and other fuel held for electric generation 296 37 237 116 121 7 2 Total inventory $ 3,351 $ 1,053 $ 1,653 $ 998 $ 656 $ 110 $ 424 December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Materials and supplies $ 2,389 $ 785 $ 1,133 $ 776 $ 357 $ 81 $ 301 Coal held for electric generation 1,114 451 370 192 178 16 267 Oil, gas and other fuel held for electric generation 307 40 248 120 128 8 2 Total inventory $ 3,810 $ 1,276 $ 1,751 $ 1,088 $ 663 $ 105 $ 570
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 September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy $ 107 $ 109 $ 285 $ 308 Duke Energy Carolinas 6 9 21 27 Progress Energy 65 67 161 174 Duke Energy Progress 4 4 13 12 Duke Energy Florida 61 63 148 162 Duke Energy Ohio 26 24 77 80 Duke Energy Indiana 10 9 26 27
Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues, which are included within Receivables and Receivables of variable interest entities (VIEs) on the Condensed Consolidated Balance Sheets, are presented in the following table. (in millions) September 30, 2016 December 31, 2015 Duke Energy $ 800 $ 748 Duke Energy Carolinas 318 283 Progress Energy 195 172 Duke Energy Progress 96 102 Duke Energy Florida 99 70 Duke Energy Ohio 2 3 Duke Energy Indiana 36 31
Duke Energy Ohio [Member] | Unbilled Revenues [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) September 30, 2016 December 31, 2015 Duke Energy Ohio $ 72 $ 71 Duke Energy Indiana 109 97
Duke Energy Indiana [Member] | Unbilled Revenues [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) September 30, 2016 December 31, 2015 Duke Energy Ohio $ 72 $ 71 Duke Energy Indiana 109 97

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The preliminary purchase price allocation of the Piedmont acquisition is estimated as follows: (in millions) Current assets $ 500 Property, plant and equipment, net 4,710 Goodwill 3,380 Other long-term assets 810 Total assets 9,400 Current liabilities, including current maturities of long-term debt 590 Long-term liabilities 1,810 Long-term debt 2,000 Total liabilities 4,400 Total purchase price $ 5,000
Income Statement Disclosures	The following table presents the results of discontinued operations for the three and nine months ended September 30, 2015 . Three Months Ended Nine Months Ended September 30, 2015 September 30, 2015 Duke Duke Duke Energy Duke Energy (in millions) Energy Ohio Energy Ohio Operating Revenues $ — $ — $ 543 $ 412 Loss on disposition (5 ) (4 ) (42 ) (48 ) (Loss) Income before income taxes (a) $ (5 ) $ (4 ) $ 62 $ 48 Income tax (benefit) expense (1 ) (2 ) 29 25 (Loss) Income from discontinued operations of the Midwest Generation Disposal Group (4 ) (2 ) 33 23 Other, net of tax (b) (1 ) — (4 ) — (Loss) Income From Discontinued Operations, net of tax $ (5 ) $ (2 ) $ 29 $ 23 (a) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the agreement in principle reached in a lawsuit related to the Midwest Generation Disposal Group for the nine months ended September 30, 2015 . Refer to Note 5 for further information related to the lawsuit. (b) Relates to discontinued operations of businesses not related to the Midwest Generation Disposal Group and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments.
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma financial information reflects the combined results of operations of Duke Energy and Piedmont. The unaudited pro forma financial 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. This information is preliminary in nature and subject to change. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Revenues $ 6,958 $ 6,627 $ 18,688 $ 19,021 Net income attributable to Duke Energy Corporation 1,180 897 2,552 2,352

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended September 30, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 6,421 $ 245 $ 140 $ 6,806 $ 15 $ — $ 6,821 Intersegment revenues 9 — — 9 17 (26 ) — Total revenues $ 6,430 $ 245 $ 140 $ 6,815 $ 32 $ (26 ) $ 6,821 Segment income (loss) (a)(b) $ 1,200 $ 64 $ (21 ) $ 1,243 $ (189 ) $ — $ 1,054 Add back noncontrolling interests 5 Income from discontinued operations, net of tax (c) 122 Net income $ 1,181 Segment assets $ 114,707 $ 3,153 $ 4,414 $ 122,274 $ 7,228 $ 184 $ 129,686 (a) Other includes after-tax charges for costs to achieve mergers of $52 million , primarily due to interest expense related to the Piedmont acquisition financing, and cost savings initiatives of $12 million primarily due to severance costs. (b) Commercial Portfolio includes an after-tax impairment of $45 million related to certain equity method investments in renewable energy projects. See Note 13, Variable Interest Entities, for additional information. (c) Represents an income tax benefit resulting from deferred tax liability adjustments related to previously sold businesses. See Note 2, Acquisitions and Dispositions, for further information. Three Months Ended September 30, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 6,138 $ 281 $ 66 $ 6,485 $ (2 ) $ — $ 6,483 Intersegment revenues 9 — — 9 19 (28 ) — Total revenues $ 6,147 $ 281 $ 66 $ 6,494 $ 17 $ (28 ) $ 6,483 Segment income (loss) (a)(b) $ 905 $ 69 $ 8 $ 982 $ (45 ) $ — $ 937 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (5 ) Net income $ 935 (a) Regulated Utilities includes an after-tax charge of $56 million related to the Edwardsport settlement. See Note 4 for further information. (b) Other includes $15 million of after-tax costs to achieve the 2012 Progress Energy merger. Nine Months Ended September 30, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 16,761 $ 761 $ 366 $ 17,888 $ 39 $ — $ 17,927 Intersegment revenues 27 — — 27 52 (79 ) — Total revenues $ 16,788 $ 761 $ 366 $ 17,915 $ 91 $ (79 ) $ 17,927 Segment income (loss) (a)(b)(c) $ 2,613 $ 85 $ 20 $ 2,718 $ (463 ) $ — $ 2,255 Add back noncontrolling interests 13 Income from discontinued operations, net of tax (d) 124 Net income $ 2,392 (a) Other includes after-tax charges for costs to achieve mergers of $195 million , primarily due to losses on forward-starting interest rate swaps related to the Piedmont acquisition, and cost savings initiatives of $39 million primarily due to severance costs. See Note 10 for additional information related to the swaps. (b) International Energy includes an after-tax impairment charge of $145 million . See Note 2 for additional information. (c) Commercial Portfolio includes an after-tax impairment of $45 million related to certain equity method investments in renewable energy projects. See Note 13, Variable Interest Entities, for additional information. (d) Includes income tax benefit of $122 million resulting from deferred tax liability adjustments related to previously sold businesses. See Note 2 for further information. Nine Months Ended September 30, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 17,062 $ 841 $ 214 $ 18,117 $ 20 $ — $ 18,137 Intersegment revenues 28 — — 28 58 (86 ) — Total revenues $ 17,090 $ 841 $ 214 $ 18,145 $ 78 $ (86 ) $ 18,137 Segment income (loss) (a)(b)(c) $ 2,311 $ 157 $ (15 ) $ 2,453 $ (139 ) $ (4 ) $ 2,310 Add back noncontrolling interests 10 Income from discontinued operations, net of tax (d) 29 Net income $ 2,349 (a) Regulated Utilities includes an after-tax charge of $56 million related to the Edwardsport settlement. Refer to Note 4 for further information. (b) Other includes $42 million of after-tax costs to achieve the 2012 Progress Energy merger. (c) Commercial Portfolio includes state tax expense of $41 million , resulting from changes to state apportionment factors due to the sale of the Midwest Generation Disposal Group, that does not qualify for discontinued operations. Refer to Note 2 for further information related to the sale. (d) Includes after-tax impact of $53 million for the settlement agreement reached in a lawsuit related to the Midwest Generation Disposal Group. Refer to Note 5 for further information related to the lawsuit. The following table provides the amount of Other net expense. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas $ (16 ) $ (10 ) $ (50 ) $ (28 ) Progress Energy (a) (45 ) (3 ) (139 ) (87 ) Duke Energy Progress (10 ) (4 ) (26 ) (12 ) Duke Energy Florida (5 ) (3 ) (14 ) (9 ) Duke Energy Ohio (10 ) (12 ) (29 ) (20 ) Duke Energy Indiana (3 ) (2 ) (10 ) (6 ) (a) Other for Progress Energy also includes interest expense on corporate debt instruments of $55 million and $166 million for the three and nine months ended September 30, 2016 , respectively, and $61 million and $180 million for the three and nine months ended September 30, 2015 , respectively.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2016
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 due to a lack of requisite environmental control equipment. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets as of September 30, 2016 . Remaining Net Capacity Book Value (a) (in MW) (in millions) Progress Energy and Duke Energy Florida Crystal River Units 1 and 2 873 123 Duke Energy Indiana Wabash River Unit 6 (b) 318 33 Gallagher Units 2 and 4 (c) 280 137 Total Duke Energy 1,471 293 (a) Remaining net book value amounts exclude any capitalized asset retirement costs. (b) In April 2016, Wabash River 6 terminated coal burning operations and is targeted for retirement by the end of 2016. The total net book value of $90 million for the retail portion of Wabash River Unit 6 and the retail portion of capitalized asset retirement costs for Wabash River Units 2 through 6 is classified as Generation facilities to be retired, net on Duke Energy Indiana's Condensed Consolidated Balance Sheet at September 30, 2016 . (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)	9 Months Ended
	Sep. 30, 2016
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 $ 69 Duke Energy Carolinas 22 Duke Energy Ohio 36 Duke Energy Indiana 7
Schedule of Loss Contingencies	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 Deferred Credits and Other 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) September 30, 2016 December 31, 2015 Reserves for Legal Matters Duke Energy $ 110 $ 166 Duke Energy Carolinas 11 11 Progress Energy 54 54 Duke Energy Progress 8 6 Duke Energy Florida 30 31 Duke Energy Ohio 5 80
Reserve for Environmental Costs [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Loss Contingencies	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 Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 Provisions/adjustments 34 5 5 2 3 6 20 Cash reductions (12 ) (4 ) (6 ) (2 ) (4 ) (1 ) (2 ) Balance at end of period $ 119 $ 11 $ 16 $ 3 $ 13 $ 59 $ 30 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 5 $ 12 $ 54 $ 10 Provisions/adjustments 4 — 3 — 3 1 3 Cash reductions (4 ) — (2 ) (1 ) (1 ) (1 ) (1 ) Balance at end of period $ 97 $ 10 $ 18 $ 4 $ 14 $ 54 $ 12

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Maturity Interest Duke Energy Energy Energy Energy Energy Energy Issuance Date Date Rate Energy (Parent) Carolinas Progress Florida Ohio Indiana Unsecured April 2016 (a) April 2023 2.875 % $ 350 $ 350 $ — $ — $ — $ — $ — August 2016 September 2021 1.800 % 750 750 — — — — — August 2016 September 2026 2.650 % 1,500 1,500 — — — — — August 2016 September 2046 3.750 % 1,500 1,500 — — — — — First Mortgage Bonds March 2016 (b) March 2023 2.500 % 500 — 500 — — — — March 2016 (b) March 2046 3.875 % 500 — 500 — — — — May 2016 (c) May 2046 3.750 % 500 — — — — — 500 June 2016 (b) June 2046 3.700 % 250 — — — — 250 — September 2016 (d) October 2046 3.400 % 600 — — — 600 — — September 2016 (b) October 2046 3.700 % 450 — — 450 — — — Secured Debt June 2016 (e) March 2020 1.196 % 183 — — — 183 — — June 2016 (e) September 2022 1.731 % 150 — — — 150 — — June 2016 (e) September 2029 2.538 % 436 — — — 436 — — June 2016 (e) March 2033 2.858 % 250 — — — 250 — — June 2016 (e) September 2036 3.112 % 275 — — — 275 — — August 2016 June 2034 2.747 % 228 — — — — — — August 2016 June 2020 2.747 % 105 — — — — — — Total issuances $ 8,527 $ 4,100 $ 1,000 $ 450 $ 1,894 $ 250 $ 500 (a) Proceeds were used to pay down outstanding commercial paper and for general corporate purposes. (b) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. (c) Proceeds were used to repay $325 million of unsecured debt due June 2016, $150 million of first mortgage bonds due July 2016 and for general corporate purposes. (d) Proceeds were used to fund capital expenditures for ongoing construction, capital maintenance, to repay short-term borrowings under the intercompany money pool borrowing arrangement and for general corporate purposes. (e) The nuclear asset-recovery bonds are sequential pay amortizing bonds. The maturity date above represents the scheduled final maturity date for the bonds.
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 September 30, 2016 Unsecured Debt Duke Energy (Parent) November 2016 2.150 % $ 500 Duke Energy (Parent) April 2017 1.034 % 400 Duke Energy (a) May 2017 15.681 % 56 Duke Energy (Parent) August 2017 1.625 % 700 Secured Debt Duke Energy June 2017 2.155 % 45 First Mortgage Bonds Duke Energy Carolinas December 2016 1.750 % 350 Duke Energy Progress March 2017 1.035 % 250 Duke Energy Florida September 2017 5.800 % 250 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Other (b) 573 Current maturities of long-term debt $ 3,201 (a) The interest rate includes country-specific risk premiums. (b) Includes capital lease obligations, amortizing debt and small bullet maturities.
Schedule Of Line Of Credit Facilities	Duke Energy has a Master Credit Facility with a capacity of $7.5 billion through January 2020. 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. September 30, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Facility size (a) $ 7,500 $ 3,400 $ 1,100 $ 1,000 $ 950 $ 450 $ 600 Reduction to backstop issuances Commercial paper (b) (1,652 ) (1,027 ) (300 ) (150 ) — (25 ) (150 ) Outstanding letters of credit (77 ) (70 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 5,155 $ 2,303 $ 511 $ 598 $ 949 $ 425 $ 369 (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 in the Condensed Consolidated Balance Sheets.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2016
Asset Retirement Obligation [Abstract]
Schedule of Asset Retirement Obligations [Table Text Block]	The following table presents the AROs recorded on the Condensed Consolidated Balance Sheets. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Decommissioning of Nuclear Power Facilities (a) $ 5,163 $ 1,808 $ 3,153 $ 2,428 $ 725 $ — $ — Closure of Ash Impoundments 5,411 2,089 2,418 2,398 20 77 828 Other 256 28 86 33 53 31 19 Total asset retirement obligation $ 10,830 $ 3,925 $ 5,657 $ 4,859 $ 798 $ 108 $ 847 Less: current portion 539 303 236 236 — — — Total noncurrent asset retirement obligation $ 10,291 $ 3,622 $ 5,421 $ 4,623 $ 798 $ 108 $ 847 (a) The Duke Energy amount includes purchase accounting adjustments related to the merger with Progress Energy.
Schedule of Change in Asset Retirement Obligation	The following table presents the change in liability associated with asset retirement obligations for Duke Energy and the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at December 31, 2015 (a) $ 10,264 $ 3,918 $ 5,369 $ 4,567 $ 802 $ 125 $ 525 Accretion expense (b) 290 141 171 144 28 4 16 Liabilities settled (c) (443 ) (204 ) (203 ) (163 ) (41 ) (4 ) (31 ) Liabilities incurred in the current year 13 — 3 3 — — — Revisions in estimates of cash flows 706 70 317 308 9 (17 ) 337 Balance at September 30, 2016 $ 10,830 $ 3,925 $ 5,657 $ 4,859 $ 798 $ 108 $ 847 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash basins, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) For the nine months ended September 30, 2016, substantially all accretion expense relates to Duke Energy's regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (c) Primarily relates to ash impoundment closures and nuclear decommissioning of Crystal River Unit 3.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2016
Goodwill [Line Items]
Goodwill By Reportable Operating Segment	The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Regulated International Commercial (in millions) Utilities Energy Portfolio Total Goodwill at December 31, 2015 $ 15,950 $ 271 $ 122 $ 16,343 Foreign exchange changes — 11 — 11 Goodwill at September 30, 2016 $ 15,950 $ 282 $ 122 $ 16,354

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2016
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 in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
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 in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
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 in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2016 2015 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 204 $ 211 $ 620 $ 632 Indemnification coverages (b) 5 6 16 18 JDA revenue (c) 10 7 21 47 JDA expense (c) 36 48 127 143 Progress Energy Corporate governance and shared service expenses (a) $ 182 $ 184 $ 515 $ 523 Indemnification coverages (b) 9 10 25 29 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Progress Corporate governance and shared service expenses (a) $ 103 $ 101 $ 292 $ 296 Indemnification coverages (b) 4 4 10 12 JDA revenue (c) 36 48 127 143 JDA expense (c) 10 7 21 47 Duke Energy Florida Corporate governance and shared service expenses (a) $ 79 $ 83 $ 223 $ 227 Indemnification coverages (b) 5 6 15 17 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 89 $ 88 $ 261 $ 276 Indemnification coverages (b) 1 1 4 5 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 96 $ 87 $ 279 $ 259 Indemnification coverages (b) 2 2 6 6 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are 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 JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	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 September 30, 2016 Intercompany income tax receivable $ — $ 113 $ 56 $ — $ — $ 67 Intercompany income tax payable 64 — — 65 27 — December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The tables below show 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. September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 2 — — — — — 2 Natural gas (millions of decatherms) 375 83 292 116 176 — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of decatherms) 398 66 332 117 215 — — The following table shows notional amounts of outstanding derivatives related to interest rate risk. September 30, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 990 $ — $ — $ — $ — $ — Undesignated contracts 927 400 500 250 250 27 Total notional amount $ 1,917 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,527 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated VIEs of $789 million and $497 million as of September 30, 2016 and December 31, 2015 , respectively. In August 2016, Duke Energy entered into $326 million of interest rate swaps related to the solar facilities financing described in Note 6 , including $103 million of 4-year swaps and $223 million of 18-year swaps.
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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 40 $ 5 $ 12 $ 7 $ 5 $ 3 $ 20 Noncurrent 13 5 8 4 4 — — Total Derivative Assets – Commodity Contracts $ 53 $ 10 $ 20 $ 11 $ 9 $ 3 $ 20 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 2 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 4 — 4 1 3 — — Noncurrent 7 — 7 3 4 — — Total Derivative Assets – Interest Rate Contracts $ 13 $ — $ 11 $ 4 $ 7 $ — $ — Total Derivative Assets $ 66 $ 10 $ 31 $ 15 $ 16 $ 3 $ 20 Derivative Liabilities September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 67 $ 5 $ 62 $ 9 $ 53 $ — $ — Noncurrent 21 2 19 3 11 — — Total Derivative Liabilities – Commodity Contracts $ 88 $ 7 $ 81 $ 12 $ 64 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — Noncurrent 46 — — — — — — Not Designated as Hedging Instruments Current 1 — — — — 1 — Noncurrent 99 92 — — — 7 — Total Derivative Liabilities – Interest Rate Contracts $ 158 $ 92 $ — $ — $ — $ 8 $ — Total Derivative Liabilities $ 246 $ 99 $ 81 $ 12 $ 64 $ 8 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 4 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 10 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 26 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 11 $ — $ — $ — $ — $ — $ — Noncurrent 33 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 63 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 419 $ 45 $ 322 $ 98 $ 216 $ 7 $ —
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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 44 $ 5 $ 16 $ 8 $ 8 $ 3 $ 20 Gross amounts offset (10 ) (3 ) (7 ) (4 ) (3 ) — — Net amounts presented in Current Assets: Other $ 34 $ 2 $ 9 $ 4 $ 5 $ 3 $ 20 Noncurrent Gross amounts recognized $ 22 $ 5 $ 15 $ 7 $ 8 $ — $ — Gross amounts offset (7 ) (2 ) (5 ) (2 ) (3 ) — — Net amounts presented in Investments and Other Assets: Other $ 15 $ 3 $ 10 $ 5 $ 5 $ — $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 8 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 4 $ — $ — $ — $ — $ — $ —
Offsetting Liabilities	Derivative Liabilities September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 80 $ 5 $ 62 $ 9 $ 53 $ 1 $ — Gross amounts offset (10 ) (3 ) (7 ) (4 ) (3 ) — — Net amounts presented in Current Liabilities: Other $ 70 $ 2 $ 55 $ 5 $ 50 $ 1 $ — Noncurrent Gross amounts recognized $ 166 $ 94 $ 19 $ 3 $ 11 $ 7 $ — Gross amounts offset (7 ) (2 ) (5 ) (2 ) (3 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 159 $ 92 $ 14 $ 1 $ 8 $ 7 $ — Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 271 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 249 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 148 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 132 $ 13 $ 82 $ 21 $ 56 $ 6 $ —
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 and Duke Energy Indiana were not material. September 30, 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 $ 171 $ 99 $ 72 $ 12 $ 60 Fair value of collateral already posted — — — — — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 171 99 72 12 60 December 31, 2015 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 $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting arrangement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral under master netting arrangements. All receivables presented below were offset against net derivative positions on the Condensed Consolidated Balance Sheets. September 30, 2016 December 31, 2015 (in millions) Receivables Receivables Duke Energy $ — $ 30 Progress Energy — 30 Duke Energy Florida — 30

Investments in Debt and Equit37

Investments in Debt and Equity Securities (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 151 $ — $ — $ 179 Equity securities 1,968 55 3,949 1,823 58 3,590 Corporate debt securities 25 2 551 7 8 432 Municipal bonds 9 1 341 5 1 185 U.S. government bonds 31 — 994 11 5 1,254 Other debt securities — 3 132 — 4 177 Total NDTF $ 2,033 $ 61 $ 6,118 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 24 $ — $ — $ 29 Equity securities 38 — 104 32 1 95 Corporate debt securities 2 1 91 1 3 92 Municipal bonds 5 1 78 3 1 74 U.S. government bonds 1 — 49 — — 45 Other debt securities — 1 55 — 2 62 Total Other Investments (a) $ 46 $ 3 $ 401 $ 36 $ 7 $ 397 Total Investments $ 2,079 $ 64 $ 6,519 $ 1,882 $ 83 $ 6,214 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts are considered other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 92 Due after one through five years 655 Due after five through 10 years 529 Due after 10 years 1,015 Total $ 2,291
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 82 $ 30 $ 200 $ 160 Realized losses 42 28 134 59
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 available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 43 $ — $ — $ 34 Equity securities 1,091 29 2,170 1,021 27 2,094 Corporate debt securities 14 2 374 3 5 292 Municipal bonds 2 — 66 1 — 33 U.S. government bonds 12 — 454 3 3 438 Other debt securities — 3 123 — 4 147 Total NDTF $ 1,119 $ 34 $ 3,230 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,119 $ 35 $ 3,233 $ 1,028 $ 40 $ 3,041 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 3 Due after one through five years 206 Due after five through 10 years 268 Due after 10 years 543 Total $ 1,020
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 58 $ 25 $ 125 $ 132 Realized losses 28 24 84 47
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 available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 108 $ — $ — $ 145 Equity securities 877 26 1,779 802 31 1,496 Corporate debt securities 11 — 177 4 3 140 Municipal bonds 7 1 275 4 1 152 U.S. government bonds 19 — 540 8 2 816 Other debt securities — — 9 — — 30 Total NDTF $ 914 $ 27 $ 2,888 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 20 $ — $ — $ 18 Municipal bonds 4 — 47 3 — 45 Total Other Investments (a) $ 4 $ — $ 67 $ 3 $ — $ 63 Total Investments $ 918 $ 27 $ 2,955 $ 821 $ 37 $ 2,842 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 67 Due after one through five years 372 Due after five through 10 years 187 Due after 10 years 422 Total $ 1,048
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 21 $ 5 $ 71 $ 26 Realized losses 13 4 49 10
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 available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 56 $ — $ — $ 110 Equity securities 657 21 1,438 596 25 1,178 Corporate debt securities 8 — 123 3 2 96 Municipal bonds 7 1 275 4 1 150 U.S. government bonds 12 — 279 6 2 486 Other debt securities — — 6 — — 18 Total NDTF $ 684 $ 22 $ 2,177 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (a) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 684 $ 22 $ 2,178 $ 609 $ 30 $ 2,039 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 21 Due after one through five years 200 Due after five through 10 years 142 Due after 10 years 320 Total $ 683
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 18 $ 4 $ 60 $ 21 Realized losses 11 3 42 8
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 available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 52 $ — $ — $ 35 Equity securities 220 5 341 206 6 318 Corporate debt securities 3 — 54 1 1 44 Municipal bonds — — — — — 2 U.S. government bonds 7 — 261 2 — 330 Other debt securities — — 3 — — 12 Total NDTF (c) $ 230 $ 5 $ 711 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 2 $ — $ — $ 6 Municipal bonds 4 — 47 3 — 45 Total Other Investments (a) $ 4 $ — $ 49 $ 3 $ — $ 51 Total Investments $ 234 $ 5 $ 760 $ 212 $ 7 $ 792 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. (c) The decrease in estimated fair value of the NDTF as of September 30, 2016, is due to reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal Unit 3 Nuclear Plant.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 46 Due after one through five years 172 Due after five through 10 years 45 Due after 10 years 102 Total $ 365
Schedule of Realized Gain (Loss)	Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were as follows. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Realized gains $ 3 $ 1 $ 11 $ 5 Realized losses 2 1 7 2
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 available-for-sale securities. September 30, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value Other Investments Cash and cash equivalents $ — $ — $ — $ — $ — $ 2 Equity securities 31 — 77 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds 1 1 28 — 1 26 Total Other Investments (a) $ 32 $ 1 $ 107 $ 27 $ 1 $ 101 Total Investments $ 32 $ 1 $ 107 $ 27 $ 1 $ 101 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2016 Due in one year or less $ 3 Due after one through five years 9 Due after five through 10 years 13 Due after 10 years 5 Total $ 30

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [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 table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,949 $ 3,871 $ — $ — $ 78 Nuclear decommissioning trust fund debt securities 2,169 664 1,505 — — Other available-for-sale equity securities 104 104 — — — Other available-for-sale debt securities 297 74 219 4 — Derivative assets 66 — 43 23 — Total assets 6,585 4,713 1,767 27 78 Derivative liabilities (246 ) — (246 ) — — Net assets $ 6,339 $ 4,713 $ 1,521 $ 27 $ 78 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 — Derivative assets 26 — 16 10 — Total assets 6,240 4,260 1,793 15 172 Derivative liabilities (419 ) — (419 ) — — Net assets $ 5,821 $ 4,260 $ 1,374 $ 15 $ 172
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 Operating Revenues. Three Months Ended September 30, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 4 $ 34 $ 38 Purchases, sales, issuances and settlements: Settlements — (9 ) (9 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (2 ) (2 ) Balance at end of period $ 4 $ 23 $ 27 Three Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 23 $ 28 Purchases, sales, issuances and settlements: Settlements — (6 ) (6 ) Balance at end of period $ 5 $ 17 $ 22 Nine Months Ended September 30, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Purchases, sales, issuances and settlements: Purchases — 34 34 Sales (1 ) — (1 ) Settlements — (22 ) (22 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 1 Balance at end of period $ 4 $ 23 $ 27 Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains included in earnings — 18 18 Purchases, sales, issuances and settlements: Purchases — 24 24 Settlements — (28 ) (28 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 4 4 Balance at end of period $ 5 $ 17 $ 22
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. As of September 30, 2016 and December 31, 2015 , all Level 3 derivatives were financial transmission rights (FTRs). September 30, 2016 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 23 RTO auction pricing FTR price – per Megawatt-Hour (MWh) $ (2.59 ) - $ 8.16 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.45 - 2.01 Duke Energy Indiana 20 RTO auction pricing FTR price – per MWh (2.59 ) - 8.16 December 31, 2015 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29
Schedule Of Long Term Debt Fair Value [Table Text Block]	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. September 30, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 47,165 $ 50,997 $ 39,569 $ 42,537 Duke Energy Carolinas 9,360 10,799 8,367 9,156 Progress Energy 16,520 19,060 14,464 15,856 Duke Energy Progress 7,011 7,787 6,518 6,757 Duke Energy Florida 6,128 7,127 4,266 4,908 Duke Energy Ohio 1,887 2,128 1,598 1,724 Duke Energy Indiana 3,787 4,538 3,768 4,219
Duke Energy Carolinas [Member]
Fair Value Disclosures [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 table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,170 $ 2,092 $ — $ — $ 78 Nuclear decommissioning trust fund debt securities 1,060 184 876 — — Other available-for-sale debt securities 3 — — 3 — Derivative assets 10 — 10 — — Total assets 3,243 2,276 886 3 78 Derivative liabilities (99 ) — (99 ) — — Net assets $ 3,144 $ 2,276 $ 787 $ 3 $ 78 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — — Other available-for-sale debt securities 3 — — 3 — Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172
Progress Energy [Member]
Fair Value Disclosures [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 table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,779 $ 1,779 $ — Nuclear decommissioning trust fund debt securities 1,109 480 629 Other available-for-sale debt securities 67 20 47 Derivative assets 31 — 31 Total assets 2,986 2,279 707 Derivative liabilities (81 ) — (81 ) Net assets $ 2,905 $ 2,279 $ 626 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591
Duke Energy Progress [Member]
Fair Value Disclosures [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 table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,438 $ 1,438 $ — Nuclear decommissioning trust fund debt securities and other 739 220 519 Other available-for-sale debt securities and other 1 1 — Derivative assets 15 — 15 Total assets 2,193 1,659 534 Derivative liabilities (12 ) — (12 ) Net assets $ 2,181 $ 1,659 $ 522 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623
Duke Energy Florida [Member]
Fair Value Disclosures [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 table below exclude cash collateral which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 341 $ 341 $ — Nuclear decommissioning trust fund debt securities and other 370 260 110 Other available-for-sale debt securities and other 49 2 47 Derivative assets 16 — 16 Total assets 776 603 173 Derivative liabilities (64 ) — (64 ) Net assets $ 712 $ 603 $ 109 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 )
Duke Energy Ohio [Member]
Fair Value Disclosures [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 table below exclude cash collateral, which are disclosed in Note 10 . September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (8 ) — (8 ) — Net (liabilities) assets $ (5 ) $ — $ (8 ) $ 3 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3
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 September 30, (in millions) 2016 2015 Balance at beginning of period $ 5 $ 5 Purchases, sales, issuances and settlements: Purchases — 5 Sales — (5 ) Settlements (2 ) (1 ) Balance at end of period $ 3 $ 4 Derivatives (net) Nine Months Ended September 30, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains included in earnings — 21 Purchases, sales, issuances and settlements: Purchases 5 5 Settlements (4 ) (4 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (1 ) — Balance at end of period $ 3 $ 4
Duke Energy Indiana [Member]
Fair Value Disclosures [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 table below exclude cash collateral, which is disclosed in Note 10 . See Note 11 for additional information related to investments by major security type. September 30, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 77 $ 77 $ — $ — Other available-for-sale debt securities and other 30 — 30 — Derivative assets 20 — — 20 Net assets $ 127 $ 77 $ 30 $ 20 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7
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 September 30, (in millions) 2016 2015 Balance at beginning of period $ 29 $ 17 Purchases, sales, issuances and settlements: Purchases — 1 Settlements (7 ) (6 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (2 ) — Balance at end of period $ 20 $ 12 Derivatives (net) Nine Months Ended September 30, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Purchases, sales, issuances and settlements: Purchases 29 19 Settlements (18 ) (25 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 2 4 Balance at end of period $ 20 $ 12

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2016
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. Amounts borrowed under the credit facilities are reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. Duke Energy Duke Energy Duke Energy Duke Energy Carolinas Progress Florida CRC DERF DEPR DEFR Expiration date December 2018 December 2018 February 2019 April 2019 Credit facility amount (in millions) $ 325 $ 425 $ 300 $ 225 Amounts borrowed at September 30, 2016 325 425 300 225 Amounts borrowed at December 31, 2015 325 425 254 225
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. September 30, 2016 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 50 $ 74 Investments in equity method unconsolidated affiliates 168 317 485 — — Investments and Other Assets: Other — 12 12 — — Total assets $ 168 $ 329 $ 497 $ 50 $ 74 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 13 13 — — Total liabilities $ — $ 15 $ 15 $ — $ — Net assets $ 168 $ 314 $ 482 $ 50 $ 74 December 31, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 235 152 387 — — Total assets $ 235 $ 152 $ 387 $ 47 $ 60 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 235 $ 135 $ 370 $ 47 $ 60
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 2016 2015 2016 2015 Anticipated credit loss ratio 0.5 % 0.6 % 0.3 % 0.3 % Discount rate 1.5 % 1.2 % 1.5 % 1.2 % Receivable turnover rate 13.3 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Receivables sold $ 217 $ 233 $ 296 $ 260 Less: Retained interests 50 47 74 60 Net receivables sold $ 167 $ 186 $ 222 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (in millions) 2016 2015 2016 2015 2016 2015 2016 2015 Sales Receivables sold $ 481 $ 449 $ 1,442 $ 1,518 $ 722 $ 679 $ 1,980 $ 2,032 Loss recognized on sale 2 2 7 7 3 3 8 8 Cash flows Cash proceeds from receivables sold $ 468 $ 461 $ 1,432 $ 1,568 $ 703 $ 692 $ 1,958 $ 2,074 Collection fees received 1 — 1 1 — — 1 1 Return received on retained interests 1 — 2 2 2 1 4 4
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) September 30, 2016 Receivables of VIEs $ 7 Regulatory Assets: Current 51 Current Assets: Other 29 Regulatory Assets and Deferred Debits: Regulatory assets 1,156 Interest accrued 9 Current maturities of long-term debt 62 Long-Term Debt 1,216
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) September 30, 2016 December 31, 2015 Current Assets: Other $ 252 $ 138 Property, plant and equipment, cost 2,583 2,015 Accumulated depreciation and amortization (400 ) (321 ) Current maturities of long-term debt 193 108 Long-Term Debt 1,151 968 Deferred Credits and Other Liabilities: Deferred income taxes 50 289 Deferred Credits and Other Liabilities: Other 270 33

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, Nine Months Ended September 30, (in millions, except per-share amounts) 2016 2015 2016 2015 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 1,053 $ 935 $ 2,252 $ 2,307 Weighted average shares outstanding – basic 689 688 689 696 Equity Forwards 2 — 1 — Weighted average shares outstanding – diluted 691 688 690 696 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 1.52 $ 1.36 $ 3.27 $ 3.31 Diluted $ 1.52 $ 1.36 $ 3.26 $ 3.31 Potentially dilutive items excluded from the calculation (a) 2 2 2 Dividends declared per common share $ 0.855 $ 0.825 $ 2.505 $ 2.42 (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)	9 Months Ended
	Sep. 30, 2016
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 Nine Months Ended September 30, September 30, (in millions) 2016 2015 2016 2015 Restricted stock unit awards $ 8 $ 9 $ 25 $ 29 Performance awards 4 5 14 18 Pretax stock-based compensation cost $ 12 $ 14 $ 39 $ 47 Tax benefit associated with stock-based compensation expense $ 5 $ 6 $ 14 $ 18 Stock-based compensation costs capitalized — 1 2 3

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Employee Savings Plan Matching Contributions	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 Three Months Ended September 30, 2016 $ 39 $ 13 $ 12 $ 8 $ 3 $ 1 $ 2 2015 34 11 10 7 3 — 1 Nine Months Ended September 30, 2016 $ 130 $ 44 $ 39 $ 27 $ 11 $ 3 $ 6 2015 120 40 36 26 10 2 5
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan Contributions by Employer	The following table includes information related to Duke Energy's contributions to its U.S. qualified defined benefit pension plans. Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the nine months ended September 30, 2016 . Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Contributions $ 143 $ 42 $ 42 $ 21 $ 21 $ 4 $ 9
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 36 $ 12 $ 11 $ 6 $ 4 $ 1 $ 2 Interest cost on projected benefit obligation 83 21 27 12 14 5 7 Expected return on plan assets (128 ) (35 ) (42 ) (21 ) (21 ) (6 ) (10 ) Amortization of actuarial loss 33 8 14 6 7 1 3 Amortization of prior service credit (4 ) (2 ) (1 ) — (1 ) — — Other 2 1 1 — 1 — — Net periodic pension costs $ 22 $ 5 $ 10 $ 3 $ 4 $ 1 $ 2 Three Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 40 $ 13 $ 11 $ 6 $ 5 $ 1 $ 3 Interest cost on projected benefit obligation 81 21 26 12 14 5 7 Expected return on plan assets (129 ) (35 ) (43 ) (20 ) (22 ) (7 ) (10 ) Amortization of actuarial loss 44 10 17 8 8 3 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 2 1 1 — — — — Net periodic pension costs $ 34 $ 8 $ 11 $ 6 $ 5 $ 2 $ 3 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 109 $ 36 $ 32 $ 18 $ 14 $ 3 $ 6 Interest cost on projected benefit obligation 249 64 80 37 42 15 21 Expected return on plan assets (386 ) (106 ) (126 ) (62 ) (63 ) (20 ) (31 ) Amortization of actuarial loss 99 24 41 17 21 3 9 Amortization of prior service credit (12 ) (6 ) (3 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 65 $ 14 $ 26 $ 10 $ 14 $ 1 $ 5 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 119 $ 38 $ 33 $ 18 $ 15 $ 3 $ 8 Interest cost on projected benefit obligation 244 62 78 36 41 14 21 Expected return on plan assets (387 ) (104 ) (127 ) (61 ) (66 ) (20 ) (31 ) Amortization of actuarial loss 131 30 51 25 24 8 10 Amortization of prior service credit (11 ) (6 ) (3 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 102 $ 22 $ 34 $ 18 $ 14 $ 5 $ 8
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 September 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 4 — 2 — — Amortization of actuarial loss 2 — 1 1 1 Amortization of prior service credit (1 ) — — — — Net periodic pension costs $ 6 $ — $ 3 $ 1 $ 1 Three Months Ended September 30, 2015 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 Amortization of actuarial loss 2 — 1 — — Net periodic pension costs $ 6 $ — $ 2 $ — $ 1 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ — $ — $ — Interest cost on projected benefit obligation 11 1 4 1 1 Amortization of actuarial loss 6 — 2 1 1 Amortization of prior service credit (1 ) — — — — Net periodic pension costs $ 18 $ 1 $ 6 $ 2 $ 2 Nine Months Ended September 30, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ 1 $ — $ — Interest cost on projected benefit obligation 10 1 3 1 2 Amortization of actuarial loss 5 — 2 — 1 Net periodic pension costs $ 17 $ 1 $ 6 $ 1 $ 3
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 September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ — $ — $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 3 — 1 Expected return on plan assets (2 ) (2 ) (1 ) — — — — Amortization of actuarial loss (gain) 2 — 5 3 2 (1 ) — Amortization of prior service credit (35 ) (4 ) (26 ) (16 ) (8 ) — (1 ) Net periodic other post-retirement benefit costs $ (26 ) $ (4 ) $ (17 ) $ (11 ) $ (3 ) $ (1 ) $ — Three Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 1 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 2 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss 6 — 7 5 3 — — Amortization of prior service credit (35 ) (4 ) (26 ) (17 ) (9 ) — — Net periodic other post-retirement benefit costs $ (22 ) $ (4 ) $ (15 ) $ (10 ) $ (4 ) $ — $ 1 Nine Months Ended September 30, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 26 6 11 6 6 1 3 Expected return on plan assets (9 ) (6 ) (1 ) — — — (1 ) Amortization of actuarial loss (gain) 5 (2 ) 16 9 7 (2 ) (1 ) Amortization of prior service credit (106 ) (10 ) (77 ) (50 ) (26 ) — (1 ) Net periodic other post-retirement benefit costs $ (82 ) $ (12 ) $ (50 ) $ (35 ) $ (13 ) $ (1 ) $ — Nine Months Ended September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 4 $ 1 $ 1 $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 27 6 11 6 5 1 3 Expected return on plan assets (9 ) (6 ) — — — — — Amortization of actuarial loss (gain) 19 (1 ) 21 14 8 — (1 ) Amortization of prior service credit (105 ) (11 ) (77 ) (50 ) (25 ) — — Net periodic other post-retirement benefit costs $ (64 ) $ (11 ) $ (44 ) $ (30 ) $ (12 ) $ 1 $ 2

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2016
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 Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Duke Energy 32.9 % 30.9 % 30.0 % 32.5 % Duke Energy Carolinas 34.3 % 36.5 % 34.4 % 36.3 % Progress Energy 32.8 % 25.0 % 34.7 % 31.8 % Duke Energy Progress 31.4 % 34.4 % 33.5 % 35.3 % Duke Energy Florida 36.0 % 30.1 % 37.0 % 35.2 % Duke Energy Ohio 36.8 % 39.3 % 32.5 % 37.6 % Duke Energy Indiana 35.2 % 37.0 % 34.0 % 36.6 %

Organization and Basis of Pre44

Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 800	$ 748
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	318	283
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	195	172
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	96	102
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	99	70
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	2	3
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	36	31
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	72	71
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 109	$ 97

Organization and Basis of Pre45

Organization and Basis of Presentation Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Inventory	$ 3,351	$ 3,810
Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	2,312	2,389
Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	743	1,114
Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	296	307
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,053	1,276
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	760	785
Duke Energy Carolinas [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	256	451
Duke Energy Carolinas [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	37	40
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,653	1,751
Progress Energy [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,139	1,133
Progress Energy [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	277	370
Progress Energy [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	237	248
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	998	1,088
Duke Energy Progress [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	781	776
Duke Energy Progress [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	101	192
Duke Energy Progress [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	116	120
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	656	663
Duke Energy Florida [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	358	357
Duke Energy Florida [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	177	178
Duke Energy Florida [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	121	128
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	110	105
Duke Energy Ohio [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	85	81
Duke Energy Ohio [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	18	16
Duke Energy Ohio [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	7	8
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	424	570
Duke Energy Indiana [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	236	301
Duke Energy Indiana [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	186	267
Duke Energy Indiana [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	$ 2	$ 2

Organization and Basis of Pre46

Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 107	$ 109	$ 285	$ 308
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	6	9	21	27
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	65	67	161	174
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4	4	13	12
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	61	63	148	162
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	26	24	77	80
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 10	$ 9	$ 26	$ 27

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisitions (Narrative) (Details) shares in Millions, $ in Millions	Oct. 05, 2016USD ($)	Oct. 03, 2016USD ($)	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)MW	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)	Oct. 28, 2016USD ($)	Aug. 31, 2016USD ($)	Aug. 01, 2016USD ($)	Feb. 22, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Payments to acquire businesses					$ 10	$ 1,317
Long-term debt assumed			$ 47,165		47,165						$ 39,569
Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs			14		22
Long-term debt assumed								$ 3,750
Facility size			$ 4,900		$ 4,900				$ 4,900
Shares offered | shares			10.6		10.6
Business Combination, After Tax Integration Related Costs			$ 41		$ 161
Piedmont Natural Gas [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Payments to acquire businesses		$ 5,000
Proceeds from Issuance or Sale of Equity	$ 723
Interest Expense [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Business Combination, Integration Related Costs			51		234
August 2016 Term Loan Facility [Member]
Business Acquisition [Line Items]
Facility size at period end			850		850
Facility size									$ 1,500	$ 1,000
August 2016 Term Loan Facility [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Facility size at period end							$ 1,500
August 2016 Term Loan Facility [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Facility size at period end			750		750
Facility size			1,500		1,500
Duke Energy Progress [Member]
Business Acquisition [Line Items]
Payments to acquire businesses						1,249
Long-term debt assumed			7,011		7,011						$ 6,518
Duke Energy Progress [Member] | NCEMPA Generating Assets [Member]
Business Acquisition [Line Items]
Payments to acquire businesses				$ 1,250
Owned Plant Capacity | MW				700
Acquisition adjustment, recorded within property, plant and equipment				$ 350		$ 350
Interest Rate Contracts [Member] | Piedmont Natural Gas [Member]
Business Acquisition [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments			$ 22		$ 190

Acquisitions and Dispositions A

Acquisitions and Dispositions Acquisitions and Dispositions - Dispositions (Narrative) (Details) $ in Millions	Oct. 10, 2016USD ($)MW	Apr. 02, 2015USD ($)MW	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Impairment Charges				$ 10		$ 111		$ 208	$ 111
Proceeds from sale of the Midwest Generation Disposal Group									2,792
International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Impairment Charges					$ 194
International Disposal Group [Member] | Scenario, Forecast [Member] | International Energy [Member] | Minimum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses							$ 1,700
Asset Impairment Charges			$ 325
International Disposal Group [Member] | Scenario, Forecast [Member] | International Energy [Member] | Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses							$ 1,900
Asset Impairment Charges			$ 375
Midwest Generation Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit				122		(1)		122	29
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Average MW Capacity | MW		5,900
Proceeds from sale of the Midwest Generation Disposal Group		$ 2,800
Income tax benefit				$ 34		$ (2)		$ 34	$ 25
Subsequent Event [Member] | DEI Brazil Holdings [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Average MW Capacity | MW	2,090
Enterprise Value	$ 1,200
Acquirer Termination Fee	$ 49
Subsequent Event [Member] | DEI Latin American [Member] | International Energy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Owned Average MW Capacity | MW	2,230
Enterprise Value	$ 1,200
Acquirer Termination Fee	$ 89

Acquisitions and Dispositions49

Acquisitions and Dispositions Acquisitions and Dispositions (Purchase Price Allocation) (Details) - USD ($) $ in Millions	Oct. 03, 2016	Sep. 30, 2016	Dec. 31, 2015
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill		$ 16,354	$ 16,343
Piedmont Natural Gas [Member] | Piedmont Acquisition
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Current assets	$ 500
Property, plant and equipment, net	4,710
Goodwill	3,380
Other long-term assets	810
Total assets	9,400
Current liabilities, including current maturities of long-term debt	590
Long-term liabilities	1,810
Long-term debt	2,000
Total liabilities	4,400
Total purchase price	$ 5,000

Acquisitions and Dispositions50

Acquisitions and Dispositions Acquisitions and Dispositions (Pro Forma Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues	$ 6,958	$ 6,627	$ 18,688	$ 19,021
Net income attributable to Duke Energy Corporation	$ 1,180	$ 897	$ 2,552	$ 2,352

Acquisitions and Dispositions51

Acquisitions and Dispositions (Midwest Generation Exit) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax	$ 122	$ (5)	$ 124	$ 29
Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax	34	(2)	36	23
Midwest Generation Business [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues				543
Loss on disposition		(5)		(42)
(Loss) Income before income taxes		(5)		62
Income tax (benefit) expense	122	(1)	122	29
(Loss) Income From Discontinued Operations, net of tax		(4)		33
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues				412
Loss on disposition		(4)		(48)
(Loss) Income before income taxes		(4)		48
Income tax (benefit) expense	$ 34	(2)	$ 34	25
(Loss) Income From Discontinued Operations, net of tax		(2)		23
Other Disposal Groups [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax		$ (1)		(4)
Antitrust Lawsuit [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Litigation Settlement, Expense				81
Antitrust Lawsuit [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Litigation Settlement, Expense				81
Antitrust Lawsuit [Member] | Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Litigation Settlement, Expense				$ 81

Business Segments (Narrative) (

Business Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenue, Net	$ 6,821	$ 6,483	$ 17,927	$ 18,137
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(1,054)	(937)	(2,255)	(2,310)
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Revenue, Net	489	462	1,433	1,453
Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Revenue, Net	140	66	366	214
Commercial Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue, Net	140	66	366	214
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	21	(8)	(20)	15
Commercial Portfolio [Member] | Duke Energy Ohio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue, Net				14
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent				9
International Energy [Member]
Segment Reporting Information [Line Items]
Revenue, Net	245	281	761	841
International Energy [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue, Net	245	281	761	841
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ (64)	$ (69)	$ (85)	$ (157)
National Methanol Company [Member] | International Energy [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	25.00%		25.00%

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating revenues	$ 6,821	$ 6,483	$ 17,927	$ 18,137
Segment income	1,054	937	2,255	2,310
Add back noncontrolling interests	5	3	13	10
(Loss) Income From Discontinued Operations, net of tax	122	(5)	124	29
Net income (loss)	1,181	935	2,392	2,349
Segment assets	129,686		129,686		$ 121,156
Income Tax Benefit	520	420	972	1,118
Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,421	6,138	16,761	17,062
Impairment Charges, net of tax		56		56
International Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	245	281	761	841
Impairment Charges, net of tax			145
Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues	140	66	366	214
Impairment Charges, net of tax	45		45
State Tax Charge				41
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,806	6,485	17,888	18,117
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	15	(2)	39	20
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,430	6,147	16,788	17,090
Segment income	1,200	905	2,613	2,311
Segment assets	114,707		114,707
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	245	281	761	841
Segment income	64	69	85	157
Segment assets	3,153		3,153
Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues	140	66	366	214
Segment income	(21)	8	20	(15)
Segment assets	4,414		4,414
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,815	6,494	17,915	18,145
Segment income	1,243	982	2,718	2,453
Segment assets	122,274		122,274
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(26)	(28)	(79)	(86)
Segment income				(4)
Segment assets	184		184
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	(9)	(9)	(27)	(28)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	(9)	(9)	(27)	(28)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	(17)	(19)	(52)	(58)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	32	17	91	78
Segment income	(189)	(45)	(463)	(139)
Segment assets	7,228		7,228
Costs to achieve merger	52	15	195	42
Cost Savings Initiative, Net of tax	12		39
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	489	462	1,433	1,453
(Loss) Income From Discontinued Operations, net of tax	34	(2)	36	23
Segment assets	7,408		7,408		$ 7,097
Income Tax Benefit	32	22	65	64
Charge for settlement agreement				53
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (10)	$ (12)	(29)	(20)
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues				14
Segment income				$ (9)
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Income Tax Benefit			$ 122

Business Segments (Schedule of

Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Interest Expense	$ 482	$ 402	$ 1,493	$ 1,208
Segment income	1,054	937	2,255	2,310
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Interest Expense	102	105	316	313
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(16)	(10)	(50)	(28)
Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	177	170	497	504
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Interest Expense	55	61	166	180
Segment income	(45)	(3)	(139)	(87)
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Interest Expense	61	59	188	175
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(4)	(26)	(12)
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Interest Expense	62	50	143	149
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(5)	(3)	(14)	(9)
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Interest Expense	22	20	63	58
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(12)	(29)	(20)
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Interest Expense	45	44	136	132
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (3)	$ (2)	$ (10)	$ (6)

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	Oct. 19, 2016USD ($)	Oct. 03, 2016USD ($)	Jan. 31, 2017USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)MW	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					$ 10		$ 111	$ 208	$ 111
Regulatory Assets, Noncurrent				$ 11,373	11,896			11,896		$ 11,373
Electric Domestic Regulated Revenue					6,303		6,017	16,321	16,564
Payments to Acquire Businesses, Gross								10	1,317
Debt issuances					8,527			8,527
Property, Plant and Equipment, Net				75,709	78,216			$ 78,216		75,709
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW								1,471
Property, Plant and Equipment, Net					$ 293			$ 293
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					40.00%			40.00%
Atlantic Coast Pipeline (ACP) [Member] | Dominion Resources [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					45.00%			45.00%
Atlantic Coast Pipeline (ACP) [Member] | Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					10.00%			10.00%
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					7.50%			7.50%
Sabal Trail Transmission Pipeline [Member] | Spectra Energy [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					59.50%			59.50%
Sabal Trail Transmission Pipeline [Member] | NextEra [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					33.00%			33.00%
Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Approved Appeal Bond					$ 98			$ 98
Subsequent Event [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		47.00%
Subsequent Event [Member] | Atlantic Coast Pipeline (ACP) [Member] | Dominion Resources [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		48.00%
Subsequent Event [Member] | Atlantic Coast Pipeline (ACP) [Member] | Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Ownership Interest in Jointly Owned Plant Transferred		3.00%
Proceeds from Divestiture of Interest in Joint Venture		$ 14
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent				2,766	3,040			3,040		2,766
Debt issuances					1,000			1,000
Property, Plant and Equipment, Net				25,877	26,370			$ 26,370		25,877
Duke Energy Carolinas [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								10.20%
Duke Energy Carolinas [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								8.49%
Duke Energy Carolinas [Member] | FERC ROE Settlement [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								10.00%
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC					$ 600			$ 600
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member] | NCEMC [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage					13.00%			13.00%
Duke Energy Carolinas [Member] | Maximum [Member] | Advanced Metering Infrastructure Deferral [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent					$ 45			$ 45
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					1		7	4	7
Regulatory Assets, Noncurrent				5,435	5,652			5,652		5,435
Payments to Acquire Businesses, Gross								10	1,249
Property, Plant and Equipment, Net				28,347	29,544			$ 29,544		28,347
Progress Energy [Member] | Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW								873
Property, Plant and Equipment, Net					123			$ 123
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					1			1
Regulatory Assets, Noncurrent				2,710	3,093			3,093		2,710
Payments to Acquire Businesses, Gross									1,249
Debt issuances					450			450
Property, Plant and Equipment, Net				17,720	18,055			$ 18,055		17,720
Duke Energy Progress [Member] | 2016 South Carolina Rate Case [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								10.75%
Public Utilities, Requested Rate Increase (Decrease), Percentage								14.50%
Public Utilities, Requested Rate Increase (Decrease), Amount								$ 79
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost					1,100			$ 1,100
Duke Energy Progress [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								10.80%
Duke Energy Progress [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								8.49%
Duke Energy Progress [Member] | FERC ROE Settlement [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								10.00%
Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW								376
Property, Plant and Equipment, Net				548	562			$ 562		548
Duke Energy Progress [Member] | Subsequent Event [Member] | 2016 South Carolina Rate Case Settlement [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage	10.10%
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 56
Duke Energy Progress [Member] | Subsequent Event [Member] | 2016 South Carolina Rate Case Settlement Year 1 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	38
Duke Energy Progress [Member] | Subsequent Event [Member] | 2016 South Carolina Rate Case Settlement Year 2 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	18.5
Duke Energy Progress [Member] | Subsequent Event [Member] | 2016 South Carolina Rate Case Settlement Year 2 Offset [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ (18.5)
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					1		7	4	7
Regulatory Assets, Noncurrent				2,725	2,559			2,559		2,725
Payments to Acquire Businesses, Gross								10
Debt issuances					1,894			1,894
Property, Plant and Equipment, Net				10,623	11,485			11,485		10,623
Duke Energy Florida [Member] | Hines Chiller Uprate Project [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost					150			150
Duke Energy Florida [Member] | Hines Chiller Uprate Project Phase 1[Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount								17
Duke Energy Florida [Member] | Hines Chiller Uprate Project Phase 2 [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount								3
Duke Energy Florida [Member] | Osprey Energy Center Acquisition [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount								$ 48
Duke Energy Florida [Member] | Osprey Energy Center Acquisition [Member] | Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Payments to Acquire Businesses, Gross			$ 166
Duke Energy Florida [Member] | Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW								873
Property, Plant and Equipment, Net					123			$ 123
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Asset, Amortization Period								20 years
Duke Energy Florida [Member] | DEFPF [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent					1,156			$ 1,156
Debt issuances					1,294			1,294
Duke Energy Florida [Member] | DEFPF [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt						$ 1,287
Debt issuances						$ 1,294
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent				497	490			490		497
Electric Domestic Regulated Revenue					390		367	1,053	1,005
Debt issuances					250			250
Property, Plant and Equipment, Net				5,243	5,453			5,453		5,243
Duke Energy Ohio [Member] | Advanced Metering Infrastructure Project [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved					10			10
Estimated capital cost					49			49
Duke Energy Ohio [Member] | Energy Efficiency and Peak Demand Reduction Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue				20
Duke Energy Ohio [Member] | MGP Remediation [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets					101			101
Duke Energy Ohio [Member] | Accelerated Natural Gas Service Line Replacement Rider [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved					240			240
Duke Energy Ohio [Member] | Regional Transmission Organization [Member]
Public Utilities, General Disclosures [Line Items]
Exit obligation				92	91			91		92
Regulatory Assets, Noncurrent				72	$ 72			$ 72		72
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Approved MVP Proposals					17			17
MISO estimate of Duke Energy Ohio's MVP obligation								$ 2,700
Duke Energy Ohio [Member] | East End Site [Member] | MGP Remediation [Member]
Public Utilities, General Disclosures [Line Items]
Environmental Exit Costs, Anticipated Cost								46
Duke Energy Ohio [Member] | Minimum [Member] | Natural Gas Pipeline Extension [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC					$ 86			86
Duke Energy Ohio [Member] | Maximum [Member] | Natural Gas Pipeline Extension [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC					110			110
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					8		$ 85	8	$ 85
Regulatory Assets, Noncurrent				716	909			909		716
Debt issuances					500			500
Property, Plant and Equipment, Net				$ 9,523	9,934			9,934		9,523
Duke Energy Indiana [Member] | Advanced Metering Infrastructure Project [Member]
Public Utilities, General Disclosures [Line Items]
Asset Impairment Charges					8
Property, Plant and Equipment, Net					48			48
Duke Energy Indiana [Member] | Coal Combustion Residual Plan [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved					380			$ 380
Federal Mandate Costs Recovered Through Tracker Mechanism								80.00%
Federally Mandated Costs Recovered In Future Rate Case								20.00%
Duke Energy Indiana [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								12.38%
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								0.50%
Duke Energy Indiana [Member] | FERC Complaint 1 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								10.32%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								8.67%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage								9.70%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost					1,900			$ 1,900
Duke Energy Indiana [Member] | Revised Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission								10.00%
Estimated capital cost					1,800			$ 1,800
Public Utilities, Approved Rate Increase (Decrease), Amount								1,400
Duke Energy Indiana [Member] | Edwardsport Igcc Plant [Member] | IGCC Rider Proceeding [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Legal Fees								5.5
Utilities Operating Expense, Other										$ 93
Public Utilities, Approved Rate Increase (Decrease), Amount								$ (87.5)
Regulatory Asset, Amortization Period								8 years
Regulatory Assets					$ 184			$ 184

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)MW	Dec. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 78,216	$ 75,709
Generation Facilities To Be Retired Net	$ 652	548
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,471
Remaining net book value (in millions)	$ 293
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	26,370	25,877
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	29,544	28,347
Generation Facilities To Be Retired Net	$ 562	548
Progress Energy [Member] | Generation Facilities To Be Retired [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 123
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	18,055	17,720
Generation Facilities To Be Retired Net	562	548
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 11,485	10,623
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 123
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	5,453	5,243
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	9,934	$ 9,523
Generation Facilities To Be Retired Net	90
Duke Energy Indiana [Member] | Wabash River Unit 6 [Member]
Public Utilities, General Disclosures [Line Items]
Generation Facilities To Be Retired Net	$ 90
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member] | Wabash River Unit 6 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	318
Remaining net book value (in millions)	$ 33
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member] | Gallagher Units 2 and 4 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Remaining net book value (in millions)	$ 137

Commitments and Contingencies57

Commitments and Contingencies (Narrative) (Details) $ in Millions

Oct. 11, 2016USD ($)

Sep. 23, 2016USD ($)

Feb. 08, 2016USD ($)

Mar. 10, 2015USD ($)

Feb. 02, 2014Tgal

Aug. 10, 2011

Aug. 09, 2011

Feb. 29, 2008

Sep. 30, 2016USD ($)plantClaims

Sep. 30, 2015USD ($)

Dec. 31, 2015USD ($)

Aug. 18, 2014gal

Mar. 31, 2014USD ($)

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

$ 110

$ 166

Progress Energy Merger Shareholder Litigation [Member]

Valuation and Qualifying Accounts [Abstract]

Gain contingency, unrecorded amount

$ 27

Brazil Expansion Lawsuit [Member]

Valuation and Qualifying Accounts [Abstract]

Obligation to expand installed generation capacity, percent

15.00%

15.00%

15.00%

NCDEQ State Enforcement Actions [Member]

Valuation and Qualifying Accounts [Abstract]

Number of Plants with No Disputed Facts | plant

7

Number of Plants with Ash Basins | plant

14

Potential Groundwater Claims [Member]

Valuation and Qualifying Accounts [Abstract]

Number of Plants with Ash Basins | plant

14

Antitrust Lawsuit [Member]

Valuation and Qualifying Accounts [Abstract]

Litigation Settlement, Expense

$ 81

Duke Energy Carolinas [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

$ 11

11

Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]

Valuation and Qualifying Accounts [Abstract]

Civil Penalty Assessed

$ 6.8

Litigation Settlement Amount

$ 6

Duke Energy Carolinas [Member] | Groundwater Violation [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency, Damages Paid, Value

1

Duke Energy Carolinas [Member] | Asbestos Issue [Member]

Valuation and Qualifying Accounts [Abstract]

Asbestos-related injuries and damages reserves

512

536

Reinsurance retention policy, excess retention, amount reinsured

814

Probable insurance recoveries

$ 567

599

Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]

Valuation and Qualifying Accounts [Abstract]

Loss contingency, pending claims, number | Claims

120

Asbestos-related injuries and damages reserves

$ 32

Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]

Valuation and Qualifying Accounts [Abstract]

Loss contingency, pending claims, number | Claims

78

Asbestos-related injuries and damages reserves

$ 14

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

24,000,000

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

27,000,000

Progress Energy [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

54

54

Duke Energy Progress [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

8

6

Duke Energy Progress [Member] | Groundwater Violation [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency, Damages Paid, Value

6

Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]

Valuation and Qualifying Accounts [Abstract]

Civil Penalty Assessed

$ 25

Duke Energy Florida [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

30

31

Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]

Valuation and Qualifying Accounts [Abstract]

Gain contingency, unrecorded amount

54

Loss Contingency, Damages Sought, Original Amount

$ 510

Loss Contingency, Damages Awarded, Value

30

Gain Contingency, Dismissed Amount

54

Duke Energy Ohio [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency Accrual

$ 5

80

Duke Energy Ohio [Member] | W.C. Beckjord Station [Member]

Valuation and Qualifying Accounts [Abstract]

Gallons of Fuel Released | gal

9,000

Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]

Valuation and Qualifying Accounts [Abstract]

Litigation Settlement Amount

$ 81

Litigation Settlement, Expense

$ 81

Subsequent Event [Member] | Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]

Valuation and Qualifying Accounts [Abstract]

Loss Contingency, Damages Sought, Original Amount

$ 482

Loss contingency, damages sought, value

$ 424

Commitments and Contingencies58

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 69
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	97	$ 97
Provisions/adjustments	34	4
Cash reductions	(12)	(4)
Ending balance	119	97
Duke Energy Carolinas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	22
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	10
Provisions/adjustments	5
Cash reductions	(4)
Ending balance	11	10
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	17
Provisions/adjustments	5	3
Cash reductions	(6)	(2)
Ending balance	16	18
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	3	5
Provisions/adjustments	2
Cash reductions	(2)	(1)
Ending balance	3	4
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	14	12
Provisions/adjustments	3	3
Cash reductions	(4)	(1)
Ending balance	13	14
Duke Energy Ohio [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	36
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	54	54
Provisions/adjustments	6	1
Cash reductions	(1)	(1)
Ending balance	59	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	12	10
Provisions/adjustments	20	3
Cash reductions	(2)	(1)
Ending balance	$ 30	$ 12

Commitments and Contingencies59

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Reserves for legal matters	$ 110	$ 166
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	11	11
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	54	54
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	8	6
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	30	31
Duke Energy Ohio [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 5	$ 80

Debt and Credit Facilities Debt

Debt and Credit Facilities Debt and Credit Facilities (Narrative) (Details) - USD ($) $ in Millions	Oct. 28, 2016	Feb. 22, 2016	Aug. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Aug. 01, 2016	Jun. 01, 2016
Debt Instrument [Line Items]
Debt issuances				$ 8,527
Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2034 [Member]
Debt Instrument [Line Items]
Debt issuances				$ 228
Interest rate				2.747%
Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2020 [Member]
Debt Instrument [Line Items]
Debt issuances				$ 105
Interest rate				2.747%
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility size				$ 4,900		$ 4,900
Piedmont Natural Gas [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances						3,750
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size				7,500
Available capacity				5,155
Term Loan Facility [Member]
Debt Instrument [Line Items]
Facility size		$ 1,000				1,500
Facility size at period end				850
Debt Instrument, Term		6 months
Term Loan Facility [Member] | Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility size				1,500
Facility size at period end				750
Term Loan Facility [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Facility size at period end	$ 1,500
Proceeds from Line of Credit	$ 650
Solar Facilities Financing [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances						333
Solar Facilities Financing [Member] | Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2034 [Member]
Debt Instrument [Line Items]
Debt issuances						228
Debt Instrument, Basis Spread on Variable Rate			1.75%
Debt Instrument, Interest Rate, Increase (Decrease)			0.125%
Solar Facilities Financing [Member] | Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2020 [Member]
Debt Instrument [Line Items]
Debt issuances						$ 105
Debt Instrument, Basis Spread on Variable Rate			1.75%
Debt Instrument, Interest Rate, Increase (Decrease)			0.125%
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances				1,000
Distributions to parent				1,800	$ 401
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size				1,100
Available capacity				511
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances				450
Distributions to parent				301
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size				1,000
Available capacity				598
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances				1,894
Distributions to parent				774	$ 350
Duke Energy Florida [Member] | DEFPF [Member]
Debt Instrument [Line Items]
Debt issuances				1,294
Duke Energy Florida [Member] | Secured Debt [Member] | DEFPF [Member]
Debt Instrument [Line Items]
Debt issuances							$ 1,294
Distributions to parent				649
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size				950
Available capacity				949
USDOJ [Member] | Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required				250
USDOJ [Member] | Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required				$ 250
Swap [Member] | Solar Facilities Financing [Member] | Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2034 [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate						1.81%
Swap [Member] | Solar Facilities Financing [Member] | Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2020 [Member]
Debt Instrument [Line Items]
Derivative, Fixed Interest Rate						1.38%

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Aug. 01, 2016
Debt Instrument [Line Items]
Debt issuances	$ 8,527	$ 8,527
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	4,100	4,100
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances	1,000	1,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances	450	450
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances	1,894	1,894
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances	250	250
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt issuances	500	500
Unsecured Debt [Member] | April 2016 2.875% Unsecured Note Maturing April 2023 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350	$ 350
Interest rate	2.875%	2.875%
Unsecured Debt [Member] | August 2016 1.800% Unsecured Note Maturing September 2021 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 750	$ 750
Interest rate	1.80%	1.80%
Unsecured Debt [Member] | August 2016 2.650% Unsecured Note Maturing September 2026 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500	$ 1,500
Interest rate	2.65%	2.65%
Unsecured Debt [Member] | August 2016 3.750% Unsecured Note Maturing September 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500	$ 1,500
Interest rate	3.75%	3.75%
Unsecured Debt [Member] | Parent Company [Member] | April 2016 2.875% Unsecured Note Maturing April 2023 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350	$ 350
Interest rate	2.875%	2.875%
Unsecured Debt [Member] | Parent Company [Member] | August 2016 1.800% Unsecured Note Maturing September 2021 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 750	$ 750
Interest rate	1.80%	1.80%
Unsecured Debt [Member] | Parent Company [Member] | August 2016 2.650% Unsecured Note Maturing September 2026 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500	$ 1,500
Interest rate	2.65%	2.65%
Unsecured Debt [Member] | Parent Company [Member] | August 2016 3.750% Unsecured Note Maturing September 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,500	$ 1,500
Interest rate	3.75%	3.75%
First Mortgage [Member] | March 2016 2.500% First Mortgage Bond Maturing March 2023 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	2.50%	2.50%
First Mortgage [Member] | March 2016 3.875% First Mortgage Bond Maturing March 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	3.875%	3.875%
First Mortgage [Member] | May 2016 3.750% First Mortgage Bond Maturing May 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	3.75%	3.75%
Repayments of Debt	$ 150	$ 325
First Mortgage [Member] | June 2016 3.700% First Mortgage Bond Maturing June 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250	$ 250
Interest rate	3.70%	3.70%
First Mortgage [Member] | September 2016 3.400% First Mortgage Bond Maturing October 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600	$ 600
Interest rate	3.40%	3.40%
First Mortgage [Member] | September 2016 3.700% First Mortgage Bond Maturing October 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450	$ 450
Interest rate	3.70%	3.70%
First Mortgage [Member] | Duke Energy Carolinas [Member] | March 2016 2.500% First Mortgage Bond Maturing March 2023 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	2.50%	2.50%
First Mortgage [Member] | Duke Energy Carolinas [Member] | March 2016 3.875% First Mortgage Bond Maturing March 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	3.875%	3.875%
First Mortgage [Member] | Duke Energy Progress [Member] | September 2016 3.700% First Mortgage Bond Maturing October 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 450	$ 450
Interest rate	3.70%	3.70%
First Mortgage [Member] | Duke Energy Florida [Member] | September 2016 3.400% First Mortgage Bond Maturing October 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600	$ 600
Interest rate	3.40%	3.40%
First Mortgage [Member] | Duke Energy Ohio [Member] | June 2016 3.700% First Mortgage Bond Maturing June 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250	$ 250
Interest rate	3.70%	3.70%
First Mortgage [Member] | Duke Energy Indiana [Member] | May 2016 3.750% First Mortgage Bond Maturing May 2046 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500	$ 500
Interest rate	3.75%	3.75%
Repayments of Debt	$ 150	$ 325
Secured Debt [Member] | June 2016 1.196% Secured Debt Maturing March 2020 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 183	$ 183
Interest rate	1.196%	1.196%
Secured Debt [Member] | June 2016 1.731% Secured Debt Maturing September 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 150	$ 150
Interest rate	1.731%	1.731%
Secured Debt [Member] | June 2016 2.538% Secured Debt Maturing September 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 436	$ 436
Interest rate	2.538%	2.538%
Secured Debt [Member] | June 2016 2.858% Secured Debt Maturing March 2033 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250	$ 250
Interest rate	2.858%	2.858%
Secured Debt [Member] | June 2016 3.112% Secured Debt Maturing September 2036 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 275	$ 275
Interest rate	3.112%	3.112%
Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2034 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 228	$ 228
Interest rate	2.747%	2.747%
Secured Debt [Member] | August 2016 2.747% Secured Debt Maturing June 2020 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 105	$ 105
Interest rate	2.747%	2.747%
Secured Debt [Member] | Duke Energy Florida [Member] | June 2016 1.196% Secured Debt Maturing March 2020 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 183	$ 183
Interest rate	1.196%	1.196%
Secured Debt [Member] | Duke Energy Florida [Member] | June 2016 1.731% Secured Debt Maturing September 2022 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 150	$ 150
Interest rate	1.731%	1.731%
Secured Debt [Member] | Duke Energy Florida [Member] | June 2016 2.538% Secured Debt Maturing September 2029 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 436	$ 436
Interest rate	2.538%	2.538%
Secured Debt [Member] | Duke Energy Florida [Member] | June 2016 2.858% Secured Debt Maturing March 2033 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250	$ 250
Interest rate	2.858%	2.858%
Secured Debt [Member] | Duke Energy Florida [Member] | June 2016 3.112% Secured Debt Maturing September 2036 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 275	$ 275
Interest rate	3.112%	3.112%
Piedmont Natural Gas [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances			$ 3,750

Debt and Credit Facilities (S62

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 3,201	$ 2,074
Unsecured Debt [Member] | 15.681% Unsecured Debt Maturing May 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 56
Interest rate	15.681%
Secured Debt [Member] | 2.155% Secured Debt Maturing June 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 45
Interest rate	2.155%
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 573
Parent Company [Member] | Unsecured Debt [Member] | 2.150% Unsecured Debt Maturing November 2016 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 500
Interest rate	2.15%
Parent Company [Member] | Unsecured Debt [Member] | 1.034% Unsecured Debt Maturing April 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 400
Interest rate	1.034%
Parent Company [Member] | Unsecured Debt [Member] | 1.625% Unsecured Debt Maturing August 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 700
Interest rate	1.625%
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 468	356
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 1.750% First Mortgage Bonds Maturing December 2016 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 350
Interest rate	1.75%
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member] | 3.600% Tax-exempt Bonds Maturing February 2017[Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 77
Interest rate	3.60%
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 252	2
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 1.035% First Mortgage Bonds Maturing March 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 250
Interest rate	1.035%
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 326	13
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 5.800% First Mortgage Bonds Maturing September 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 250
Interest rate	5.80%
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 54	106
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 71	$ 547

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member] $ in Millions	Sep. 30, 2016USD ($)
Line of Credit Facility [Line Items]
Facility size	$ 7,500
Commercial paper	(1,652)
Outstanding letters of credit	(77)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	5,155
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	3,400
Commercial paper	(1,027)
Outstanding letters of credit	(70)
Available capacity	2,303
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,100
Commercial paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	511
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,000
Commercial paper	(150)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	598
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	950
Outstanding letters of credit	(1)
Available capacity	949
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	450
Commercial paper	(25)
Available capacity	425
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600
Commercial paper	(150)
Tax exempt bonds	(81)
Available capacity	369
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member]
Line of Credit Facility [Line Items]
Commercial paper	$ (625)

Asset Retirement Obligations As

Asset Retirement Obligations Asset Retirement Obligations (Narrative) (Details)	Sep. 30, 2016plantbasin
Coal Ash Act Intermediate Ranking [Member]
Asset Retirement Obligation [Line Items]
Number of Ash Basins | basin	12
Number of Plants with Ash Basins | plant	4
Coal Ash Act Low Ranking [Member]
Asset Retirement Obligation [Line Items]
Number of Ash Basins | basin	4
Number of Plants with Ash Basins | plant	3
Coal Ash Act Low to Intermediate Ranking [Member]
Asset Retirement Obligation [Line Items]
Number of Ash Basins | basin	9
Number of Plants with Ash Basins | plant	6

Asset Retirement Obligations 65

Asset Retirement Obligations Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	$ 10,830	$ 10,264
Asset Retirement Obligation, Current	539
Asset Retirement Obligations, Noncurrent	10,291	10,264
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	3,925	3,918
Asset Retirement Obligation, Current	303
Asset Retirement Obligations, Noncurrent	3,622	3,918
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,657	5,369
Asset Retirement Obligation, Current	236
Asset Retirement Obligations, Noncurrent	5,421	5,369
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	4,859	4,567
Asset Retirement Obligation, Current	236
Asset Retirement Obligations, Noncurrent	4,623	4,567
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	798	802
Asset Retirement Obligations, Noncurrent	798	802
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	108	125
Asset Retirement Obligations, Noncurrent	108	125
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	847	525
Asset Retirement Obligations, Noncurrent	847	$ 525
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,163
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	1,808
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	3,153
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,428
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	725
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,411
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,089
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,418
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,398
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	20
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	77
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	828
Other [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	256
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	28
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	86
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	33
Other [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	53
Other [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	31
Other [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	$ 19

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO Rollforward) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 10,264
Accretion expense	290
Liabilities settled	(443)
Liabilities incurred in the current year	13
Revision in estimates of cash flows	706
Balance at end of period	10,830
Duke Energy Carolinas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	3,918
Accretion expense	141
Liabilities settled	(204)
Revision in estimates of cash flows	70
Balance at end of period	3,925
Progress Energy [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	5,369
Accretion expense	171
Liabilities settled	(203)
Liabilities incurred in the current year	3
Revision in estimates of cash flows	317
Balance at end of period	5,657
Duke Energy Progress [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	4,567
Accretion expense	144
Liabilities settled	(163)
Liabilities incurred in the current year	3
Revision in estimates of cash flows	308
Balance at end of period	4,859
Duke Energy Florida [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	802
Accretion expense	28
Liabilities settled	(41)
Revision in estimates of cash flows	9
Balance at end of period	798
Duke Energy Ohio [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	125
Accretion expense	4
Liabilities settled	(4)
Revision in estimates of cash flows	(17)
Balance at end of period	108
Duke Energy Indiana [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	525
Accretion expense	16
Liabilities settled	(31)
Revision in estimates of cash flows	337
Balance at end of period	$ 847

Goodwill and Intangible Asset67

Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill	$ 16,354	$ 16,343
Foreign exchange changes	11
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill	15,950	15,950
International [Member]
Goodwill [Roll Forward]
Goodwill	282	271
Foreign exchange changes	11
Commercial Portfolio [Member]
Goodwill [Roll Forward]
Goodwill	122	122
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	920	920
Accumulated impairment charges	$ 216	$ 216

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 204	$ 211	$ 620	$ 632
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6	16	18
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	10	7	21	47
Related party transaction, expenses from transactions with related party	36	48	127	143
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	182	184	515	523
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	10	25	29
Progress Energy [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	36	48	127	143
Related party transaction, expenses from transactions with related party	10	7	21	47
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	103	101	292	296
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	4	10	12
Duke Energy Progress [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	36	48	127	143
Related party transaction, expenses from transactions with related party	10	7	21	47
Duke Energy Florida [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	79	83	223	227
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6	15	17
Duke Energy Ohio [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	89	88	261	276
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	1	4	5
Duke Energy Indiana [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	96	87	279	259
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 2	$ 2	$ 6	$ 6

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - Duke Energy Ohio [Member] - USD ($) $ in Millions	Dec. 31, 2015	Apr. 01, 2015
Related Party Transaction [Line Items]
Intercompany loan payable	$ 103
DECAM [Member]
Related Party Transaction [Line Items]
Intercompany loan payable		$ 294

Related Party Transactions Rela

Related Party Transactions Related Party Transactions (Intercompany Income Taxes) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Duke Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	$ 88	$ 107
Due to Related Parties, Current	149	229
Duke Energy Carolinas [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current		122
Due to Related Parties, Current	64
Progress Energy [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	8	375
Due to Related Parties, Current	202	311
Progress Energy [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	113	120
Duke Energy Progress [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	5	16
Due to Related Parties, Current	143	190
Duke Energy Progress [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	56	104
Duke Energy Florida [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	5	84
Due to Related Parties, Current	61	116
Duke Energy Florida [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due to Related Parties, Current	65	96
Duke Energy Ohio [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	96	84
Due to Related Parties, Current	49	53
Duke Energy Ohio [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current		54
Due to Related Parties, Current	27
Duke Energy Indiana [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	74	71
Due to Related Parties, Current	82	83
Duke Energy Indiana [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	$ 67
Due to Related Parties, Current		$ 47

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Bcf in Millions, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2016USD ($)GWhBcf	Dec. 31, 2015USD ($)GWhBcf	Aug. 31, 2016USD ($)
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh		2	70
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		375	398
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 1,917	$ 1,917	$ 2,527
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	990	990	700
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	927	927	1,827
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	789	789	$ 497
Piedmont Natural Gas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	22	190
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,400	1,400
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	22	$ 190
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		83	66
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	400	$ 400	$ 400
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	400	$ 400	$ 400
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		292	332
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	500	$ 500	$ 500
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	500	$ 500	$ 500
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		116	117
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	$ 250	$ 250
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	$ 250	$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		176	215
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	$ 250	$ 250
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	250	$ 250
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh			34
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27	$ 27
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27	$ 27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh		2	36
Commercial Portfolio [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount				$ 326
Commercial Portfolio [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | 4YearInterestRateContract [Member]
Derivative [Line Items]
Notional amount				103
Commercial Portfolio [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | 18YearInterestRateContract [Member]
Derivative [Line Items]
Notional amount				$ 223

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	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 66	$ 26
Location and fair value amounts of derivatives (Liability)	246	419
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	44	18
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	8
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	80	271
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	166	148
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	53	16
Location and fair value amounts of derivatives (Liability)	88	356
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	10
Location and fair value amounts of derivatives (Liability)	158	63
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	12	11
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	4
Location and fair value amounts of derivatives (Liability)	46	33
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	40	12
Location and fair value amounts of derivatives (Liability)	67	256
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	4
Location and fair value amounts of derivatives (Liability)	21	100
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Location and fair value amounts of derivatives (Liability)	1	4
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Location and fair value amounts of derivatives (Liability)	99	15
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Location and fair value amounts of derivatives (Liability)	99	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	32
Duke Energy Carolinas [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	94	13
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Location and fair value amounts of derivatives (Liability)	7	40
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	92	5
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	5	32
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Location and fair value amounts of derivatives (Liability)	2	8
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	92	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	31	11
Location and fair value amounts of derivatives (Liability)	81	322
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	7
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	15	4
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	62	225
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	97
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	20	5
Location and fair value amounts of derivatives (Liability)	81	314
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	6
Location and fair value amounts of derivatives (Liability)		8
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	1
Location and fair value amounts of derivatives (Liability)	62	222
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Location and fair value amounts of derivatives (Liability)	19	92
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Location and fair value amounts of derivatives (Liability)		3
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	15	2
Location and fair value amounts of derivatives (Liability)	12	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	77
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	21
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11
Location and fair value amounts of derivatives (Liability)	12	93
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	2
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Location and fair value amounts of derivatives (Liability)	9	77
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Location and fair value amounts of derivatives (Liability)	3	16
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	16	7
Location and fair value amounts of derivatives (Liability)	64	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	3
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	53	145
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	11	71
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9	5
Location and fair value amounts of derivatives (Liability)	64	216
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	1
Location and fair value amounts of derivatives (Liability)	53	145
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	4
Location and fair value amounts of derivatives (Liability)	11	71
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	3
Location and fair value amounts of derivatives (Liability)	8	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	3
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] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	6
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	3
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	7
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	3
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [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] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	6
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	20	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	20	7
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	20	7
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 20	$ 7

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 66	$ 26
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	26
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	246	419
Net amounts recognized on the Condensed Consolidated Balance Sheet	246	419
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	44	18
Gross amounts offset	(10)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	22	8
Gross amounts offset	(7)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	4
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	80	271
Gross amounts offset	(10)	(22)
Net amounts recognized on the Condensed Consolidated Balance Sheet	70	249
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	166	148
Gross amounts offset	(7)	(16)
Net amounts recognized on the Condensed Consolidated Balance Sheet	159	132
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	99	45
Net amounts recognized on the Condensed Consolidated Balance Sheet	99	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	32
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	94	13
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	92	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	31	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	81	322
Net amounts recognized on the Condensed Consolidated Balance Sheet	81	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Gross amounts offset	(7)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	4
Gross amounts offset	(5)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	62	225
Gross amounts offset	(7)	(21)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	97
Gross amounts offset	(5)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	98
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	2
Gross amounts offset	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	77
Gross amounts offset	(4)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	3	21
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	64	216
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	3
Gross amounts offset	(3)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Gross amounts offset	(3)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	53	145
Gross amounts offset	(3)	(20)
Net amounts recognized on the Condensed Consolidated Balance Sheet	50	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	11	71
Gross amounts offset	(3)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	3
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	3
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	7	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 20	$ 7

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
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	$ 171	$ 334
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	171	304
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability		30
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	99	45
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	99	45
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	72	290
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	72	260
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability		30
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	12	93
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	12	93
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	60	194
Fair value of collateral already posted		30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 60	164
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability		$ 30

Investments in Debt and Equit75

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 2,079	$ 1,882
Gross Unrealized Holding Losses	64	83
Estimated Fair Value	6,519	6,214
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2,033	1,846
Gross Unrealized Holding Losses	61	76
Estimated Fair Value	6,118	5,817
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	151	179
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,968	1,823
Gross Unrealized Holding Losses	55	58
Estimated Fair Value	3,949	3,590
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	25	7
Gross Unrealized Holding Losses	2	8
Estimated Fair Value	551	432
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	9	5
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	341	185
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	31	11
Gross Unrealized Holding Losses		5
Estimated Fair Value	994	1,254
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	3	4
Estimated Fair Value	132	177
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	46	36
Gross Unrealized Holding Losses	3	7
Estimated Fair Value	401	397
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	24	29
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	38	32
Gross Unrealized Holding Losses		1
Estimated Fair Value	104	95
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	1	3
Estimated Fair Value	91	92
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	78	74
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1
Estimated Fair Value	49	45
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	55	62
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,119	1,028
Gross Unrealized Holding Losses	35	40
Estimated Fair Value	3,233	3,041
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,119	1,028
Gross Unrealized Holding Losses	34	39
Estimated Fair Value	3,230	3,038
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	43	34
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,091	1,021
Gross Unrealized Holding Losses	29	27
Estimated Fair Value	2,170	2,094
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	14	3
Gross Unrealized Holding Losses	2	5
Estimated Fair Value	374	292
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Estimated Fair Value	66	33
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12	3
Gross Unrealized Holding Losses		3
Estimated Fair Value	454	438
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	3	4
Estimated Fair Value	123	147
Duke Energy Carolinas [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	918	821
Gross Unrealized Holding Losses	27	37
Estimated Fair Value	2,955	2,842
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	914	818
Gross Unrealized Holding Losses	27	37
Estimated Fair Value	2,888	2,779
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	108	145
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	877	802
Gross Unrealized Holding Losses	26	31
Estimated Fair Value	1,779	1,496
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	11	4
Gross Unrealized Holding Losses		3
Estimated Fair Value	177	140
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	7	4
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	275	152
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	19	8
Gross Unrealized Holding Losses		2
Estimated Fair Value	540	816
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	9	30
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Estimated Fair Value	67	63
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	20	18
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Estimated Fair Value	47	45
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	684	609
Gross Unrealized Holding Losses	22	30
Estimated Fair Value	2,178	2,039
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	684	609
Gross Unrealized Holding Losses	22	30
Estimated Fair Value	2,177	2,038
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	56	110
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	657	596
Gross Unrealized Holding Losses	21	25
Estimated Fair Value	1,438	1,178
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8	3
Gross Unrealized Holding Losses		2
Estimated Fair Value	123	96
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	7	4
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	275	150
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12	6
Gross Unrealized Holding Losses	0	2
Estimated Fair Value	279	486
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	6	18
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
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	234	212
Gross Unrealized Holding Losses	5	7
Estimated Fair Value	760	792
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	230	209
Gross Unrealized Holding Losses	5	7
Estimated Fair Value	711	741
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	52	35
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	220	206
Gross Unrealized Holding Losses	5	6
Estimated Fair Value	341	318
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	1
Gross Unrealized Holding Losses		1
Estimated Fair Value	54	44
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value		2
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	7	2
Estimated Fair Value	261	330
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3	12
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Estimated Fair Value	49	51
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	6
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	3
Estimated Fair Value	47	45
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	32	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	107	101
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	32	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	107	101
Duke Energy Indiana [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value		2
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	31	27
Estimated Fair Value	77	71
Duke Energy Indiana [Member] | Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	2
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	$ 28	$ 26

Investments in Debt and Equit76

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Sep. 30, 2016USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 92
Due after one through five years	655
Due after five through 10 years	529
Due after 10 years	1,015
Total	2,291
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	3
Due after one through five years	206
Due after five through 10 years	268
Due after 10 years	543
Total	1,020
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	67
Due after one through five years	372
Due after five through 10 years	187
Due after 10 years	422
Total	1,048
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	21
Due after one through five years	200
Due after five through 10 years	142
Due after 10 years	320
Total	683
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	46
Due after one through five years	172
Due after five through 10 years	45
Due after 10 years	102
Total	365
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	3
Due after one through five years	9
Due after five through 10 years	13
Due after 10 years	5
Total	$ 30

Investments in Debt and Equit77

Investments in Debt and Equity Securities (Realized Gains and Losses)(Details) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$ 82	$ 30	$ 200	$ 160
Realized losses	42	28	134	59
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	58	25	125	132
Realized losses	28	24	84	47
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	21	5	71	26
Realized losses	13	4	49	10
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	18	4	60	21
Realized losses	11	3	42	8
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	3	1	11	5
Realized losses	$ 2	$ 1	$ 7	$ 2

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$ 66	$ 26
Total assets	6,585	6,240
Derivative liabilities	(246)	(419)
Net assets	6,339	5,821
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	4,713	4,260
Derivative liabilities	0
Net assets	4,713	4,260
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	43	16
Total assets	1,767	1,793
Derivative liabilities	(246)	(419)
Net assets	1,521	1,374
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	23	10
Total assets	27	15
Net assets	27	15
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	78	172
Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	78	172
Investments	3,949	3,590
Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,871	3,418
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	104	95
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	104	95
Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,169	2,227
Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	664	672
Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,505	1,555
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	297	302
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	74	75
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	219	222
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	4	5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	10
Total assets	3,243	3,041
Derivative liabilities	(99)	(45)
Net assets	3,144	2,996
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,276	2,168
Derivative liabilities	0
Net assets	2,276	2,168
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	10
Total assets	886	698
Derivative liabilities	(99)	(45)
Net assets	787	653
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3	3
Net assets	3	3
Duke Energy Carolinas [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	78	172
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative Investments, Fair Value Disclosure	78	172
Investments	2,170	2,094
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,092	1,922
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,060	944
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	184	246
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	876	698
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	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	3
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	31	11
Total assets	2,986	2,853
Derivative liabilities	(81)	(322)
Net assets	2,905	2,531
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	2,279	1,940
Derivative liabilities	0
Net assets	2,279	1,940
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	31	11
Total assets	707	913
Derivative liabilities	(81)	(322)
Net assets	626	591
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,779	1,496
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,779	1,496
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,109	1,283
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	480	426
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	629	857
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	67	63
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	20	18
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	47	45
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15	2
Total assets	2,193	2,041
Derivative liabilities	(12)	(98)
Net assets	2,181	1,943
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	1,659	1,320
Derivative liabilities	0
Net assets	1,659	1,320
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15	2
Total assets	534	721
Derivative liabilities	(12)	(98)
Net assets	522	623
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,438	1,178
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,438	1,178
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	739	860
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	220	141
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	519	719
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	16	7
Total assets	776	799
Derivative liabilities	(64)	(216)
Net assets	712	583
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	603	609
Net assets	603	609
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	7
Total assets	173	190
Derivative liabilities	(64)	(216)
Net assets	109	(26)
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	341	318
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	341	318
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	370	423
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	260	285
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	110	138
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	49	51
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2	6
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	45
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	3
Derivative liabilities	(8)	(7)
Net assets	(5)	(4)
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(8)	(7)
Net assets	(8)	(7)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	3
Net assets	3	3
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	20	7
Net assets	127	108
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Net assets	77	73
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets	30	28
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	20	7
Net assets	20	7
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	77	71
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	77	71
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	30	30
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments		2
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 30	$ 28

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 ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments
Beginning balance	$ 38	$ 28	$ 15	$ 4
Total pretax gains (losses) included in earnings				18
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases			34	24
Sales			(1)
Settlements	(9)	(6)	(22)	(28)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(2)		1	4
Ending balance	27	22	27	22
Derivatives (net)
Beginning balance	34	23	10	(1)
Total pretax gains (losses) included in earnings				18
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases			34	24
Settlements	(9)	(6)	(22)	(28)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(2)		1	4
Ending balance	23	17	23	17
Investments [Member]
Investments
Beginning balance	4	5	5	5
Sales			(1)
Ending balance	4	5	4	5
Duke Energy Ohio [Member]
Derivatives (net)
Beginning balance	5	5	3	(18)
Total pretax gains (losses) included in earnings				21
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases		5	5	5
Sales		(5)
Settlements	(2)	(1)	(4)	(4)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities			(1)
Ending balance	3	4	3	4
Duke Energy Indiana [Member]
Derivatives (net)
Beginning balance	29	17	7	14
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases		1	29	19
Settlements	(7)	(6)	(18)	(25)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(2)		2	4
Ending balance	$ 20	$ 12	$ 20	$ 12

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)$ / MWh	Dec. 31, 2015USD ($)$ / MWh	Jun. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 23	$ 10	$ 34	$ 17	$ 23	$ (1)
Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 23	$ 10
Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	(2.59)	(0.74)
Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	8.16	7.29
Duke Energy Ohio [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 3	$ 3	5	4	5	(18)
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 3	$ 3
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	0.45	0.67
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	2.01	2.53
Duke Energy Indiana [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 20	$ 7	$ 29	$ 12	$ 17	$ 14
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 20	$ 7
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	(2.59)	(0.74)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	8.16	7.29

Fair Value Measurements (Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 47,165	$ 39,569
Long-term debt, fair value	50,997	42,537
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	9,360	8,367
Long-term debt, fair value	10,799	9,156
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	16,520	14,464
Long-term debt, fair value	19,060	15,856
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	7,011	6,518
Long-term debt, fair value	7,787	6,757
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	6,128	4,266
Long-term debt, fair value	7,127	4,908
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	1,887	1,598
Long-term debt, fair value	2,128	1,724
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	3,787	3,768
Long-term debt, fair value	$ 4,538	$ 4,219

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 8,527		$ 8,527
Asset Impairment Charges	10	$ 111	208	$ 111
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Asset Impairment Charges			71
Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Minimum equity balance required by Cinergy Receivables	$ 3		$ 3
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Percent of proceeds received as cash	75.00%		75.00%
Percent of proceeds received as subordinated note	25.00%		25.00%
Duke American Transmission Company [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest			50.00%
Atlantic Coast Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest			40.00%
Sabal Trail Transmission Pipeline [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest			7.50%
OVEC [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Ownership Interest			9.00%
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 1,000		$ 1,000
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	450		450
Asset Impairment Charges	1		1
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	1,894		1,894
Asset Impairment Charges	1	7	4	7
Duke Energy Florida [Member] | DEFPF [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	1,294		1,294
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	250		$ 250
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate			1.00%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	500		$ 500
Asset Impairment Charges	$ 8	$ 85	$ 8	$ 85
Duke Energy Indiana [Member] | Cinergy Receivables [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	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Variable Interest Entities [Line Items]
Long-Term Debt	$ 43,964	$ 37,495
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,592	7,711
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	6,609	6,366
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 5,802	4,253
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	$ 300	254
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	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 6,179	$ 857	$ 1,370	$ 2,036
Restricted receivables of VIEs	2,139	1,748
Regulatory Assets, Current	853	877
Other current assets	429	327
Regulatory Assets, Noncurrent	11,896	11,373
Interest accrued	504	430
Investments and other assets	2,948	3,042
Property, plant and equipment, cost	116,376	112,826
Accumulated depreciation and amortization	(38,812)	(37,665)
Other deferred debits	22	43
Accounts payable	2,138	2,400
Current maturities of long-term debt	3,201	2,074
Other current liabilities	1,728	2,115
Long-Term Debt	43,964	37,495
Deferred income taxes	13,201	12,705
Asset retirement obligations	10,291	10,264
Other liabilities	1,851	1,706
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	82	13	198	13
Restricted receivables of VIEs	780	596
Regulatory Assets, Current	256	305
Other current assets	22	128
Regulatory Assets, Noncurrent	3,040	2,766
Interest accrued	125	95
Investments and other assets	923	999
Property, plant and equipment, cost	40,495	39,398
Accumulated depreciation and amortization	(14,125)	(13,521)
Other deferred debits	3	4
Accounts payable	582	753
Current maturities of long-term debt	468	356
Other current liabilities	417	519
Long-Term Debt	8,592	7,711
Deferred income taxes	6,464	6,146
Asset retirement obligations	3,622	3,918
Other liabilities	685	621
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	136	15	123	9
Restricted receivables of VIEs	473	349
Regulatory Assets, Current	186	264
Other current assets	83	121
Regulatory Assets, Noncurrent	3,093	2,710
Interest accrued	81	96
Investments and other assets	518	486
Property, plant and equipment, cost	28,001	27,313
Accumulated depreciation and amortization	(10,508)	(10,141)
Other deferred debits	2	3
Accounts payable	319	399
Current maturities of long-term debt	252	2
Other current liabilities	326	412
Long-Term Debt	6,609	6,366
Deferred income taxes	3,279	3,027
Asset retirement obligations	4,623	4,567
Other liabilities	23	45
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	10	8	$ 16	$ 8
Restricted receivables of VIEs	385	308
Regulatory Assets, Current	161	98
Other current assets	46	21
Regulatory Assets, Noncurrent	2,559	2,725
Interest accrued	58	43
Investments and other assets	292	292
Property, plant and equipment, cost	16,139	15,343
Accumulated depreciation and amortization	(4,654)	(4,720)
Other deferred debits	2	2
Accounts payable	354	322
Current maturities of long-term debt	326	13
Other current liabilities	367	452
Long-Term Debt	5,802	4,253
Deferred income taxes	2,597	2,460
Asset retirement obligations	798	802
Other liabilities	167	146
DEFPF [Member] | Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	7
Regulatory Assets, Current	51
Other current assets	29
Regulatory Assets, Noncurrent	1,156
Interest accrued	9
Current maturities of long-term debt	62
Long-Term Debt	1,216
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	300	254
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	252	138
Property, plant and equipment, cost	2,583	2,015
Accumulated depreciation and amortization	(400)	(321)
Current maturities of long-term debt	193	108
Long-Term Debt	1,151	968
Deferred income taxes	50	289
Other liabilities	$ 270	$ 33

Variable Interest Entities (S85

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 604	$ 499
Investments and other assets	2,948	3,042
Other current liabilities	1,728	2,115
Deferred credits and other liabilities	33,100	32,490
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	485	387
Investments and other assets	12
Total assets	497	387
Other current liabilities	2	3
Deferred credits and other liabilities	13	14
Total liabilities	15	17
Net assets	482	370
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	168	235
Total assets	168	235
Net assets	168	235
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	317	152
Investments and other assets	12
Total assets	329	152
Other current liabilities	2	3
Deferred credits and other liabilities	13	14
Total liabilities	15	17
Net assets	314	135
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	96	84
Investments and other assets	18	20
Other current liabilities	84	153
Deferred credits and other liabilities	1,987	1,998
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	50	47
Total assets	50	47
Net assets	50	47
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	74	71
Other current liabilities	95	97
Deferred credits and other liabilities	3,710	3,219
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	74	60
Total assets	74	60
Net assets	$ 74	$ 60

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions)(Details) - Cinergy Receivables [Member]	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.50%	0.60%
Discount rate	1.50%	1.20%
Receivable turnover rate	13.30%	12.90%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.50%	1.20%
Receivable turnover rate	10.60%	10.60%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold)(Details) - Cinergy Receivables [Member] - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 217	$ 233
Less: Retained interests	50	47
Net receivables sold	167	186
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	296	260
Less: Retained interests	74	60
Net receivables sold	$ 222	$ 200

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows)(Details) - Cinergy Receivables [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 481	$ 449	$ 1,442	$ 1,518
Loss recognized on sale	2	2	7	7
Cash proceeds from receivables sold	468	461	1,432	1,568
Collection fees received	1		1	1
Return received on retained interests	1		2	2
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	722	679	1,980	2,032
Loss recognized on sale	3	3	8	8
Cash proceeds from receivables sold	703	692	1,958	2,074
Collection fees received	0		1	1
Return received on retained interests	$ 2	$ 1	$ 4	$ 4

Common Stock (Earnings Per Shar

Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Common Stock [Line Items]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 1,054	$ 937	$ 2,255	$ 2,310
Average shares, basic	689	688	689	696
Average shares, diluted	691	688	690	696
EPS, basic (usd per share)	$ 1.52	$ 1.36	$ 3.27	$ 3.31
EPS, diluted (usd per share)	$ 1.52	$ 1.36	$ 3.26	$ 3.31
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 1,053	$ 935	$ 2,252	$ 2,307
Average shares, basic	689	688	689	696
Incremental Common Shares Attributable to Dilutive Effect of Equity Forward Agreements	2		1
Average shares, diluted	691	688	690	696
EPS, basic (usd per share)	$ 1.52	$ 1.36	$ 3.27	$ 3.31
EPS, diluted (usd per share)	$ 1.52	1.36	$ 3.26	$ 3.31
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation	2		2	2
Dividends declared per share (usd per share)	$ 0.855	$ 0.825	$ 2.505	$ 2.42

Common Stock Common Stock (Acce

Common Stock Common Stock (Accelerated Share Repurchase) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		9 Months Ended
	Jun. 30, 2015	Apr. 30, 2015	Sep. 30, 2015	Apr. 06, 2015
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount		$ 1,500
Payments for Repurchase of Common Stock		$ 1,500	$ 1,500
Delivered Shares from Dealers	3.2	16.6	19.8
Fair Market Value of Delivered Shares	$ 225	$ 1,275
Percentage of ASR common stock received				85.00%
Accelerated Share Repurchases, Final Price Paid Per Share			$ 75.75
Goldman Sachs [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock		750
JPMorgan Chase [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock		$ 750

Common Stock Common Stock (Equi

Common Stock Common Stock (Equity Securities Offering) (Details) - Piedmont Natural Gas [Member] - USD ($) shares in Millions, $ in Millions	Oct. 05, 2016	Sep. 30, 2016
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered		10.6
Subsequent Event [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Proceeds from Issuance or Sale of Equity	$ 723

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$ 12	$ 14	$ 39	$ 47
Tax benefit associated with stock-based compensation expense	5	6	14	18
Stock-based compensation costs capitalized		1	2	3
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	8	9	25	29
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$ 4	$ 5	$ 14	$ 18

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details)	9 Months Ended
	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Matching contribution percentage	100.00%
Eligible pay percentage	6.00%
Additional savings plan account contribution percentage for employees not participating in defined pension plans	4.00%

Employee Benefit Plans Employee

Employee Benefit Plans Employee Benefit Plans (Plan Contributions) (Details) - Pension Plan [Member] $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	$ 143
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	42
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	42
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	21
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	21
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	4
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	$ 9

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		$ 1	$ 2	$ 4
Interest cost on projected benefit obligation	$ 9	9	26	27
Expected return on plan assets	(2)	(3)	(9)	(9)
Amortization of actuarial loss (gain)	2	6	5	19
Amortization of prior service cost (credit)	(35)	(35)	(106)	(105)
Net periodic costs	(26)	(22)	(82)	(64)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				1
Interest cost on projected benefit obligation	2	2	6	6
Expected return on plan assets	(2)	(2)	(6)	(6)
Amortization of actuarial loss (gain)			(2)	(1)
Amortization of prior service cost (credit)	(4)	(4)	(10)	(11)
Net periodic costs	(4)	(4)	(12)	(11)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1	1
Interest cost on projected benefit obligation	4	4	11	11
Expected return on plan assets	(1)		(1)
Amortization of actuarial loss (gain)	5	7	16	21
Amortization of prior service cost (credit)	(26)	(26)	(77)	(77)
Net periodic costs	(17)	(15)	(50)	(44)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2	6	6
Amortization of actuarial loss (gain)	3	5	9	14
Amortization of prior service cost (credit)	(16)	(17)	(50)	(50)
Net periodic costs	(11)	(10)	(35)	(30)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	3	2	6	5
Amortization of actuarial loss (gain)	2	3	7	8
Amortization of prior service cost (credit)	(8)	(9)	(26)	(25)
Net periodic costs	(3)	(4)	(13)	(12)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation			1	1
Amortization of actuarial loss (gain)	(1)		(2)
Net periodic costs	(1)		(1)	1
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1	1	3	3
Expected return on plan assets			(1)
Amortization of actuarial loss (gain)			(1)	(1)
Amortization of prior service cost (credit)	(1)		(1)
Net periodic costs		1		2
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	36	40	109	119
Interest cost on projected benefit obligation	83	81	249	244
Expected return on plan assets	(128)	(129)	(386)	(387)
Amortization of actuarial loss (gain)	33	44	99	131
Amortization of prior service cost (credit)	(4)	(4)	(12)	(11)
Other	2	2	6	6
Net periodic costs	22	34	65	102
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12	13	36	38
Interest cost on projected benefit obligation	21	21	64	62
Expected return on plan assets	(35)	(35)	(106)	(104)
Amortization of actuarial loss (gain)	8	10	24	30
Amortization of prior service cost (credit)	(2)	(2)	(6)	(6)
Other	1	1	2	2
Net periodic costs	5	8	14	22
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11	11	32	33
Interest cost on projected benefit obligation	27	26	80	78
Expected return on plan assets	(42)	(43)	(126)	(127)
Amortization of actuarial loss (gain)	14	17	41	51
Amortization of prior service cost (credit)	(1)	(1)	(3)	(3)
Other	1	1	2	2
Net periodic costs	10	11	26	34
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	6	6	18	18
Interest cost on projected benefit obligation	12	12	37	36
Expected return on plan assets	(21)	(20)	(62)	(61)
Amortization of actuarial loss (gain)	6	8	17	25
Amortization of prior service cost (credit)			(1)	(1)
Other			1	1
Net periodic costs	3	6	10	18
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	4	5	14	15
Interest cost on projected benefit obligation	14	14	42	41
Expected return on plan assets	(21)	(22)	(63)	(66)
Amortization of actuarial loss (gain)	7	8	21	24
Amortization of prior service cost (credit)	(1)		(1)	(1)
Other	1		1	1
Net periodic costs	4	5	14	14
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	3	3
Interest cost on projected benefit obligation	5	5	15	14
Expected return on plan assets	(6)	(7)	(20)	(20)
Amortization of actuarial loss (gain)	1	3	3	8
Net periodic costs	1	2	1	5
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	3	6	8
Interest cost on projected benefit obligation	7	7	21	21
Expected return on plan assets	(10)	(10)	(31)	(31)
Amortization of actuarial loss (gain)	3	3	9	10
Net periodic costs	2	3	5	8
Non-Qualified Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	2	2
Interest cost on projected benefit obligation	4	3	11	10
Amortization of actuarial loss (gain)	2	2	6	5
Amortization of prior service cost (credit)	(1)		(1)
Net periodic costs	6	6	18	17
Non-Qualified Pension Plan [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation			1	1
Net periodic costs			1	1
Non-Qualified Pension Plan [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				1
Interest cost on projected benefit obligation	2	1	4	3
Amortization of actuarial loss (gain)	1	1	2	2
Net periodic costs	3	2	6	6
Non-Qualified Pension Plan [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation			1	1
Amortization of actuarial loss (gain)	1		1
Net periodic costs	1		2	1
Non-Qualified Pension Plan [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation		1	1	2
Amortization of actuarial loss (gain)	1		1	1
Net periodic costs	$ 1	$ 1	$ 2	$ 3

Employee Benefit Plans (Employe

Employee Benefit Plans (Employee Savings Plans) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Savings Plans [Abstract]
Employer contributions	$ 39	$ 34	$ 130	$ 120
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Employer contributions	13	11	44	40
Progress Energy [Member]
Employee Savings Plans [Abstract]
Employer contributions	12	10	39	36
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Employer contributions	8	7	27	26
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Employer contributions	3	3	11	10
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Employer contributions	1		3	2
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Employer contributions	$ 2	$ 1	$ 6	$ 5

Income Taxes Income Taxes (Taxe

Income Taxes Income Taxes (Taxes on Foreign Earnings) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Previously Remitted Earnings [Member]
Income Tax Disclosure [Line Items]
U.S. Income Taxes on Foreign Earnings	$ (95)

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
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	32.90%	30.90%	30.00%	32.50%
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	34.30%	36.50%	34.40%	36.30%
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	32.80%	25.00%	34.70%	31.80%
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	31.40%	34.40%	33.50%	35.30%
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	36.00%	30.10%	37.00%	35.20%
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	36.80%	39.30%	32.50%	37.60%
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	35.20%	37.00%	34.00%	36.60%