Duke Energy (DUK) 10-Q 5 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Nov. 03, 2015
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, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		688,334,378
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, Inc.
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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenues
Regulated electric	$ 6,017	$ 5,861	$ 16,564	$ 16,549
Nonregulated electric and other	377	449	1,157	1,403
Regulated natural gas	89	85	416	414
Total operating revenues	6,483	6,395	18,137	18,366
Operating Expenses
Fuel used in electric generation and purchased power – regulated	2,113	2,132	5,775	5,940
Fuel used in electric generation and purchased power – nonregulated	61	148	283	410
Cost of natural gas and other	21	27	158	181
Operation, maintenance and other	1,426	1,409	4,274	4,254
Depreciation and amortization	774	788	2,341	2,305
Property and other taxes	293	275	836	936
Impairment charges	111	1	111	81
Total operating expenses	4,799	4,780	13,778	14,107
Gains (Losses) on Sales of Other Assets and Other, net	4	4	31	11
Operating Income	1,688	1,619	4,390	4,270
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	17	28	53	97
Other income and expenses, net	57	109	203	293
Total other income and expenses	74	137	256	390
Interest Expense	402	405	1,208	1,212
Income From Continuing Operations Before Income Taxes	1,360	1,351	3,438	3,448
Income Tax Expense from Continuing Operations	420	460	1,118	1,081
Income from Continuing Operations	940	891	2,320	2,367
(Loss) Income From Discontinued Operations, net of tax	(5)	378	29	(578)
Net income	935	1,269	2,349	1,789
Less: Net Income (Loss) Attributable to Noncontrolling Interests	3	(5)	10	3
Net Income (Loss) Attributable to Parent	932	1,274	2,339	1,786
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	(3)	1	(1)	1
Reclassification into earnings from cash flow hedges	1	2	6	5
Unrealized gains (losses) on available-for-sale securities	(2)		(5)	2
Other Comprehensive Income, net of tax	(135)	(97)	(245)	(52)
Comprehensive Income	800	1,172	2,104	1,737
Less: Comprehensive Income Attributable to Noncontrolling Interests	(2)	(1)		8
Comprehensive Income Attributable to Parent	$ 802	$ 1,173	$ 2,104	$ 1,729
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
Diluted (usd per share)	1.36	1.25	3.31	3.33
(Loss) Income from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	(0.01)	0.55	0.05	(0.81)
Diluted (usd per share)	(0.01)	0.55	0.05	(0.81)
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	1.35	1.80	3.36	2.52
Diluted (usd per share)	$ 1.35	$ 1.80	$ 3.36	$ 2.52
Weighted-average shares outstanding
Basic (shares)	688	707	696	707
Diluted (shares)	688	707	696	707
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 2,061	$ 1,938	$ 5,669	$ 5,693
Operating Expenses
Fuel used in electric generation and purchased power – regulated	548	524	1,553	1,685
Operation, maintenance and other	511	465	1,469	1,415
Depreciation and amortization	269	260	779	750
Property and other taxes	67	59	204	263
Impairment charges				3
Total operating expenses	1,395	1,308	4,005	4,116
Operating Income	666	630	1,664	1,577
Other Income and Expenses
Other income and expenses, net	42	44	125	137
Interest Expense	105	104	313	307
Income From Continuing Operations Before Income Taxes	603	570	1,476	1,407
Income Tax Expense from Continuing Operations	220	193	536	474
Net Income (Loss) Attributable to Parent	383	377	940	933
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges	1		1	2
Unrealized gains (losses) on available-for-sale securities	1		1
Other Comprehensive Income, net of tax	2		2	2
Comprehensive Income Attributable to Parent	385	377	942	935
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,929	2,863	7,941	7,825
Operating Expenses
Fuel used in electric generation and purchased power – regulated	1,238	1,214	3,273	3,234
Operation, maintenance and other	539	564	1,672	1,714
Depreciation and amortization	261	294	831	851
Property and other taxes	132	127	367	415
Impairment charges	7	1	7	(16)
Total operating expenses	2,177	2,200	6,150	6,198
Gains (Losses) on Sales of Other Assets and Other, net	4	2	18	3
Operating Income	756	665	1,809	1,630
Other Income and Expenses
Other income and expenses, net	17	26	63	54
Interest Expense	170	166	504	502
Income From Continuing Operations Before Income Taxes	603	525	1,368	1,182
Income Tax Expense from Continuing Operations	151	195	435	441
Income from Continuing Operations	452	330	933	741
(Loss) Income From Discontinued Operations, net of tax	(1)		(2)	(6)
Net income	451	330	931	735
Less: Net Income (Loss) Attributable to Noncontrolling Interests	3	1	8	2
Net Income (Loss) Attributable to Parent	448	329	923	733
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	(3)	1	(1)	2
Reclassification into earnings from cash flow hedges	3	1	2	5
Unrealized gains (losses) on available-for-sale securities		1	(1)	1
Other Comprehensive Income, net of tax	0	3	0	8
Comprehensive Income	451	333	931	743
Less: Comprehensive Income Attributable to Noncontrolling Interests	3	1	8	2
Comprehensive Income Attributable to Parent	448	332	923	741
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,488	1,367	4,130	3,980
Operating Expenses
Fuel used in electric generation and purchased power – regulated	584	552	1,608	1,579
Operation, maintenance and other	329	346	1,066	1,074
Depreciation and amortization	147	155	462	441
Property and other taxes	35	29	102	150
Impairment charges				(18)
Total operating expenses	1,095	1,082	3,238	3,226
Gains (Losses) on Sales of Other Assets and Other, net	1		2	1
Operating Income	394	285	894	755
Other Income and Expenses
Other income and expenses, net	14	18	49	34
Interest Expense	59	57	175	172
Income From Continuing Operations Before Income Taxes	349	246	768	617
Income Tax Expense from Continuing Operations	120	89	271	226
Net Income (Loss) Attributable to Parent	229	157	497	391
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,436	1,491	3,803	3,832
Operating Expenses
Fuel used in electric generation and purchased power – regulated	654	662	1,665	1,655
Operation, maintenance and other	208	212	598	626
Depreciation and amortization	113	139	369	410
Property and other taxes	97	99	265	266
Impairment charges	7	1	7	2
Total operating expenses	1,079	1,113	2,904	2,959
Operating Income	357	378	899	873
Other Income and Expenses
Other income and expenses, net	2	6	12	17
Interest Expense	50	51	149	150
Income From Continuing Operations Before Income Taxes	309	333	762	740
Income Tax Expense from Continuing Operations	93	128	268	285
Net Income (Loss) Attributable to Parent	216	205	494	455
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges				1
Other Comprehensive Income, net of tax				1
Comprehensive Income Attributable to Parent	216	205	494	456
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	367	352	1,005	998
Nonregulated electric and other	6	6	29	17
Regulated natural gas	89	88	419	418
Total operating revenues	462	446	1,453	1,433
Operating Expenses
Fuel used in electric generation and purchased power – regulated	128	129	350	360
Fuel used in electric generation and purchased power – nonregulated	10	5	36	24
Cost of natural gas and other	7	8	116	129
Operation, maintenance and other	124	134	370	378
Depreciation and amortization	57	54	172	167
Property and other taxes	60	58	187	170
Impairment charges				94
Total operating expenses	386	388	1,231	1,322
Gains (Losses) on Sales of Other Assets and Other, net			8
Operating Income	76	58	230	111
Other Income and Expenses
Other income and expenses, net		3	(2)	9
Interest Expense	20	20	58	60
Income From Continuing Operations Before Income Taxes	56	41	170	60
Income Tax Expense from Continuing Operations	22	15	64	21
Income from Continuing Operations	34	26	106	39
(Loss) Income From Discontinued Operations, net of tax	(2)	413	23	(597)
Net Income (Loss) Attributable to Parent	32	439	129	(558)
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	749	790	2,223	2,383
Operating Expenses
Fuel used in electric generation and purchased power – regulated	250	319	779	945
Operation, maintenance and other	164	160	525	485
Depreciation and amortization	109	104	320	309
Property and other taxes	23	25	41	69
Impairment charges	85		85
Total operating expenses	631	608	1,750	1,808
Gains (Losses) on Sales of Other Assets and Other, net	(1)
Operating Income	117	182	473	575
Other Income and Expenses
Other income and expenses, net		5	9	16
Interest Expense	44	40	132	127
Income From Continuing Operations Before Income Taxes	73	147	350	464
Income Tax Expense from Continuing Operations	27	46	128	163
Net Income (Loss) Attributable to Parent	46	101	222	301
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges	(1)		(2)
Other Comprehensive Income, net of tax			(2)
Comprehensive Income Attributable to Parent	$ 45	$ 101	$ 220	$ 301

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income (loss)	$ 935	$ 1,269	$ 2,349	$ 1,789
Other Comprehensive Loss, net of tax
Foreign currency translation adjustments	(122)	(102)	(238)	(50)
Pension and OPEB adjustments	(3)	1	(1)	1
Net unrealized (losses) gains on cash flow hedges	(9)	2	(7)	(10)
Reclassification into earnings from cash flow hedges	1	2	6	5
Unrealized gains (losses) on available-for-sale securities	(2)		(5)	2
Other Comprehensive Loss, net of tax	(135)	(97)	(245)	(52)
Comprehensive Income	800	1,172	2,104	1,737
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests	(2)	(1)		8
Comprehensive Income Attributable to Parent	$ 802	$ 1,173	$ 2,104	$ 1,729

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 1,370	$ 2,036
Receivables (net of allowance for doubtful accounts)	722	791
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	2,037	1,973
Inventory	3,537	3,459
Assets held for sale		364
Regulatory assets	963	1,115
Other	1,566	1,837
Total current assets	10,195	11,575
Investments and Other Assets
Investments in equity method unconsolidated affiliates	501	358
Nuclear decommissioning trust funds	5,566	5,546
Goodwill	16,312	16,321
Assets held for sale		2,642
Other	3,205	3,008
Total investments and other assets	25,584	27,875
Property, Plant and Equipment
Cost	110,795	104,861
Accumulated depreciation and amortization	(37,479)	(34,824)
Generation Facilities To Be Retired Net	460	9
Net property, plant and equipment	73,776	70,046
Regulatory Assets and Deferred Debits
Regulatory assets	11,290	11,042
Other	188	171
Total regulatory assets and deferred debits	11,478	11,213
Total Assets	121,033	120,709
Current Liabilities
Accounts payable	2,078	2,271
Notes payable and commercial paper	2,419	2,514
Taxes accrued	628	569
Interest accrued	483	418
Current maturities of long-term debt	2,536	2,807
Liabilities associated with assets held for sale		262
Regulatory liabilities	320	204
Other	2,052	2,188
Total current liabilities	10,516	11,233
Long-Term Debt	37,667	37,213
Deferred Credits and Other Liabilities
Deferred income taxes	13,999	13,423
Investment tax credits	416	427
Accrued pension and other post-retirement benefit costs	1,130	1,145
Liabilities associated with assets held for sale		35
Asset retirement obligations	9,713	8,466
Regulatory liabilities	6,129	6,193
Other	1,595	1,675
Total deferred credits and other liabilities	$ 32,982	$ 31,364
Commitments and Contingencies
Equity
Common stock	$ 1	$ 1
Additional paid-in capital	37,953	39,405
Retained earnings	2,656	2,012
Accumulated other comprehensive income (loss)	(778)	(543)
Total Duke Energy Corporation stockholders' equity	39,832	40,875
Noncontrolling interests	36	24
Total equity	39,868	40,899
Total Liabilities and Equity	121,033	120,709
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	198	13
Receivables (net of allowance for doubtful accounts)	110	129
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	687	647
Receivables from affiliated companies	75	75
Notes receivable from affiliated companies	699	150
Inventory	1,167	1,124
Regulatory assets	322	399
Other	164	77
Total current assets	3,422	2,614
Investments and Other Assets
Nuclear decommissioning trust funds	2,953	3,042
Other	1,018	959
Total investments and other assets	3,971	4,001
Property, Plant and Equipment
Cost	38,653	37,372
Accumulated depreciation and amortization	(13,445)	(12,700)
Net property, plant and equipment	25,208	24,672
Regulatory Assets and Deferred Debits
Regulatory assets	2,741	2,465
Other	43	42
Total regulatory assets and deferred debits	2,784	2,507
Total Assets	35,385	33,794
Current Liabilities
Accounts payable	623	709
Accounts payable to affiliated companies	143	154
Taxes accrued	335	146
Interest accrued	146	95
Current maturities of long-term debt	506	507
Regulatory liabilities	36	34
Other	415	434
Total current liabilities	2,204	2,079
Long-Term Debt	8,078	7,584
Long-Term Debt Payable to Affiliated Companies	300	300
Deferred Credits and Other Liabilities
Deferred income taxes	6,067	5,812
Investment tax credits	200	204
Accrued pension and other post-retirement benefit costs	107	111
Asset retirement obligations	3,599	3,428
Regulatory liabilities	2,747	2,710
Other	618	642
Total deferred credits and other liabilities	$ 13,338	$ 12,907
Commitments and Contingencies
Equity
Member's equity	$ 11,476	$ 10,937
Accumulated other comprehensive income (loss)	(11)	(13)
Total member's equity	11,465	10,924
Total Liabilities and Equity	35,385	33,794
Progress Energy [Member]
Current Assets
Cash and cash equivalents	158	42
Receivables (net of allowance for doubtful accounts)	172	129
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	863	741
Receivables from affiliated companies	121	59
Notes receivable from affiliated companies	251	220
Inventory	1,604	1,590
Regulatory assets	442	491
Other	633	1,285
Total current assets	4,244	4,557
Investments and Other Assets
Nuclear decommissioning trust funds	2,612	2,503
Goodwill	3,655	3,655
Other	850	670
Total investments and other assets	7,117	6,828
Property, Plant and Equipment
Cost	41,940	38,650
Accumulated depreciation and amortization	(14,862)	(13,506)
Generation Facilities To Be Retired Net	460
Net property, plant and equipment	27,538	25,144
Regulatory Assets and Deferred Debits
Regulatory assets	5,535	5,408
Other	92	91
Total regulatory assets and deferred debits	5,627	5,499
Total Assets	44,526	42,028
Current Liabilities
Accounts payable	697	847
Accounts payable to affiliated companies	238	203
Notes payable to affiliated companies	434	835
Taxes accrued	192	114
Interest accrued	198	184
Current maturities of long-term debt	1,265	1,507
Regulatory liabilities	193	106
Other	954	1,021
Total current liabilities	4,171	4,817
Long-Term Debt	14,131	13,247
Deferred Credits and Other Liabilities
Deferred income taxes	5,001	4,759
Accrued pension and other post-retirement benefit costs	545	533
Asset retirement obligations	5,222	4,711
Regulatory liabilities	2,382	2,379
Other	345	406
Total deferred credits and other liabilities	$ 13,495	$ 12,788
Commitments and Contingencies
Equity
Additional paid-in capital	$ 8,092	$ 7,467
Retained earnings	4,703	3,782
Accumulated other comprehensive income (loss)	(41)	(41)
Total Duke Energy Corporation stockholders' equity	12,754	11,208
Noncontrolling interests	(25)	(32)
Total equity	12,729	11,176
Total Liabilities and Equity	44,526	42,028
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	123	9
Receivables (net of allowance for doubtful accounts)	63	43
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	468	436
Receivables from affiliated companies	6	10
Notes receivable from affiliated companies	307	237
Inventory	986	966
Regulatory assets	333	287
Other	53	384
Total current assets	2,339	2,372
Investments and Other Assets
Nuclear decommissioning trust funds	1,943	1,701
Other	484	412
Total investments and other assets	2,427	2,113
Property, Plant and Equipment
Cost	26,919	24,207
Accumulated depreciation and amortization	(10,207)	(9,021)
Generation Facilities To Be Retired Net	460
Net property, plant and equipment	17,172	15,186
Regulatory Assets and Deferred Debits
Regulatory assets	2,816	2,675
Other	40	34
Total regulatory assets and deferred debits	2,856	2,709
Total Assets	24,794	22,380
Current Liabilities
Accounts payable	381	481
Accounts payable to affiliated companies	141	120
Taxes accrued	83	47
Interest accrued	86	81
Current maturities of long-term debt	402	945
Regulatory liabilities	80	71
Other	375	409
Total current liabilities	1,548	2,154
Long-Term Debt	6,449	5,256
Deferred Credits and Other Liabilities
Deferred income taxes	3,097	2,908
Accrued pension and other post-retirement benefit costs	277	290
Asset retirement obligations	4,489	3,905
Regulatory liabilities	1,825	1,832
Other	120	168
Total deferred credits and other liabilities	$ 9,808	$ 9,103
Commitments and Contingencies
Equity
Member's equity	$ 6,989
Common stock		$ 2,159
Retained earnings		3,708
Total equity		5,867
Total member's equity	6,989
Total Liabilities and Equity	24,794	22,380
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	16	8
Receivables (net of allowance for doubtful accounts)	107	84
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	395	305
Receivables from affiliated companies	98	40
Inventory	618	623
Regulatory assets	108	203
Other	179	521
Total current assets	1,521	1,784
Investments and Other Assets
Nuclear decommissioning trust funds	669	803
Other	308	204
Total investments and other assets	977	1,007
Property, Plant and Equipment
Cost	15,011	14,433
Accumulated depreciation and amortization	(4,648)	(4,478)
Net property, plant and equipment	10,363	9,955
Regulatory Assets and Deferred Debits
Regulatory assets	2,719	2,733
Other	36	39
Total regulatory assets and deferred debits	2,755	2,772
Total Assets	15,616	15,518
Current Liabilities
Accounts payable	316	365
Accounts payable to affiliated companies	80	70
Notes payable to affiliated companies	245	84
Taxes accrued	108	65
Interest accrued	62	47
Current maturities of long-term debt	563	562
Regulatory liabilities	113	35
Other	553	586
Total current liabilities	2,040	1,814
Long-Term Debt	4,287	4,298
Deferred Credits and Other Liabilities
Deferred income taxes	2,579	2,452
Accrued pension and other post-retirement benefit costs	249	221
Asset retirement obligations	732	806
Regulatory liabilities	556	547
Other	157	158
Total deferred credits and other liabilities	$ 4,273	$ 4,184
Commitments and Contingencies
Equity
Member's equity	$ 5,016
Common stock		$ 1,762
Retained earnings		3,460
Total equity		5,222
Total member's equity	5,016
Total Liabilities and Equity	15,616	15,518
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	24	20
Receivables (net of allowance for doubtful accounts)	81	93
Receivables from affiliated companies	61	107
Notes receivable from affiliated companies		145
Inventory	103	97
Assets held for sale		316
Regulatory assets	32	49
Other	167	167
Total current assets	468	994
Investments and Other Assets
Goodwill	920	920
Assets held for sale		2,605
Other	17	23
Total investments and other assets	937	3,548
Property, Plant and Equipment
Cost	7,649	7,141
Accumulated depreciation and amortization	(2,474)	(2,213)
Generation Facilities To Be Retired Net		9
Net property, plant and equipment	5,175	4,937
Regulatory Assets and Deferred Debits
Regulatory assets	495	512
Other	8	8
Total regulatory assets and deferred debits	503	520
Total Assets	7,083	9,999
Current Liabilities
Accounts payable	219	209
Accounts payable to affiliated companies	42	74
Notes payable to affiliated companies	134	491
Taxes accrued	131	163
Interest accrued	28	19
Current maturities of long-term debt	56	157
Liabilities associated with assets held for sale		246
Regulatory liabilities	25	10
Other	151	66
Total current liabilities	786	1,435
Long-Term Debt	1,524	1,584
Long-Term Debt Payable to Affiliated Companies	25	25
Deferred Credits and Other Liabilities
Deferred income taxes	1,395	1,765
Accrued pension and other post-retirement benefit costs	52	48
Liabilities associated with assets held for sale		34
Asset retirement obligations	143	27
Regulatory liabilities	251	241
Other	165	166
Total deferred credits and other liabilities	$ 2,006	$ 2,281
Commitments and Contingencies
Equity
Common stock	$ 762	$ 762
Additional paid-in capital	2,721	4,782
Retained earnings	(741)	(870)
Total equity	2,742	4,674
Total Liabilities and Equity	7,083	9,999
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	62	6
Receivables (net of allowance for doubtful accounts)	90	87
Receivables from affiliated companies	72	115
Notes receivable from affiliated companies	166
Inventory	564	537
Regulatory assets	97	93
Other	167	326
Total current assets	1,218	1,164
Investments and Other Assets
Total investments and other assets	243	251
Property, Plant and Equipment
Cost	13,765	13,034
Accumulated depreciation and amortization	(4,425)	(4,219)
Net property, plant and equipment	9,340	8,815
Regulatory Assets and Deferred Debits
Regulatory assets	645	685
Other	22	24
Total regulatory assets and deferred debits	667	709
Total Assets	11,468	10,939
Current Liabilities
Accounts payable	149	179
Accounts payable to affiliated companies	50	58
Notes payable to affiliated companies		71
Taxes accrued	43	54
Interest accrued	53	56
Current maturities of long-term debt	480	5
Regulatory liabilities	67	54
Other	89	98
Total current liabilities	931	575
Long-Term Debt	3,160	3,636
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	1,774	1,591
Investment tax credits	138	139
Accrued pension and other post-retirement benefit costs	83	82
Asset retirement obligations	449	32
Regulatory liabilities	758	796
Other	107	90
Total deferred credits and other liabilities	$ 3,309	$ 2,730
Commitments and Contingencies
Equity
Common stock	$ 1	$ 1
Additional paid-in capital	1,384	1,384
Retained earnings	2,532	2,460
Accumulated other comprehensive income (loss)	1	3
Total equity	3,918	3,848
Total Liabilities and Equity	$ 11,468	$ 10,939

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Receivables, allowance for doubtful accounts	$ 17	$ 17
Restricted receivables, allowance for doubtful accounts	$ 54	$ 51
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	688,000,000	707,000,000
Duke Energy Carolinas [Member]
Receivables, allowance for doubtful accounts	$ 3	$ 3
Restricted receivables, allowance for doubtful accounts	6	6
Progress Energy [Member]
Receivables, allowance for doubtful accounts	6	8
Restricted receivables, allowance for doubtful accounts	$ 9	$ 8
Common stock, par or stated value	$ 0.01	$ 0.01
Common stock, shares authorized	100	100
Common stock, shares outstanding	100	100
Duke Energy Progress [Member]
Receivables, allowance for doubtful accounts	$ 4	$ 7
Restricted receivables, allowance for doubtful accounts	6	$ 5
Common stock, shares authorized		200,000,000
Common stock, shares outstanding		160,000,000
Duke Energy Florida [Member]
Receivables, allowance for doubtful accounts	2	$ 2
Restricted receivables, allowance for doubtful accounts	3	$ 3
Common stock, shares authorized		60,000,000
Common stock, shares outstanding		100
Duke Energy Ohio [Member]
Receivables, allowance for doubtful accounts	$ 3	$ 2
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	$ 2	$ 1
Common stock, par or stated value	$ 0.01	$ 0.01
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares outstanding	53,913,701	53,913,701

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 2,349	$ 1,789
Net Income (Loss) Attributable to Parent	2,339	1,786
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	2,680	2,641
Equity component of AFUDC	(123)	(99)
Gains on sales of other assets	(44)	(27)
Impairment charges	145	848
Deferred income taxes	1,104	562
Equity in earnings of unconsolidated affiliates	(53)	(97)
Accrued pension and other post-retirement benefit costs	53	81
Contributions to pension plans	(143)
Payments for asset retirement obligations	(208)	(52)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(23)	128
Receivables	67	(24)
Inventory	(13)	(17)
Other current assets	(119)	(315)
Increase (decrease) in
Accounts payable	(182)	(303)
Taxes accrued	41	37
Other current liabilities	79	(99)
Other assets	(143)	(100)
Other liabilities	(71)	214
Net cash provided by operating activities	5,396	5,167
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(4,642)	(3,755)
Investment expenditures	(209)	(65)
Acquisitions	(1,317)	(16)
Purchases of available-for-sale securities	(3,017)	(2,424)
Proceeds from sales and maturities of available-for-sale securities	3,037	2,445
Net proceeds from the sale of Midwest generation business and sales of equity investments and other assets	2,916	172
Change in restricted cash	(49)	(15)
Other	(10)	(76)
Net cash used in investing activities	(3,291)	(3,734)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,780	2,217
Proceeds from the issuance of common stock related to employee benefit plans	16	24
Payments for the redemption of long-term debt	(1,264)	(2,503)
Proceeds from issuance of short-term debt with original maturities greater than 90 days	287
Payments for the redemption of short-term debt with original maturities greater than 90 days	(931)
Notes payable and commercial paper	531	941
Distributions to noncontrolling interests	(7)	(45)
Dividends paid	(1,685)	(1,670)
Repurchase of common shares	(1,500)
Other	2	33
Net cash used in financing activities	(2,771)	(1,003)
Net (decrease) increase in cash and cash equivalents	(666)	430
Cash and cash equivalents at beginning of period	2,036	1,501
Cash and cash equivalents at end of period	1,370	1,931
Significant non-cash transactions:
Accrued capital expenditures	610	466
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	940	933
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,016	952
Equity component of AFUDC	(73)	(68)
Impairment charges		3
Deferred income taxes	183	47
Accrued pension and other post-retirement benefit costs	11	16
Contributions to pension plans	(42)
Payments for asset retirement obligations	(104)
(Increase) decrease in
Receivables	(9)	5
Receivable from affiliated companies		(42)
Inventory	(48)	91
Other current assets	42	(130)
Increase (decrease) in
Accounts payable	(141)	(167)
Accounts payable to affiliated companies	(11)	15
Taxes accrued	182	173
Other current liabilities	49	7
Other assets	97	23
Other liabilities	(61)	21
Net cash provided by operating activities	2,031	1,879
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,372)	(1,289)
Purchases of available-for-sale securities	(1,926)	(1,533)
Proceeds from sales and maturities of available-for-sale securities	1,926	1,516
Notes receivable from affiliated companies	(549)	(117)
Other	(13)	(27)
Net cash used in investing activities	(1,934)	(1,450)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	496
Payments for the redemption of long-term debt	(3)	(42)
Distributions to parent	(401)	(376)
Other	(4)
Net cash used in financing activities	88	(418)
Net (decrease) increase in cash and cash equivalents	185	11
Cash and cash equivalents at beginning of period	13	23
Cash and cash equivalents at end of period	198	34
Significant non-cash transactions:
Accrued capital expenditures	229	177
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	931	735
Net Income (Loss) Attributable to Parent	923	733
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	962	985
Equity component of AFUDC	(40)	(18)
Gains on sales of other assets	(24)	1
Impairment charges	7	(16)
Deferred income taxes	512	231
Accrued pension and other post-retirement benefit costs	(4)	20
Contributions to pension plans	(42)
Payments for asset retirement obligations	(90)	(52)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	6	28
Receivables	(103)	(162)
Receivable from affiliated companies	(62)	(32)
Inventory	44	(45)
Other current assets	298	(147)
Increase (decrease) in
Accounts payable	(157)	(73)
Accounts payable to affiliated companies	35	142
Taxes accrued	75	166
Other current liabilities	115	(96)
Other assets	(116)	(126)
Other liabilities	(87)	43
Net cash provided by operating activities	2,260	1,584
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,816)	(1,383)
Acquisitions	(1,249)
Purchases of available-for-sale securities	(829)	(609)
Proceeds from sales and maturities of available-for-sale securities	895	594
Proceeds from the Sale of Nuclear Fuel	81
Notes receivable from affiliated companies	(31)	(89)
Other	(44)	(37)
Net cash used in investing activities	(2,993)	(1,524)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,195	875
Payments for the redemption of long-term debt	(555)	(479)
Notes payable to affiliated companies	(401)	(391)
Distributions to noncontrolling interests	(4)	(37)
Capital contribution from parent	625
Other	(11)	(39)
Net cash used in financing activities	849	(71)
Net (decrease) increase in cash and cash equivalents	116	(11)
Cash and cash equivalents at beginning of period	42	58
Cash and cash equivalents at end of period	158	47
Significant non-cash transactions:
Accrued capital expenditures	276	159
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	497	391
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	587	570
Equity component of AFUDC	(35)	(17)
Gains on sales of other assets	(5)	(1)
Impairment charges		(18)
Deferred income taxes	308	152
Accrued pension and other post-retirement benefit costs	(11)	(5)
Contributions to pension plans	(21)
Payments for asset retirement obligations	(53)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(3)	9
Receivables	(51)	33
Receivable from affiliated companies	4	(7)
Inventory	37	(53)
Other current assets	187	(97)
Increase (decrease) in
Accounts payable	(69)	(67)
Accounts payable to affiliated companies	21	102
Taxes accrued	34	95
Other current liabilities	22	(46)
Other assets	(41)	(28)
Other liabilities	(64)	(23)
Net cash provided by operating activities	1,344	990
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,120)	(871)
Acquisitions	(1,249)
Purchases of available-for-sale securities	(511)	(371)
Proceeds from sales and maturities of available-for-sale securities	488	351
Notes receivable from affiliated companies	(70)
Other	(35)	(25)
Net cash used in investing activities	(2,497)	(916)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,195	650
Payments for the redemption of long-term debt	(544)	(169)
Notes payable to affiliated companies		(340)
Dividends to parent		(224)
Capital contribution from parent	625
Other	(9)	(6)
Net cash used in financing activities	1,267	(89)
Net (decrease) increase in cash and cash equivalents	114	(15)
Cash and cash equivalents at beginning of period	9	21
Cash and cash equivalents at end of period	123	6
Significant non-cash transactions:
Accrued capital expenditures	136	107
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	494	455
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	373	413
Equity component of AFUDC	(4)	(1)
Impairment charges	7	2
Deferred income taxes	341	194
Accrued pension and other post-retirement benefit costs	4	22
Contributions to pension plans	(21)
Payments for asset retirement obligations	(37)	(52)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	3	13
Receivables	(52)	(118)
Receivable from affiliated companies	(58)	(37)
Inventory	7	7
Other current assets	78	(90)
Increase (decrease) in
Accounts payable	(88)	32
Accounts payable to affiliated companies	10	29
Taxes accrued	43	68
Other current liabilities	97	(50)
Other assets	(73)	(92)
Other liabilities	(29)	(1)
Net cash provided by operating activities	1,095	794
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(696)	(513)
Purchases of available-for-sale securities	(318)	(238)
Proceeds from sales and maturities of available-for-sale securities	408	243
Proceeds from the Sale of Nuclear Fuel	81
Notes receivable from affiliated companies		(182)
Other	(12)	(14)
Net cash used in investing activities	(537)	(704)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		225
Payments for the redemption of long-term debt	(11)	(10)
Notes payable to affiliated companies	161	(181)
Dividends to parent	(350)	(124)
Distributions to parent	(350)
Other		(1)
Net cash used in financing activities	(550)	(91)
Net (decrease) increase in cash and cash equivalents	8	(1)
Cash and cash equivalents at beginning of period	8	16
Cash and cash equivalents at end of period	16	15
Significant non-cash transactions:
Accrued capital expenditures	140	52
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	129	(558)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	175	205
Equity component of AFUDC	(2)	(3)
Gains on sales of other assets	(8)
Impairment charges	40	889
Deferred income taxes	127	(285)
Accrued pension and other post-retirement benefit costs	7	6
Contributions to pension plans	(4)
Payments for asset retirement obligations	(2)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(11)	124
Receivables	8	(66)
Receivable from affiliated companies	46	62
Inventory	2	(16)
Other current assets	6	56
Increase (decrease) in
Accounts payable	7	(42)
Accounts payable to affiliated companies	(32)	(6)
Taxes accrued	(58)	13
Other current liabilities	101	46
Other assets	28	(8)
Other liabilities	(57)	(20)
Net cash provided by operating activities	502	397
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(266)	(242)
Notes receivable from affiliated companies	145	(178)
Other	(9)
Net cash used in investing activities	(130)	(420)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	(153)	(406)
Notes payable to affiliated companies	(64)	520
Dividends to parent	(149)	(100)
Other	(2)	1
Net cash used in financing activities	(368)	15
Net (decrease) increase in cash and cash equivalents	4	(8)
Cash and cash equivalents at beginning of period	20	36
Cash and cash equivalents at end of period	24	28
Significant non-cash transactions:
Accrued capital expenditures	24	21
Distribution of membership interest of Duke Energy SAM, LLC to parent	1,912
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	222	301
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	323	311
Equity component of AFUDC	(9)	(10)
Impairment charges	85
Deferred income taxes	276	136
Accrued pension and other post-retirement benefit costs	10	12
Contributions to pension plans	(9)
Payments for asset retirement obligations	(12)
(Increase) decrease in
Receivables	(5)	(20)
Receivable from affiliated companies	43	72
Inventory	(27)	(30)
Other current assets	67	40
Increase (decrease) in
Accounts payable	11	(44)
Accounts payable to affiliated companies	(8)	4
Taxes accrued	(11)	(36)
Other current liabilities	16	3
Other assets	(50)	(15)
Other liabilities	(1)	44
Net cash provided by operating activities	921	768
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(506)	(462)
Purchases of available-for-sale securities	(5)	(17)
Proceeds from sales and maturities of available-for-sale securities	8	13
Net proceeds from the sale of Midwest generation business and sales of equity investments and other assets	14
Notes receivable from affiliated companies	(166)	96
Other	13	4
Net cash used in investing activities	(642)	(366)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	(2)	(2)
Notes payable to affiliated companies	(71)	61
Dividends to parent	(150)	(451)
Other		(1)
Net cash used in financing activities	(223)	(393)
Net (decrease) increase in cash and cash equivalents	56	9
Cash and cash equivalents at beginning of period	6	15
Cash and cash equivalents at end of period	62	24
Significant non-cash transactions:
Accrued capital expenditures	$ 46	$ 64

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 Cash Flow Hedges [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]Net Gains (Losses) on Cash Flow Hedges [Member]
Balance at Dec. 31, 2013	$ 41,408	$ 1	$ 39,365	$ 2,363	$ (307)	$ (40)		$ (52)	$ 41,330	$ 78					$ 10,864	$ 7,467	$ 3,452	$ (43)		$ (16)	$ 10,860	$ 4	$ 5,625	$ 2,159	$ 3,466		$ 4,797	$ 1,762	$ 3,036		$ (1)	$ 5,269	$ 762	$ 4,882	$ (375)	$ 3,939	$ 1	$ 1,384	$ 2,551	$ 3
Balance, in shares at Dec. 31, 2013		706,000,000
Beginning member's equity at Dec. 31, 2013											$ 10,350	$ 10,365	$ (14)	$ (1)
Net income (loss)	1,789			1,786					1,786	3					735		733				733	2
Net Income (Loss) Attributable to Parent	1,786										933	933			733								391		391		455		455			(558)			(558)	301			301
Other comprehensive (loss) income, net of tax	(52)				(55)	(5)	$ 2	1	(57)	5	2		2		8			5	$ 1	2	8						1				$ 1
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	23		23						23
Common stock dividends	(1,670)			(1,670)					(1,670)														(224)		(224)		(124)		(124)			(100)		(100)		(451)			(451)
Distributions to parent											(376)	(376)
Distributions to noncontrolling interest in subsidiaries	(45)									(45)					(37)							(37)
Transfer of service company net assets to Duke Energy															(538)		(538)				(538)
Balance at Sep. 30, 2014	41,453	$ 1	39,388	2,479	(362)	(45)	2	(51)	41,412	41					11,032	7,467	3,647	(38)	1	(14)	11,063	(31)	5,792	2,159	3,633		5,129	1,762	3,367			4,611	762	4,782	(933)	3,789	1	1,384	2,401	3
Balance, in shares at Sep. 30, 2014		707,000,000
Ending member's equity at Sep. 30, 2014											10,909	10,922	(12)	(1)
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	707,000,000													100								160,000,000				100					89,663,086				53,913,701
Beginning member's equity at Dec. 31, 2014											10,924	10,937	(12)	(1)
Net income (loss)	$ 2,349			2,339					2,339	10					$ 931		923				923	8
Net Income (Loss) Attributable to Parent	2,339										940	940			923								$ 497		355	$ 142	$ 494		351	$ 143		$ 129			129	$ 222			222
Other comprehensive (loss) income, net of tax	(245)				(228)	(1)	(5)	(1)	(235)	(10)	2		1	$ 1	0			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 repurchase, Shares	(19,800,000)	(20,000,000)
Stock Repurchase	$ (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		(2)				(2)	3		$ (2,159)	$ (4,063)	6,222		$ (1,762)	$ (3,461)	5,223
Contributions from parent															625	625					625		625			625
Distribution of membership interest of Duke Energy SAM, LLC to parent																																(1,912)		(1,912)
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)										$ 2,742	$ 762	$ 2,721	$ (741)	$ 3,918	$ 1	$ 1,384	$ 2,532	$ 1
Balance, in shares at Sep. 30, 2015	688,000,000	688,000,000													100																	89,663,086				53,913,701
Ending member's equity at Sep. 30, 2015											$ 11,465	$ 11,476	$ (11)										$ 6,989			$ 6,989	$ 5,016			$ 5,016

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Organization and Basis of Presentation	Index to Combined Notes to Condensed Consolidated Financial Statements The unaudited notes to the condensed consolidated financial statements that follow are a combined presentation. The following list indicates the registrants to which the footnotes apply. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 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, Inc. • • • • • • • • • • • • • • 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. 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, formerly Duke Energy Progress, Inc.); Duke Energy Florida, LLC (Duke Energy Florida, formerly Duke Energy Florida, Inc.); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, Inc. (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 the 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. On August 1, 2015, Duke Energy Progress, a North Carolina corporation, converted into a North Carolina limited liability company. 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. On August 1, 2015, Duke Energy Florida, a Florida corporation, converted into a Florida limited liability company. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, in 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 full requirements service price is recovered from retail customers. 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 (Midwest Generation Exit) 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. BASIS OF PRESENTATION Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales LLC (Duke Energy Retail), 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 for all periods presented. 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, assets held for sale and liabilities associated with assets held for sale. See Note 2 (Midwest Generation Exit) 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, 2014 . 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 and meter reading schedules. Unbilled revenues are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets as shown in the following table. (in millions) September 30, 2015 December 31, 2014 Duke Energy $ 748 $ 827 Duke Energy Carolinas 247 295 Progress Energy 220 217 Duke Energy Progress 123 135 Duke Energy Florida 97 82 Duke Energy Ohio 6 — Duke Energy Indiana 25 27 Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. 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, 2015 December 31, 2014 Duke Energy Ohio $ 64 $ 79 Duke Energy Indiana 93 112 AMOUNTS ATTRIBUTABLE TO CONTROLLING INTERESTS For the three and nine months ended September 30, 2015, the amount of Loss From Discontinued Operations, net of tax presented on the Condensed Consolidated Statements of Operations is fully attributable to controlling interests. During 2014, Duke Energy and Progress Energy's amount of Income (Loss) from Discontinued Operations, net of tax presented on the Condensed Consolidated Statements of Operations includes amounts attributable to noncontrolling interest. The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations for the three and nine months ended September 30, 2014. Three Months Ended Nine Months Ended September 30, 2014 September 30, 2014 Duke Progress Duke Progress (in millions) Energy Energy Energy Energy Income From Continuing Operations $ 891 $ 330 $ 2,367 $ 741 Income From Continuing Operations Attributable to Noncontrolling Interests 3 1 11 2 Income From Continuing Operations Attributable to Duke Energy Corporation $ 888 $ 329 $ 2,356 $ 739 Income (Loss) From Discontinued Operations, net of tax $ 378 $ — $ (578 ) $ (6 ) Loss From Discontinued Operations Attributable to Noncontrolling Interests, net of tax (8 ) — (8 ) — Income (Loss) From Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ 386 $ — $ (570 ) $ (6 ) Net income $ 1,269 $ 330 $ 1,789 $ 735 Net (Loss) Income Attributable to Noncontrolling Interests (5 ) 1 3 2 Net Income Attributable to Duke Energy Corporation $ 1,274 $ 329 $ 1,786 $ 733 Other comprehensive income reported on the Condensed Consolidated Statements of Changes in Equity for Progress Energy is attributable only to controlling interests for all periods presented. ACCUMULATED OTHER COMPREHENSIVE INCOME For the three and nine months ended September 30, 2015 and 2014 , reclassifications out of accumulated other comprehensive income (AOCI) for the Duke Energy Registrants were not material. Changes in AOCI for the Duke Energy Registrants are presented in their respective Condensed Consolidated Statements of Equity. 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 recognized on a gross basis are recorded as Operating Revenues and Property and other taxes on the Condensed Consolidated Statements of Operations. The following table provides the amount of excise taxes accounted for on a gross basis. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2015 2014 2015 2014 Duke Energy $ 109 $ 101 $ 308 $ 416 Duke Energy Carolinas 9 4 27 93 Progress Energy 67 63 174 214 Duke Energy Progress 4 — 12 56 Duke Energy Florida 63 63 162 158 Duke Energy Ohio 24 24 80 80 Duke Energy Indiana 9 10 27 29 During the third quarter of 2014, the North Carolina gross receipts tax was terminated due to the North Carolina Tax Simplification and Rate Reduction Act. The North Carolina gross receipts tax is no longer imposed effective July 1, 2014. NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2015 and 2014 had no significant impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. During the fourth quarter of 2015, Duke Energy will early adopt certain accounting standards not required until the first quarter of 2016. Adoption of these standards will not have a material impact on the results of operations, cash flows, financial position or disclosures of the Duke Energy Registrants. ASC 205 – Reporting Discontinued Operations. In April 2014, the Financial Accounting Standards Board (FASB) issued revised accounting guidance for reporting discontinued operations. A discontinued operation would be either (i) a component of an entity or a group of components of an entity that represents a separate major line of business or major geographical area of operations that either has been disposed of or is part of a single coordinated plan to be classified as held for sale or (ii) a business that, upon acquisition, meets the criteria to be classified as held for sale. For Duke Energy, the revised accounting guidance is effective on a prospective basis for qualified disposals of components or classifications as held for sale that occur after January 1, 2015. Under the standard, the guidance is not effective for a component classified as held for sale before the effective date even if the disposal occurs after the effective date of the guidance. Duke Energy has not reported any discontinued operations under the revised accounting guidance. The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by the Duke Energy, as of September 30, 2015 . ASC 606 – Revenue from Contracts with Customers. In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this revised accounting 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 the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, although it can be early adopted for annual periods beginning as early as January 1, 2017. Duke Energy is currently evaluating the requirements. Other than increased disclosures, the revised accounting guidance and impacts to the Duke Energy Registrants have not yet been determined. ASC 835 – Presentation of Debt Issuance Costs. In April and August 2015, the FASB issued revised accounting guidance for the presentation of debt issuance costs. The core principle of this revised accounting guidance is that debt issuance costs are not assets, but adjustments to the carrying cost of debt. For Duke Energy, this revised accounting guidance is effective retroactively beginning January 1, 2016, but can be adopted earlier. Duke Energy intends to early adopt this accounting standard during the fourth quarter of 2015. The implementation of this accounting standard will result in a reduction of approximately $165 million in Other within Regulatory Assets and Deferred Debits, and in Long-Term Debt, based on the amount of debt issuance costs reported on the Condensed Consolidated Balance Sheets as of September 30, 2015.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS ACQUISITIONS Acquisition of Piedmont Natural Gas On October 24, 2015, Duke Energy entered into an Agreement and Plan of Merger (Merger Agreement) with Piedmont Natural Gas Company, Inc., (Piedmont) a North Carolina corporation. Under the terms of the Merger Agreement, Duke Energy will acquire Piedmont for $4.9 billion in cash. Upon closing, Piedmont will become a wholly-owned subsidiary of Duke Energy. Pursuant to the Merger Agreement, upon the closing of the merger, each share of Piedmont common stock issued and outstanding immediately prior to the closing will be converted automatically into the right to receive $60 in cash per share. In addition, Duke Energy will assume $1.8 billion in Piedmont existing debt. Duke Energy expects to finance the transaction with a combination of debt, between $500 million and $750 million of newly issued equity and other cash sources. Duke Energy has a fully underwritten bridge facility to support funding of the merger. Completion of the transaction is conditioned upon approval by the NCUC, expiration or termination of any applicable waiting period under the federal Hart-Scott-Rodino Antitrust Improvements Act of 1976, and Piedmont shareholder approval. The Merger Agreement contains certain termination rights for both Duke Energy and Piedmont, and provides that, upon termination of the Merger Agreement under specified circumstances, Duke Energy would be required to pay a termination fee of $250 million to Piedmont and Piedmont would be required to pay Duke Energy a termination fee of $125 million . Subject to receipt of required regulatory approvals and meeting closing conditions, Duke Energy and Piedmont target a closing by the end of 2016. See Note 4 for additional information regarding Duke Energy and Piedmont's joint investment in Atlantic Coast Pipeline, LLC (ACP). 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. The NRC approved the transfer of control of licenses for the Brunswick Nuclear Plant and Shearon Harris Nuclear Plant from NCEMPA to Duke Energy Progress on July 6, 2015. 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 exceeds the historical carrying value of the acquired assets by $350 million , which is a purchase acquisition adjustment, recorded in property, plant and equipment. Duke Energy Progress received FERC approval for inclusion of the purchase acquisition adjustment in wholesale power formula rates on December 9, 2014. On July 8, 2015, the NCUC adopted a new rule that enables a rider mechanism for recovery of the costs to acquire, operate and maintain interests in the assets purchased as allocated to Duke Energy Progress' North Carolina retail operations, including the purchase acquisition adjustment. Duke Energy Progress filed an application with the NCUC to implement the rider to be effective December 1, 2015. Duke Energy Progress also received an order from the PSCSC to defer the recovery of the South Carolina retail allocated costs of the asset purchased until the Company's next general rate case. Purchase Price Allocation The ownership interests in generating assets acquired are subject to rate-setting authority of the FERC, NCUC and PSCSC and accordingly, the assets are recorded at historical cost. The purchase price allocation is presented in the following table. (in millions) Inventory $ 56 Net property, plant and equipment 845 Total assets 901 Purchase acquisition adjustment 350 Total purchase price $ 1,251 In connection with the acquisition, Duke Energy Progress acquired NCEMPA's nuclear decommissioning trust fund assets of $287 million and assumed asset retirement obligations of $204 million associated with NCEMPA's interest in the generation assets. The nuclear decommissioning trust fund and the asset retirement obligation are subject to regulatory accounting treatment with any difference between the trust fund assets and the asset retirement obligation accounted for within regulatory assets and liabilities. Impact of the Acquisition Incremental costs following the acquisition are allocated between retail and wholesale operations. Costs allocated to Duke Energy Progress' retail operations are being deferred until the costs are reflected in retail rates in North Carolina through a rate rider. Costs allocated to the South Carolina jurisdiction are being deferred until the next rate case when recovery of these costs will be considered. The impact of the acquired NCEMPA assets and the 30-year wholesale power agreement on Duke Energy Progress' Operating Revenues and Net Income and Comprehensive Income in the Condensed Consolidated Statements of Operations was $40 million and $7 million , respectively, for the three and nine months ended September 30, 2015. DISPOSITIONS Midwest Generation Exit Duke Energy, through indirect subsidiaries, completed the sale of the nonregulated Midwest generation business and Duke Energy Retail (Disposal Group) to a subsidiary of Dynegy on April 2, 2015, for approximately $2.8 billion in cash. 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. The assets and liabilities of the Disposal Group prior to the sale were included in the Commercial Portfolio (formerly Commercial Power) segment and classified as held for sale in Duke Energy's and Duke Energy Ohio's Condensed Consolidated Balance Sheet. The following table presents information related to the Duke Energy Ohio generation plants included in the Disposal Group. Total MW Owned MW Ownership Facility Plant Type Primary Fuel Location Capacity (d) Capacity (d) Interest Stuart (a)(c) Fossil Steam Coal OH 2,308 900 39 % Zimmer (a) Fossil Steam Coal OH 1,300 605 46.5 % Hanging Rock Combined Cycle Natural Gas OH 1,226 1,226 100 % Miami Fort (Units 7 and 8) (b) Fossil Steam Coal OH 1,020 652 64 % Conesville (a)(c) Fossil Steam Coal OH 780 312 40 % Washington Combined Cycle Natural Gas OH 617 617 100 % Fayette Combined Cycle Natural Gas PA 614 614 100 % Killen (b)(c) Fossil Steam Coal OH 600 198 33 % Lee Combustion Turbine Natural Gas IL 568 568 100 % Dick's Creek Combustion Turbine Natural Gas OH 136 136 100 % Miami Fort Combustion Turbine Oil OH 56 56 100 % Total Midwest Generation 9,225 5,884 (a) Jointly owned with America Electric Power Generation Resources and The Dayton Power & Light Company. (b) Jointly owned with The Dayton Power & Light Company. (c) Facility was not operated by Duke Energy Ohio. (d) Total megawatt (MW) capacity is based on summer capacity. The Disposal Group also included a retail sales business owned by Duke Energy. In the second quarter of 2014, Duke Energy Ohio removed Ohio Valley Electric Corporation's (OVEC) purchase power agreement from the Disposal Group as it no longer intended to sell it with the Disposal Group. The results of operations of the Disposal Group prior to the date of sale are classified as discontinued operations in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Income. Certain immaterial costs that may be eliminated as a result of the sale have remained in continuing operations. The following table presents the results of discontinued operations. Duke Energy Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Operating Revenues $ — $ 620 $ 543 $ 1,233 (Loss) Gain on disposition (a) (5 ) 460 (42 ) (847 ) (Loss) Income before income taxes (b) $ (5 ) $ 623 $ 62 $ (864 ) Income tax (benefit) expense (1 ) 218 29 (321 ) (Loss) Income from discontinued operations of the Disposal Group (4 ) 405 33 (543 ) Other, net of tax (c) (1 ) (27 ) (4 ) (35 ) (Loss) Income from Discontinued Operations, net of tax $ (5 ) $ 378 $ 29 $ (578 ) (a) The (Loss) Gain on disposition includes impairments and reversals to the impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Disposal Group for the nine months ended September 30, 2015. Refer to Note 5 for further information related to the lawsuit. (c) Includes other discontinued operations related to prior sales of businesses and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments. Duke Energy Ohio Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Operating Revenues $ — $ 536 $ 412 $ 853 (Loss) Gain on disposition (a) (4 ) 466 (48 ) (878 ) (Loss) Income before income taxes (b) $ (4 ) $ 647 $ 48 $ (917 ) Income tax (benefit) expense (2 ) 234 25 (320 ) (Loss) Income from Discontinued Operations, net of tax $ (2 ) $ 413 $ 23 $ (597 ) (a) The (Loss) Gain on disposition includes impairments and reversals to the impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Disposal Group for the nine months ended September 30, 2015, respectively. Refer to Note 5 for further information related to the lawsuit. Commercial Portfolio has a revolving credit agreement (RCA) which was used 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 Disposal Group for a portion of its standard service offer (SSO) supply requirement. The agreement and the SSO expired in May 2015. Duke Energy will also provide, and receive reimbursement for, transition services provided to Dynegy for a period of up to 12 months. The continuing cash flows are not considered direct cash flows and are not expected to be material. Duke Energy or Duke Energy Ohio will not significantly influence the operations of the Disposal Group during the transition service period. See Notes 4 and 5 for a discussion of contingencies related to the Disposal Group that are retained by Duke Energy Ohio subsequent to the sale.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Operating segments are determined based on information used by the chief operating decision-maker in deciding how to allocate resources and evaluate the performance of the business. Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income, 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. Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets presented in the following tables 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 principally 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 relate to power generation in Latin America. Additionally, International Energy owns a 25 percent interest in National Methanol Company (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. Commercial Portfolio builds, develops and operates wind and solar renewable generation and energy transmission projects throughout the U.S. The segment was renamed as a result of the sale of the nonregulated Midwest generation business, as discussed in Note 2 . For periods subsequent to the sale, 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, 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 $ (3 ) $ 971 $ (34 ) $ — $ 937 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (5 ) Net income $ 935 Segment assets $ 110,520 $ 3,730 $ 3,841 $ 118,091 $ 2,757 $ 185 $ 121,033 (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 $ 15 million of after-tax costs to achieve the 2012 Progress Energy merger. Three Months Ended September 30, 2014 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,975 $ 366 $ 50 $ 6,391 $ 4 $ — $ 6,395 Intersegment revenues 11 — — 11 21 (32 ) — Total revenues $ 5,986 $ 366 $ 50 $ 6,402 $ 25 $ (32 ) $ 6,395 Segment income (loss) (a) $ 920 $ 80 $ (17 ) $ 983 $ (92 ) $ (3 ) $ 888 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 378 Net income $ 1,269 (a) Other includes $35 million of after-tax costs to achieve the 2012 Progress Energy merger. 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 $ (35 ) $ 2,433 $ (119 ) $ (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 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 Disposal Group. Refer to Note 5 for further information related to the lawsuit. Nine Months Ended September 30, 2014 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 17,041 $ 1,111 $ 195 $ 18,347 $ 19 $ — $ 18,366 Intersegment revenues 33 — — 33 60 (93 ) — Total revenues $ 17,074 $ 1,111 $ 195 $ 18,380 $ 79 $ (93 ) $ 18,366 Segment income (loss) (a)(b) $ 2,346 $ 356 $ (70 ) $ 2,632 $ (269 ) $ (7 ) $ 2,356 Add back noncontrolling interest 11 Loss from discontinued operations, net of tax (578 ) Net income $ 1,789 (a) Commercial Portfolio includes a pretax impairment charge of $94 million related to OVEC. Refer to Note 13 for further information. (b) Other includes $107 million of after-tax costs to achieve the 2012 Progress Energy merger. DUKE ENERGY OHIO Duke Energy Ohio had two reportable operating segments, Regulated Utilities and Commercial Portfolio, prior to the sale of the nonregulated Midwest generation business. As a result of the sale discussed in Note 2 , Commercial Portfolio no longer qualifies as a Duke Energy Ohio reportable operating segment. Therefore, for periods subsequent to the sale, 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. Regulated Utilities transmits and distributes electricity in portions of Ohio and Kentucky, and generates and sells electricity in portions of Kentucky. Regulated Utilities also transports and sells natural gas in portions of Ohio and northern Kentucky. It conducts operations primarily through Duke Energy Ohio and its wholly owned subsidiary, Duke Energy Kentucky. Other is primarily comprised of governance costs allocated by its parent, Duke Energy, and revenues and expenses related to Duke Energy Ohio's contractual arrangement to buy power from OVEC's power plants. For additional information on related party transactions refer to Note 9 . Duke Energy Ohio had no intersegment revenues for the three and nine months ended September 30, 2015 . Three Months Ended September 30, 2015 Regulated (in millions) Utilities Other Eliminations Consolidated Total revenues $ 456 $ 6 $ — $ 462 Segment income (loss) $ 46 $ (12 ) $ — $ 34 Loss from discontinued operations, net of tax (2 ) Net income $ 32 Segment assets $ 6,961 $ 126 $ (4 ) $ 7,083 Three Months Ended September 30, 2014 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 440 $ 6 $ 446 $ — $ — $ 446 Intersegment revenues 1 — 1 — (1 ) — Total revenues $ 441 $ 6 $ 447 $ — $ (1 ) $ 446 Segment income (loss) $ 43 $ (13 ) $ 30 $ (4 ) $ — $ 26 Income from discontinued operations, net of tax 413 Net income $ 439 Nine Months Ended September 30, 2015 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Total revenues $ 1,424 $ 14 $ 1,438 $ 15 $ — $ 1,453 Segment income (loss) $ 135 $ (9 ) $ 126 $ (20 ) $ — $ 106 Income from discontinued operations, net of tax (a) 23 Net income $ 129 (a) Includes an after-tax charge of $53 million for the settlement agreement reached in a lawsuit related to the Disposal Group. Refer to Note 5 for further information. Nine Months Ended September 30, 2014 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 1,416 $ 17 $ 1,433 $ — $ — $ 1,433 Intersegment revenues 1 — 1 — (1 ) — Total revenues $ 1,417 $ 17 $ 1,434 $ — $ (1 ) $ 1,433 Segment income (loss) (a) $ 151 $ (101 ) $ 50 $ (11 ) $ — $ 39 Loss from discontinued operations, net of tax (597 ) Net loss $ (558 ) (a) Commercial Portfolio includes a pretax impairment charge of $94 million related to OVEC. See Note 13 for additional information. DUKE ENERGY CAROLINAS, PROGRESS ENERGY, DUKE ENERGY PROGRESS, DUKE ENERGY FLORIDA AND DUKE ENERGY INDIANA The remaining Subsidiary Registrants each have one reportable operating segment, Regulated Utilities, which generates, transmits, distributes and sells electricity. The remainder of each company’s operations is classified as Other. While not considered a reportable segment for any of these companies, Other consists of certain unallocated corporate costs. The following table summarizes the net loss for Other at each of these registrants. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Duke Energy Carolinas $ (10 ) $ (19 ) $ (28 ) $ (67 ) Progress Energy (a) (3 ) (48 ) (87 ) (145 ) Duke Energy Progress (4 ) (10 ) (12 ) (23 ) Duke Energy Florida (3 ) (5 ) (9 ) (16 ) Duke Energy Indiana (2 ) (3 ) (6 ) (10 ) (a) Other for Progress Energy also includes interest expense on corporate debt instruments of $61 million and $180 million for the three and nine months ended September 30, 2015 , respectively, and $58 million and $181 million for the three and nine months ended September 30, 2014 , respectively. The assets of Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana are substantially all included within the Regulated Utilities segment at September 30, 2015 and 2014 .

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2015
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 respective 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 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 and Southern Alliance for Clean Energy jointly filed a Notice of Appeal with the Court of Appeals of South Carolina 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 case has been fully briefed and is pending in the Court of Appeals. Oral arguments are expected to be heard in January 2016. Duke Energy Carolinas cannot predict the outcome of this matter. Duke Energy Progress Sutton Black Start Combustion Turbine CPCN On April 15, 2015, Duke Energy Progress filed a Certificate of Public Convenience and Necessity (CPCN) application with the NCUC for approval to construct an 84 MW black start combustion turbine (CT) project at the existing Sutton Plant (Sutton Black Start CT Project). The Sutton Black Start CT Project would replace three existing CTs with total capacity of 61 MW with two new 42 MW CT units with black start and fast start capability. In addition to peaking system capacity, the Sutton Black Start CT Project will provide regional black start capability and tertiary backup power services for the Brunswick Nuclear Plant. In June 2015, the Public Staff of the NCUC recommended the NCUC approve Duke Energy Progress' application. On August 3, 2015, the NCUC issued an order granting the application and requiring annual construction and cost progress reports. The new units are expected to be commercially available in the summer of 2017. Western Carolinas Modernization Plan In May 2015, Duke Energy Progress announced a $1.1 billion plan to modernize the Western Carolinas energy system. The plan included retirement of the Asheville coal-fired plant, building a 650 MW combined-cycle natural gas power plant, installing solar generation at the site, building new transmission lines, a new substation and upgrades to area substations. On June 24, 2015, the North Carolina governor signed into law the North Carolina Mountain Energy Act of 2015 (Mountain Energy Act) which provides for an expedited CPCN process for the proposed Asheville combined-cycle project and extends certain North Carolina Coal Ash Management Act of 2014 (Coal Ash Act) deadlines for the coal ash basin at the Asheville Plant site. On November 4, 2015, in response to community feedback, Duke Energy Progress announced a revised plan. The revised plan replaces the planned 650 MW plant with two 280 MW combined-cycle natural gas plants having duel fuel capability, with the option to build a third gas 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. These investments will be made within the next five years in North Carolina. 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 plans to file for a CPCN with the NCUC for the new gas units in January 2016. The carrying value of the 376 MW Asheville coal-fired plant, including associated ash basin closure costs, of $460 million is included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheet as of September 30, 2015 . Duke Energy Florida FERC Transmission Return on Equity Complaint Seminole Electric Cooperative, Inc. and Florida Municipal Power Agency filed multiple complaints with the FERC alleging Duke Energy Florida's current rate of return on equity in transmission formula rates of 10.8 percent is unjust and unreasonable. The latest complaint, filed on August 12, 2014, claims the rate of return on equity should be reduced to 8.69 percent . The FERC consolidated all complaints for the purposes of settlement, hearing and decision. On July 21, 2015, the parties filed with the FERC for approval of a settlement agreement under which (i) Duke Energy Florida will pay a total of $14.1 million as refunds for all periods through December 31, 2014, (ii) the rate of return on equity will be 10 percent effective January 1, 2015, and (iii) none of the parties will seek a change in the rate of return on equity prior to January 1, 2018. Amounts to be refunded are included in Other within Current Liabilities on the Condensed Consolidated Balance Sheets as of September 30, 2015. FERC approval of the settlement is pending. Citrus County Combined Cycle Facility On October 2, 2014, the FPSC granted Duke Energy Florida a Determination of Need for the construction of a 1,640 MW combined-cycle natural gas plant in Citrus County, Florida. On May 5, 2015, the Florida Department of Environmental Protection approved Duke Energy Florida's Site Certification Application. The facility is expected to be commercially available in 2018 at an estimated cost of $1.5 billion , including AFUDC. The project has received all required permits and approvals and construction began in October 2015. 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 . On January 30, 2015, Duke Energy Florida petitioned the FPSC requesting a determination that the Osprey Plant acquisition or, alternatively, the construction of a 320 MW combustion turbine at its existing Suwannee generating facility (Suwannee project) with an estimated cost of $197 million , is the most cost-effective generation alternative to meet Duke Energy Florida's remaining generation need prior to 2018. On July 21, 2015, the FPSC approved the Osprey Plant acquisition as the most cost-effective alternative and issued an order of approval on July 31, 2015. On July 24, 2015, the FERC issued an order approving the Osprey Plant acquisition. Closing of the acquisition is contingent upon the expiration of the Hart-Scott-Rodino waiting period and is expected to occur by the first quarter of 2017, upon the expiration of an existing Power Purchase Agreement between Calpine and Duke Energy Florida. Crystal River Unit 3 On May 22, 2015, Duke Energy Florida petitioned the FPSC for approval to include in base rates the revenue requirement for the projected $1.298 billion Crystal River Unit 3 regulatory asset as authorized by the 2013 Revised and Restated Stipulation and Settlement Agreement (2013 Agreement). On September 15, 2015, the FPSC approved Duke Energy Florida's motion for approval of a settlement agreement with intervenors to reduce the value of the projected Crystal River Unit 3 regulatory asset to be recovered to $1.283 billion as of December 31, 2015. An impairment charge of $15 million was recognized in the third quarter of 2015 to adjust the regulatory asset balance. The initial annual revenue requirement for this approved value is estimated to be $168 million . In June 2015, the governor of Florida signed legislation to allow utilities to petition for a financing order for securitization of certain retired nuclear generation assets. On July 27, 2015, Duke Energy Florida petitioned the FPSC for a financing order to issue nuclear asset-recovery bonds to finance the Crystal River Unit 3 regulatory asset. If the FPSC issues an acceptable financing order and Duke Energy Florida issues the bonds, the securitization would replace the base rate recovery methodology authorized by the 2013 Agreement and result in a lower rate impact to customers. The annual revenue requirement with securitization, subject to changes in assumed interest rates and timing of issuance of the securitization bonds, is estimated to be approximately $93 million . On October 14, 2015, the FPSC approved an agreement on all securitization-related issues and is expected to issue a final financing order in the fourth quarter of 2015. If approved, Duke Energy Florida expects to issue securitization bonds in early 2016. Levy Nuclear Project On April 16, 2015, the FPSC approved Duke Energy Florida’s petition to cease collection of the Levy Nuclear Project fixed charge beginning with the first billing cycle in May 2015. Duke Energy Florida also sought approval to defer collection of the $54 million regulatory asset until the conclusion of litigation with Westinghouse Electric Co. The FPSC determined it was unnecessary to act on the request, finding that its previous order requiring a downward adjustment in projected costs primarily affected the timing of when the fixed charge would end and did not disallow the recovery of costs previously determined to be prudent. On August 18, 2015, the FPSC approved to leave the Levy Nuclear Project portion of the Nuclear Cost Recovery Clause charge at zero dollars for 2016 and 2017, consistent with the 2013 Settlement. Duke Energy Florida will submit by May 2017 a true-up of Levy Nuclear Project costs or credits to be recovered no earlier than January 2018. To the extent costs become known after May 2017, Duke Energy Florida will petition for recovery at that time. Duke Energy Ohio DE Ohio 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. As a result of the PUCO’s decision, Duke Energy Ohio reversed $23 million in revenues for the period between January 2013 and April 2015 in second quarter 2015. The PUCO granted Duke Energy Ohio's application for rehearing on July 8, 2015. Substantive ruling on the application for rehearing is pending. 2014 Electric Security Plan In April 2015, the PUCO modified and approved Duke Energy Ohio's proposed ESP, with a three-year term and an effective date of June 1, 2015. The PUCO approved a competitive procurement process for SSO load, a distribution capital investment rider and a tracking mechanism for incremental distribution expenses caused by major storms. The PUCO order also approved a placeholder tariff for a price stabilization rider, but denied Duke Energy Ohio's specific request to include OVEC in the rider at this time; however, the order allows Duke Energy Ohio to submit additional information to request recovery in the future. On May 4, 2015, Duke Energy Ohio filed an application for rehearing requesting the PUCO to modify or amend certain aspects of the order. On May 14, 2015, Duke Energy Ohio completed a competitive bidding process to procure a portion of the supply for its SSO load for the term of the ESP. The PUCO approved the results on May 15, 2015. On May 28, 2015, the PUCO granted all applications for rehearing filed in the case for future consideration. Duke Energy Ohio cannot predict the outcome of this matter. 2012 Natural Gas Rate Case On November 13, 2013, the PUCO issued an order approving a settlement among Duke Energy Ohio, the PUCO Staff and intervening parties (the Gas Settlement). The Gas Settlement provided for (i) no increase in base rates for natural gas distribution service and (ii) a return on equity of 9.84 percent . The Gas Settlement provided for a subsequent hearing on Duke Energy Ohio’s request for rider recovery of environmental remediation costs associated with its former manufactured gas plant (MGP) sites. The PUCO authorized Duke Energy Ohio to recover $56 million , excluding carrying costs, of environmental remediation costs. The MGP rider became effective in April 2014 for a five-year period. On March 31, 2014, Duke Energy Ohio filed an application with the PUCO to adjust the MGP rider for investigation and remediation costs incurred in 2013. Certain consumer groups appealed the PUCO’s decision authorizing the MGP rider to the Ohio Supreme Court and asked the court to stay implementation of the PUCO’s order and collections under the MGP rider pending their appeal. The Ohio Supreme Court granted the motion to stay and subsequently required the posting of a bond to effectuate the stay. When the bond was not posted, the PUCO approved Duke Energy Ohio’s request, in January 2015, to reinstate collections under the MGP rider and Duke Energy Ohio resumed billings. Amounts collected prior to the suspension of the rider were immaterial. On March 31, 2015, Duke Energy Ohio filed an application to adjust the MGP rider to recover remediation costs incurred in 2014. Duke Energy Ohio cannot predict the outcome of the appeal of this matter. Regional Transmission Organization (RTO) 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. On December 22, 2010, the KPSC approved Duke Energy Kentucky’s 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. On May 25, 2011, the PUCO approved a settlement between Duke Energy Ohio, Ohio Energy Group, the Office of Ohio Consumers’ Counsel and the PUCO Staff related to Duke Energy Ohio’s recovery of certain costs of the 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. Upon its exit from MISO on December 31, 2011, Duke Energy Ohio recorded a liability for its exit obligation and share of MTEP costs, excluding MVP. This liability was recorded within Other in Current liabilities and Other in Deferred credits and other liabilities on Duke Energy Ohio’s Condensed Consolidated Balance Sheets. As of September 30, 2015 , Duke Energy Ohio had recorded obligations of $91 million related to its withdrawal from MISO and a Regulatory asset of $72 million recorded on the Condensed Consolidated Balance Sheets. MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. 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 the FERC overturn the ALJ’s decision. On October 29, 2015, the FERC issued an order reversing the ALJ's decision. FERC ruled that 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. MISO has 30 days from the date of the order to file a request for rehearing with FERC. FERC Transmission Return on Equity and MTEP Cost Settlement On October 14, 2011, Duke Energy Ohio and Duke Energy Kentucky submitted with the FERC proposed modifications to the PJM Interconnection Open Access Transmission Tariff pertaining to recovery of the transmission revenue requirement as PJM transmission owners. The filing was made in connection with Duke Energy Ohio's and Duke Energy Kentucky's move from MISO to PJM effective December 31, 2011. On April 24, 2012, the FERC issued an order accepting the proposed filing effective January 1, 2012, except that the order denied a request to recover certain costs associated with the move from MISO to PJM without prejudice to the right to submit another filing seeking such recovery and including certain additional evidence, and set the rate of return on equity of 12.38 percent for settlement and hearing. On April 16, 2015, the FERC approved a settlement agreement between Duke Energy Ohio, Duke Energy Kentucky and six PJM transmission customers with load in the Duke Energy Ohio and Duke Energy Kentucky zone. The principal terms of the settlement agreement are that, effective upon the date of FERC approval, (i) the return on equity for wholesale transmission service is reduced to 11.38 percent , (ii) the settling parties agreed not to seek a change in the return on equity that would be effective prior to June 1, 2017, and (iii) Duke Energy Ohio and Duke Energy Kentucky will recover 30 percent of the wholesale portion of costs arising from their obligation to pay any portion of the costs of projects included in any MTEP that was approved prior to the date of Duke Energy Ohio's and Duke Energy Kentucky's integration into PJM. Duke Energy Indiana Edwardsport Integrated Gasification Combined Cycle (IGCC) Plant On November 20, 2007, the IURC granted Duke Energy Indiana a CPCN for the construction of the Edwardsport 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, the IGCC rider. Updates to the IGCC rider are filed semi-annually. The ninth semi-annual IGCC rider order was appealed by the Joint Intervenors. On September 8, 2014, the Indiana Court of Appeals remanded the IURC order in the ninth IGCC rider proceeding back to the IURC for further findings. On February 25, 2015, the IURC issued a new order upholding its prior decision and provided additional detailed findings. Joint Intervenors appealed this remand order to the Indiana Court of Appeals. On September 23, 2015, the Indiana Court of Appeals affirmed the IURC remand decision on one of the key financial issues. The Indiana Court of Appeals found that there was sufficient evidence for the IURC to find that the three-month delay in construction for this time period was not unreasonable and therefore the costs of such delay should be borne by Duke Energy Indiana customers. The Indiana Court of Appeals found that the IURC did not support its findings regarding the ratemaking impact of the tax in-service declaration and reversed and remanded this issue back to the IURC, with direction to hold further proceedings and issue additional findings on the issue. The Joint Intervenors have requested a rehearing of the Indiana Court of Appeals decision. The 10th semi-annual IGCC rider order was also appealed by the Joint Intervenors. On August 21, 2014 the Indiana Court of Appeals affirmed the IURC order in the 10th IGCC rider proceeding and on October 29, 2014 denied the Joint Intervenors' request for rehearing. The Joint Intervenors requested the Indiana Supreme Court to review the decision, which was denied on April 23, 2015, concluding the appeal. Duke Energy Indiana has filed the 14th and 15th semi-annual IGCC rider proceedings. The 11th through 15th semi-annual IGCC riders and a subdocket to Duke Energy Indiana's fuel adjustment clause are currently in various stages of approval by the IURC in the filing process. Issues in these filings include 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 OUCC, the Industrial Group and Nucor Steel Indiana reached a settlement agreement to resolve these pending issues. The proposed settlement will result in customers not being billed for previously incurred but deferred operating costs of $78 million , a refund of previously recovered operating costs of $7 million and for additional Duke Energy Indiana payments and commitments of $5 million for attorneys’ fees and to fund consumer programs. Duke Energy Indiana recorded Impairment charges of $85 million and Other Income and Expenses, net of $5 million in the Condensed Consolidated Statements of Operations and Comprehensive Income for the three and nine months ended September 30, 2015 . Duke Energy Indiana also recorded a $78 million reduction of Regulatory assets within Regulatory Assets and Deferred Debits, an additional $7 million of Other within Deferred Credits and Other Liabilities and $5 million of Accounts payable within Current Liabilities on the Condensed Consolidated Balance Sheets at September 30, 2015 . Additionally, under the proposed settlement, the operating and maintenance expenses and ongoing maintenance capital at the plant are subject to certain caps during the years of 2016 and 2017. Pursuant to the 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. As of September 30, 2015 , deferred costs related to the project are approximately $108 million . Future IGCC riders will be filed annually, rather than every six months, with the next filing scheduled for first quarter 2017. The settlement is subject to IURC approval, which the parties hope to receive in the first half of 2016. Duke Energy Indiana cannot predict the outcome of the settlement of these matters or future IGCC rider proceedings. FERC Transmission Return on Equity Complaint Customer groups have filed with the FERC complaints against MISO and its transmission-owning members, including Duke Energy Indiana, alleging, among other things, that the current base rate of return on equity earned by MISO transmission owners of 12.38 percent is unjust and unreasonable. The 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. On January 5, 2015, the 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 complaint. A hearing in the base return on equity proceeding was held in August 2015. The motion to consolidate complaints was denied. A hearing on the second complaint proceeding is scheduled to begin February 16, 2016. Duke Energy Indiana cannot predict the outcome of this matter. Grid Infrastructure Improvement Plan On August 29, 2014, 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. In May 2015, the IURC denied the proposal due to an insufficient level of detailed projects and cost estimates in the plan. Duke Energy Indiana is evaluating the order and plans to file a revised infrastructure improvement plan by the end of 2015. OTHER REGULATORY MATTERS Atlantic Coast Pipeline On September 2, 2014, Duke Energy, Dominion Resources (Dominion), Piedmont and AGL Resources announced the formation of a company, ACP, to build and own the proposed Atlantic Coast Pipeline (the pipeline), a 564-mile interstate natural gas pipeline. The pipeline is designed to meet the needs identified in requests for proposals by Duke Energy Carolinas, Duke Energy Progress and Piedmont Natural Gas. Dominion will build and operate the pipeline and has a 45 percent ownership percentage in ACP. Duke Energy has a 40 percent ownership interest in ACP through its Commercial Portfolio segment. Piedmont owns 10 percent and the remaining share is owned by AGL Resources. Duke Energy Carolinas and Duke Energy Progress, among others, will be customers of the pipeline. Purchases will be made under several 20-year supply contracts, subject to state regulatory approval. In October 2014, the NCUC and PSCSC approved the Duke Energy Carolinas and Duke Energy Progress requests to enter into certain affiliate agreements, pay compensation to ACP and to grant a waiver of certain Code of Conduct provisions relating to contractual and jurisdictional matters. On September 18, 2015, ACP filed an application with the FERC requesting a CPCN authorizing ACP to construct the pipeline. ACP requested approval of the application by July 1, 2016 to enable construction to begin by September 2016, with an in-service date of on or before November 1, 2018. ACP also requested approval of an open access tariff and the precedent agreements it entered into with future pipeline customers, including Duke Energy Carolinas and Duke Energy Progress. On October 24, 2015, Duke Energy entered into a Merger Agreement with Piedmont. The ACP partnership agreement includes provisions to allow Dominion an option to purchase additional ownership interest in ACP to maintain a leading ownership percentage. Any change in ownership interests is not expected to be material to Duke Energy. Refer to Note 2 for further information related to Duke Energy's proposed acquisition of Piedmont. Sabal Trail Transmission, LLC Pipeline On May 4, 2015, Duke Energy acquired a 7.5 percent ownership interest from Spectra Energy in the proposed 500-mile Sabal Trail natural gas pipeline. Spectra Energy will continue to own 59.5 percent of the Sabal Trail pipeline and NextEra Energy will own the remaining 33 percent . The Sabal Trail pipeline will traverse Alabama, Georgia and Florida to meet rapidly growing demand for natural gas in those states. The primary customers of the Sabal Trail pipeline, Duke Energy Florida and Florida Power & Light Company, have each contracted to buy pipeline capacity for 25-year initial terms. The Sabal Trail pipeline, scheduled to begin service in 2017, requires federal and other regulatory approvals. East Bend Station On December 30, 2014, Duke Energy Ohio acquired The Dayton Power and Light Company's (DP&L) 31 percent interest in the jointly owned East Bend Station for approximately $12.4 million . The purchase price, in accordance with FERC guidelines, was reflected with the net purchase amount as an increase to property, plant and equipment as of December 31, 2014 and with the DP&L's historical original cost as an increase to property, plant and equipment and accumulated depreciation as of September 30, 2015 . On August 20, 2015, the KPSC approved Duke Energy Kentucky's application to use the purchase price as the value of the newly acquired interest in the East Bend Station for depreciation purposes and ratemaking. NC WARN FERC Complaint On December 16, 2014, North Carolina Waste Awareness and Reduction Network filed a complaint with the FERC against Duke Energy Carolinas and Duke Energy Progress that alleged (i) Duke Energy Carolinas and Duke Energy Progress manipulated the electricity market by constructing costly and unneeded generation facilities leading to unjust and unreasonable rates; (ii) Duke Energy Carolinas and Duke Energy Progress failed to comply with Order 1000 by not effectively connecting their transmission systems with neighboring utilities which also have excess capacity; (iii) the plans of Duke Energy Carolinas and Duke Energy Progress for unrealistic future growth lead to unnecessary and expensive generating plants; (iv) the FERC should investigate the practices of Duke Energy Carolinas and Duke Energy Progress and the potential benefits of having them enter into a regional transmission organization; and (v) the FERC should force Duke Energy Carolinas and Duke Energy Progress to purchase power from other utilities rather than construct wasteful and redundant power plants. NC WARN also filed a copy of the complaint with the PSCSC on January 6, 2015. In April 2015, the FERC and the PSCSC issued separate orders dismissing the NC WARN petition. On May 14, 2015, NC WARN filed with FERC a motion for reconsideration. Potential Coal Plant Retirements The Subsidiary Registrants periodically file Integrated Resource Plans (IRP) with their state regulatory commissions. The IRPs provide a view of forecasted energy needs over a long term (10 to 20 years), and options being considered to meet those needs. Recent IRPs filed by the Subsidiary Registrants included planning assumptions to potentially retire certain coal-fired generating facilities in North Carolina, Florida and Indiana earlier than their current estimated useful lives. These facilities do not have the requisite emission control equipment, primarily to meet United States Environmental Protection Agency (EPA) regulations recently approved or proposed. 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. September 30, 2015 Duke Duke Duke Progress Energy Energy Energy Energy (b) Florida (b) Indiana (c) Capacity (in MW) 1,541 873 873 668 Remaining net book value (in millions) (a) $ 207 $ 121 $ 121 $ 86 (a) Remaining net book value amounts presented exclude any capitalized asset retirement costs related to closure of ash basins. (b) Includes Crystal River Units 1 and 2. (c) Includes Wabash River Units 2 through 6. Wabash River Unit 6 is being evaluated for potential conversion to natural gas. Duke Energy Indiana committed to retire or convert the Wabash River Units 2 through 6 by June 2018 in conjunction with a settlement agreement associated with the Edwardsport air permit. On October 23, 2015, the EPA published in the Federal Register the Clean Power Plan (CPP) rule for regulating carbon dioxide (CO 2 ) emissions from existing fossil fuel-fired electric gene

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
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. The following environmental matters impact all of the Duke Energy Registrants. Remediation Activities The Duke Energy Registrants are responsible for environmental remediation at various contaminated 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 contamination 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. 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, 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 Nine Months Ended September 30, 2014 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 $ 79 $ 11 $ 27 $ 8 $ 19 $ 27 $ 7 Provisions/adjustments 34 (1 ) 4 3 1 28 3 Cash reductions (8 ) — (6 ) (4 ) (2 ) (1 ) (1 ) Balance at end of period $ 105 $ 10 $ 25 $ 7 $ 18 $ 54 $ 9 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 presented in the table below. (in millions) Duke Energy $ 79 Duke Energy Carolinas 25 Progress Energy 4 Duke Energy Progress 1 Duke Energy Florida 3 Duke Energy Ohio 43 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. Total repairs and remediation expenses incurred by Duke Energy Carolinas related to the release were approximately $24 million . No additional expenses were recorded in 2015. Duke Energy Carolinas will not seek recovery of these costs from ratepayers. See the "Litigation" section below for additional information on litigation, investigations and enforcement actions related to ash basins, including the Memorandum of Plea Agreement (Plea Agreements) in connection to the North Carolina Ash Basin Grand Jury Investigation. Other 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. On September 20, 2014, the Coal Ash Act became law and was amended on June 24, 2015, by the Mountain Energy Act. The Coal Ash Act, as amended, (i) establishes a Coal Ash Management Commission (Coal Ash Commission) to oversee handling of coal ash within the state; (ii) prohibits construction of new and expansion of existing ash impoundments and use of existing impoundments at retired facilities; (iii) requires closure of ash impoundments at Duke Energy Progress' Asheville and Sutton plants and Duke Energy Carolinas' Riverbend and Dan River stations no later than August 1, 2019 (the Mountain Energy Act provides for the potential extension of closure of the Asheville impoundment until 2022); (iv) requires dry disposal of fly ash at active plants, excluding the Asheville Plant, not retired by December 31, 2018; (v) requires dry disposal of bottom ash at active plants, excluding the Asheville Plant, by December 31, 2019, or retirement of active plants; (vi) requires all remaining ash impoundments in North Carolina to be categorized as high-risk, intermediate-risk or low-risk no later than December 31, 2015 by the North Carolina Department of Environmental Quality (NCDEQ), formerly the North Carolina Department of Environment and Natural Resources, with the method of closure and timing to be based upon the assigned risk, with closure no later than December 31, 2029; (vii) establishes requirements to deal with groundwater and surface water impacts from impoundments; and (viii) increases the level of regulation for structural fills utilizing coal ash. The Coal Ash Act includes a variance procedure for compliance deadlines and modification of requirements regarding structural fills and compliance boundaries. Provisions of the Coal Ash Act prohibit cost recovery in customer rates for unlawful discharge of ash basin waters occurring after January 1, 2014. The Coal Ash Act leaves the decision on cost recovery determinations related to closure of coal combustion residual (CCR) surface impoundments (ash basins or impoundments) to the normal ratemaking processes before utility regulatory commissions. Duke Energy has and will periodically submit to NCDEQ site-specific coal ash impoundment closure plans or excavation plans in advance of closure plans. These plans and all associated permits must be approved by NCDEQ before any excavation or closure work can begin. In September 2014, Duke Energy Carolinas executed a consent agreement with the South Carolina Department of Health and Environmental Control (SCDHEC) requiring the excavation of an inactive ash basin and ash fill area at the W.S. Lee Steam Station. As part of this agreement, in December 2014, Duke Energy Carolinas filed an ash removal plan and schedule with SCDHEC. In April 2015, the federal CCR rules were published and Duke Energy Carolinas subsequently executed an agreement with the conservation groups Upstate Forever and Save Our Saluda that requires Duke Energy Carolinas to remediate all active and inactive ash storage areas at the W.S. Lee Steam Station. Coal-fired generation at W.S. Lee ceased in 2014 and unit 3 was converted to natural gas in March 2015. In July 2015, Duke Energy Progress executed a consent agreement with the SCDHEC requiring the excavation of an inactive ash fill area at the Robinson Plant within eight years. The Robinson Plant and W.S. Lee Station sites are required to be closed pursuant to the recently issued CCR rule and the provisions of these consent agreements are consistent with the federal CCR closure requirements. Asset retirement obligations recorded on the Duke Energy Carolinas and Duke Energy Progress Condensed Consolidated Balance Sheets at September 30, 2015 and December 31, 2014 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's CCR rule and other agreements. Cost recovery for future expenditures 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. See Note 7 for additional information. Coal Combustion Residuals On April 17, 2015, the EPA published in the Federal Register a rule to regulate the disposal of CCR from electric utilities as solid waste. The federal regulation classifies CCR as nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act and allows beneficial use of CCRs with some restrictions. The regulation applies to all new and existing landfills, new and existing surface impoundments receiving CCR and existing surface impoundments that are no longer receiving CCR but contain liquid located at stations currently generating electricity (regardless of fuel source). The rule establishes requirements regarding landfill design, structural integrity design and assessment criteria for surface impoundments, groundwater monitoring and protection procedures and other operational and reporting procedures to ensure the safe disposal and management of CCR. In addition to the requirements of the federal CCR regulation, CCR landfills and surface impoundments will continue to be independently regulated by most states. Duke Energy records an asset retirement obligation 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. Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana recorded additional asset retirement obligation amounts in the second quarter of 2015 as a result of the EPA's CCR rule. Cost recovery for future expenditures 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. See Note 7 for additional information. 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 (collectively, the “Duke Energy Defendants”). Duke Energy is named as a nominal defendant. The Consolidated Complaint alleges the Duke Energy Defendants breached their fiduciary duties by failing to adequately oversee Duke Energy’s ash basins and that these breaches of fiduciary duty may have contributed to the incident at Dan River and continued thereafter. The lawsuit also asserts claims against the Duke Energy Defendants for corporate waste (relating to the money Duke Energy has spent and will spend as a result of the fines, penalties and coal ash removal) and unjust enrichment (relating to the compensation and director remuneration that was received despite these alleged breaches of fiduciary duty). The lawsuit seeks both injunctive relief against Duke Energy and restitution from the Duke Energy Defendants. On 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 through November 15, 2015. In October 2015, the Duke Energy Defendants provided an update to the court on the related coal ash litigation. 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 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. In addition to the above derivative complaints, Duke Energy has also received two shareholder litigation demand letters. On May 28, 2014, Duke Energy received a shareholder litigation demand letter sent on behalf of shareholder Mitchell Pinsly. The letter alleges 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. The letter demands that the Board of Directors take action to recover damages associated with those breaches of fiduciary duty; otherwise, the attorney will file a shareholder derivative action. By letter dated July 3, 2014, counsel for the shareholder was informed that the Board of Directors appointed a Demand Review Committee to evaluate the allegations in the demand letter. On March 24, 2015, Duke Energy received a shareholder litigation demand letter sent on behalf of shareholder Saul Bresalier. The letter alleges that the members of the Board of Directors and certain officers breached their fiduciary duties in their management of Duke Energy's environmental practices, as well as in their decision-making relating to the leadership changes following the close of the Progress Energy merger in July 2012. The letter demands that the Board of Directors take action to recover damages associated with those alleged breaches of fiduciary duty; otherwise, the attorney will file a shareholder derivative action. In May 2015, counsel for the shareholder was informed that the matter had been referred to the Demand Review Committee. By letter dated September 4, 2015, attorneys for the shareholders were informed that, on the recommendation of the Demand Review Committee, the Board of Directors concluded not to pursue potential claims against individuals. Shareholder Mitchell Pinsly sent a formal demand for records and Duke Energy is responding 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 the Duke Energy Defendants breached their fiduciary duties in connection with coal ash environmental issues, the post-merger change in Chief Executive Officer 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 Duke Energy Defendants. 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. Ash Basin Shareholder Securities Litigation On May 26, 2015, Plaintiff E.F. Greenberg (Plaintiff) filed a lawsuit against the members of the Duke Energy Board of Directors (the Board) alleging violations of Section 14(a) of the Exchange Act for false or misleading statements contained in Duke Energy’s 2015 Proxy Statement. The plaintiff contends the Board caused Duke Energy to omit material facts from the 2015 Proxy Statement that a reasonable shareholder would consider important in casting a vote, especially with respect to the election of directors. Accordingly, Plaintiff alleges that shareholders were misled in casting their votes. Plaintiff seeks a determination that the 2015 Proxy Statement was false and misleading, an order from the court invalidating all votes from the Annual Meeting and requiring a revised 2015 Proxy Statement, as well as attorneys’ fees. On July 31, 2015, the defendants filed a Motion to Dismiss the case. On October 2, 2015, the Plaintiff filed a Motion for Summary Judgment. On October 30, 2015, the parties signed an agreement whereby the Plaintiff will voluntarily dismiss the case. The terms of the agreement are immaterial to Duke Energy. Progress Energy Merger Shareholder Litigation Duke Energy, the 11 members of the Board of Directors who were also members of the pre-merger Board of Directors (Legacy Duke Energy Directors) and certain Duke Energy officers are defendants in a purported securities class action lawsuit (Nieman v. Duke Energy Corporation, et al) . This lawsuit consolidates three lawsuits originally filed in July 2012 and is pending in the United States District Court for the Western District of North Carolina. The plaintiffs allege federal Securities Act and Exchange Act claims based on allegations of materially false and misleading representations and omissions in the Registration Statement filed on July 7, 2011, and purportedly incorporated into other documents, all in connection with the post-merger change in Chief Executive Officer (CEO). On August 15, 2014 the parties reached an agreement in principle to settle the litigation. On March 10, 2015, the parties filed a Stipulation of Settlement and a Motion for Preliminary Approval of the Settlement. The court issued an order for preliminary approval of the settlement on March 25, 2015. Under the terms of the agreement, Duke Energy agreed to pay $146 million to settle the claim. On April 22, 2015, Duke Energy made a payment of $25 million into the settlement escrow account. The remainder of $121 million was paid by insurers into the settlement escrow account. Notice has been sent to members of the class and a final approval hearing was held on August 12, 2015. The final order approving the settlement was issued on November 2, 2015. 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 . The lawsuit names as defendants the Legacy Duke Energy Directors. Duke Energy is named as a nominal defendant. The case alleges claims for breach of fiduciary duties of loyalty and care in connection with the post-merger change in CEO. The case is stayed pending resolution of the Nieman v. Duke Energy Corporation, et al. case in North Carolina. 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 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. Pursuant to an order entered on September 2, 2014, the court administratively closed this consolidated derivative action. The parties filed a status report with the court on December 1, 2014, and will continue to do so every six months thereafter until the Nieman v. Duke Energy Corporation, et al. case in North Carolina has been resolved. 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 the remaining litigation. Price Reporting Cases Five lawsuits filed against a Duke Energy affiliate, Duke Energy Trading and Marketing, LLC, and other energy companies remain pending in a consolidated, single 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. On July 18, 2011, the judge granted a defendant’s motion for summary judgment in two of five cases. The U.S. Court of Appeals for the Ninth Circuit subsequently reversed the lower court’s decision. On April 21, 2015, the Supreme Court affirmed the U.S. Court of Appeals decision. The case has been reassigned to the same consolidated federal court proceeding in Nevada for further 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 the remaining matters. 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 ex parte 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. Brazil Generation Record drought conditions in Brazil continue to impact Duke Energy International, Geracao Paranapanema S.A. (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. 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. The APINE decision is subject to appeal and the outcome of these lawsuits is uncertain. It is not possible to predict the impact to Duke Energy from the outcome of these matters. Duke Energy Carolinas and Duke Energy Progress NCDEQ Notices of Violation (NOV) In August 2014, NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' L.V. Sutton Plant. On March 10, 2015, 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, NCDEQ issued an NOV for alleged groundwater violations at Duke Energy Progress' Asheville Plant. Duke Energy Progress responded to NCDEQ regarding this NOV. On September 29, 2015, Duke Energy Progress and Duke Energy Carolinas entered into a settlement agreement with NCDEQ resolving all former, current and future groundwater issues at all Duke Energy Carolinas and Duke Energy Progress coal facilities in North Carolina. Under the agreement, Duke Energy Progress will pay approximately $6 million and Duke Energy Carolinas will pay 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 court entered a consent order resolving the contested case relating to the Sutton plant and NCDEQ rescinded the NOVs relating to alleged groundwater violations at both the Sutton and Asheville plants. On October 13, 2015, the SELC, representing multiple conservation groups, filed a lawsuit in North Carolina Superior Court seeking judicial review of the order approving the settlement agreement with NCDEQ. The conservation groups contend that the Administrative Judge 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. It is not possible to predict the outcome of this matter. NCDEQ State Enforcement Actions In the first quarter of 2013, non-government environmental organizations sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged groundwater violations and CWA violations from coal ash basins at two of their coal-fired power plants in North Carolina. NCDEQ filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The case against Duke Energy Carolinas was filed in Mecklenburg County Superior Court. The case against Duke Energy Progress was filed in Wake County Superior Court. The cases are being heard before a single judge. On October 4, 2013, Duke Energy Carolinas, Duke Energy Progress and NCDEQ negotiated a proposed consent order covering these two plants. The consent order would have assessed civil penalties and imposed a compliance schedule requiring Duke Energy Carolinas and Duke Energy Progress to undertake monitoring and data collection activities toward making appropriate corrective action to address any substantiated violations. In light of the coal ash release that occurred at Dan River on February 2, 2014, on March 21, 2014, NCDEQ withdrew its support of the consent orders and requested that the court proceed with the litigation. On August 16, 2013, 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. The case against Duke Energy Carolinas was filed in Mecklenburg County Superior Court. The case against Duke Energy Progress was filed in Wake County Superior Court. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. The Southern Environmental Law Center (SELC), on behalf of several environmental groups, has been permitted to intervene in these cases. On July 10, 2015, Duke Energy Carolinas and Duke Energy Progress filed 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. The court requested the parties reach agreement on the language of the order by October 30, 2015, or submit separate proposed orders and objections on November 2, 2015. Deadlines for discovery and motions for the remaining seven plants were extended by 180 days. 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. North Carolina Declaratory Judgment Action On October 10, 2012, the SELC, on behalf of the same environmental groups that were permitted to challenge the consent decrees discussed above, filed a petition with the North Carolina Environmental Management Commission (EMC) asking for a declaratory ruling seeking to clarify the application of the state’s groundwater protection rules to coal ash basins. The petition sought to change the interpretation of regulations that permitted NCDEQ to assess the extent, cause and significance of any groundwater contamination before ordering action to eliminate the source of contamination, among other issues. Duke Energy Carolinas and Duke Energy Progress were both permitted to intervene in the matter. On December 3, 2012, the EMC affirmed this interpretation of the regulations. On March 6, 2014, the North Carolina State Court judge overturned the ruling of the EMC holding that in the case of groundwater contamination, NCDEQ was required to issue an order to immediately eliminate the source of the contamination before an assessment of the nature, significance and extent of the contamination or the continuing damage to the groundwater was conducted. Duke Energy Carolinas, Duke Energy Progress and the EMC appealed the ruling in April 2014. On May 16, 2014, the North Carolina Court of Appeals denied a petition to stay the case during the appeal. On October 10, 2014, the parties were notified the case has been transferred to the North Carolina Supreme Court (NCSC). Oral argument was held on March 16, 2015. On June 11, 2015, the NCSC issued its opinion in favor of Duke Energy Carolinas, Duke Energy Progress and the EMC and remanded the matter to the state court judge with instructions to dismiss the case. Federal Citizens Suits There are currently five cases filed in various North Carolina federal courts contending that the NCDEQ state enforcement actions discussed above do not adequately address the issues raised in the notices of intent to sue related to the Riverbend, Sutton, Cape Fear, H.F. Lee and Buck plants. On June 11, 2013, Catawba Riverkeeper Foundation, Inc. (Catawba Riverkeeper) filed a separate action in the United States Court for the Western District of North Carolina. The lawsuit contends the state enforcement action discussed above does not adequately address issues raised in Catawba Riverkeeper’s notice of intent to sue relating to the Riverbend Steam Station. On April 11, 2014, the Court denied Catawba Riverkeeper’s objections to the Magistrate Judge’s recommendation that plaintiff’s case be dismissed as well as Duke Energy Carolinas’ motion to dismiss. The Court allowed limited discovery, after which Duke Energy Carolinas may file any renewed motions to dismiss. On August 13, 2015, the court issued an order suspending all proceedings until further order from the court. 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 moti

Debt and Credit Facilities

Debt and Credit Facilities	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Debt And Credit Facilities	DEBT AND CREDIT FACILITIES SUMMARY OF SIGNIFICANT DEBT ISSUANCES The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2015 Duke Duke Maturity Interest Duke Energy Energy Issuance Date Date Rate Energy Carolinas Progress First Mortgage Bonds March 2015 (a) June 2045 3.750 % $ 500 $ 500 $ — August 2015 (b) August 2025 3.250 % 500 — 500 August 2015 (b) August 2045 4.200 % 700 — 700 Total issuances $ 1,700 $ 500 $ 1,200 (a) Proceeds were used to redeem at maturity $500 million of first mortgage bonds due October 2015. (b) Proceeds were used to repay short-term money pool and commercial paper borrowings issued to fund a portion of the NCEMPA acquisition, see Note 2 for further information. Additionally, proceeds will be used to refinance at maturity $400 million of first mortgage bonds due December 2015. 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, 2015 Unsecured Debt Progress Energy (Parent) January 2016 5.625 % $ 300 Duke Energy Indiana June 2016 6.05 % 325 First Mortgage Bonds Duke Energy Carolinas October 2015 5.300 % 500 Duke Energy Florida November 2015 0.650 % 250 Duke Energy Florida December 2015 5.100 % 300 Duke Energy Progress December 2015 5.250 % 400 Duke Energy Indiana July 2016 0.636 % 150 Other 311 Current maturities of long-term debt $ 2,536 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, variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder and as security to meet obligations under the Plea Agreements. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. September 30, 2015 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 $ 3,300 $ 800 $ 1,300 $ 1,200 $ 400 $ 500 Reduction to backstop issuances Commercial paper (b) (1,793 ) (1,318 ) (300 ) — — (25 ) (150 ) Outstanding letters of credit (72 ) (64 ) (4 ) (3 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (c) (500 ) — (250 ) (250 ) — — — Available capacity $ 5,019 $ 1,918 $ 211 $ 1,047 $ 1,199 $ 375 $ 269 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $475 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, 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. (c) On May 14, 2015, the United States District Court for the Eastern District of North Carolina approved the separate Plea Agreements entered into by Duke Energy Carolinas, Duke Energy Progress and DEBS, a wholly owned subsidiary of Duke Energy, in connection with the investigation initiated by the USDOJ. Duke Energy Carolinas and Duke Energy Progress are required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet their obligations under the Plea Agreements, in addition to certain other conditions. See Note 5 for further details.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS COAL COMBUSTION RESIDUALS Duke Energy records an asset retirement obligation (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. On April 17, 2015, the EPA published in the Federal Register a rule to regulate the disposal of CCR from electric utilities as solid waste. The federal regulation, which became effective in October 2015, classifies CCR as nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act and allows beneficial use of CCRs with some restrictions. The regulation applies to all new and existing landfills, new and existing surface impoundments receiving CCR and existing surface impoundments that are no longer receiving CCR but contain liquid located at stations currently generating electricity (regardless of fuel source). The rule establishes requirements regarding landfill design, structural integrity design and assessment criteria for surface impoundments, groundwater monitoring and protection procedures and other operational and reporting procedures to ensure the safe disposal and management of CCR. In addition to the requirements of the federal CCR regulation, CCR landfills and surface impoundments will continue to be independently regulated by most states. As a result of the EPA rule, Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana recorded additional asset retirement obligation amounts during the second quarter of 2015 . Cost recovery is believed to be probable and will be pursued through normal ratemaking processes. See footnote 5 for additional information. The ARO amount recorded that relates to the EPA rule was based upon estimated closure costs for ash basins at seven plants located in South Carolina, Indiana and Kentucky. The amount recorded represents the discounted cash flows for estimated closure costs of these ash basins based upon probability weightings of the potential closure methods as evaluated on a site-by-site basis. Actual costs to be incurred will be dependent upon factors that vary from site to site. The most significant factors are the method and time frame of closure at the individual sites. Closure methods considered include removing the water from the basins and capping the ash with a synthetic barrier, excavating and relocating the ash to a lined structural fill or lined landfill, or recycling the ash for concrete or some other beneficial use. The ultimate method and timetable for closure will be in compliance with standards set by the EPA rule and any state regulations. The ARO amount will be adjusted as additional information is gained through the closure process, including acceptance and approval of compliance approaches which may change management assumptions, and may result in a material change to the balance. The following table presents changes in the 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, 2014 (a) $ 8,466 $ 3,428 $ 4,711 $ 3,905 $ 806 $ 27 $ 32 Acquisitions (b) 213 — 204 204 — — — Accretion expense (c) 278 123 150 123 26 2 11 Liabilities settled (d) (274 ) (107 ) (153 ) (53 ) (100 ) (2 ) (12 ) Liabilities incurred in the current year (e) 983 178 270 270 — 116 418 Revisions in estimates of cash flows 47 (23 ) 40 40 — — — Balance at September 30, 2015 $ 9,713 $ 3,599 $ 5,222 $ 4,489 $ 732 $ 143 $ 449 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash basins in North Carolina and South Carolina, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) Primarily relates to the NCEMPA acquisition. See footnote 2 for additional information. (c) For the nine months ended September 30, 2015 , substantially all accretion expense relates to previously established asset retirement obligations from Duke Energy's regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (d) Primarily relates to ash basin closures in North Carolina and South Carolina and nuclear decommissioning of Crystal River Unit 3 in Florida. (e) Primarily relates to amounts recorded in the second quarter of 2015 as a result of the EPA's rule for disposal of CCR as solid waste. 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. The following table summarizes the associated long-lived assets related to ARO liabilities incurred during the nine months ended September 30, 2015 . September 30, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Ohio Indiana Net property, plant and equipment $ 535 $ — $ — $ — $ 116 $ 418 Regulatory Assets 448 178 270 270 — —

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2015
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, 2014 (a) 15,950 307 64 16,321 Foreign exchange and other changes — (33 ) — (33 ) Acquisitions — — 24 24 Goodwill at September 30, 2015 $ 15,950 $ 274 $ 88 $ 16,312 (a) Excludes fully impaired Goodwill related to the nonregulated Midwest generation business which was sold in the second quarter of 2015. See Note 2 for further information related to the sale. 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, 2015 and December 31, 2014 . 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 exceeded their respective carrying values at the date of the annual impairment analysis, no impairment charges were recorded in the third quarter of 2015. INTANGIBLE ASSETS During 2014, Duke Energy Ohio reduced the carrying amount of OVEC to zero. A charge of $94 million is recorded in Impairment charges on Duke Energy Ohio's Condensed Consolidated Statement of Operations for the nine months ended September 30, 2014 . See Note 13 for additional information.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with the applicable state and federal commission regulations and are generally performed at cost. 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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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 of other affiliate transactions in net income, 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, 2015 and 2014 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 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 . The intercompany loan payable recorded in Notes payable to affiliated companies on Duke Energy Ohio’s Condensed Consolidated Balance Sheets was $459 million as of December 31, 2014 . Refer to Note 2 for further information on the sale of the Disposal Group.

Derivatives and Hedging

Derivatives and Hedging	9 Months Ended
	Sep. 30, 2015
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 and interest rate risks. The primary use of energy 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 agreement is offset against the collateralized derivatives on the balance sheet. The cash impacts of settled derivatives are recorded as operating activities on the Condensed Consolidated Statements of Cash Flows. Changes in the fair value of derivative instruments that either do not qualify for or have not been designated as hedges are reflected in current earnings or as regulatory assets or liabilities. FAIR VALUE AND 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 effects earnings. Gains and losses reclassified out of AOCI for the three and nine months ended September 30, 2015 and 2014 were immaterial. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. At September 30, 2015 , there were no open commodity derivative instruments designated as hedges. COMMODITY PRICE RISK The Duke Energy Registrants are exposed to the impact of changes in the future prices of electricity, coal and natural gas. Exposure to commodity price risk is influenced by a number of factors including the term of contracts, the liquidity of markets and delivery locations. Regulated public utilities may have cost-based rate regulations and various other cost recovery mechanisms that result in a limited exposure to market volatility of commodity fuel prices. Financial derivative contracts, where approved by the respective state regulatory commission, can be used to manage the risk of price volatility. Wholesale generating capacity used to sell electricity results in exposure to market volatility in energy-related commodity prices. Undesignated Contracts Undesignated contracts may include contracts not designated as a hedge because they are accounted for under Regulated Operations accounting, contracts that do not qualify for hedge accounting, derivatives that do not or no longer qualify for the NPNS scope exception, and de-designated hedge contracts. Mark-to-market gains or losses on contracts accounted for under Regulated Operations are deferred and recorded as Regulatory Liabilities or Regulatory Assets, respectively. The Subsidiary Registrants utilize cost-tracking mechanisms, commonly referred to as fuel adjustment clauses. These clauses allow for the recovery of fuel and fuel-related costs, including settlements of undesignated derivatives for fuel commodities, and portions of purchased power costs through surcharges on customer rates. The difference between the costs incurred and the surcharge revenues is recorded as an adjustment to Fuel used in electric generation and purchased power – regulated or as Operating Revenues – Regulated electric on the Consolidated Statements of Operations with an offsetting impact on regulatory assets or liabilities. Therefore, due to the regulatory accounting followed by our Regulated Operations for undesignated derivatives, realized and unrealized gains and losses on undesignated derivatives do not have an immediate impact on reported net income. Mark-to-market gains and losses related to the nonregulated Midwest generation business are recorded in discontinued operations and open positions at April 2, 2015 were included in the sale of the Disposal Group. Refer to Note 2 for further information on the sale of the Disposal Group. Gains and losses on undesignated derivative contracts for nonregulated continuing operations are immaterial, including electric contracts used to hedge renewables generation in Electric Reliability Council of Texas (ERCOT), hedges for a business that is winding down by the end of 2016, and revenues during 2014 for mitigation contracts which were terminated by December 31, 2014. Undesignated contracts expire as late as 2018. Volumes The tables below show information relating to 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, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 76 — — — — 3 39 Natural gas (millions of decatherms) 389 61 328 110 218 — — December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) (a)(b) 25,370 — — — — 19,141 — Natural gas (millions of decatherms) (a) 676 35 328 116 212 313 — (a) Amounts at Duke Energy Ohio include volumes related to the nonregulated Midwest generation business sold during the second quarter of 2015. Refer to Note 2 for further information on the sale. (b) Amounts at Duke Energy Ohio include intercompany positions that eliminate at Duke Energy. 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. Pretax gains or losses recognized from inception to termination of the hedges are amortized as a component of interest expense over the life of the debt. Duke’s interest rate swaps for its Regulated Utilities operations employ Regulated Operations accounting. Regulated Operations accounting records the Mark-to-Market on the swaps as Regulatory Assets or Regulatory Liabilities. The accrual of interest on the swaps is recorded as Interest Expense. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The following table shows notional amounts for derivatives related to interest rate risk. September 30, 2015 December 31, 2014 Duke Duke Duke Duke Duke Duke Progress Energy Energy Energy Duke Progress Energy Energy (in millions) Energy Energy Progress Florida Ohio Energy Energy Florida Ohio Cash flow hedges (a) $ 714 $ — $ — $ — $ — $ 750 $ — $ — $ — Undesignated contracts (b) 527 500 250 250 27 277 250 250 27 Total notional amount $ 1,241 $ 500 $ 250 $ 250 $ 27 $ 1,027 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $509 million and $541 million at September 30, 2015 and December 31, 2014 , respectively. (b) In January 2015, Duke Energy Progress executed fixed-to-floating rate swaps. The swaps were issued to economically convert $250 million of fixed rate first mortgage bonds due September 15, 2021, to floating rate with an initial rate of approximately 1.75 percent . In October 2015, Duke Energy Carolinas entered into $400 million notional amount of forward starting interest rate swaps that was designated as a hedge of debt anticipated to be issued in 2018. LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED IN THE CONDENSED CONSOLIDATED BALANCE SHEETS The following tables show the fair value of derivatives and the line items in the Condensed Consolidated Balance Sheets where they are reported. 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, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Current Assets: Other $ 1 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Other 17 — — — — 4 12 Current Liabilities: Other 2 — 1 — 1 — — Deferred Credits and Other Liabilities: Other 2 — 2 — 2 — — Total Derivative Assets – Commodity Contracts $ 22 $ — $ 3 $ — $ 3 $ 4 $ 12 Interest Rate Contracts Designated as Hedging Instruments Investments and Other Assets: Other $ 1 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Other 6 — 6 2 4 — — Investments and Other Assets: Other 4 — 4 — 4 — — Total Derivative Assets – Interest Rate Contracts $ 11 $ — $ 10 $ 2 $ 8 $ — $ — Total Derivative Assets $ 33 $ — $ 13 $ 2 $ 11 $ 4 $ 12 Derivative Liabilities September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Not Designated as Hedging Instruments Current Liabilities: Other $ 242 $ 25 $ 215 $ 77 $ 138 $ — $ — Deferred Credits and Other Liabilities: Other 100 8 91 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 342 $ 33 $ 306 $ 93 $ 209 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current Liabilities: Other $ 14 $ — $ — $ — $ — $ — $ — Deferred Credits and Other Liabilities: Other 41 — — — — — Not Designated as Hedging Instruments Current Liabilities: Other 1 — — — — 1 — Deferred Credits and Other Liabilities: Other 8 — 3 2 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 64 $ — $ 3 $ 2 $ — $ 7 $ — Total Derivative Liabilities $ 406 $ 33 $ 309 $ 95 $ 209 $ 7 $ — Derivative Assets December 31, 2014 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 Assets: Other $ 18 $ — $ — $ — $ — $ 1 $ 14 Current Assets: Assets held for sale 15 — — — — 28 — Investments and Other Assets: Other 3 — — — — — — Investments and Other Assets: Assets held for sale 15 — — — — 26 — Current Liabilities: Other 1 — — — — — — Current Liabilities: Assets held for sale 174 — — — — 175 — Deferred Credits and Other Liabilities: Other 2 — — — — — — Deferred Credits and Other Liabilities: Assets held for sale 111 — — — — 111 — Total Derivative Assets – Commodity Contracts $ 339 $ — $ — $ — $ — $ 341 $ 14 Interest Rate Contracts Designated as Hedging Instruments Investments and Other Assets: Other 10 — — — — — — Not Designated as Hedging Instruments Current Assets: Other 2 — 2 — 2 — — Total Derivative Assets – Interest Rate Contracts $ 12 $ — $ 2 $ — $ 2 $ — $ — Total Derivative Assets $ 351 $ — $ 2 $ — $ 2 $ 341 $ 14 Derivative Liabilities December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Current Liabilities: Other $ — $ — $ 1 $ 1 $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Assets held for sale — — — — — 4 — Investments and Other Assets: Assets held for sale — — — — — 4 — Current Liabilities: Other 307 14 288 108 180 — — Current Liabilities: Assets held for sale 253 — — — — 252 — Deferred Credits and Other Liabilities: Other 91 5 80 23 57 — — Deferred Credits and Other Liabilities: Assets held for sale 208 — — — — 207 — Total Derivative Liabilities – Commodity Contracts $ 859 $ 19 $ 369 $ 132 $ 237 $ 467 $ — Interest Rate Contracts Designated as Hedging Instruments Current Liabilities: Other $ 13 $ — $ — $ — $ — $ — $ — Deferred Credits and Other Liabilities: Other 29 — — — — — — Not Designated as Hedging Instruments Current Liabilities: Other 1 — — — — 1 — Deferred Credits and Other Liabilities: Other 7 — 2 — 2 5 — Total Derivative Liabilities – Interest Rate Contracts $ 50 $ — $ 2 $ — $ 2 $ 6 $ — Total Derivative Liabilities $ 909 $ 19 $ 371 $ 132 $ 239 $ 473 $ — OFFSETTING ASSETS AND LIABILITIES The following tables show the balance sheet location of derivative contracts subject to enforceable master netting agreements and include collateral posted to offset the net position. This disclosure is intended to enable users to evaluate the effect of netting arrangements on financial position. The amounts shown were 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, 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 $ 26 $ — $ 7 $ 2 $ 5 $ 4 $ 12 Gross amounts offset (2 ) — (1 ) — (1 ) — — Net amounts subject to master netting 24 — 6 2 4 4 12 Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 24 $ — $ 6 $ 2 $ 4 $ 4 $ 12 Non-Current Gross amounts recognized $ 7 $ — $ 6 $ — $ 6 $ — $ — Gross amounts offset (2 ) — (2 ) — (2 ) — — Net amounts subject to master netting 5 — 4 — 4 — — Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 5 $ — $ 4 $ — $ 4 $ — $ — Derivative Liabilities September 30, 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 $ 257 $ 25 $ 215 $ 77 $ 138 $ 1 $ — Gross amounts offset (15 ) — (14 ) — (14 ) — — Net amounts subject to master netting 242 25 201 77 124 1 — Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 242 $ 25 $ 201 $ 77 $ 124 $ 1 $ — Non-Current Gross amounts recognized $ 144 $ 8 $ 89 $ 18 $ 71 $ 6 $ — Gross amounts offset (9 ) — (9 ) — (9 ) — — Net amounts subject to master netting 135 8 80 18 62 6 — Amounts not subject to master netting 5 — 5 — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 140 $ 8 $ 85 $ 18 $ 62 $ 6 $ — Derivative Assets December 31, 2014 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 $ 210 $ — $ 2 $ — $ 2 $ 204 $ 14 Gross amounts offset (153 ) — (2 ) — (2 ) (179 ) — Net amounts subject to master netting 57 — — — — 25 14 Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 57 $ — $ — $ — $ — $ 25 $ 14 Non-Current Gross amounts recognized $ 136 $ — $ — $ — $ — $ 137 $ — Gross amounts offset (88 ) — — — — (114 ) — Net amounts subject to master netting 48 — — — — 23 — Amounts not subject to master netting 5 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 53 $ — $ — $ — $ — $ 23 $ — Derivative Liabilities December 31, 2014 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 $ 573 $ 14 $ 289 $ 109 $ 180 $ 257 $ — Gross amounts offset (213 ) — (17 ) — (17 ) (222 ) — Net amounts subject to master netting 360 14 272 109 163 35 — Amounts not subject to master netting 1 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 361 $ 14 $ 272 $ 109 $ 163 $ 35 $ — Non-Current Gross amounts recognized $ 319 $ 5 $ 82 $ 23 $ 59 $ 216 $ — Gross amounts offset (173 ) — (8 ) — (8 ) (193 ) — Net amounts subject to master netting 146 5 74 23 51 23 — Amounts not subject to master netting 16 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 162 $ 5 $ 74 $ 23 $ 51 $ 23 $ — CREDIT RISK Certain derivative contracts contain contingent credit features. These features may include (i) material adverse change clauses or payment acceleration clauses that could result in immediate payments or (ii) the posting of letters of credit or termination of the derivative contract before maturity 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 Indiana were not material. September 30, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Aggregate fair value amounts of derivative instruments in a net liability position $ 316 $ 33 $ 301 $ 94 $ 207 $ — Fair value of collateral already posted 20 — 20 — 20 — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 296 33 281 94 187 — December 31, 2014 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Aggregate fair value amounts of derivative instruments in a net liability position $ 845 $ 19 $ 370 $ 131 $ 239 $ 456 Fair value of collateral already posted 209 — 23 — 23 186 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 407 19 347 131 216 41 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 agreement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral and payables related to the obligation to return cash collateral under master netting arrangements. September 30, 2015 December 31, 2014 (in millions) Receivables Receivables Duke Energy Amounts offset against net derivative positions $ 20 $ 145 Amounts not offset against net derivative positions — 64 Progress Energy Amounts offset against net derivative positions 20 23 Duke Energy Florida Amounts offset against net derivative positions 20 23 Duke Energy Ohio Amounts offset against net derivative positions — 122 Amounts not offset against net derivative positions — 64

Investments in Debt and Equity

Investments in Debt and Equity Securities	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investments In Debt And Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES The Duke Energy Registrants classify their investments in debt and equity securities as either trading or available-for-sale. TRADING SECURITIES Investments in debt and equity securities held in grantor trusts associated with certain deferred compensation plans and certain other investments are classified as trading securities. These investments were sold prior to September 30, 2015 . The fair value of these investments was $7 million at December 31, 2014 . AVAILABLE-FOR-SALE SECURITIES All other investments in debt and equity securities are classified as available-for-sale securities. Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the Nuclear Decommissioning Trust Fund (NDTF) at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to other post-retirement benefit obligations (OPEB) plans and deferred compensation plans, (iii) Duke Energy’s captive insurance investment portfolio and (iv) Duke Energy’s foreign operations investment portfolio. Duke Energy classifies all other investments in debt and equity securities as long term, unless otherwise noted. Investment Trusts The investments within the NDTF at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida 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. Pursuant to regulatory accounting, substantially all realized and unrealized gains and losses associated with investments within the Investment Trusts are deferred as a regulatory asset or liability. As a result, there is no immediate 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. If an other-than-temporary impairment exists, the unrealized loss is included in earnings based on the criteria discussed below. 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. Criteria used to evaluate whether an impairment associated with equity securities is other-than-temporary includes, but is not limited to, (i) the length of time over which the market value has been lower than the cost basis of the investment, (ii) the percentage decline compared to the cost of the investment and (iii) management’s intent and ability to retain its investment for a period of time sufficient to allow for any anticipated recovery in market value. If a decline in fair value is determined to be other-than-temporary, the investment is written down to its fair value through a charge to earnings. If the entity does not have an intent to sell a debt security and it is not more likely than not management will be required to sell the debt security before the recovery of its cost basis, the impairment write-down to fair value would be recorded as a component of other comprehensive income, except for when it is determined a credit loss exists. In determining whether a credit loss exists, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than the amortized cost basis, (ii) changes in the financial condition of the issuer of the security, or in the case of an asset-backed security, the financial condition of the underlying loan obligors, (iii) consideration of underlying collateral and guarantees of amounts by government entities, (iv) ability of the issuer of the security to make scheduled interest or principal payments and (v) any changes to the rating of the security by rating agencies. If a credit loss exists, the amount of impairment write-down to fair value is split between credit loss and other factors. The amount related to credit loss is recognized in earnings. The amount related to other factors is recognized in other comprehensive income. There were no credit losses as of September 30, 2015 and December 31, 2014 . DUKE ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 156 $ — $ — $ 136 Equity securities 1,655 71 3,396 1,926 29 3,650 Corporate debt securities 9 7 500 14 2 454 Municipal bonds 4 2 207 5 — 184 U.S. government bonds 23 1 1,131 19 2 978 Other debt securities 1 3 172 1 2 147 Total NDTF (c) $ 1,692 $ 84 $ 5,562 $ 1,965 $ 35 $ 5,549 Other Investments Cash and cash equivalents $ — $ — $ 32 $ — $ — $ 15 Equity securities 27 1 90 34 — 96 Corporate debt securities 1 2 98 1 1 58 Municipal bonds 3 1 73 3 1 76 U.S. government bonds 1 — 52 — — 27 Other debt securities — 1 69 1 1 80 Total Other Investments (a) $ 32 $ 5 $ 414 $ 39 $ 3 $ 352 Total Investments $ 1,724 $ 89 $ 5,976 $ 2,004 $ 38 $ 5,901 (a) These amounts are recorded in Other with 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. (c) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information. This increase in estimated fair value compared to December 31, 2014, is partially offset due to reimbursements from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 74 Due after one through five years 781 Due after five through 10 years 635 Due after 10 years 812 Total $ 2,302 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) 2015 2014 2015 2014 Realized gains $ 30 $ 28 $ 160 $ 90 Realized losses 28 51 59 57 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 25 $ — $ — $ 51 Equity securities 930 42 1,990 1,102 17 2,162 Corporate debt securities 5 6 342 8 2 316 Municipal bonds 1 1 69 1 — 62 U.S. government bonds 6 1 383 7 1 308 Other debt securities 1 3 141 1 2 133 Total NDTF $ 943 $ 53 $ 2,950 $ 1,119 $ 22 $ 3,032 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 943 $ 54 $ 2,953 $ 1,119 $ 23 $ 3,035 (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, 2015 Due in one year or less $ 13 Due after one through five years 209 Due after five through 10 years 293 Due after 10 years 423 Total $ 938 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) 2015 2014 2015 2014 Realized gains $ 25 $ 20 $ 132 $ 72 Realized losses 24 48 47 50 PROGRESS ENERGY The following table presents the estimated fair value investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 131 $ — $ — $ 85 Equity securities 725 29 1,406 824 12 1,488 Corporate debt securities 4 1 158 6 — 138 Municipal bonds 3 1 138 4 — 122 U.S. government bonds 17 — 748 12 1 670 Other debt securities — — 31 — — 14 Total NDTF (c) $ 749 $ 31 $ 2,612 $ 846 $ 13 $ 2,517 Other Investments Cash and cash equivalents $ — $ — $ 23 $ — $ — $ 15 Municipal bonds 3 — 43 3 — 43 Total Other Investments (a) $ 3 $ — $ 66 $ 3 $ — $ 58 Total Investments $ 752 $ 31 $ 2,678 $ 849 $ 13 $ 2,575 (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) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information. This increase in estimated fair value compared to December 31, 2014, is partially offset due to reimbursements from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 38 Due after one through five years 476 Due after five through 10 years 271 Due after 10 years 333 Total $ 1,118 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) 2015 2014 2015 2014 Realized gains $ 5 $ 8 $ 26 $ 17 Realized losses 4 3 10 6 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 87 $ — $ — $ 50 Equity securities 535 23 1,107 612 10 1,171 Corporate debt securities 3 1 109 5 — 97 Municipal bonds 3 1 136 4 — 120 U.S. government bonds 12 — 485 9 1 265 Other debt securities — — 19 — — 8 Total NDTF (c) $ 553 $ 25 $ 1,943 $ 630 $ 11 $ 1,711 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ — Total Other Investments (a) $ — $ — $ 1 $ — $ — $ — Total Investments $ 553 $ 25 $ 1,944 $ 630 $ 11 $ 1,711 (a) These amounts are recorded in Other with 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) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 12 Due after one through five years 278 Due after five through 10 years 219 Due after 10 years 240 Total $ 749 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) 2015 2014 2015 2014 Realized gains $ 4 $ 4 $ 21 $ 11 Realized losses 3 2 8 4 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 44 $ — $ — $ 35 Equity securities 190 6 299 212 2 317 Corporate debt securities 1 — 49 1 — 41 Municipal bonds — — 2 — — 2 U.S. government bonds 5 — 263 3 — 405 Other debt securities — — 12 — — 6 Total NDTF (c) $ 196 $ 6 $ 669 $ 216 $ 2 $ 806 Other Investments Cash and cash equivalents $ — $ — $ 11 $ — $ — $ 1 Municipal bonds 3 — 43 3 — 43 Total Other Investments (a) $ 3 $ — $ 54 $ 3 $ — $ 44 Total Investments $ 199 $ 6 $ 723 $ 219 $ 2 $ 850 (a) These amounts are recorded in Other with 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 estimated fair value at September 30, 2015, compared to the balance at December 31, 2014, is lower due to current year reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant. The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 26 Due after one through five years 198 Due after five through 10 years 52 Due after 10 years 93 Total $ 369 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) 2015 2014 2015 2014 Realized gains $ 1 $ 3 $ 5 $ 5 Realized losses 1 1 2 2 DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 Equity securities $ 23 $ — $ 67 $ 28 $ — $ 71 Corporate debt securities — — 3 — — — Municipal bonds — 1 27 — 1 30 Total Other Investments (a) $ 23 $ 1 $ 97 $ 28 $ 1 $ 101 Total Investments $ 23 $ 1 $ 97 $ 28 $ 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, 2015 Due in one year or less $ 2 Due after one through five years 16 Due after five through 10 years 8 Due after 10 years 4 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, 2015 and 2014 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
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 and (iii) 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. 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. Transfers between levels 1 and 2 during the three and nine months ended September 30, 2015 and 2014 were immaterial. Transfers out of Level 3 during the three and nine months ended September 30, 2015 are the result of forward commodity prices becoming observable due to the passage of time. Valuation methods of the primary fair value measurements disclosed 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 equity securities that are Level 2 or 3 are typically ownership interests in commingled investment funds. Investments in debt securities With the exception of U.S. Treasuries which are classified as Level 1, 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 fair valued using internally developed discounted cash flow models which incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or nonperformance 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 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. Goodwill, long-lived assets and assets held for sale See Note 8 for a discussion of the valuation of goodwill and long-lived assets. See Note 2 related to the assets and liabilities of the Disposal Group classified as held for sale, and the purchase of NCEMPA's ownership interests in certain generating assets. DUKE ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 3,396 $ 3,224 $ 1 $ 171 Nuclear decommissioning trust fund debt securities 2,166 557 1,609 — Other trading and available-for-sale equity securities 90 90 — — Other trading and available-for-sale debt securities 324 85 234 5 Derivative assets 33 — 16 17 Total assets 6,009 3,956 1,860 193 Derivative liabilities (406 ) (4 ) (402 ) — Net assets $ 5,603 $ 3,952 $ 1,458 $ 193 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 3,650 $ 3,493 $ 6 $ 151 Nuclear decommissioning trust fund debt securities 1,899 648 1,251 — Other trading and available-for-sale equity securities 96 96 — — Other trading and available-for-sale debt securities 263 41 217 5 Derivative assets 110 49 24 37 Total assets 6,018 4,327 1,498 193 Derivative liabilities (668 ) (162 ) (468 ) (38 ) Net assets $ 5,350 $ 4,165 $ 1,030 $ 155 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, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 173 $ 23 $ 196 Purchases, sales, issuances and settlements: Purchases 2 — 2 Sales (3 ) — (3 ) Settlements — (6 ) (6 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 176 $ 17 $ 193 Three Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 188 $ 22 $ 210 Total pretax realized or unrealized gains (losses) included in earnings — (33 ) (33 ) Purchases, sales, issuances and settlements: Purchases 13 (1 ) 12 Sales (13 ) — (13 ) Issuances — 1 1 Transfers out of Level 3 due to observability of inputs — (1 ) (1 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 (10 ) (6 ) Balance at end of period $ 192 $ (22 ) $ 170 Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding $ — $ (49 ) $ (49 ) Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 156 $ (1 ) $ 155 Total pretax realized or unrealized gains (losses) included in earnings (a) — 18 18 Purchases, sales, issuances and settlements: Purchases 14 24 38 Sales (7 ) — (7 ) Settlements — (28 ) (28 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 13 4 17 Balance at end of period $ 176 $ 17 $ 193 (a) Includes amounts related to nonregulated operations and classified as (Loss) Income From Discontinued Operations, net of tax in Duke Energy's Condensed Consolidated Statements of Operations. Nine Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 98 $ 13 $ 111 Total pretax realized or unrealized gains (losses) included in earnings — (21 ) (21 ) Purchases, sales, issuances and settlements: Purchases 29 50 79 Sales (15 ) — (15 ) Settlements — (45 ) (45 ) Transfers out of Level 3 due to observability of inputs 68 (4 ) 64 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 12 (15 ) (3 ) Balance at end of period $ 192 $ (22 ) $ 170 Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding $ — $ (49 ) $ (49 ) 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,990 $ 1,818 $ 1 $ 171 Nuclear decommissioning trust fund debt securities 960 203 757 — Other trading and available-for-sale debt securities 3 — — 3 Total assets 2,953 2,021 758 174 Derivative liabilities (33 ) — (33 ) — Net assets $ 2,920 $ 2,021 $ 725 $ 174 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 2,162 $ 2,005 $ 6 $ 151 Nuclear decommissioning trust fund debt securities 870 138 732 — Other trading and available-for-sale debt securities 3 — — 3 Total assets 3,035 2,143 738 154 Derivative liabilities (19 ) — (19 ) — Net assets $ 3,016 $ 2,143 $ 719 $ 154 The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Three Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 171 $ — $ 171 Purchases, sales, issuances and settlements: Purchases 2 — 2 Sales (3 ) — (3 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 174 $ — $ 174 Three Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 171 $ (3 ) $ 168 Purchases, sales, issuances and settlements: Purchases 13 — 13 Sales (13 ) — (13 ) Settlements — 3 3 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 175 $ — $ 175 Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 154 $ — $ 154 Purchases, sales, issuances and settlements: Purchases 14 — 14 Sales (7 ) — (7 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 13 — 13 Balance at end of period $ 174 $ — $ 174 Nine Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 81 $ (2 ) $ 79 Purchases, sales, issuances and settlements: Purchases 29 — 29 Sales (15 ) — (15 ) Settlements — 2 2 Transfers out of Level 3 to observability of inputs 68 — 68 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 12 — 12 Balance at end of period $ 175 $ — $ 175 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,406 $ 1,406 $ — $ — Nuclear decommissioning trust fund debt securities 1,206 354 852 — Other trading and available-for-sale debt securities 66 23 43 — Derivative assets 13 — 13 — Total assets 2,691 1,783 908 — Derivative liabilities (309 ) — (309 ) — Net assets $ 2,382 $ 1,783 $ 599 $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,488 $ 1,488 $ — $ — Nuclear decommissioning trust fund debt securities 1,029 510 519 — Other trading and available-for-sale debt securities 58 15 43 — Derivative assets 4 — 4 — Total assets 2,579 2,013 566 — Derivative liabilities (373 ) — (373 ) — Net assets $ 2,206 $ 2,013 $ 193 $ — 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,107 $ 1,107 $ — $ — Nuclear decommissioning trust fund debt securities 836 136 700 — Other trading and available-for-sale debt securities 1 1 — — Derivative assets 2 — 2 — Total assets 1,946 1,244 702 — Derivative liabilities (95 ) — (95 ) — Net assets $ 1,851 $ 1,244 $ 607 $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,171 $ 1,171 $ — $ — Nuclear decommissioning trust fund debt securities 540 151 389 — Total assets 1,711 1,322 389 — Derivative liabilities (132 ) — (132 ) — Net assets $ 1,579 $ 1,322 $ 257 $ — 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 299 $ 299 $ — $ — Nuclear decommissioning trust fund debt securities and other 370 219 151 — Other trading and available-for-sale debt securities and other 54 11 43 — Derivative assets 11 — 11 — Total assets 734 529 205 — Derivative liabilities (209 ) — (209 ) — Net assets (liabilities) $ 525 $ 529 $ (4 ) $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 317 $ 317 $ — $ — Nuclear decommissioning trust fund debt securities and other 489 359 130 — Other trading and available-for-sale debt securities and other 44 — 44 — Derivative assets 4 — 4 — Total assets 854 676 178 — Derivative liabilities (241 ) — (241 ) — Net assets (liabilities) $ 613 $ 676 $ (63 ) $ — 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 is disclosed in Note 10 . September 30, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 4 $ — $ — $ 4 Derivative liabilities (7 ) — (7 ) — Net liabilities $ (3 ) $ — $ (7 ) $ 4 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 49 $ 20 $ 9 $ 20 Derivative liabilities (181 ) (117 ) (26 ) (38 ) Net liabilities $ (132 ) $ (97 ) $ (17 ) $ (18 ) The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 5 $ (28 ) $ (18 ) $ (4 ) Total pretax realized or unrealized gains (losses) included in earnings (a) — (24 ) 21 (43 ) Purchases, sales, issuances and settlements: Purchases 5 — 5 1 Sales (5 ) — — — Settlements (1 ) (2 ) (4 ) (6 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (1 ) — 1 Transfers out of Level 3 due to observability of inputs — — — (4 ) Balance at end of period $ 4 $ (55 ) $ 4 $ (55 ) Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at September 30, 2014 $ — $ — $ — (52 ) (a) Includes amounts related to nonregulated operations and classified as (Loss) Income From Discontinued Operations, net of tax in Duke Energy Ohio's Condensed Consolidated Statements of Operations and Comprehensive Income. 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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Available-for-sale equity securities $ 67 $ 67 $ — $ — Available-for-sale debt securities 30 — 30 — Derivative assets 12 — — 12 Net assets $ 109 $ 67 $ 30 $ 12 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Available-for-sale equity securities $ 71 $ 71 $ — $ — Available-for-sale debt securities 30 — 30 — Derivative assets 14 — — 14 Net assets $ 115 $ 71 $ 30 $ 14 The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 17 $ 45 $ 14 $ 12 Total pretax realized or unrealized gains (losses) included in earnings — (13 ) — 14 Purchases, sales, issuances and settlements: Purchases 1 — 19 49 Settlements (6 ) — (25 ) (38 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (10 ) 4 (15 ) Balance at end of period $ 12 $ 22 $ 12 $ 22 QUANTITATIVE DISCLOSURES ABOUT UNOBSERVABLE INPUTS The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. September 30, 2015 Investment Type Fair Value (in millions) Valuation Technique Unobservable Input Range Duke Energy Swing options 1 Discounted cash flow Forward capacity option curves – price per MMBtu $ 18.50 – $ 84.35 Financial transmission rights (FTRs) 16 RTO auction pricing FTR price – per MWh (0.81 ) – 7.23 Total Level 3 derivatives $ 17 Duke Energy Ohio FTRs 4 RTO auction pricing FTR price – per MWh 0.37 – 2.17 Duke Energy Indiana FTRs $ 12 RTO auction pricing FTR price – per MWh (0.81 ) – 7.23 December 31, 2014 Investment Type Fair Value (in millions) Valuation Technique Unobservable Input Range Duke Energy Natural gas contracts $ (5 ) Discounted cash flow Forward natural gas curves – price per MMBtu $ 2.12 – $ 4.35 Financial transmission rights (FTRs) 14 RTO auction pricing FTR price – per MWh (1.92 ) – 9.86 Electricity contracts (1 ) Discounted cash flow Forward electricity curves – price per MWh 25.16 – 51.75 Commodity capacity option contracts 2 Discounted cash flow Forward capacity option curves – price per MW day 21.00 – 109.00 Commodity contract reserves (11 ) Bid-ask spreads, implied volatility, probability of default Total Level 3 derivatives $ (1 ) Duke Energy Ohio Electricity contracts $ (6 ) Discounted cash flow Forward electricity curves – price per MWh 25.25 – 51.75 Natural gas contracts (5 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.12 – 4.35 Commodity contract reserves (7 ) Bid-ask spreads, implied volatility, probability of default Total Level 3 derivatives $ (18 ) Duke Energy Indiana FTRs $ 14 RTO auction pricing FTR price – per MWh (1.92 ) – 9.86 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, 2015 December 31, 2014 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 40,203 $ 43,864 $ 40,020 $ 44,566 Duke Energy Carolinas 8,884 9,860 8,391 9,626 Progress Energy 15,396 17,146 14,754 16,951 Duke Energy Progress 6,851 7,214 6,201 6,696 Duke Energy Florida 4,850 5,585 4,860 5,767 Duke Energy Ohio 1,605 1,766 1,766 1,970 Duke Energy Indiana 3,790 4,330 3,791 4,456 At both September 30, 2015 and December 31, 2014 , the fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and nonrecourse notes payable of variable interest entities 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, 2015
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. No financial support was provided to any of the consolidated VIEs during the nine months ended September 30, 2015 and the year ended December 31, 2014 , or is expected to be provided in the future, that was not previously contractually required. CONSOLIDATED VIEs The following tables summarize the impact of VIEs consolidated by Duke Energy and the Subsidiary Registrants on the Condensed Consolidated Balance Sheets. September 30, 2015 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress Florida (in millions) DERF DEPR (c) DEFR (c) CRC Renewables Other Total ASSETS Current Assets Cash and Cash Equivalents $ — $ — $ — $ — $ 2 $ — $ 2 Restricted receivables of variable interest entities (net of allowance for doubtful accounts) 687 468 395 453 12 22 2,037 Other — 1 2 — 215 4 222 Investments and Other Assets Other — — — — 20 5 25 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 1,926 19 1,945 Accumulated depreciation and amortization — — — — (302 ) (5 ) (307 ) Regulatory Assets and Deferred Debits Other — — — — 37 1 38 Total assets $ 687 $ 469 $ 397 $ 453 $ 1,910 $ 46 $ 3,962 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 6 $ — $ 6 Taxes accrued 5 3 1 — 6 — 15 Current maturities of long-term debt — — — — 73 18 91 Other — — — — 23 4 27 Long-Term Debt (b) 400 300 225 325 916 3 2,169 Deferred Credits and Other Liabilities Deferred income taxes — — — — 325 — 325 Asset retirement obligations — — — — 30 — 30 Other — — — — 42 — 42 Total liabilities $ 405 $ 303 $ 226 $ 325 $ 1,421 $ 25 $ 2,705 Net assets of consolidated variable interest entities $ 282 $ 166 $ 171 $ 128 $ 489 $ 21 $ 1,257 (a) Restricted as collateral for nonrecourse debt of VIEs. (b) Nonrecourse to the general assets of the applicable registrant. (c) The amount for Progress Energy is equal to the sum of the amounts for Duke Energy Progress Receivables Company, LLC (DEPR) and Duke Energy Florida Receivables Company, LLC (DEFR). December 31, 2014 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress Florida (in millions) DERF DEPR (c) DEFR (c) CRC Renewables Other Total ASSETS Current Assets Restricted receivables of variable interest entities (net of allowance for doubtful accounts) $ 647 $ 436 $ 305 $ 547 $ 20 $ 18 $ 1,973 Other — — — — 68 6 74 Investments and Other Assets Other — — — — 25 25 50 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 1,855 18 1,873 Accumulated depreciation and amortization — — — — (250 ) (5 ) (255 ) Regulatory Assets and Deferred Debits Other — — — — 34 2 36 Total assets $ 647 $ 436 $ 305 $ 547 $ 1,752 $ 64 $ 3,751 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 3 $ — $ 3 Taxes accrued — — — — 6 — 6 Current maturities of long-term debt — — — — 68 16 84 Other — — — — 16 5 21 Long-Term Debt (b) 400 300 225 325 967 17 2,234 Deferred Credits and Other Liabilities Deferred income taxes — — — — 283 — 283 Asset retirement obligations — — — — 29 — 29 Other — — — — 34 4 38 Total liabilities $ 400 $ 300 $ 225 $ 325 $ 1,406 $ 42 $ 2,698 Net assets of consolidated variable interest entities $ 247 $ 136 $ 80 $ 222 $ 346 $ 22 $ 1,053 (a) Restricted as collateral for nonrecourse debt of VIEs. (b) Nonrecourse to the general assets of the applicable registrant. (c) The amount for Progress Energy is equal to the sum of the amounts for DEPR and DEFR. The obligations of these VIEs are nonrecourse to Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress and Duke Energy Florida. These entities have no requirement to provide liquidity to, purchase assets of or guarantee performance of these VIEs unless noted in the following paragraphs. DERF / DEPR / DEFR Duke Energy Receivables Finance Company, LLC (DERF), DEPR and DEFR are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. On a daily basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and/or related services from their parent companies. DERF, DEPR and DEFR are wholly owned limited liability companies with separate legal existence from their parents, and their assets are not generally available to creditors of their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy the receivables. Borrowing availability is limited to the amount of qualified receivables sold, which is generally expected to be in excess of the credit facilities. The credit facilities are reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. The secured credit facilities were not structured to meet the criteria for sale accounting treatment under the accounting guidance for transfers and servicing of financial assets. The following table summarizes the amounts and expiration dates of the credit facilities reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. DERF DEPR DEFR Credit facility amount (in millions) $ 400 $ 300 $ 225 Expiration date December 2016 December 2016 March 2017 The activities that most significantly impact 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 are the related parties most closely associated with the VIE. CRC On a revolving basis, CRC buys certain accounts receivable arising from the sale of electricity and/or related services from Duke Energy Ohio and Duke Energy Indiana. Receivables sold are securitized by CRC through a credit facility managed by two unrelated third parties. 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. Cash collections from the receivables are the sole source of funds to satisfy the related debt obligation. Depending on experience with collections, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million . Borrowing availability is limited to the amount of qualified receivables sold, which is generally expected to be in excess of the credit facility. The credit facility expires in November 2016 and is reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. 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, Cinergy, and (iii) deficiencies in net worth of CRC are not funded by Cinergy, but by Duke Energy. The most significant activities of CRC are decisions made related to the management of delinquent receivables. Duke Energy consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC. Renewables Certain of Duke Energy’s 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 of Duke Energy’s renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. 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 makes all of these decisions. NON-CONSOLIDATED VIEs The following tables include VIEs not consolidated and how these entities impact the Condensed Consolidated Balance Sheets. September 30, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables $ — $ — $ — $ 43 $ 64 Investments in equity method unconsolidated affiliates 223 125 348 — — Total assets $ 223 $ 125 $ 348 $ 43 $ 64 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 16 $ 16 $ — $ — Net assets $ 223 $ 109 $ 332 $ 43 $ 64 December 31, 2014 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables $ — $ — $ — $ 91 $ 113 Investments in equity method unconsolidated affiliates 150 38 188 — — Investments and other assets — 4 4 — — Total assets $ 150 $ 42 $ 192 $ 91 $ 113 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 150 $ 25 $ 175 $ 91 $ 113 The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the power purchase agreement with OVEC, which is discussed below, and various guarantees, reflected in the table above as Deferred credits and other liabilities. For more information on various guarantees, refer to Note 5 , "Commitments and Contingencies." 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. 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. 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. 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 rule-making could increase the costs of OVEC, which would be passed through to Duke Energy Ohio. In 2014, Duke Energy Ohio recorded a $94 million impairment related to OVEC. CRC See discussion under Consolidated VIEs for additional information related to CRC. Amounts included in Receivables 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 2015 2014 2015 2014 Anticipated credit loss ratio 0.6 % 0.6 % 0.3 % 0.3 % Discount rate 1.2 % 1.2 % 1.2 % 1.2 % Receivable turnover rate 12.9 % 12.8 % 10.6 % 10.5 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Receivables sold $ 221 $ 273 $ 271 $ 310 Less: Retained interests 43 91 64 113 Net receivables sold $ 178 $ 182 $ 207 $ 197 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) 2015 2014 2015 2014 2015 2014 2015 2014 Sales Receivables sold $ 449 $ 477 $ 1,518 $ 1,705 $ 679 $ 739 $ 2,032 $ 2,173 Loss recognized on sale 2 3 7 9 3 3 8 8 Cash flows Cash proceeds from receivables sold 461 494 1,568 1,761 692 759 2,074 2,233 Collection fees received — — 1 1 — — 1 1 Return received on retained interests — — 2 3 1 2 4 5 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 London Interbank Offered Rate (LIBOR) plus a fixed rate of 1.00 percent .

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Common Stock	COMMON STOCK Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common shareholders, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted-average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common shareholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted-average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options, were exercised or settled. Duke Energy’s participating securities are restricted stock units that are entitled to dividends declared on Duke Energy common shares 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) 2015 2014 2015 2014 Income from continuing operations attributable to Duke Energy common shareholders $ 935 $ 887 $ 2,307 $ 2,351 Weighted-average shares outstanding – basic 688 707 696 707 Weighted-average shares outstanding – diluted 688 707 696 707 Earnings per share from continuing operations attributable to Duke Energy common shareholders Basic $ 1.36 $ 1.25 $ 3.31 $ 3.33 Diluted $ 1.36 $ 1.25 $ 3.31 $ 3.33 Potentially dilutive shares excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.825 $ 0.795 $ 2.42 $ 2.355 (a) Performance stock awards and certain stock options were not included in the dilutive securities calculation because either the performance measures related to the awards had not been met or the option exercise prices were greater than the average market price of the common shares during the presented periods. 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 $225 million unsettled portion met the criteria to be accounted for as a forward contract indexed to Duke Energy's stock and qualified as an equity instrument. 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, 2015
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. The Duke Energy Corporation 2015 Long-Term Incentive Plan (the 2015 Plan) provides for the grant of stock-based compensation awards to employees and outside directors. The 2015 Plan reserves 10 million shares of common stock for issuance under the Plan. The 2015 Plan supersedes the 2010 Long-Term Incentive Plan, as amended (the 2010 Plan), and the Progress Energy, Inc. 2007 Equity Incentive Plan (the Progress Plan). No additional grants will be made from the 2010 Plan and the Progress Plan. 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) 2015 2014 2015 2014 Restricted stock unit awards $ 9 $ 8 $ 29 $ 30 Performance awards 5 4 18 14 Pretax stock-based compensation cost $ 14 $ 12 $ 47 $ 44 Tax benefit associated with stock-based compensation expense $ 6 $ 5 $ 18 $ 17 Stock-based compensation costs capitalized 1 1 3 3

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2015
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 and/or 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 accumulates a retirement benefit equal to the sum of percentages of their (i) highest three-year or four-year average earnings, (ii) highest three-year or four-year average earnings in excess of covered compensation per year of participation (maximum of 35 years ) and/or (iii) highest three-year or four-year average earnings times years of participation in excess of 35 years . 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 uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. 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 the Duke Energy Registrants’ contributions to its U.S. qualified defined benefit pension plans. 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 Duke Energy and Duke Energy Ohio made contributions of $11 million and $3 million , respectively, to their U.S. qualified defined benefit pension plans during the three months ended September 30, 2015 . Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the nine months ended September 30, 2014 . 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 . QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for qualified pension plans. 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 Three Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 34 $ 10 $ 10 $ 6 $ 5 $ 1 $ 3 Interest cost on projected benefit obligation 86 22 28 13 14 5 7 Expected return on plan assets (128 ) (33 ) (44 ) (21 ) (21 ) (7 ) (10 ) Amortization of actuarial loss 37 8 17 8 8 1 3 Amortization of prior service credit (4 ) (2 ) — — — — — Other 3 1 1 — — — — Net periodic pension costs $ 28 $ 6 $ 12 $ 6 $ 6 $ — $ 3 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 102 $ 31 $ 30 $ 16 $ 15 $ 3 $ 7 Interest cost on projected benefit obligation 258 64 84 40 43 15 22 Expected return on plan assets (383 ) (99 ) (130 ) (64 ) (64 ) (20 ) (30 ) Amortization of actuarial loss 111 26 51 24 24 3 9 Amortization of prior service credit (11 ) (6 ) (2 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 83 $ 18 $ 35 $ 16 $ 18 $ 1 $ 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, 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 Three Months Ended September 30, 2014 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ 1 $ — Interest cost on projected benefit obligation 3 1 2 — — Amortization of actuarial loss 1 — — — — Amortization of prior service credit — — (1 ) — — Net periodic pension costs $ 5 $ 1 $ 1 $ 1 $ — 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ 1 $ 1 $ — Interest cost on projected benefit obligation 10 1 4 1 1 Amortization of actuarial loss 2 — 1 — — Amortization of prior service cost — — (1 ) — — Net periodic pension costs $ 14 $ 1 $ 5 $ 2 $ 1 OTHER POST-RETIREMENT BENEFIT PLANS Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. The health care benefits include medical, dental and prescription drug coverage and are subject to certain limitations, such as deductibles and co-payments. Duke Energy did not make any pre-funding contributions to its other post-retirement benefit plans during the nine months ended September 30, 2015 and 2014 . The following tables include the components of net periodic other post-retirement benefit costs. 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 Three Months Ended September 30, 2014 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 13 3 6 3 3 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss 9 1 10 8 3 — — Amortization of prior service credit (31 ) (3 ) (24 ) (19 ) (5 ) — — Net periodic other post-retirement benefit costs $ (10 ) $ (1 ) $ (7 ) $ (8 ) $ 1 $ — $ 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 7 $ 1 $ 3 $ 1 $ 2 $ — $ — Interest cost on accumulated post-retirement benefit obligation 38 9 17 8 9 1 4 Expected return on plan assets (9 ) (6 ) — — — — (1 ) Amortization of actuarial loss (gain) 29 2 31 23 8 (1 ) — Amortization of prior service credit (94 ) (8 ) (71 ) (55 ) (16 ) — — Net periodic other post-retirement benefit costs $ (29 ) $ (2 ) $ (20 ) $ (23 ) $ 3 $ — $ 3 EMPLOYEE SAVINGS PLANS Duke Energy sponsors, and the Subsidiary Registrants participate in, employee savings plans that cover substantially all U.S. employees. Effective January 1, 2015, all then-existing employee savings plans were merged into a single plan. 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. Prior to 2015, Duke Energy also provided a match on after-tax contributions for certain plans. Dividends on Duke Energy shares held by the savings plans are charged to retained earnings when declared and shares held in the plans 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 three-year vesting, is provided to the employee’s savings plan account. The following table includes employer matching contributions, as well as the additional contribution of 4 percent of eligible pay per pay period for employees not eligible to participate in a defined benefit plan, 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, 2015 $ 34 $ 11 $ 10 $ 7 $ 3 $ — $ 1 2014 30 10 10 7 3 — 1 Nine Months Ended September 30, 2015 $ 120 $ 40 $ 36 $ 26 $ 10 $ 2 $ 5 2014 110 36 33 23 10 2 5

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES 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, 2015 2014 2015 2014 Duke Energy 30.9 % 34.0 % 32.5 % 31.4 % Duke Energy Carolinas 36.5 % 33.9 % 36.3 % 33.7 % Progress Energy 25.0 % 37.1 % 31.8 % 37.3 % Duke Energy Progress 34.4 % 36.3 % 35.3 % 36.6 % Duke Energy Florida 30.1 % 38.5 % 35.2 % 38.6 % Duke Energy Ohio 39.3 % 38.3 % 37.6 % 34.9 % Duke Energy Indiana 37.0 % 31.6 % 36.6 % 35.2 % The decrease in the effective tax rate for Duke Energy for the three months ended September 30, 2015, is primarily due to the tax benefit related to the manufacturing deduction in 2015, which was limited in the prior year due to taxable income, and a tax benefit from the legal entity restructuring of Duke Energy Florida and Duke Energy Progress. The increase in the effective tax rate for the nine months ended September 30, 2015, is primarily due to a deferred tax benefit related to the merger of two Chilean subsidiaries recorded in the second quarter of 2014 and a deferred tax charge for changes in apportionment related to state income taxes recorded in the second quarter of 2015 offset by the tax benefit related to the manufacturing deduction in 2015, which was limited in the prior year due to taxable income, and a tax benefit from the legal entity restructuring of Duke Energy Florida and Duke Energy Progress. The increase in the effective tax rate for Duke Energy Carolinas for the three months ended September 30, 2015, is primarily due to a decrease in the tax benefit of the manufacturing deduction in 2015 as compared to 2014, partially offset by a reduction of the North Carolina statutory corporate state income tax rate. The increase in the effective tax rate for the nine months ended September 30, 2015, is primarily due to favorable prior year audit settlements and changes in apportionment related to state income tax. The decrease in the effective tax rate for Progress Energy for the three and nine months ended September 30, 2015, is primarily due to a reduction of the North Carolina statutory corporate state income tax rate and release of tax reserves due to expired tax statutes. The decrease in the effective tax rate for Duke Energy Progress for the three and nine months ended September 30, 2015, is primarily due to a reduction of the North Carolina statutory corporate state income tax rate. The decrease in the effective tax rate for Duke Energy Florida for the three and nine months ended September 30, 2015, is primarily due to a release of tax reserves due to expired tax statutes. The increase in the effective tax rate for Duke Energy Ohio for the three months ended September 30, 2015, is primarily due to certain nondeductible book depreciation offset by the tax benefit related to the manufacturing deduction in 2014. The increase in the effective tax rate for the nine months ended September 30, 2015, is primarily due to the tax benefit related to the manufacturing deduction in 2014. The increase in the effective tax rate for Duke Energy Indiana for the three and nine months ended September 30, 2015, is primarily due to a prior period audit settlement in 2014, partially offset by a reduction in the Indiana statutory corporate state income tax rate.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to acquisitions and dispositions, regulatory matters, commitments and contingencies, and derivatives and hedging see Notes 2, 4, 5 and 10, respectively.

Organization and Basis of Pre26

Organization and Basis of Presentation (Policy)	9 Months Ended
	Sep. 30, 2015
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. 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, formerly Duke Energy Progress, Inc.); Duke Energy Florida, LLC (Duke Energy Florida, formerly Duke Energy Florida, Inc.); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, Inc. (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 the 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. On August 1, 2015, Duke Energy Progress, a North Carolina corporation, converted into a North Carolina limited liability company. 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. On August 1, 2015, Duke Energy Florida, a Florida corporation, converted into a Florida limited liability company. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, in 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 full requirements service price is recovered from retail customers. 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 (Midwest Generation Exit) 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.
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 LLC (Duke Energy Retail), 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 for all periods presented. 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, assets held for sale and liabilities associated with assets held for sale. See Note 2 (Midwest Generation Exit) 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, 2014 . 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 and meter reading schedules.
Duke Energy Ohio [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. 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.
Duke Energy Indiana [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. 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.

Organization and Basis of Pre27

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2015
Organization And Basis Of Presentation [Line Items]
Amounts Attributable to Controlling Interests [Table Text Block]	The following table presents Net Income Attributable to Duke Energy Corporation for continuing operations and discontinued operations for the three and nine months ended September 30, 2014. Three Months Ended Nine Months Ended September 30, 2014 September 30, 2014 Duke Progress Duke Progress (in millions) Energy Energy Energy Energy Income From Continuing Operations $ 891 $ 330 $ 2,367 $ 741 Income From Continuing Operations Attributable to Noncontrolling Interests 3 1 11 2 Income From Continuing Operations Attributable to Duke Energy Corporation $ 888 $ 329 $ 2,356 $ 739 Income (Loss) From Discontinued Operations, net of tax $ 378 $ — $ (578 ) $ (6 ) Loss From Discontinued Operations Attributable to Noncontrolling Interests, net of tax (8 ) — (8 ) — Income (Loss) From Discontinued Operations Attributable to Duke Energy Corporation, net of tax $ 386 $ — $ (570 ) $ (6 ) Net income $ 1,269 $ 330 $ 1,789 $ 735 Net (Loss) Income Attributable to Noncontrolling Interests (5 ) 1 3 2 Net Income Attributable to Duke Energy Corporation $ 1,274 $ 329 $ 1,786 $ 733
Schedule of Excise Taxes	Excise taxes recognized on a gross basis are recorded as Operating Revenues and Property and other taxes on the Condensed Consolidated Statements of Operations. The following table provides the amount of excise taxes accounted for on a gross basis. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2015 2014 2015 2014 Duke Energy $ 109 $ 101 $ 308 $ 416 Duke Energy Carolinas 9 4 27 93 Progress Energy 67 63 174 214 Duke Energy Progress 4 — 12 56 Duke Energy Florida 63 63 162 158 Duke Energy Ohio 24 24 80 80 Duke Energy Indiana 9 10 27 29
Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets as shown in the following table. (in millions) September 30, 2015 December 31, 2014 Duke Energy $ 748 $ 827 Duke Energy Carolinas 247 295 Progress Energy 220 217 Duke Energy Progress 123 135 Duke Energy Florida 97 82 Duke Energy Ohio 6 — Duke Energy Indiana 25 27
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, 2015 December 31, 2014 Duke Energy Ohio $ 64 $ 79 Duke Energy Indiana 93 112
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, 2015 December 31, 2014 Duke Energy Ohio $ 64 $ 79 Duke Energy Indiana 93 112

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Schedule of purchase price allocation	The purchase price allocation is presented in the following table. (in millions) Inventory $ 56 Net property, plant and equipment 845 Total assets 901 Purchase acquisition adjustment 350 Total purchase price $ 1,251
Generation Facilities of Disposal Group	The following table presents information related to the Duke Energy Ohio generation plants included in the Disposal Group. Total MW Owned MW Ownership Facility Plant Type Primary Fuel Location Capacity (d) Capacity (d) Interest Stuart (a)(c) Fossil Steam Coal OH 2,308 900 39 % Zimmer (a) Fossil Steam Coal OH 1,300 605 46.5 % Hanging Rock Combined Cycle Natural Gas OH 1,226 1,226 100 % Miami Fort (Units 7 and 8) (b) Fossil Steam Coal OH 1,020 652 64 % Conesville (a)(c) Fossil Steam Coal OH 780 312 40 % Washington Combined Cycle Natural Gas OH 617 617 100 % Fayette Combined Cycle Natural Gas PA 614 614 100 % Killen (b)(c) Fossil Steam Coal OH 600 198 33 % Lee Combustion Turbine Natural Gas IL 568 568 100 % Dick's Creek Combustion Turbine Natural Gas OH 136 136 100 % Miami Fort Combustion Turbine Oil OH 56 56 100 % Total Midwest Generation 9,225 5,884 (a) Jointly owned with America Electric Power Generation Resources and The Dayton Power & Light Company. (b) Jointly owned with The Dayton Power & Light Company. (c) Facility was not operated by Duke Energy Ohio. (d) Total megawatt (MW) capacity is based on summer capacity.
Income Statement Disclosures	The following table presents the results of discontinued operations. Duke Energy Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Operating Revenues $ — $ 620 $ 543 $ 1,233 (Loss) Gain on disposition (a) (5 ) 460 (42 ) (847 ) (Loss) Income before income taxes (b) $ (5 ) $ 623 $ 62 $ (864 ) Income tax (benefit) expense (1 ) 218 29 (321 ) (Loss) Income from discontinued operations of the Disposal Group (4 ) 405 33 (543 ) Other, net of tax (c) (1 ) (27 ) (4 ) (35 ) (Loss) Income from Discontinued Operations, net of tax $ (5 ) $ 378 $ 29 $ (578 ) (a) The (Loss) Gain on disposition includes impairments and reversals to the impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Disposal Group for the nine months ended September 30, 2015. Refer to Note 5 for further information related to the lawsuit. (c) Includes other discontinued operations related to prior sales of businesses and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments. Duke Energy Ohio Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Operating Revenues $ — $ 536 $ 412 $ 853 (Loss) Gain on disposition (a) (4 ) 466 (48 ) (878 ) (Loss) Income before income taxes (b) $ (4 ) $ 647 $ 48 $ (917 ) Income tax (benefit) expense (2 ) 234 25 (320 ) (Loss) Income from Discontinued Operations, net of tax $ (2 ) $ 413 $ 23 $ (597 ) (a) The (Loss) Gain on disposition includes impairments and reversals to the impairments recorded to adjust the carrying amount of the assets to the estimated fair value of the business, based on the selling price to Dynegy less cost to sell. (b) The (Loss) Income before income taxes includes the pretax impact of an $81 million charge for the settlement agreement reached in a lawsuit related to the Disposal Group for the nine months ended September 30, 2015, respectively. Refer to Note 5 for further information related to the lawsuit.

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting Information [Line Items]
Business Segment Data	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 $ (3 ) $ 971 $ (34 ) $ — $ 937 Add back noncontrolling interests 3 Loss from discontinued operations, net of tax (5 ) Net income $ 935 Segment assets $ 110,520 $ 3,730 $ 3,841 $ 118,091 $ 2,757 $ 185 $ 121,033 (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 $ 15 million of after-tax costs to achieve the 2012 Progress Energy merger. Three Months Ended September 30, 2014 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,975 $ 366 $ 50 $ 6,391 $ 4 $ — $ 6,395 Intersegment revenues 11 — — 11 21 (32 ) — Total revenues $ 5,986 $ 366 $ 50 $ 6,402 $ 25 $ (32 ) $ 6,395 Segment income (loss) (a) $ 920 $ 80 $ (17 ) $ 983 $ (92 ) $ (3 ) $ 888 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 378 Net income $ 1,269 (a) Other includes $35 million of after-tax costs to achieve the 2012 Progress Energy merger. 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 $ (35 ) $ 2,433 $ (119 ) $ (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 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 Disposal Group. Refer to Note 5 for further information related to the lawsuit. Nine Months Ended September 30, 2014 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 17,041 $ 1,111 $ 195 $ 18,347 $ 19 $ — $ 18,366 Intersegment revenues 33 — — 33 60 (93 ) — Total revenues $ 17,074 $ 1,111 $ 195 $ 18,380 $ 79 $ (93 ) $ 18,366 Segment income (loss) (a)(b) $ 2,346 $ 356 $ (70 ) $ 2,632 $ (269 ) $ (7 ) $ 2,356 Add back noncontrolling interest 11 Loss from discontinued operations, net of tax (578 ) Net income $ 1,789 (a) Commercial Portfolio includes a pretax impairment charge of $94 million related to OVEC. Refer to Note 13 for further information. (b) Other includes $107 million of after-tax costs to achieve the 2012 Progress Energy merger. The following table summarizes the net loss for Other at each of these registrants. Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Duke Energy Carolinas $ (10 ) $ (19 ) $ (28 ) $ (67 ) Progress Energy (a) (3 ) (48 ) (87 ) (145 ) Duke Energy Progress (4 ) (10 ) (12 ) (23 ) Duke Energy Florida (3 ) (5 ) (9 ) (16 ) Duke Energy Indiana (2 ) (3 ) (6 ) (10 ) (a) Other for Progress Energy also includes interest expense on corporate debt instruments of $61 million and $180 million for the three and nine months ended September 30, 2015 , respectively, and $58 million and $181 million for the three and nine months ended September 30, 2014 , respectively.
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended September 30, 2015 Regulated (in millions) Utilities Other Eliminations Consolidated Total revenues $ 456 $ 6 $ — $ 462 Segment income (loss) $ 46 $ (12 ) $ — $ 34 Loss from discontinued operations, net of tax (2 ) Net income $ 32 Segment assets $ 6,961 $ 126 $ (4 ) $ 7,083 Three Months Ended September 30, 2014 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 440 $ 6 $ 446 $ — $ — $ 446 Intersegment revenues 1 — 1 — (1 ) — Total revenues $ 441 $ 6 $ 447 $ — $ (1 ) $ 446 Segment income (loss) $ 43 $ (13 ) $ 30 $ (4 ) $ — $ 26 Income from discontinued operations, net of tax 413 Net income $ 439 Nine Months Ended September 30, 2015 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Total revenues $ 1,424 $ 14 $ 1,438 $ 15 $ — $ 1,453 Segment income (loss) $ 135 $ (9 ) $ 126 $ (20 ) $ — $ 106 Income from discontinued operations, net of tax (a) 23 Net income $ 129 (a) Includes an after-tax charge of $53 million for the settlement agreement reached in a lawsuit related to the Disposal Group. Refer to Note 5 for further information. Nine Months Ended September 30, 2014 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 1,416 $ 17 $ 1,433 $ — $ — $ 1,433 Intersegment revenues 1 — 1 — (1 ) — Total revenues $ 1,417 $ 17 $ 1,434 $ — $ (1 ) $ 1,433 Segment income (loss) (a) $ 151 $ (101 ) $ 50 $ (11 ) $ — $ 39 Loss from discontinued operations, net of tax (597 ) Net loss $ (558 ) (a) Commercial Portfolio includes a pretax impairment charge of $94 million related to OVEC. See Note 13 for additional information.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2015
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. September 30, 2015 Duke Duke Duke Progress Energy Energy Energy Energy (b) Florida (b) Indiana (c) Capacity (in MW) 1,541 873 873 668 Remaining net book value (in millions) (a) $ 207 $ 121 $ 121 $ 86 (a) Remaining net book value amounts presented exclude any capitalized asset retirement costs related to closure of ash basins. (b) Includes Crystal River Units 1 and 2. (c) Includes Wabash River Units 2 through 6. Wabash River Unit 6 is being evaluated for potential conversion to natural gas. Duke Energy Indiana committed to retire or convert the Wabash River Units 2 through 6 by June 2018 in conjunction with a settlement agreement associated with the Edwardsport air permit.

Commitments and Contingencies (

Commitments and Contingencies (Table)	9 Months Ended
	Sep. 30, 2015
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 presented in the table below. (in millions) Duke Energy $ 79 Duke Energy Carolinas 25 Progress Energy 4 Duke Energy Progress 1 Duke Energy Florida 3 Duke Energy Ohio 43 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. 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, 2015 December 31, 2014 Reserves for Legal Matters Duke Energy $ 178 $ 323 Duke Energy Carolinas 12 72 Progress Energy 74 93 Duke Energy Progress 17 37 Duke Energy Florida 36 36 Duke Energy Ohio 81 —
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, 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 Nine Months Ended September 30, 2014 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 $ 79 $ 11 $ 27 $ 8 $ 19 $ 27 $ 7 Provisions/adjustments 34 (1 ) 4 3 1 28 3 Cash reductions (8 ) — (6 ) (4 ) (2 ) (1 ) (1 ) Balance at end of period $ 105 $ 10 $ 25 $ 7 $ 18 $ 54 $ 9

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
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, 2015 Unsecured Debt Progress Energy (Parent) January 2016 5.625 % $ 300 Duke Energy Indiana June 2016 6.05 % 325 First Mortgage Bonds Duke Energy Carolinas October 2015 5.300 % 500 Duke Energy Florida November 2015 0.650 % 250 Duke Energy Florida December 2015 5.100 % 300 Duke Energy Progress December 2015 5.250 % 400 Duke Energy Indiana July 2016 0.636 % 150 Other 311 Current maturities of long-term debt $ 2,536
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, variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder and as security to meet obligations under the Plea Agreements. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. September 30, 2015 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 $ 3,300 $ 800 $ 1,300 $ 1,200 $ 400 $ 500 Reduction to backstop issuances Commercial paper (b) (1,793 ) (1,318 ) (300 ) — — (25 ) (150 ) Outstanding letters of credit (72 ) (64 ) (4 ) (3 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (c) (500 ) — (250 ) (250 ) — — — Available capacity $ 5,019 $ 1,918 $ 211 $ 1,047 $ 1,199 $ 375 $ 269 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $475 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, 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. (c) On May 14, 2015, the United States District Court for the Eastern District of North Carolina approved the separate Plea Agreements entered into by Duke Energy Carolinas, Duke Energy Progress and DEBS, a wholly owned subsidiary of Duke Energy, in connection with the investigation initiated by the USDOJ. Duke Energy Carolinas and Duke Energy Progress are required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet their obligations under the Plea Agreements, in addition to certain other conditions. See Note 5 for further details.
Schedule of Long-term Debt Instruments [Table Text Block]	The following table summarizes significant debt issuances (in millions). Nine Months Ended September 30, 2015 Duke Duke Maturity Interest Duke Energy Energy Issuance Date Date Rate Energy Carolinas Progress First Mortgage Bonds March 2015 (a) June 2045 3.750 % $ 500 $ 500 $ — August 2015 (b) August 2025 3.250 % 500 — 500 August 2015 (b) August 2045 4.200 % 700 — 700 Total issuances $ 1,700 $ 500 $ 1,200 (a) Proceeds were used to redeem at maturity $500 million of first mortgage bonds due October 2015. (b) Proceeds were used to repay short-term money pool and commercial paper borrowings issued to fund a portion of the NCEMPA acquisition, see Note 2 for further information. Additionally, proceeds will be used to refinance at maturity $400 million of first mortgage bonds due December 2015.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation [Abstract]
Schedule of Change in Asset Retirement Obligation	The following table presents changes in the 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, 2014 (a) $ 8,466 $ 3,428 $ 4,711 $ 3,905 $ 806 $ 27 $ 32 Acquisitions (b) 213 — 204 204 — — — Accretion expense (c) 278 123 150 123 26 2 11 Liabilities settled (d) (274 ) (107 ) (153 ) (53 ) (100 ) (2 ) (12 ) Liabilities incurred in the current year (e) 983 178 270 270 — 116 418 Revisions in estimates of cash flows 47 (23 ) 40 40 — — — Balance at September 30, 2015 $ 9,713 $ 3,599 $ 5,222 $ 4,489 $ 732 $ 143 $ 449 (a) Primarily relates to decommissioning nuclear power facilities, closure of ash basins in North Carolina and South Carolina, asbestos removal, closure of landfills at fossil generation facilities, retirement of natural gas mains and removal of renewable energy generation assets. (b) Primarily relates to the NCEMPA acquisition. See footnote 2 for additional information. (c) For the nine months ended September 30, 2015 , substantially all accretion expense relates to previously established asset retirement obligations from Duke Energy's regulated electric operations and has been deferred in accordance with regulatory accounting treatment. (d) Primarily relates to ash basin closures in North Carolina and South Carolina and nuclear decommissioning of Crystal River Unit 3 in Florida. (e) Primarily relates to amounts recorded in the second quarter of 2015 as a result of the EPA's rule for disposal of CCR as solid waste. The following table summarizes the associated long-lived assets related to ARO liabilities incurred during the nine months ended September 30, 2015 . September 30, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Ohio Indiana Net property, plant and equipment $ 535 $ — $ — $ — $ 116 $ 418 Regulatory Assets 448 178 270 270 — —

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2014 (a) 15,950 307 64 16,321 Foreign exchange and other changes — (33 ) — (33 ) Acquisitions — — 24 24 Goodwill at September 30, 2015 $ 15,950 $ 274 $ 88 $ 16,312 (a) Excludes fully impaired Goodwill related to the nonregulated Midwest generation business which was sold in the second quarter of 2015. See Note 2 for further information related to the sale.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2015
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.
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) 2015 2014 2015 2014 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 211 $ 199 $ 632 $ 638 Indemnification coverages (b) 6 5 18 16 Joint Dispatch Agreement (JDA) revenue (c) 7 13 47 125 Joint Dispatch Agreement (JDA) expense (c) 48 36 143 127 Progress Energy Corporate governance and shared service expenses (a) $ 184 $ 182 $ 523 $ 560 Indemnification coverages (b) 10 8 29 25 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Progress Corporate governance and shared service expenses (a) $ 101 $ 91 $ 296 $ 291 Indemnification coverages (b) 4 4 12 13 JDA revenue (c) 48 36 143 127 JDA expense (c) 7 13 47 125 Duke Energy Florida Corporate governance and shared service expenses (a) $ 83 $ 91 $ 227 $ 269 Indemnification coverages (b) 6 4 17 12 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 88 $ 83 $ 276 $ 242 Indemnification coverages (b) 1 3 5 10 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 87 $ 94 $ 259 $ 293 Indemnification coverages (b) 2 3 6 8 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, 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.

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	The following table shows notional amounts for derivatives related to interest rate risk. September 30, 2015 December 31, 2014 Duke Duke Duke Duke Duke Duke Progress Energy Energy Energy Duke Progress Energy Energy (in millions) Energy Energy Progress Florida Ohio Energy Energy Florida Ohio Cash flow hedges (a) $ 714 $ — $ — $ — $ — $ 750 $ — $ — $ — Undesignated contracts (b) 527 500 250 250 27 277 250 250 27 Total notional amount $ 1,241 $ 500 $ 250 $ 250 $ 27 $ 1,027 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $509 million and $541 million at September 30, 2015 and December 31, 2014 , respectively. (b) In January 2015, Duke Energy Progress executed fixed-to-floating rate swaps. The swaps were issued to economically convert $250 million of fixed rate first mortgage bonds due September 15, 2021, to floating rate with an initial rate of approximately 1.75 percent . The tables below show information relating to 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, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 76 — — — — 3 39 Natural gas (millions of decatherms) 389 61 328 110 218 — — December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) (a)(b) 25,370 — — — — 19,141 — Natural gas (millions of decatherms) (a) 676 35 328 116 212 313 — (a) Amounts at Duke Energy Ohio include volumes related to the nonregulated Midwest generation business sold during the second quarter of 2015. Refer to Note 2 for further information on the sale. (b) Amounts at Duke Energy Ohio include intercompany positions that eliminate at Duke Energy.
Location And Fair Value Of Derivatives Recognized in the Condensed Consolidated Balance Sheets	The following tables show the fair value of derivatives and the line items in the Condensed Consolidated Balance Sheets where they are reported. 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, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Current Assets: Other $ 1 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Other 17 — — — — 4 12 Current Liabilities: Other 2 — 1 — 1 — — Deferred Credits and Other Liabilities: Other 2 — 2 — 2 — — Total Derivative Assets – Commodity Contracts $ 22 $ — $ 3 $ — $ 3 $ 4 $ 12 Interest Rate Contracts Designated as Hedging Instruments Investments and Other Assets: Other $ 1 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Other 6 — 6 2 4 — — Investments and Other Assets: Other 4 — 4 — 4 — — Total Derivative Assets – Interest Rate Contracts $ 11 $ — $ 10 $ 2 $ 8 $ — $ — Total Derivative Assets $ 33 $ — $ 13 $ 2 $ 11 $ 4 $ 12 Derivative Liabilities September 30, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Not Designated as Hedging Instruments Current Liabilities: Other $ 242 $ 25 $ 215 $ 77 $ 138 $ — $ — Deferred Credits and Other Liabilities: Other 100 8 91 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 342 $ 33 $ 306 $ 93 $ 209 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current Liabilities: Other $ 14 $ — $ — $ — $ — $ — $ — Deferred Credits and Other Liabilities: Other 41 — — — — — Not Designated as Hedging Instruments Current Liabilities: Other 1 — — — — 1 — Deferred Credits and Other Liabilities: Other 8 — 3 2 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 64 $ — $ 3 $ 2 $ — $ 7 $ — Total Derivative Liabilities $ 406 $ 33 $ 309 $ 95 $ 209 $ 7 $ — Derivative Assets December 31, 2014 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 Assets: Other $ 18 $ — $ — $ — $ — $ 1 $ 14 Current Assets: Assets held for sale 15 — — — — 28 — Investments and Other Assets: Other 3 — — — — — — Investments and Other Assets: Assets held for sale 15 — — — — 26 — Current Liabilities: Other 1 — — — — — — Current Liabilities: Assets held for sale 174 — — — — 175 — Deferred Credits and Other Liabilities: Other 2 — — — — — — Deferred Credits and Other Liabilities: Assets held for sale 111 — — — — 111 — Total Derivative Assets – Commodity Contracts $ 339 $ — $ — $ — $ — $ 341 $ 14 Interest Rate Contracts Designated as Hedging Instruments Investments and Other Assets: Other 10 — — — — — — Not Designated as Hedging Instruments Current Assets: Other 2 — 2 — 2 — — Total Derivative Assets – Interest Rate Contracts $ 12 $ — $ 2 $ — $ 2 $ — $ — Total Derivative Assets $ 351 $ — $ 2 $ — $ 2 $ 341 $ 14 Derivative Liabilities December 31, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Designated as Hedging Instruments Current Liabilities: Other $ — $ — $ 1 $ 1 $ — $ — $ — Not Designated as Hedging Instruments Current Assets: Assets held for sale — — — — — 4 — Investments and Other Assets: Assets held for sale — — — — — 4 — Current Liabilities: Other 307 14 288 108 180 — — Current Liabilities: Assets held for sale 253 — — — — 252 — Deferred Credits and Other Liabilities: Other 91 5 80 23 57 — — Deferred Credits and Other Liabilities: Assets held for sale 208 — — — — 207 — Total Derivative Liabilities – Commodity Contracts $ 859 $ 19 $ 369 $ 132 $ 237 $ 467 $ — Interest Rate Contracts Designated as Hedging Instruments Current Liabilities: Other $ 13 $ — $ — $ — $ — $ — $ — Deferred Credits and Other Liabilities: Other 29 — — — — — — Not Designated as Hedging Instruments Current Liabilities: Other 1 — — — — 1 — Deferred Credits and Other Liabilities: Other 7 — 2 — 2 5 — Total Derivative Liabilities – Interest Rate Contracts $ 50 $ — $ 2 $ — $ 2 $ 6 $ — Total Derivative Liabilities $ 909 $ 19 $ 371 $ 132 $ 239 $ 473 $ —
Offsetting Assets	Derivative Assets December 31, 2014 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 $ 210 $ — $ 2 $ — $ 2 $ 204 $ 14 Gross amounts offset (153 ) — (2 ) — (2 ) (179 ) — Net amounts subject to master netting 57 — — — — 25 14 Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 57 $ — $ — $ — $ — $ 25 $ 14 Non-Current Gross amounts recognized $ 136 $ — $ — $ — $ — $ 137 $ — Gross amounts offset (88 ) — — — — (114 ) — Net amounts subject to master netting 48 — — — — 23 — Amounts not subject to master netting 5 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 53 $ — $ — $ — $ — $ 23 $ — The following tables show the balance sheet location of derivative contracts subject to enforceable master netting agreements and include collateral posted to offset the net position. This disclosure is intended to enable users to evaluate the effect of netting arrangements on financial position. The amounts shown were 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, 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 $ 26 $ — $ 7 $ 2 $ 5 $ 4 $ 12 Gross amounts offset (2 ) — (1 ) — (1 ) — — Net amounts subject to master netting 24 — 6 2 4 4 12 Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 24 $ — $ 6 $ 2 $ 4 $ 4 $ 12 Non-Current Gross amounts recognized $ 7 $ — $ 6 $ — $ 6 $ — $ — Gross amounts offset (2 ) — (2 ) — (2 ) — — Net amounts subject to master netting 5 — 4 — 4 — — Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 5 $ — $ 4 $ — $ 4 $ — $ —
Offsetting Liabilities	Derivative Liabilities December 31, 2014 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 $ 573 $ 14 $ 289 $ 109 $ 180 $ 257 $ — Gross amounts offset (213 ) — (17 ) — (17 ) (222 ) — Net amounts subject to master netting 360 14 272 109 163 35 — Amounts not subject to master netting 1 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 361 $ 14 $ 272 $ 109 $ 163 $ 35 $ — Non-Current Gross amounts recognized $ 319 $ 5 $ 82 $ 23 $ 59 $ 216 $ — Gross amounts offset (173 ) — (8 ) — (8 ) (193 ) — Net amounts subject to master netting 146 5 74 23 51 23 — Amounts not subject to master netting 16 — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 162 $ 5 $ 74 $ 23 $ 51 $ 23 $ — Derivative Liabilities September 30, 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 $ 257 $ 25 $ 215 $ 77 $ 138 $ 1 $ — Gross amounts offset (15 ) — (14 ) — (14 ) — — Net amounts subject to master netting 242 25 201 77 124 1 — Amounts not subject to master netting — — — — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 242 $ 25 $ 201 $ 77 $ 124 $ 1 $ — Non-Current Gross amounts recognized $ 144 $ 8 $ 89 $ 18 $ 71 $ 6 $ — Gross amounts offset (9 ) — (9 ) — (9 ) — — Net amounts subject to master netting 135 8 80 18 62 6 — Amounts not subject to master netting 5 — 5 — — — — Net amounts recognized on the Condensed Consolidated Balance Sheet $ 140 $ 8 $ 85 $ 18 $ 62 $ 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 Indiana were not material. September 30, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Aggregate fair value amounts of derivative instruments in a net liability position $ 316 $ 33 $ 301 $ 94 $ 207 $ — Fair value of collateral already posted 20 — 20 — 20 — Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 296 33 281 94 187 — December 31, 2014 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Aggregate fair value amounts of derivative instruments in a net liability position $ 845 $ 19 $ 370 $ 131 $ 239 $ 456 Fair value of collateral already posted 209 — 23 — 23 186 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 407 19 347 131 216 41 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 agreement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral and payables related to the obligation to return cash collateral under master netting arrangements. September 30, 2015 December 31, 2014 (in millions) Receivables Receivables Duke Energy Amounts offset against net derivative positions $ 20 $ 145 Amounts not offset against net derivative positions — 64 Progress Energy Amounts offset against net derivative positions 20 23 Duke Energy Florida Amounts offset against net derivative positions 20 23 Duke Energy Ohio Amounts offset against net derivative positions — 122 Amounts not offset against net derivative positions — 64

Investments in Debt and Equit37

Investments in Debt and Equity Securities (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 December 31, 2014 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 $ — $ — $ 156 $ — $ — $ 136 Equity securities 1,655 71 3,396 1,926 29 3,650 Corporate debt securities 9 7 500 14 2 454 Municipal bonds 4 2 207 5 — 184 U.S. government bonds 23 1 1,131 19 2 978 Other debt securities 1 3 172 1 2 147 Total NDTF (c) $ 1,692 $ 84 $ 5,562 $ 1,965 $ 35 $ 5,549 Other Investments Cash and cash equivalents $ — $ — $ 32 $ — $ — $ 15 Equity securities 27 1 90 34 — 96 Corporate debt securities 1 2 98 1 1 58 Municipal bonds 3 1 73 3 1 76 U.S. government bonds 1 — 52 — — 27 Other debt securities — 1 69 1 1 80 Total Other Investments (a) $ 32 $ 5 $ 414 $ 39 $ 3 $ 352 Total Investments $ 1,724 $ 89 $ 5,976 $ 2,004 $ 38 $ 5,901 (a) These amounts are recorded in Other with 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. (c) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information. This increase in estimated fair value compared to December 31, 2014, is partially offset due to reimbursements from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 74 Due after one through five years 781 Due after five through 10 years 635 Due after 10 years 812 Total $ 2,302
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) 2015 2014 2015 2014 Realized gains $ 30 $ 28 $ 160 $ 90 Realized losses 28 51 59 57
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, 2015 December 31, 2014 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 $ — $ — $ 25 $ — $ — $ 51 Equity securities 930 42 1,990 1,102 17 2,162 Corporate debt securities 5 6 342 8 2 316 Municipal bonds 1 1 69 1 — 62 U.S. government bonds 6 1 383 7 1 308 Other debt securities 1 3 141 1 2 133 Total NDTF $ 943 $ 53 $ 2,950 $ 1,119 $ 22 $ 3,032 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 943 $ 54 $ 2,953 $ 1,119 $ 23 $ 3,035 (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, 2015 Due in one year or less $ 13 Due after one through five years 209 Due after five through 10 years 293 Due after 10 years 423 Total $ 938
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) 2015 2014 2015 2014 Realized gains $ 25 $ 20 $ 132 $ 72 Realized losses 24 48 47 50
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value investments in available-for-sale securities. September 30, 2015 December 31, 2014 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 $ — $ — $ 131 $ — $ — $ 85 Equity securities 725 29 1,406 824 12 1,488 Corporate debt securities 4 1 158 6 — 138 Municipal bonds 3 1 138 4 — 122 U.S. government bonds 17 — 748 12 1 670 Other debt securities — — 31 — — 14 Total NDTF (c) $ 749 $ 31 $ 2,612 $ 846 $ 13 $ 2,517 Other Investments Cash and cash equivalents $ — $ — $ 23 $ — $ — $ 15 Municipal bonds 3 — 43 3 — 43 Total Other Investments (a) $ 3 $ — $ 66 $ 3 $ — $ 58 Total Investments $ 752 $ 31 $ 2,678 $ 849 $ 13 $ 2,575 (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) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information. This increase in estimated fair value compared to December 31, 2014, is partially offset due to reimbursements from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 38 Due after one through five years 476 Due after five through 10 years 271 Due after 10 years 333 Total $ 1,118
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) 2015 2014 2015 2014 Realized gains $ 5 $ 8 $ 26 $ 17 Realized losses 4 3 10 6
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, 2015 December 31, 2014 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 $ — $ — $ 87 $ — $ — $ 50 Equity securities 535 23 1,107 612 10 1,171 Corporate debt securities 3 1 109 5 — 97 Municipal bonds 3 1 136 4 — 120 U.S. government bonds 12 — 485 9 1 265 Other debt securities — — 19 — — 8 Total NDTF (c) $ 553 $ 25 $ 1,943 $ 630 $ 11 $ 1,711 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ — Total Other Investments (a) $ — $ — $ 1 $ — $ — $ — Total Investments $ 553 $ 25 $ 1,944 $ 630 $ 11 $ 1,711 (a) These amounts are recorded in Other with 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) As of September 30, 2015 , the estimated fair value of the NDTF includes NDTF assets acquired with the purchase of NCEMPA's ownership interest in certain generating assets. Refer to Note 2 for further information.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 12 Due after one through five years 278 Due after five through 10 years 219 Due after 10 years 240 Total $ 749
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) 2015 2014 2015 2014 Realized gains $ 4 $ 4 $ 21 $ 11 Realized losses 3 2 8 4
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, 2015 December 31, 2014 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 $ — $ — $ 44 $ — $ — $ 35 Equity securities 190 6 299 212 2 317 Corporate debt securities 1 — 49 1 — 41 Municipal bonds — — 2 — — 2 U.S. government bonds 5 — 263 3 — 405 Other debt securities — — 12 — — 6 Total NDTF (c) $ 196 $ 6 $ 669 $ 216 $ 2 $ 806 Other Investments Cash and cash equivalents $ — $ — $ 11 $ — $ — $ 1 Municipal bonds 3 — 43 3 — 43 Total Other Investments (a) $ 3 $ — $ 54 $ 3 $ — $ 44 Total Investments $ 199 $ 6 $ 723 $ 219 $ 2 $ 850 (a) These amounts are recorded in Other with 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 estimated fair value at September 30, 2015, compared to the balance at December 31, 2014, is lower due to current year reimbursements from the NDTF for costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Plant.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) September 30, 2015 Due in one year or less $ 26 Due after one through five years 198 Due after five through 10 years 52 Due after 10 years 93 Total $ 369
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) 2015 2014 2015 2014 Realized gains $ 1 $ 3 $ 5 $ 5 Realized losses 1 1 2 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, 2015 December 31, 2014 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 Equity securities $ 23 $ — $ 67 $ 28 $ — $ 71 Corporate debt securities — — 3 — — — Municipal bonds — 1 27 — 1 30 Total Other Investments (a) $ 23 $ 1 $ 97 $ 28 $ 1 $ 101 Total Investments $ 23 $ 1 $ 97 $ 28 $ 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, 2015 Due in one year or less $ 2 Due after one through five years 16 Due after five through 10 years 8 Due after 10 years 4 Total $ 30

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 3,396 $ 3,224 $ 1 $ 171 Nuclear decommissioning trust fund debt securities 2,166 557 1,609 — Other trading and available-for-sale equity securities 90 90 — — Other trading and available-for-sale debt securities 324 85 234 5 Derivative assets 33 — 16 17 Total assets 6,009 3,956 1,860 193 Derivative liabilities (406 ) (4 ) (402 ) — Net assets $ 5,603 $ 3,952 $ 1,458 $ 193 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 3,650 $ 3,493 $ 6 $ 151 Nuclear decommissioning trust fund debt securities 1,899 648 1,251 — Other trading and available-for-sale equity securities 96 96 — — Other trading and available-for-sale debt securities 263 41 217 5 Derivative assets 110 49 24 37 Total assets 6,018 4,327 1,498 193 Derivative liabilities (668 ) (162 ) (468 ) (38 ) Net assets $ 5,350 $ 4,165 $ 1,030 $ 155
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, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 173 $ 23 $ 196 Purchases, sales, issuances and settlements: Purchases 2 — 2 Sales (3 ) — (3 ) Settlements — (6 ) (6 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 176 $ 17 $ 193 Three Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 188 $ 22 $ 210 Total pretax realized or unrealized gains (losses) included in earnings — (33 ) (33 ) Purchases, sales, issuances and settlements: Purchases 13 (1 ) 12 Sales (13 ) — (13 ) Issuances — 1 1 Transfers out of Level 3 due to observability of inputs — (1 ) (1 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 (10 ) (6 ) Balance at end of period $ 192 $ (22 ) $ 170 Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding $ — $ (49 ) $ (49 ) Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 156 $ (1 ) $ 155 Total pretax realized or unrealized gains (losses) included in earnings (a) — 18 18 Purchases, sales, issuances and settlements: Purchases 14 24 38 Sales (7 ) — (7 ) Settlements — (28 ) (28 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 13 4 17 Balance at end of period $ 176 $ 17 $ 193 (a) Includes amounts related to nonregulated operations and classified as (Loss) Income From Discontinued Operations, net of tax in Duke Energy's Condensed Consolidated Statements of Operations. Nine Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 98 $ 13 $ 111 Total pretax realized or unrealized gains (losses) included in earnings — (21 ) (21 ) Purchases, sales, issuances and settlements: Purchases 29 50 79 Sales (15 ) — (15 ) Settlements — (45 ) (45 ) Transfers out of Level 3 due to observability of inputs 68 (4 ) 64 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 12 (15 ) (3 ) Balance at end of period $ 192 $ (22 ) $ 170 Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding $ — $ (49 ) $ (49 )
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. September 30, 2015 Investment Type Fair Value (in millions) Valuation Technique Unobservable Input Range Duke Energy Swing options 1 Discounted cash flow Forward capacity option curves – price per MMBtu $ 18.50 – $ 84.35 Financial transmission rights (FTRs) 16 RTO auction pricing FTR price – per MWh (0.81 ) – 7.23 Total Level 3 derivatives $ 17 Duke Energy Ohio FTRs 4 RTO auction pricing FTR price – per MWh 0.37 – 2.17 Duke Energy Indiana FTRs $ 12 RTO auction pricing FTR price – per MWh (0.81 ) – 7.23 December 31, 2014 Investment Type Fair Value (in millions) Valuation Technique Unobservable Input Range Duke Energy Natural gas contracts $ (5 ) Discounted cash flow Forward natural gas curves – price per MMBtu $ 2.12 – $ 4.35 Financial transmission rights (FTRs) 14 RTO auction pricing FTR price – per MWh (1.92 ) – 9.86 Electricity contracts (1 ) Discounted cash flow Forward electricity curves – price per MWh 25.16 – 51.75 Commodity capacity option contracts 2 Discounted cash flow Forward capacity option curves – price per MW day 21.00 – 109.00 Commodity contract reserves (11 ) Bid-ask spreads, implied volatility, probability of default Total Level 3 derivatives $ (1 ) Duke Energy Ohio Electricity contracts $ (6 ) Discounted cash flow Forward electricity curves – price per MWh 25.25 – 51.75 Natural gas contracts (5 ) Discounted cash flow Forward natural gas curves – price per MMBtu 2.12 – 4.35 Commodity contract reserves (7 ) Bid-ask spreads, implied volatility, probability of default Total Level 3 derivatives $ (18 ) Duke Energy Indiana FTRs $ 14 RTO auction pricing FTR price – per MWh (1.92 ) – 9.86
Schedule of Long-term debt, including current	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, 2015 December 31, 2014 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 40,203 $ 43,864 $ 40,020 $ 44,566 Duke Energy Carolinas 8,884 9,860 8,391 9,626 Progress Energy 15,396 17,146 14,754 16,951 Duke Energy Progress 6,851 7,214 6,201 6,696 Duke Energy Florida 4,850 5,585 4,860 5,767 Duke Energy Ohio 1,605 1,766 1,766 1,970 Duke Energy Indiana 3,790 4,330 3,791 4,456
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,990 $ 1,818 $ 1 $ 171 Nuclear decommissioning trust fund debt securities 960 203 757 — Other trading and available-for-sale debt securities 3 — — 3 Total assets 2,953 2,021 758 174 Derivative liabilities (33 ) — (33 ) — Net assets $ 2,920 $ 2,021 $ 725 $ 174 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 2,162 $ 2,005 $ 6 $ 151 Nuclear decommissioning trust fund debt securities 870 138 732 — Other trading and available-for-sale debt securities 3 — — 3 Total assets 3,035 2,143 738 154 Derivative liabilities (19 ) — (19 ) — Net assets $ 3,016 $ 2,143 $ 719 $ 154
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. Three Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 171 $ — $ 171 Purchases, sales, issuances and settlements: Purchases 2 — 2 Sales (3 ) — (3 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 174 $ — $ 174 Three Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 171 $ (3 ) $ 168 Purchases, sales, issuances and settlements: Purchases 13 — 13 Sales (13 ) — (13 ) Settlements — 3 3 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 4 — 4 Balance at end of period $ 175 $ — $ 175 Nine Months Ended September 30, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 154 $ — $ 154 Purchases, sales, issuances and settlements: Purchases 14 — 14 Sales (7 ) — (7 ) Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 13 — 13 Balance at end of period $ 174 $ — $ 174 Nine Months Ended September 30, 2014 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 81 $ (2 ) $ 79 Purchases, sales, issuances and settlements: Purchases 29 — 29 Sales (15 ) — (15 ) Settlements — 2 2 Transfers out of Level 3 to observability of inputs 68 — 68 Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities 12 — 12 Balance at end of period $ 175 $ — $ 175
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,406 $ 1,406 $ — $ — Nuclear decommissioning trust fund debt securities 1,206 354 852 — Other trading and available-for-sale debt securities 66 23 43 — Derivative assets 13 — 13 — Total assets 2,691 1,783 908 — Derivative liabilities (309 ) — (309 ) — Net assets $ 2,382 $ 1,783 $ 599 $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,488 $ 1,488 $ — $ — Nuclear decommissioning trust fund debt securities 1,029 510 519 — Other trading and available-for-sale debt securities 58 15 43 — Derivative assets 4 — 4 — Total assets 2,579 2,013 566 — Derivative liabilities (373 ) — (373 ) — Net assets $ 2,206 $ 2,013 $ 193 $ —
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,107 $ 1,107 $ — $ — Nuclear decommissioning trust fund debt securities 836 136 700 — Other trading and available-for-sale debt securities 1 1 — — Derivative assets 2 — 2 — Total assets 1,946 1,244 702 — Derivative liabilities (95 ) — (95 ) — Net assets $ 1,851 $ 1,244 $ 607 $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 1,171 $ 1,171 $ — $ — Nuclear decommissioning trust fund debt securities 540 151 389 — Total assets 1,711 1,322 389 — Derivative liabilities (132 ) — (132 ) — Net assets $ 1,579 $ 1,322 $ 257 $ —
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 299 $ 299 $ — $ — Nuclear decommissioning trust fund debt securities and other 370 219 151 — Other trading and available-for-sale debt securities and other 54 11 43 — Derivative assets 11 — 11 — Total assets 734 529 205 — Derivative liabilities (209 ) — (209 ) — Net assets (liabilities) $ 525 $ 529 $ (4 ) $ — December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Nuclear decommissioning trust fund equity securities $ 317 $ 317 $ — $ — Nuclear decommissioning trust fund debt securities and other 489 359 130 — Other trading and available-for-sale debt securities and other 44 — 44 — Derivative assets 4 — 4 — Total assets 854 676 178 — Derivative liabilities (241 ) — (241 ) — Net assets (liabilities) $ 613 $ 676 $ (63 ) $ —
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 is disclosed in Note 10 . September 30, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 4 $ — $ — $ 4 Derivative liabilities (7 ) — (7 ) — Net liabilities $ (3 ) $ — $ (7 ) $ 4 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 49 $ 20 $ 9 $ 20 Derivative liabilities (181 ) (117 ) (26 ) (38 ) Net liabilities $ (132 ) $ (97 ) $ (17 ) $ (18 )
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. Derivatives (net) Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 5 $ (28 ) $ (18 ) $ (4 ) Total pretax realized or unrealized gains (losses) included in earnings (a) — (24 ) 21 (43 ) Purchases, sales, issuances and settlements: Purchases 5 — 5 1 Sales (5 ) — — — Settlements (1 ) (2 ) (4 ) (6 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (1 ) — 1 Transfers out of Level 3 due to observability of inputs — — — (4 ) Balance at end of period $ 4 $ (55 ) $ 4 $ (55 ) Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at September 30, 2014 $ — $ — $ — (52 ) (a) Includes amounts related to nonregulated operations and classified as (Loss) Income From Discontinued Operations, net of tax in Duke Energy Ohio's Condensed Consolidated Statements of Operations and Comprehensive Income.
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, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Available-for-sale equity securities $ 67 $ 67 $ — $ — Available-for-sale debt securities 30 — 30 — Derivative assets 12 — — 12 Net assets $ 109 $ 67 $ 30 $ 12 December 31, 2014 (in millions) Total Fair Value Level 1 Level 2 Level 3 Available-for-sale equity securities $ 71 $ 71 $ — $ — Available-for-sale debt securities 30 — 30 — Derivative assets 14 — — 14 Net assets $ 115 $ 71 $ 30 $ 14
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. Derivatives (net) Three Months Ended Nine Months Ended September 30, September 30, (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 17 $ 45 $ 14 $ 12 Total pretax realized or unrealized gains (losses) included in earnings — (13 ) — 14 Purchases, sales, issuances and settlements: Purchases 1 — 19 49 Settlements (6 ) — (25 ) (38 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (10 ) 4 (15 ) Balance at end of period $ 12 $ 22 $ 12 $ 22

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2015
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 reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. DERF DEPR DEFR Credit facility amount (in millions) $ 400 $ 300 $ 225 Expiration date December 2016 December 2016 March 2017 The following tables summarize the impact of VIEs consolidated by Duke Energy and the Subsidiary Registrants on the Condensed Consolidated Balance Sheets. September 30, 2015 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress Florida (in millions) DERF DEPR (c) DEFR (c) CRC Renewables Other Total ASSETS Current Assets Cash and Cash Equivalents $ — $ — $ — $ — $ 2 $ — $ 2 Restricted receivables of variable interest entities (net of allowance for doubtful accounts) 687 468 395 453 12 22 2,037 Other — 1 2 — 215 4 222 Investments and Other Assets Other — — — — 20 5 25 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 1,926 19 1,945 Accumulated depreciation and amortization — — — — (302 ) (5 ) (307 ) Regulatory Assets and Deferred Debits Other — — — — 37 1 38 Total assets $ 687 $ 469 $ 397 $ 453 $ 1,910 $ 46 $ 3,962 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 6 $ — $ 6 Taxes accrued 5 3 1 — 6 — 15 Current maturities of long-term debt — — — — 73 18 91 Other — — — — 23 4 27 Long-Term Debt (b) 400 300 225 325 916 3 2,169 Deferred Credits and Other Liabilities Deferred income taxes — — — — 325 — 325 Asset retirement obligations — — — — 30 — 30 Other — — — — 42 — 42 Total liabilities $ 405 $ 303 $ 226 $ 325 $ 1,421 $ 25 $ 2,705 Net assets of consolidated variable interest entities $ 282 $ 166 $ 171 $ 128 $ 489 $ 21 $ 1,257 (a) Restricted as collateral for nonrecourse debt of VIEs. (b) Nonrecourse to the general assets of the applicable registrant. (c) The amount for Progress Energy is equal to the sum of the amounts for Duke Energy Progress Receivables Company, LLC (DEPR) and Duke Energy Florida Receivables Company, LLC (DEFR). December 31, 2014 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress Florida (in millions) DERF DEPR (c) DEFR (c) CRC Renewables Other Total ASSETS Current Assets Restricted receivables of variable interest entities (net of allowance for doubtful accounts) $ 647 $ 436 $ 305 $ 547 $ 20 $ 18 $ 1,973 Other — — — — 68 6 74 Investments and Other Assets Other — — — — 25 25 50 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 1,855 18 1,873 Accumulated depreciation and amortization — — — — (250 ) (5 ) (255 ) Regulatory Assets and Deferred Debits Other — — — — 34 2 36 Total assets $ 647 $ 436 $ 305 $ 547 $ 1,752 $ 64 $ 3,751 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 3 $ — $ 3 Taxes accrued — — — — 6 — 6 Current maturities of long-term debt — — — — 68 16 84 Other — — — — 16 5 21 Long-Term Debt (b) 400 300 225 325 967 17 2,234 Deferred Credits and Other Liabilities Deferred income taxes — — — — 283 — 283 Asset retirement obligations — — — — 29 — 29 Other — — — — 34 4 38 Total liabilities $ 400 $ 300 $ 225 $ 325 $ 1,406 $ 42 $ 2,698 Net assets of consolidated variable interest entities $ 247 $ 136 $ 80 $ 222 $ 346 $ 22 $ 1,053 (a) Restricted as collateral for nonrecourse debt of VIEs. (b) Nonrecourse to the general assets of the applicable registrant. (c) The amount for Progress Energy is equal to the sum of the amounts for DEPR and DEFR.
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following tables include VIEs not consolidated and how these entities impact the Condensed Consolidated Balance Sheets. September 30, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables $ — $ — $ — $ 43 $ 64 Investments in equity method unconsolidated affiliates 223 125 348 — — Total assets $ 223 $ 125 $ 348 $ 43 $ 64 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 16 $ 16 $ — $ — Net assets $ 223 $ 109 $ 332 $ 43 $ 64 December 31, 2014 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables $ — $ — $ — $ 91 $ 113 Investments in equity method unconsolidated affiliates 150 38 188 — — Investments and other assets — 4 4 — — Total assets $ 150 $ 42 $ 192 $ 91 $ 113 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 150 $ 25 $ 175 $ 91 $ 113
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 2015 2014 2015 2014 Anticipated credit loss ratio 0.6 % 0.6 % 0.3 % 0.3 % Discount rate 1.2 % 1.2 % 1.2 % 1.2 % Receivable turnover rate 12.9 % 12.8 % 10.6 % 10.5 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Receivables sold $ 221 $ 273 $ 271 $ 310 Less: Retained interests 43 91 64 113 Net receivables sold $ 178 $ 182 $ 207 $ 197 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) 2015 2014 2015 2014 2015 2014 2015 2014 Sales Receivables sold $ 449 $ 477 $ 1,518 $ 1,705 $ 679 $ 739 $ 2,032 $ 2,173 Loss recognized on sale 2 3 7 9 3 3 8 8 Cash flows Cash proceeds from receivables sold 461 494 1,568 1,761 692 759 2,074 2,233 Collection fees received — — 1 1 — — 1 1 Return received on retained interests — — 2 3 1 2 4 5

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2015
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) 2015 2014 2015 2014 Income from continuing operations attributable to Duke Energy common shareholders $ 935 $ 887 $ 2,307 $ 2,351 Weighted-average shares outstanding – basic 688 707 696 707 Weighted-average shares outstanding – diluted 688 707 696 707 Earnings per share from continuing operations attributable to Duke Energy common shareholders Basic $ 1.36 $ 1.25 $ 3.31 $ 3.33 Diluted $ 1.36 $ 1.25 $ 3.31 $ 3.33 Potentially dilutive shares excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.825 $ 0.795 $ 2.42 $ 2.355 (a) Performance stock awards and certain stock options were not included in the dilutive securities calculation because either the performance measures related to the awards had not been met or the option exercise prices were greater than the average market price of the common shares during the presented periods.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
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) 2015 2014 2015 2014 Restricted stock unit awards $ 9 $ 8 $ 29 $ 30 Performance awards 5 4 18 14 Pretax stock-based compensation cost $ 14 $ 12 $ 47 $ 44 Tax benefit associated with stock-based compensation expense $ 6 $ 5 $ 18 $ 17 Stock-based compensation costs capitalized 1 1 3 3

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Employee Savings Plan Matching Contributions	The following table includes employer matching contributions, as well as the additional contribution of 4 percent of eligible pay per pay period for employees not eligible to participate in a defined benefit plan, 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, 2015 $ 34 $ 11 $ 10 $ 7 $ 3 $ — $ 1 2014 30 10 10 7 3 — 1 Nine Months Ended September 30, 2015 $ 120 $ 40 $ 36 $ 26 $ 10 $ 2 $ 5 2014 110 36 33 23 10 2 5
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan Contributions by Employer	The following table includes information related to the Duke Energy Registrants’ contributions to its U.S. qualified defined benefit pension plans. 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 Duke Energy and Duke Energy Ohio made contributions of $11 million and $3 million , respectively, to their U.S. qualified defined benefit pension plans during the three months ended September 30, 2015 . Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the nine months ended September 30, 2014 .
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, 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 Three Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 34 $ 10 $ 10 $ 6 $ 5 $ 1 $ 3 Interest cost on projected benefit obligation 86 22 28 13 14 5 7 Expected return on plan assets (128 ) (33 ) (44 ) (21 ) (21 ) (7 ) (10 ) Amortization of actuarial loss 37 8 17 8 8 1 3 Amortization of prior service credit (4 ) (2 ) — — — — — Other 3 1 1 — — — — Net periodic pension costs $ 28 $ 6 $ 12 $ 6 $ 6 $ — $ 3 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 102 $ 31 $ 30 $ 16 $ 15 $ 3 $ 7 Interest cost on projected benefit obligation 258 64 84 40 43 15 22 Expected return on plan assets (383 ) (99 ) (130 ) (64 ) (64 ) (20 ) (30 ) Amortization of actuarial loss 111 26 51 24 24 3 9 Amortization of prior service credit (11 ) (6 ) (2 ) (1 ) (1 ) — — Other 6 2 2 1 1 — — Net periodic pension costs $ 83 $ 18 $ 35 $ 16 $ 18 $ 1 $ 8
Other 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, 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 Three Months Ended September 30, 2014 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 1 $ — $ — $ 1 $ — Interest cost on projected benefit obligation 3 1 2 — — Amortization of actuarial loss 1 — — — — Amortization of prior service credit — — (1 ) — — Net periodic pension costs $ 5 $ 1 $ 1 $ 1 $ — 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Service cost $ 2 $ — $ 1 $ 1 $ — Interest cost on projected benefit obligation 10 1 4 1 1 Amortization of actuarial loss 2 — 1 — — Amortization of prior service cost — — (1 ) — — Net periodic pension costs $ 14 $ 1 $ 5 $ 2 $ 1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended 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 Three Months Ended September 30, 2014 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 13 3 6 3 3 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss 9 1 10 8 3 — — Amortization of prior service credit (31 ) (3 ) (24 ) (19 ) (5 ) — — Net periodic other post-retirement benefit costs $ (10 ) $ (1 ) $ (7 ) $ (8 ) $ 1 $ — $ 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 Nine Months Ended September 30, 2014 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 7 $ 1 $ 3 $ 1 $ 2 $ — $ — Interest cost on accumulated post-retirement benefit obligation 38 9 17 8 9 1 4 Expected return on plan assets (9 ) (6 ) — — — — (1 ) Amortization of actuarial loss (gain) 29 2 31 23 8 (1 ) — Amortization of prior service credit (94 ) (8 ) (71 ) (55 ) (16 ) — — Net periodic other post-retirement benefit costs $ (29 ) $ (2 ) $ (20 ) $ (23 ) $ 3 $ — $ 3

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 2014 2015 2014 Duke Energy 30.9 % 34.0 % 32.5 % 31.4 % Duke Energy Carolinas 36.5 % 33.9 % 36.3 % 33.7 % Progress Energy 25.0 % 37.1 % 31.8 % 37.3 % Duke Energy Progress 34.4 % 36.3 % 35.3 % 36.6 % Duke Energy Florida 30.1 % 38.5 % 35.2 % 38.6 % Duke Energy Ohio 39.3 % 38.3 % 37.6 % 34.9 % Duke Energy Indiana 37.0 % 31.6 % 36.6 % 35.2 %

Organization and Basis of Pre44

Organization and Basis of Presentation Organization and Basis of Presentation (Narrative)(Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 165

Organization and Basis of Pre45

Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 748	$ 827
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	247	295
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	220	217
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	123	135
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	97	82
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	6
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	25	27
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	64	79
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 93	$ 112

Organization and Basis of Pre46

Organization and Basis of Presentation Organization and Basis of Presentation (Amounts Attributable to Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Organization And Basis Of Presentation [Line Items]
Income From Continuing Operations	$ 940	$ 891	$ 2,320	$ 2,367
Income From Continuing Operations Attributable to Noncontrolling Interests	3	3	10	11
Income (Loss) from Continuing Operations Attributable to Parent	937	888	2,310	2,356
(Loss) Income From Discontinued Operations, net of tax	(5)	378	29	(578)
Loss From Discontinued Operations Attributable to Noncontrolling Interests, net of tax		(8)		(8)
Income (Loss) From Discontinued Operations Attributable to Duke Energy Corporation, net of tax		386		(570)
Net Income	935	1,269	2,349	1,789
Net Income (Loss) Attributable to Noncontrolling Interests	3	(5)	10	3
Net Income (Loss) Attributable to Parent	932	1,274	2,339	1,786
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Income From Continuing Operations	452	330	933	741
Income From Continuing Operations Attributable to Noncontrolling Interests		1		2
Income (Loss) from Continuing Operations Attributable to Parent		329		739
(Loss) Income From Discontinued Operations, net of tax	(1)		(2)	(6)
Income (Loss) From Discontinued Operations Attributable to Duke Energy Corporation, net of tax		0		(6)
Net Income	451	330	931	735
Net Income (Loss) Attributable to Noncontrolling Interests	3	1	8	2
Net Income (Loss) Attributable to Parent	$ 448	$ 329	$ 923	$ 733

Organization and Basis of Pre47

Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 109	$ 101	$ 308	$ 416
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	9	4	27	93
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	67	63	174	214
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4		12	56
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	63	63	162	158
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	24	24	80	80
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 9	$ 10	$ 27	$ 29

Acquisitions and Dispositions48

Acquisitions and Dispositions (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 24, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses			$ 1,317	$ 16
Asset retirement obligations assumed			213
Piedmont Natural Gas [Member] | Subsequent Event [Member] | Scenario, Forecast [Member]
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses	$ 4,900
Business Acquisition, Share Price	$ 60
Long-term debt assumed	$ 1,800
Acquirer Termination Fee	250
Acquiree Termination Fee	125
Piedmont Natural Gas [Member] | Subsequent Event [Member] | Scenario, Forecast [Member] | Minimum [Member]
Significant Acquisitions and Disposals [Abstract]
Proceeds from Issuance or Sale of Equity	500
Piedmont Natural Gas [Member] | Subsequent Event [Member] | Scenario, Forecast [Member] | Maximum [Member]
Significant Acquisitions and Disposals [Abstract]
Proceeds from Issuance or Sale of Equity	$ 750
Duke Energy Progress [Member]
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses			1,249
Asset retirement obligations assumed			204
Duke Energy Progress [Member] | NCEMPA Generating Assets [Member]
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses		$ 1,250
Purchase acquisition adjustment		350	350
Nuclear decommissioning trust fund assets transferred		287	287
Asset retirement obligations assumed		204
Impact on revenue from acquisition		40	40
Impact on net income from acquisition		7	7
Duke Energy Ohio [Member] | Midwest Generation Business [Member]
Discontinued Operations and Disposal Groups [Abstract]
Disposal Group, Including Discontinued Operation, Consideration		$ 2,800	$ 2,800

Acquisitions and Dispositions P

Acquisitions and Dispositions Purchase Price Allocation (Details) - Duke Energy Progress [Member] - NCEMPA Generating Assets [Member] $ in Millions	Sep. 30, 2015USD ($)
Business Acquisition [Line Items]
Inventory	$ 56
Net property, plant, and equipment	845
Total assets	901
Purchase acquisition adjustment	350
Total purchase price	$ 1,251

Acquisitions and Dispositions50

Acquisitions and Dispositions (Plants in Disposal Group) (Details) - Duke Energy Ohio [Member]	3 Months Ended
	Mar. 31, 2015MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	9,225
Owned Average MW Capacity	5,884
Stuart [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	2,308
Owned Average MW Capacity	900
Ownership Interest	39.00%
Zimmer [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	1,300
Owned Average MW Capacity	605
Ownership Interest	46.50%
Hanging Rock [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	1,226
Owned Average MW Capacity	1,226
Ownership Interest	100.00%
Miami Fort Units 7 and 8 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	1,020
Owned Average MW Capacity	652
Ownership Interest	64.00%
Conesville [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	780
Owned Average MW Capacity	312
Ownership Interest	40.00%
Washington [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	617
Owned Average MW Capacity	617
Ownership Interest	100.00%
Fayette [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	614
Owned Average MW Capacity	614
Ownership Interest	100.00%
Killen [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	600
Owned Average MW Capacity	198
Ownership Interest	33.00%
Lee [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	568
Owned Average MW Capacity	568
Ownership Interest	100.00%
Dicks Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	136
Owned Average MW Capacity	136
Ownership Interest	100.00%
Miami Fort [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Average MW Capacity	56
Owned Average MW Capacity	56
Ownership Interest	100.00%

Acquisitions and Dispositions51

Acquisitions and Dispositions (Assets Held For Sale) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax	$ (5)	$ 378	$ 29	$ (578)
Charge for settlement agreement			53
Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax	(2)	413	23	(597)
Charge for settlement agreement			53
Midwest Generation Business [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues		620	543	1,233
(Loss) Gain on disposition	(5)	460	(42)	(847)
(Loss) Income before income taxes	(5)	623	62	(864)
Income tax (benefit) expense	(1)	218	29	(321)
(Loss) Income From Discontinued Operations, net of tax	(4)	405	33	(543)
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues		536	412	853
(Loss) Gain on disposition	(4)	466	(48)	(878)
(Loss) Income before income taxes	(4)	647	48	(917)
Income tax (benefit) expense	(2)	234	25	(320)
Other Disposal Groups [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
(Loss) Income From Discontinued Operations, net of tax	$ (1)	$ (27)	(4)	$ (35)
Antitrust Lawsuit [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Charge for settlement agreement			81
Antitrust Lawsuit [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Charge for settlement agreement			$ 81

Business Segments (Narrative) (

Business Segments (Narrative) (Details)	Sep. 30, 2015
National Methanol Company [Member] | International Energy [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	25.00%

Business Segments (Business Seg

Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 6,483	$ 6,395	$ 18,137	$ 18,366
Segment income	937	888	2,310	2,356
Add back noncontrolling interests	3	3	10	11
(Loss) Income From Discontinued Operations, net of tax	(5)	378	29	(578)
Net income (loss) attributable to parent	932	1,274	2,339	1,786
Net income (loss)	935	1,269	2,349	1,789
Segment assets	121,033		121,033		$ 120,709
Impairment charges	111	1	111	81
Charge for settlement agreement, net of tax			53
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,138	5,975	17,062	17,041
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	281	366	841	1,111
Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	66	50	214	195
State Tax Charge			41
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(2)	4	20	19
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,485	6,391	18,117	18,347
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,147	5,986	17,090	17,074
Segment income	905	920	2,311	2,346
Segment assets	110,520		110,520
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	281	366	841	1,111
Segment income	69	80	157	356
Segment assets	3,730		3,730
Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	66	50	214	195
Segment income	(3)	(17)	(35)	(70)
Segment assets	3,841		3,841
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,494	6,402	18,145	18,380
Segment income	971	983	2,433	2,632
Segment assets	118,091		118,091
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(28)	(32)	(86)	(93)
Segment income		(3)	(4)	(7)
Segment assets	185		185
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(11)	(28)	(33)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(19)	(21)	(58)	(60)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(11)	(28)	(33)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	17	25	78	79
Segment income	(34)	(92)	(119)	(269)
Segment assets	2,757		2,757
Costs to achieve Progress Energy merger	15	35	42	107
Other VIEs [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				94
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	462	446	1,453	1,433
Segment income	34	26	106	39
(Loss) Income From Discontinued Operations, net of tax	(2)	413	23	(597)
Net income (loss) attributable to parent	32	439	129	(558)
Segment assets	7,083		7,083		9,999
Impairment charges				94
Charge for settlement agreement, net of tax			53
Duke Energy Ohio [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		440		1,416
Duke Energy Ohio [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		6		17
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		446		1,433
Duke Energy Ohio [Member] | Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	456	441	1,424	1,417
Segment income	46	43	135	151
Segment assets	6,961		6,961
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		6	14	17
Segment income		(13)	(9)	(101)
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		447	1,438	1,434
Segment income		30	126	50
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		(1)		(1)
Segment assets	(4)		(4)
Duke Energy Ohio [Member] | Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		(1)		(1)
Duke Energy Ohio [Member] | Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		(1)		(1)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6		15
Segment income	(12)	$ (4)	(20)	(11)
Segment assets	126		126
Duke Energy Ohio [Member] | Other VIEs [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				94	$ 94
Duke Energy Ohio [Member] | Other VIEs [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				$ 94
Edwardsport Igcc Plant [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges	$ 56		$ 56

Business Segments (Net Loss) (D

Business Segments (Net Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Segment income	$ 937	$ 888	$ 2,310	$ 2,356
Interest expense	402	405	1,208	1,212
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Interest expense	105	104	313	307
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(19)	(28)	(67)
Progress Energy [Member]
Segment Reporting Information [Line Items]
Segment income		329		739
Interest expense	170	166	504	502
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(3)	(48)	(87)	(145)
Interest expense	61	58	180	181
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Interest expense	59	57	175	172
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(4)	(10)	(12)	(23)
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Interest expense	50	51	149	150
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(3)	(5)	(9)	(16)
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Interest expense	44	40	132	127
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (2)	$ (3)	$ (6)	$ (10)

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details)	3 Months Ended			9 Months Ended		12 Months Ended
	Mar. 31, 2017USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)MW	Sep. 30, 2014USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue		$ (6,017,000,000)	$ (5,861,000,000)	$ (16,564,000,000)	$ (16,549,000,000)
Regulatory assets, noncurrent		11,290,000,000		11,290,000,000			$ 11,042,000,000
Impairment charges		111,000,000	1,000,000	111,000,000	81,000,000
Other Nonoperating Income (Expense)		(57,000,000)	(109,000,000)	(203,000,000)	(293,000,000)
Payments to Acquire Businesses, Gross				1,317,000,000	16,000,000
Property, Plant and Equipment, Net		73,776,000,000		73,776,000,000			70,046,000,000
Payments to Acquire Property, Plant, and Equipment				4,642,000,000	3,755,000,000
Other liabilities		1,595,000,000		1,595,000,000			1,675,000,000
Accounts Payable, Current		$ 2,078,000,000		$ 2,078,000,000			2,271,000,000
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%
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				1,541
Property, Plant and Equipment, Net		$ 207,000,000		$ 207,000,000
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		2,741,000,000		2,741,000,000			2,465,000,000
Impairment charges					3,000,000
Other Nonoperating Income (Expense)		(42,000,000)	(44,000,000)	(125,000,000)	(137,000,000)
Property, Plant and Equipment, Net		25,208,000,000		25,208,000,000			24,672,000,000
Payments to Acquire Property, Plant, and Equipment				1,372,000,000	1,289,000,000
Other liabilities		618,000,000		618,000,000			642,000,000
Accounts Payable, Current		623,000,000		623,000,000			709,000,000
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		$ 600,000,000		$ 600,000,000
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] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net		$ 110,000,000		$ 110,000,000
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		2,816,000,000		2,816,000,000			2,675,000,000
Impairment charges					(18,000,000)
Other Nonoperating Income (Expense)		(14,000,000)	(18,000,000)	(49,000,000)	(34,000,000)
Payments to Acquire Businesses, Gross				1,249,000,000
Property, Plant and Equipment, Net		17,172,000,000		17,172,000,000			15,186,000,000
Payments to Acquire Property, Plant, and Equipment				1,120,000,000	871,000,000
Other liabilities		120,000,000		120,000,000			168,000,000
Accounts Payable, Current		381,000,000		381,000,000			481,000,000
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		1,100,000,000		$ 1,100,000,000
Duke Energy Progress [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				376
Property, Plant and Equipment, Net		460,000,000		$ 460,000,000
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		2,719,000,000		2,719,000,000			2,733,000,000
Impairment charges		7,000,000	1,000,000	7,000,000	2,000,000
Other Nonoperating Income (Expense)		(2,000,000)	(6,000,000)	(12,000,000)	(17,000,000)
Property, Plant and Equipment, Net		10,363,000,000		10,363,000,000			9,955,000,000
Payments to Acquire Property, Plant, and Equipment				696,000,000	513,000,000
Other liabilities		157,000,000		157,000,000			158,000,000
Accounts Payable, Current		316,000,000		$ 316,000,000			365,000,000
Duke Energy Florida [Member] | Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Payments to Acquire Businesses, Gross	$ 166,000,000
Duke Energy Florida [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage				10.00%
Approved return on equity percentage amount by state commission				10.80%
Customer Refund Liability, Noncurrent		14,100,000		$ 14,100,000
Duke Energy Florida [Member] | FERC Complaint 3 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				8.69%
Duke Energy Florida [Member] | Citrus County Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		1,500,000,000		$ 1,500,000,000
Duke Energy Florida [Member] | Suwannee Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		197,000,000		197,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement[Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges		15,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement[Member] | FPSC [Member] | Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved						$ 1,298,000,000
Regulatory assets, noncurrent						1,283,000,000
Approved rate increase amount by state commission						168,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | Crystal River Unit 3 Requested Financing Order [Member] | FPSC [Member] | Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount						$ 93,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		54,000,000		54,000,000
Approved rate increase amount by state commission				$ 0
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				873
Property, Plant and Equipment, Net		121,000,000		$ 121,000,000
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue		(367,000,000)	(352,000,000)	(1,005,000,000)	(998,000,000)
Regulatory assets, noncurrent		495,000,000		495,000,000			512,000,000
Impairment charges					94,000,000
Other Nonoperating Income (Expense)			(3,000,000)	2,000,000	(9,000,000)
Property, Plant and Equipment, Net		5,175,000,000		5,175,000,000			4,937,000,000
Payments to Acquire Property, Plant, and Equipment				266,000,000	242,000,000
Other liabilities		165,000,000		165,000,000			166,000,000
Accounts Payable, Current		$ 219,000,000		219,000,000			209,000,000
Duke Energy Ohio [Member] | EE and Peak Demand Reduction Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue				$ 23,000,000
Duke Energy Ohio [Member] | Natural Gas Rate Case [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				9.84%
Duke Energy Ohio [Member] | MGP Remediation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission				$ 56,000,000
Duke Energy Ohio [Member] | FERC Complaint 1 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				11.38%
Duke Energy Ohio [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				12.38%
Percentage Recovered Through Future Rate Case				30.00%
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				$ 2,700,000,000
Duke Energy Ohio [Member] | East Bend Station [Member] | Dayton Power and Light [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		31.00%		31.00%
Payments to Acquire Property, Plant, and Equipment				$ 12,400,000
Duke Energy Ohio [Member] | Regional Transmission Organization [Member]
Public Utilities, General Disclosures [Line Items]
Restructuring Reserve		$ 91,000,000		91,000,000
Regulatory assets, noncurrent		72,000,000		72,000,000
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		645,000,000		645,000,000			685,000,000
Impairment charges		85,000,000		85,000,000
Other Nonoperating Income (Expense)			$ (5,000,000)	(9,000,000)	(16,000,000)
Property, Plant and Equipment, Net		9,340,000,000		9,340,000,000			8,815,000,000
Payments to Acquire Property, Plant, and Equipment				506,000,000	$ 462,000,000
Other liabilities		107,000,000		107,000,000			90,000,000
Accounts Payable, Current		149,000,000		$ 149,000,000			$ 179,000,000
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 2 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				8.67%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		1,900,000,000		$ 1,900,000,000
Duke Energy Indiana [Member] | Edwardsport Igcc Plant [Member] | IGCC Rider Proceeding [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount				(7,000,000)
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount				78,000,000
Legal Fees				5,000,000
Impairment charges				85,000,000
Other Nonoperating Income (Expense)				5,000,000
Amount of Impairment to Carrying Amount of Regulatory Assets		78,000,000		78,000,000
Other liabilities		7,000,000		7,000,000
Accounts Payable, Current		5,000,000		$ 5,000,000
Regulatory Asset, Amortization Period				8 years
Regulatory Assets		108,000,000		$ 108,000,000
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW				668
Property, Plant and Equipment, Net		$ 86,000,000		$ 86,000,000

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)MW	Dec. 31, 2014USD ($)
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 73,776	$ 70,046
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,541
Remaining net book value (in millions)	$ 207
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	25,208	24,672
Duke Energy Carolinas [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	110
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 27,538	25,144
Progress Energy [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 121
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 17,172	15,186
Duke Energy Progress [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	376
Remaining net book value (in millions)	$ 460
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 10,363	9,955
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 121
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	5,175	4,937
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 9,340	$ 8,815
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	668
Remaining net book value (in millions)	$ 86

Commitments and Contingencies57

Commitments and Contingencies (Narrative) (Details)	Feb. 02, 2014galT	Mar. 31, 2014USD ($)	Sep. 30, 2015USD ($)plantClaimsproject	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)plantClaimsproject	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)	Aug. 18, 2014gal
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			$ 178,000,000		$ 178,000,000		$ 323,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			1,426,000,000	$ 1,409,000,000	4,274,000,000	$ 4,254,000,000
Investments and other assets			3,205,000,000		3,205,000,000		3,008,000,000
Accounts Payable, Current			2,078,000,000		2,078,000,000		2,271,000,000
Charge for settlement agreement					53,000,000
Progress Energy Merger Shareholder Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement Amount					146,000,000
Payments for Legal Settlements					25,000,000
Litigation Settlement Covered by Insurance			121,000,000		$ 121,000,000
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent					15.00%
Ash Basins Fines and Restitution [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense					$ 68,000,000
Ash Basins Community Service and Mitigation [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense					34,000,000
Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement					81,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			12,000,000		12,000,000		72,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			511,000,000	465,000,000	1,469,000,000	1,415,000,000
Investments and other assets			1,018,000,000		1,018,000,000		959,000,000
Accounts Payable, Current			623,000,000		623,000,000		709,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required			250,000,000		250,000,000
Loss Contingency Accrual			$ 5,000,000		5,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Environmental remediation expense					24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Minimum [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] | North Carolina Ash Basins [Member] | Maximum [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
Duke Energy Carolinas [Member] | New Source Review Provisions Of Clean Air Act [Member]
Valuation and Qualifying Accounts [Abstract]
Maximum civil penalties per day for each violation					$ 37,500
Projects with Alleged NSR Violations | project			29		29
Number of Coal Plants with Alleged NSR Violations | plant			25		25
Loss contingency, pending claims, number | Claims			13		13
Remaining Number of Coal Plants with Alleged NSR Violations | plant			13		13
Number of Retired Plants | plant			11		11
Gain (Loss) Related to Litigation Settlement					$ 4,000,000
Litigation Settlement, Expense					1,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			$ 2,000,000		2,000,000
Investments and other assets			3,000,000		3,000,000
Accounts Payable, Current			5,000,000		5,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves			551,000,000		551,000,000		575,000,000
Reinsurance retention policy, excess retention, amount reinsured					847,000,000
Probable insurance recoveries			$ 599,000,000		$ 599,000,000		616,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims			150		150
Asbestos-related injuries and damages reserves			$ 37,000,000		$ 37,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims			63		63
Asbestos-related injuries and damages reserves			$ 9,000,000		$ 9,000,000
Duke Energy Carolinas [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement					1,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			74,000,000		74,000,000		93,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			539,000,000	564,000,000	1,672,000,000	1,714,000,000
Investments and other assets			850,000,000		850,000,000		670,000,000
Accounts Payable, Current			697,000,000		697,000,000		847,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			17,000,000		17,000,000		37,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			329,000,000	346,000,000	1,066,000,000	1,074,000,000
Investments and other assets			484,000,000		484,000,000		412,000,000
Accounts Payable, Current			381,000,000		381,000,000		481,000,000
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required			250,000,000		250,000,000
Loss Contingency Accrual			5,000,000		5,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement					6,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed					25,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			36,000,000		36,000,000		36,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			208,000,000	212,000,000	598,000,000	626,000,000
Investments and other assets			308,000,000		308,000,000		204,000,000
Accounts Payable, Current			316,000,000		316,000,000		365,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount			54,000,000		54,000,000
Loss contingency, damages sought, value		$ 510,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			81,000,000		81,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			124,000,000	134,000,000	370,000,000	378,000,000
Investments and other assets			17,000,000		17,000,000		23,000,000
Accounts Payable, Current			219,000,000		219,000,000		209,000,000
Charge for settlement agreement					53,000,000
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					81,000,000
Charge for settlement agreement					81,000,000
Duke Energy Indiana [Member]
Valuation and Qualifying Accounts [Abstract]
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			164,000,000	$ 160,000,000	525,000,000	$ 485,000,000
Accounts Payable, Current			$ 149,000,000		$ 149,000,000		$ 179,000,000

Commitments and Contingencies58

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 79
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	97	$ 79
Provisions/adjustments	4	34
Cash reductions	(4)	(8)
Ending balance	97	105
Duke Energy Carolinas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	25
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	11
Provisions/adjustments	0	(1)
Ending balance	10	10
Progress Energy [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	4
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	27
Provisions/adjustments	3	4
Cash reductions	(2)	(6)
Ending balance	18	25
Duke Energy Progress [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	1
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5	8
Provisions/adjustments	0	3
Cash reductions	(1)	(4)
Ending balance	4	7
Duke Energy Florida [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	3
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	12	19
Provisions/adjustments	3	1
Cash reductions	(1)	(2)
Ending balance	14	18
Duke Energy Ohio [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	43
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	54	27
Provisions/adjustments	1	28
Cash reductions	(1)	(1)
Ending balance	54	54
Duke Energy Indiana [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	7
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	7
Provisions/adjustments	3	3
Cash reductions	(1)	(1)
Ending balance	$ 12	$ 9

Commitments and Contingencies59

Commitments and Contingencies (Schedule of Reserves) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Reserves for legal matters	$ 178	$ 323
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	12	72
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	74	93
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	17	37
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	36	$ 36
Duke Energy Ohio [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 81

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Dec. 31, 2015	Sep. 30, 2015
Debt Instrument [Line Items]
Debt issuances		$ 1,700
March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of debt		$ 500
Interest rate		3.75%
Debt issuances		$ 500
August 2015 3.250% First Mortgage Bond maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate		3.25%
Debt issuances		$ 500
August 2015 3.250% First Mortgage Bond maturing August 2025 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt	$ 400
August 2015 4.200% First Mortgage Bond maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate		4.20%
Debt issuances		$ 700
August 2015 4.200% First Mortgage Bond maturing August 2045 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt	400
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances		500
Duke Energy Carolinas [Member] | March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Repayments of debt		$ 500
Interest rate		3.75%
Debt issuances		$ 500
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances		$ 1,200
Duke Energy Progress [Member] | August 2015 3.250% First Mortgage Bond maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate		3.25%
Debt issuances		$ 500
Duke Energy Progress [Member] | August 2015 3.250% First Mortgage Bond maturing August 2025 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt	400
Duke Energy Progress [Member] | August 2015 4.200% First Mortgage Bond maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate		4.20%
Debt issuances		$ 700
Duke Energy Progress [Member] | August 2015 4.200% First Mortgage Bond maturing August 2045 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt	$ 400

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) $ in Millions	Sep. 30, 2015USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	$ 7,500
Commercial paper	(1,793)
Outstanding letters of credit	(72)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	5,019
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	3,300
Commercial paper	(1,318)
Outstanding letters of credit	(64)
Available capacity	1,918
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Commercial paper	(475)
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required	250
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	800
Commercial paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	211
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required	250
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required	250
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,300
Outstanding letters of credit	(3)
Coal ash set-aside	(250)
Available capacity	1,047
Duke Energy Progress [Member] | Revolving Credit Facility [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required	250
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,200
Outstanding letters of credit	(1)
Available capacity	1,199
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	400
Commercial paper	(25)
Available capacity	375
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	500
Commercial paper	(150)
Tax exempt bonds	(81)
Available capacity	$ 269

Debt and Credit Facilities (S62

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,536	$ 2,807
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	311
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 506	507
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 5.300% First Mortgage Bonds Maturing October 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.30%
Current maturities of long-term debt	$ 500
Progress Energy Parent [Member] | Unsecured Debt [Member] | 5.625% Unsecured Debt Maturing January 2016 [Member]
Debt Instrument [Line Items]
Interest rate	5.625%
Current maturities of long-term debt	$ 300
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 402	945
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 5.250% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.25%
Current maturities of long-term debt	$ 400
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 563	562
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 0.650% First Mortgage Bonds Maturing November 2015 [Member]
Debt Instrument [Line Items]
Interest rate	0.65%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 5.100% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.10%
Current maturities of long-term debt	$ 300
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	56	157
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 480	$ 5
Duke Energy Indiana [Member] | Unsecured Debt [Member] | 6.05% Unsecured Debt Maturing June 2016 [Member]
Debt Instrument [Line Items]
Interest rate	6.05%
Current maturities of long-term debt	$ 325
Duke Energy Indiana [Member] | First Mortgage Bonds [Member] | 0.636% First Mortgage Bonds Maturing July 2016 [Member]
Debt Instrument [Line Items]
Interest rate	0.636%
Current maturities of long-term debt	$ 150

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO Rollforward) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 8,466
Acquisitions	213
Accretion expense	278
Liabilities settled	(274)
Liabilities incurred in the current year	983
Revision in estimates of cash flows	47
Balance at end of period	9,713
Duke Energy Carolinas [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	3,428
Accretion expense	123
Liabilities settled	(107)
Liabilities incurred in the current year	178
Revision in estimates of cash flows	(23)
Balance at end of period	3,599
Progress Energy [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	4,711
Acquisitions	204
Accretion expense	150
Liabilities settled	(153)
Liabilities incurred in the current year	270
Revision in estimates of cash flows	40
Balance at end of period	5,222
Duke Energy Progress [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	3,905
Acquisitions	204
Accretion expense	123
Liabilities settled	(53)
Liabilities incurred in the current year	270
Revision in estimates of cash flows	40
Balance at end of period	4,489
Duke Energy Florida [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	806
Accretion expense	26
Liabilities settled	(100)
Balance at end of period	732
Duke Energy Ohio [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	27
Accretion expense	2
Liabilities settled	(2)
Liabilities incurred in the current year	116
Balance at end of period	143
Duke Energy Indiana [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	32
Accretion expense	11
Liabilities settled	(12)
Liabilities incurred in the current year	418
Balance at end of period	$ 449

Asset Retirement Obligations As

Asset Retirement Obligations Asset Retirement Obligations (Asset Retirement Costs) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	$ 73,776	$ 70,046
Regulatory assets	11,290	11,042
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	25,208	24,672
Regulatory assets	2,741	2,465
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	27,538	25,144
Regulatory assets	5,535	5,408
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	17,172	15,186
Regulatory assets	2,816	2,675
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	5,175	4,937
Regulatory assets	495	512
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	9,340	8,815
Regulatory assets	645	$ 685
Asset Retirement Obligation Costs [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	535
Regulatory assets	448
Asset Retirement Obligation Costs [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	178
Asset Retirement Obligation Costs [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	270
Asset Retirement Obligation Costs [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	270
Asset Retirement Obligation Costs [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	116
Asset Retirement Obligation Costs [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	$ 418

Goodwill and Intangible Asset65

Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Goodwill [Roll Forward]
Foreign exchange and other changes			$ (33)
Goodwill, Acquired During Period			24
Goodwill as adjusted for accumulated impairment charges	$ 16,312		16,312		$ 16,321
Asset impairment charges	111	$ 1	111	$ 81
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill as adjusted for accumulated impairment charges	15,950		15,950		15,950
International [Member]
Goodwill [Roll Forward]
Foreign exchange and other changes			(33)
Goodwill as adjusted for accumulated impairment charges	274		274		307
Commercial Portfolio [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period			24
Goodwill as adjusted for accumulated impairment charges	88		88		64
Commercial Portfolio [Member] | Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				94
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	920		920		920
Goodwill as adjusted for accumulated impairment charges	920		920		920
Goodwill, Impaired, Accumulated Impairment Loss	$ 216		$ 216		216
Asset impairment charges				94
Duke Energy Ohio [Member] | Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				94	$ 94
Duke Energy Ohio [Member] | Commercial Portfolio [Member] | Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				$ 94

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	$ 211	$ 199	$ 632	$ 638
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	5	18	16
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	7	13	47	125
Related party transaction, expenses from transactions with related party	48	36	143	127
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	184	182	523	560
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	10	8	29	25
Progress Energy [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	48	36	143	127
Related party transaction, expenses from transactions with related party	7	13	47	125
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	101	91	296	291
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	4	12	13
Duke Energy Progress [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	48	36	143	127
Related party transaction, expenses from transactions with related party	7	13	47	125
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	83	91	227	269
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	4	17	12
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	88	83	276	242
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	3	5	10
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	87	94	259	293
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 2	$ 3	$ 6	$ 8

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - Duke Energy Ohio [Member] - USD ($) $ in Millions	Sep. 30, 2015	Apr. 01, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Intercompany loan payable	$ 134		$ 491
DECAM [Member]
Related Party Transaction [Line Items]
Intercompany loan payable		$ 294	$ 459

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Bcf in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)GWhBcf	Dec. 31, 2014USD ($)GWhBcf	Oct. 31, 2015USD ($)
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	76	25,370
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	389	676
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 1,241	$ 1,027
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	61	35
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	328	328
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 500	$ 250
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	110	116
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	218	212
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 250
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	3	19,141
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf		313
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	39
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 714	750
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	527	277
Not Designated as Hedging Instrument [Member] | Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	500	250
Not Designated as Hedging Instrument [Member] | Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250
Floating interest rate	1.75%
Not Designated as Hedging Instrument [Member] | Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	250
Not Designated as Hedging Instrument [Member] | Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 509	$ 541
Subsequent Event [Member] | Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount			$ 400

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, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 33	$ 351
Location and fair value amounts of derivatives (Liability)	406	909
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	26	210
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	136
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	257	573
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	144	319
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	339
Location and fair value amounts of derivatives (Liability)	342	859
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	12
Location and fair value amounts of derivatives (Liability)	64	50
Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	10
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	14	13
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	41	29
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	18
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		15
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		15
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Location and fair value amounts of derivatives (Liability)	242	307
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		174
Location and fair value amounts of derivatives (Liability)		253
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	2
Location and fair value amounts of derivatives (Liability)	100	91
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		111
Location and fair value amounts of derivatives (Liability)		208
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	7
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	19
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	14
Duke Energy Carolinas [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	5
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	19
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	14
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	2
Location and fair value amounts of derivatives (Liability)	309	371
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	215	289
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	89	82
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	306	369
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10	2
Location and fair value amounts of derivatives (Liability)	3	2
Progress Energy [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	215	288
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	91	80
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	2
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	95	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	77	109
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	23
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	93	132
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	77	108
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	16	23
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	2
Location and fair value amounts of derivatives (Liability)	209	239
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	138	180
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	71	59
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	209	237
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	2
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	138	180
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	71	57
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	341
Location and fair value amounts of derivatives (Liability)	7	473
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	204
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		137
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	257
Duke Energy Ohio [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	216
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	341
Location and fair value amounts of derivatives (Liability)		467
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 7	6
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 4	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		28
Location and fair value amounts of derivatives (Liability)		4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		26
Location and fair value amounts of derivatives (Liability)		4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		175
Location and fair value amounts of derivatives (Liability)		252
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		111
Location and fair value amounts of derivatives (Liability)		207
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 12	$ 14

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 33	$ 351
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	110
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	406	909
Net amounts recognized on the Condensed Consolidated Balance Sheet	406	668
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	26	210
Gross amounts offset	(2)	(153)
Net amount subject to master netting	24	57
Net amounts recognized on the Condensed Consolidated Balance Sheet	24	57
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	136
Gross amounts offset	(2)	(88)
Net amount subject to master netting	5	48
Amounts not subject to master netting		5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	53
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	257	573
Gross amounts offset	(15)	(213)
Net amounts subject to master netting	242	360
Amounts not subject to master netting		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	242	361
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	144	319
Gross amounts offset	(9)	(173)
Net amounts subject to master netting	135	146
Amounts not subject to master netting	5	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	140	162
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	33	19
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	19
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	25	14
Net amounts subject to master netting	25	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	14
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	5
Net amounts subject to master netting	8	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	5
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	13	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	309	371
Net amounts recognized on the Condensed Consolidated Balance Sheet	309	373
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	2
Gross amounts offset	(1)	(2)
Net amount subject to master netting	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	6
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6
Gross amounts offset	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	215	289
Gross amounts offset	(14)	(17)
Net amounts subject to master netting	201	272
Net amounts recognized on the Condensed Consolidated Balance Sheet	201	272
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	89	82
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	80	74
Amounts not subject to master netting	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	85	74
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	95	132
Net amounts recognized on the Condensed Consolidated Balance Sheet	95	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amount subject to master netting	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	77	109
Net amounts subject to master netting	77	109
Net amounts recognized on the Condensed Consolidated Balance Sheet	77	109
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	23
Net amounts subject to master netting	18	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	23
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	209	239
Net amounts recognized on the Condensed Consolidated Balance Sheet	209	241
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Gross amounts offset	(1)	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6
Gross amounts offset	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	138	180
Gross amounts offset	(14)	(17)
Net amounts subject to master netting	124	163
Net amounts recognized on the Condensed Consolidated Balance Sheet	124	163
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	71	59
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	62	51
Net amounts recognized on the Condensed Consolidated Balance Sheet	62	51
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	341
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	49
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	473
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	181
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	204
Gross amounts offset		(179)
Net amount subject to master netting	4	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	25
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		137
Gross amounts offset		(114)
Net amount subject to master netting		23
Net amounts recognized on the Condensed Consolidated Balance Sheet		23
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	257
Gross amounts offset		(222)
Net amounts subject to master netting	1	35
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	35
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	216
Gross amounts offset		(193)
Net amounts subject to master netting	6	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	23
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12	14
Net amount subject to master netting	12	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 12	$ 14

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
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	$ 316	$ 845
Fair value of collateral already posted	20	209
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	296	407
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	20	145
Amounts not offset against net derivative positions		64
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	33	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	33	19
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	301	370
Fair value of collateral already posted	20	23
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	281	347
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	20	23
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	94	131
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	94	131
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	207	239
Fair value of collateral already posted	20	23
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	187	216
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	$ 20	23
Duke Energy Ohio [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		456
Fair value of collateral already posted		186
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered		41
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables		122
Amounts not offset against net derivative positions		$ 64

Investments in Debt and Equit72

Investments in Debt and Equity Securities (Narrative) (Details) $ in Millions	Dec. 31, 2014USD ($)
Investments, Debt and Equity Securities [Abstract]
Trading Securities	$ 7

Investments in Debt and Equit73

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$ 1,724	$ 2,004
Gross Unrealized Holding Losses	89	38
Estimated Fair Value	5,976	5,901
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,692	1,965
Gross Unrealized Holding Losses	84	35
Estimated Fair Value	5,562	5,549
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	156	136
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,655	1,926
Gross Unrealized Holding Losses	71	29
Estimated Fair Value	3,396	3,650
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	9	14
Gross Unrealized Holding Losses	7	2
Estimated Fair Value	500	454
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	5
Gross Unrealized Holding Losses	2
Estimated Fair Value	207	184
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	23	19
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	1,131	978
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	3	2
Estimated Fair Value	172	147
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	32	39
Gross Unrealized Holding Losses	5	3
Estimated Fair Value	414	352
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	32	15
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	27	34
Gross Unrealized Holding Losses	1
Estimated Fair Value	90	96
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	2	1
Estimated Fair Value	98	58
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	73	76
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1
Estimated Fair Value	52	27
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	69	80
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	943	1,119
Gross Unrealized Holding Losses	54	23
Estimated Fair Value	2,953	3,035
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	943	1,119
Gross Unrealized Holding Losses	53	22
Estimated Fair Value	2,950	3,032
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	25	51
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	930	1,102
Gross Unrealized Holding Losses	42	17
Estimated Fair Value	1,990	2,162
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	8
Gross Unrealized Holding Losses	6	2
Estimated Fair Value	342	316
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	1
Estimated Fair Value	69	62
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6	7
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	383	308
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	3	2
Estimated Fair Value	141	133
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	752	849
Gross Unrealized Holding Losses	31	13
Estimated Fair Value	2,678	2,575
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	749	846
Gross Unrealized Holding Losses	31	13
Estimated Fair Value	2,612	2,517
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	131	85
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	725	824
Gross Unrealized Holding Losses	29	12
Estimated Fair Value	1,406	1,488
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	4	6
Gross Unrealized Holding Losses	1
Estimated Fair Value	158	138
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	4
Gross Unrealized Holding Losses	1
Estimated Fair Value	138	122
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	17	12
Gross Unrealized Holding Losses		1
Estimated Fair Value	748	670
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	31	14
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	66	58
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	23	15
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	43	43
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	553	630
Gross Unrealized Holding Losses	25	11
Estimated Fair Value	1,944	1,711
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	553	630
Gross Unrealized Holding Losses	25	11
Estimated Fair Value	1,943	1,711
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	87	50
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	535	612
Gross Unrealized Holding Losses	23	10
Estimated Fair Value	1,107	1,171
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	5
Gross Unrealized Holding Losses	1
Estimated Fair Value	109	97
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	4
Gross Unrealized Holding Losses	1
Estimated Fair Value	136	120
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	12	9
Gross Unrealized Holding Losses		1
Estimated Fair Value	485	265
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	19	8
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	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
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	199	219
Gross Unrealized Holding Losses	6	2
Estimated Fair Value	723	850
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	196	216
Gross Unrealized Holding Losses	6	2
Estimated Fair Value	669	806
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	44	35
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	190	212
Gross Unrealized Holding Losses	6	2
Estimated Fair Value	299	317
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Estimated Fair Value	49	41
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	2
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	3
Estimated Fair Value	263	405
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	12	6
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	54	44
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	11	1
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	43	43
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	23	28
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	97	101
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	23	28
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	97	101
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	23	28
Estimated Fair Value	67	71
Duke Energy Indiana [Member] | Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	3
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	$ 27	$ 30

Investments in Debt and Equit74

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Sep. 30, 2015USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 74
Due after one through five years	781
Due after five through 10 years	635
Due after 10 years	812
Total	2,302
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	13
Due after one through five years	209
Due after five through 10 years	293
Due after 10 years	423
Total	938
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	38
Due after one through five years	476
Due after five through 10 years	271
Due after 10 years	333
Total	1,118
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	12
Due after one through five years	278
Due after five through 10 years	219
Due after 10 years	240
Total	749
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	26
Due after one through five years	198
Due after five through 10 years	52
Due after 10 years	93
Total	369
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	2
Due after one through five years	16
Due after five through 10 years	8
Due after 10 years	4
Total	$ 30

Investments in Debt and Equit75

Investments in Debt and Equity Securities (Realized Gains and Losses)(Details) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$ 30	$ 28	$ 160	$ 90
Realized losses	28	51	59	57
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	25	20	132	72
Realized losses	24	48	47	50
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	5	8	26	17
Realized losses	4	3	10	6
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	4	4	21	11
Realized losses	3	2	8	4
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	1	3	5	5
Realized losses	$ 1	$ 1	$ 2	$ 2

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$ 33	$ 110
Assets, fair value disclosure	6,009	6,018
Derivative liabilities	(406)	(668)
Net assets, fair value	5,603	5,350
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		49
Assets, fair value disclosure	3,956	4,327
Derivative liabilities	(4)	(162)
Net assets, fair value	3,952	4,165
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	24
Assets, fair value disclosure	1,860	1,498
Derivative liabilities	(402)	(468)
Net assets, fair value	1,458	1,030
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	17	37
Assets, fair value disclosure	193	193
Derivative liabilities		(38)
Net assets, fair value	193	155
Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,396	3,650
Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,224	3,493
Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	6
Equity Securities [Member] | Ndtf [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	171	151
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	90	96
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	90	96
Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,166	1,899
Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	557	648
Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,609	1,251
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	324	263
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	85	41
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	234	217
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	5	5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	2,953	3,035
Derivative liabilities	(33)	(19)
Net assets, fair value	2,920	3,016
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	2,021	2,143
Net assets, fair value	2,021	2,143
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	758	738
Derivative liabilities	(33)	(19)
Net assets, fair value	725	719
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	174	154
Net assets, fair value	174	154
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,990	2,162
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,818	2,005
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	6
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	171	151
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	960	870
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	203	138
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	757	732
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	13	4
Assets, fair value disclosure	2,691	2,579
Derivative liabilities	(309)	(373)
Net assets, fair value	2,382	2,206
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	1,783	2,013
Net assets, fair value	1,783	2,013
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	13	4
Assets, fair value disclosure	908	566
Derivative liabilities	(309)	(373)
Net assets, fair value	599	193
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,406	1,488
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,406	1,488
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,206	1,029
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	354	510
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	852	519
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	66	58
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	23	15
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	43	43
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Assets, fair value disclosure	1,946	1,711
Derivative liabilities	(95)	(132)
Net assets, fair value	1,851	1,579
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	1,244	1,322
Net assets, fair value	1,244	1,322
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Assets, fair value disclosure	702	389
Derivative liabilities	(95)	(132)
Net assets, fair value	607	257
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,107	1,171
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,107	1,171
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	836	540
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	136	151
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	700	389
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	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
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	11	4
Assets, fair value disclosure	734	854
Derivative liabilities	(209)	(241)
Net assets, fair value	525	613
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	529	676
Net assets, fair value	529	676
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	11	4
Assets, fair value disclosure	205	178
Derivative liabilities	(209)	(241)
Net assets, fair value	(4)	(63)
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	299	317
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	299	317
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	370	489
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	219	359
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	151	130
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	54	44
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	11
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	43	44
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	49
Derivative liabilities	(7)	(181)
Net assets, fair value	(3)	(132)
Duke Energy Ohio [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		20
Derivative liabilities		(117)
Net assets, fair value		(97)
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		9
Derivative liabilities	(7)	(26)
Net assets, fair value	(7)	(17)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	20
Derivative liabilities		(38)
Net assets, fair value	4	(18)
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	12	14
Net assets, fair value	109	115
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets, fair value	67	71
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets, fair value	30	30
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	12	14
Net assets, fair value	12	14
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale equity securities	67	71
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale equity securities	67	71
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale debt securities	30	30
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale debt securities	$ 30	$ 30

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments
Beginning balance	$ 196	$ 210	$ 155	$ 111
Total pretax gains (losses) included in earnings		(33)	18	(21)
Purchases	2	12	38	79
Sales	(3)	(13)	(7)	(15)
Issuances		1
Settlements	(6)		(28)	(45)
Transfers in and/or out of level 3		(1)		64
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	4	(6)	17	(3)
Ending balance	193	170	193	170
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance			(1)
Ending balance	17		17
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		(49)		(49)
Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	23	22	(1)	13
Total pretax gains (losses) included in earnings		(33)	18	(21)
Purchases		(1)	24	50
Issuances		1
Settlements	(6)		(28)	(45)
Transfers out of level 3		1		4
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities		(10)	4	(15)
Ending balance	17	(22)	17	(22)
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		(49)		(49)
Investments [Member]
Investments
Beginning balance	173	188	156	98
Purchases	2	13	14	29
Sales	(3)	(13)	(7)	(15)
Transfers in and/or out of level 3				68
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	4	4	13	12
Ending balance	176	192	176	192
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding				0
Duke Energy Carolinas [Member]
Investments
Beginning balance	171	168	154	79
Purchases	2	13	14	29
Sales	(3)	(13)	(7)	(15)
Settlements		3		2
Transfers in and/or out of level 3				68
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	4	4	13	12
Ending balance	174	175	174	175
Duke Energy Carolinas [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance		(3)		(2)
Settlements		3		2
Duke Energy Carolinas [Member] | Investments [Member]
Investments
Beginning balance	171	171	154	81
Purchases	2	13	14	29
Sales	(3)	(13)	(7)	(15)
Transfers in and/or out of level 3				68
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	4	4	13	12
Ending balance	174	175	174	175
Duke Energy Ohio [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance			(18)
Duke Energy Ohio [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	5	(28)	(18)	(4)
Total pretax gains (losses) included in earnings		(24)	21	(43)
Purchases	5		5	1
Sales	(5)
Settlements	(1)	(2)	(4)	(6)
Transfers out of level 3				(4)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities		(1)		1
Ending balance	4	(55)	4	(55)
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding				(52)
Duke Energy Indiana [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	17	45	14	12
Total pretax gains (losses) included in earnings		(13)		14
Purchases	1		19	49
Settlements	(6)		(25)	(38)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities		(10)	4	(15)
Ending balance	$ 12	$ 22	$ 12	$ 22

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)$ / MWh	Dec. 31, 2014USD ($)$ / MWh$ / MMBTU$ / MW
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ 17	$ (1)
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (5)
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu | $ / MMBTU		2.12
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu | $ / MMBTU		4.35
Derivative Financial Instruments Liabilities Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ 1
Derivative Financial Instruments Liabilities Power Sale Agreements [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh	18.50
Derivative Financial Instruments Liabilities Power Sale Agreements [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh	84.35
Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ 16	$ 14
Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh	(0.81)	(1.92)
Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh	7.23	9.86
Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (1)
Commodity Power Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh		25.16
Commodity Power Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh		51.75
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ 2
Commodity Capacity Option Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MW day | $ / MW		21
Commodity Capacity Option Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MW day | $ / MW		109
Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (11)
Duke Energy Ohio [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(18)
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (5)
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu | $ / MMBTU		2.12
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu | $ / MMBTU		4.35
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)	$ 4
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 MWh | $ / MWh	0.37
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 MWh | $ / MWh	2.17
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (6)
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh		25.25
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh | $ / MWh		51.75
Duke Energy Ohio [Member] | Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		$ (7)
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)	$ 12	$ 14
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 MWh | $ / MWh	(0.81)	(1.92)
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 MWh | $ / MWh	7.23	9.86

Fair Value Measurements (Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 40,203	$ 40,020
Long-term debt, fair value	43,864	44,566
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,884	8,391
Long-term debt, fair value	9,860	9,626
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	15,396	14,754
Long-term debt, fair value	17,146	16,951
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	6,851	6,201
Long-term debt, fair value	7,214	6,696
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,850	4,860
Long-term debt, fair value	5,585	5,767
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,605	1,766
Long-term debt, fair value	1,766	1,970
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,790	3,791
Long-term debt, fair value	$ 4,330	$ 4,456

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Variable Interest Entities [Line Items]
Asset impairment charges	$ 111	$ 1	$ 111	$ 81
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]
Asset impairment charges				3
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Asset impairment charges				(18)
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Asset impairment charges	$ 7	$ 1	$ 7	2
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Asset impairment charges				94
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 Ohio [Member] | Other VIEs [Member]
Variable Interest Entities [Line Items]
Asset impairment charges				$ 94	$ 94
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Asset impairment charges	$ 85		$ 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 Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 1,370	$ 2,036	$ 1,931	$ 1,501
Restricted receivables of VIEs	2,037	1,973
Other current assets	1,566	1,837
Investments and other assets	3,205	3,008
Property, plant and equipment, cost	110,795	104,861
Accumulated depreciation and amortization	(37,479)	(34,824)
Other deferred debits	188	171
Accounts payable	2,078	2,271
Current maturities of long-term debt	2,536	2,807
Other current liabilities	2,052	2,188
Long-Term Debt	37,667	37,213
Deferred income taxes	13,999	13,423
Asset retirement obligation	9,713	8,466
Other liabilities	1,595	1,675
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	2
Restricted receivables of VIEs	2,037	1,973
Other current assets	222	74
Investments and other assets	25	50
Property, plant and equipment, cost	1,945	1,873
Accumulated depreciation and amortization	(307)	(255)
Other deferred debits	38	36
Total assets	3,962	3,751
Accounts payable	6	3
Taxes accrued	15	6
Current maturities of long-term debt	91	84
Other current liabilities	27	21
Long-Term Debt	2,169	2,234
Deferred income taxes	325	283
Asset retirement obligation	30	29
Other liabilities	42	38
Total liabilities	2,705	2,698
Net assets of consolidated VIEs	1,257	1,053
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	198	13	34	23
Restricted receivables of VIEs	687	647
Other current assets	164	77
Investments and other assets	1,018	959
Property, plant and equipment, cost	38,653	37,372
Accumulated depreciation and amortization	(13,445)	(12,700)
Other deferred debits	43	42
Accounts payable	623	709
Current maturities of long-term debt	506	507
Other current liabilities	415	434
Long-Term Debt	8,078	7,584
Deferred income taxes	6,067	5,812
Asset retirement obligation	3,599	3,428
Other liabilities	618	642
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	123	9	6	21
Restricted receivables of VIEs	468	436
Other current assets	53	384
Investments and other assets	484	412
Property, plant and equipment, cost	26,919	24,207
Accumulated depreciation and amortization	(10,207)	(9,021)
Other deferred debits	40	34
Accounts payable	381	481
Current maturities of long-term debt	402	945
Other current liabilities	375	409
Long-Term Debt	6,449	5,256
Deferred income taxes	3,097	2,908
Asset retirement obligation	4,489	3,905
Other liabilities	120	168
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	16	8	$ 15	$ 16
Restricted receivables of VIEs	395	305
Other current assets	179	521
Investments and other assets	308	204
Property, plant and equipment, cost	15,011	14,433
Accumulated depreciation and amortization	(4,648)	(4,478)
Other deferred debits	36	39
Accounts payable	316	365
Current maturities of long-term debt	563	562
Other current liabilities	553	586
Long-Term Debt	4,287	4,298
Deferred income taxes	2,579	2,452
Asset retirement obligation	732	806
Other liabilities	157	158
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	687	647
Total assets	687	647
Taxes accrued	5
Long-Term Debt	400	400
Total liabilities	405	400
Net assets of consolidated VIEs	282	247
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	468	436
Other current assets	1
Total assets	469	436
Taxes accrued	3
Long-Term Debt	300	300
Total liabilities	303	300
Net assets of consolidated VIEs	166	136
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	395	305
Other current assets	2
Total assets	397	305
Taxes accrued	1
Long-Term Debt	225	225
Total liabilities	226	225
Net assets of consolidated VIEs	171	80
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	453	547
Total assets	453	547
Long-Term Debt	325	325
Total liabilities	325	325
Net assets of consolidated VIEs	128	222
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	2
Restricted receivables of VIEs	12	20
Other current assets	215	68
Investments and other assets	20	25
Property, plant and equipment, cost	1,926	1,855
Accumulated depreciation and amortization	(302)	(250)
Other deferred debits	37	34
Total assets	1,910	1,752
Accounts payable	6	3
Taxes accrued	6	6
Current maturities of long-term debt	73	68
Other current liabilities	23	16
Long-Term Debt	916	967
Deferred income taxes	325	283
Asset retirement obligation	30	29
Other liabilities	42	34
Total liabilities	1,421	1,406
Net assets of consolidated VIEs	489	346
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	22	18
Other current assets	4	6
Investments and other assets	5	25
Property, plant and equipment, cost	19	18
Accumulated depreciation and amortization	(5)	(5)
Other deferred debits	1	2
Total assets	46	64
Current maturities of long-term debt	18	16
Other current liabilities	4	5
Long-Term Debt	3	17
Other liabilities		4
Total liabilities	25	42
Net assets of consolidated VIEs	$ 21	$ 22

Variable Interest Entities (S82

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details)	Sep. 30, 2015USD ($)
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 1,700,000,000
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	500,000,000
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	1,200,000,000
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	400,000,000
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	300,000,000
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 225,000,000

Variable Interest Entities (S83

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 501	$ 358
Investments and other assets	3,205	3,008
Other current liabilities	2,052	2,188
Deferred credits and other liabilities	32,982	31,364
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	348	188
Investments and other assets		4
Total assets	348	192
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets	332	175
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	223	150
Total assets	223	150
Total liabilities	0
Net assets	223	150
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	125	38
Investments and other assets		4
Total assets	125	42
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets	109	25
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Investments and other assets	17	23
Other current liabilities	151	66
Deferred credits and other liabilities	2,006	2,281
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables	43	91
Total assets	43	91
Total liabilities	0
Net assets	43	91
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Other current liabilities	89	98
Deferred credits and other liabilities	3,309	2,730
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables	64	113
Total assets	64	113
Total liabilities	0
Net assets	$ 64	$ 113

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions)(Details) - Cinergy Receivables [Member]	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.60%	0.60%
Discount rate	1.20%	1.20%
Receivable turnover rate	12.90%	12.80%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.20%	1.20%
Receivable turnover rate	10.60%	10.50%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold)(Details) - Cinergy Receivables [Member] - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 221	$ 273
Less: Retained interests	43	91
Net receivables sold	178	182
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	271	310
Less: Retained interests	64	113
Net receivables sold	$ 207	$ 197

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 449	$ 477	$ 1,518	$ 1,705
Loss recognized on sale	2	3	7	9
Cash proceeds from receivables sold	461	494	1,568	1,761
Collection fees received	0		1	1
Return received on retained interests	0		2	3
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	679	739	2,032	2,173
Loss recognized on sale	3	3	8	8
Cash proceeds from receivables sold	692	759	2,074	2,233
Collection fees received	0		1	1
Return received on retained interests	$ 1	$ 2	$ 4	$ 5

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 937	$ 888	$ 2,310	$ 2,356
Average shares, basic	688	707	696	707
Average shares, diluted	688	707	696	707
EPS, basic (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
EPS, diluted (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 935	$ 887	$ 2,307	$ 2,351
Average shares, basic	688	707	696	707
Average shares, diluted	688	707	696	707
EPS, basic (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
EPS, diluted (usd per share)	1.36	1.25	$ 3.31	$ 3.33
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation			2	2
Dividends declared per share (usd per share)	$ 0.825	$ 0.795	$ 2.42	$ 2.355

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	$ 1,500
Percentage of ASR common stock received				85.00%
Forward Contracts Indexed to Issuer's Equity, Value	$ 225
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

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	10		10
Pretax stock-based compensation expense	$ 14	$ 12	$ 47	$ 44
Tax benefit associated with stock-based compensation expense	6	5	18	17
Stock-based compensation costs capitalized	1	1	3	3
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	9	8	29	30
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$ 5	$ 4	$ 18	$ 14

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Maximum years of participation		35 years
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%
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 11	$ 143
Duke Energy Carolinas [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		42
Progress Energy [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		42
Duke Energy Progress [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		21
Duke Energy Florida [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		21
Duke Energy Ohio [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 3	4
Duke Energy Indiana [Member] | Qualified Pension Plans [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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 40	$ 34	$ 119	$ 102
Interest cost on projected benefit obligation	81	86	244	258
Expected return on plan assets	(129)	(128)	(387)	(383)
Amortization of actuarial loss (gain)	44	37	131	111
Amortization of prior service cost (credit)	(4)	(4)	(11)	(11)
Other	2	3	6	6
Net periodic costs	34	28	102	83
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	13	10	38	31
Interest cost on projected benefit obligation	21	22	62	64
Expected return on plan assets	(35)	(33)	(104)	(99)
Amortization of actuarial loss (gain)	10	8	30	26
Amortization of prior service cost (credit)	(2)	(2)	(6)	(6)
Other	1	1	2	2
Net periodic costs	8	6	22	18
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11	10	33	30
Interest cost on projected benefit obligation	26	28	78	84
Expected return on plan assets	(43)	(44)	(127)	(130)
Amortization of actuarial loss (gain)	17	17	51	51
Amortization of prior service cost (credit)	(1)		(3)	(2)
Other	1	1	2	2
Net periodic costs	11	12	34	35
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	6	6	18	16
Interest cost on projected benefit obligation	12	13	36	40
Expected return on plan assets	(20)	(21)	(61)	(64)
Amortization of actuarial loss (gain)	8	8	25	24
Amortization of prior service cost (credit)			(1)	(1)
Other			1	1
Net periodic costs	6	6	18	16
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5	5	15	15
Interest cost on projected benefit obligation	14	14	41	43
Expected return on plan assets	(22)	(21)	(66)	(64)
Amortization of actuarial loss (gain)	8	8	24	24
Amortization of prior service cost (credit)			(1)	(1)
Other			1	1
Net periodic costs	5	6	14	18
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	14	15
Expected return on plan assets	(7)	(7)	(20)	(20)
Amortization of actuarial loss (gain)	3	1	8	3
Net periodic costs	2		5	1
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3	3	8	7
Interest cost on projected benefit obligation	7	7	21	22
Expected return on plan assets	(10)	(10)	(31)	(30)
Amortization of actuarial loss (gain)	3	3	10	9
Net periodic costs	3	3	8	8
Other Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	2	2
Interest cost on projected benefit obligation	3	3	10	10
Amortization of actuarial loss (gain)	2	1	5	2
Net periodic costs	6	5	17	14
Other Pension Plan [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation		1	1	1
Net periodic costs		1	1	1
Other Pension Plan [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			1	1
Interest cost on projected benefit obligation	1	2	3	4
Amortization of actuarial loss (gain)	1		2	1
Amortization of prior service cost (credit)		(1)		(1)
Net periodic costs	2	1	6	5
Other Pension Plan [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1		1
Interest cost on projected benefit obligation			1	1
Net periodic costs		1	1	2
Other Pension Plan [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1		2	1
Amortization of actuarial loss (gain)			1
Net periodic costs	1		3	1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	2	4	7
Interest cost on projected benefit obligation	9	13	27	38
Expected return on plan assets	(3)	(3)	(9)	(9)
Amortization of actuarial loss (gain)	6	9	19	29
Amortization of prior service cost (credit)	(35)	(31)	(105)	(94)
Net periodic costs	(22)	(10)	(64)	(29)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			1	1
Interest cost on projected benefit obligation	2	3	6	9
Expected return on plan assets	(2)	(2)	(6)	(6)
Amortization of actuarial loss (gain)		1	(1)	2
Amortization of prior service cost (credit)	(4)	(3)	(11)	(8)
Net periodic costs	(4)	(1)	(11)	(2)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1	3
Interest cost on projected benefit obligation	4	6	11	17
Amortization of actuarial loss (gain)	7	10	21	31
Amortization of prior service cost (credit)	(26)	(24)	(77)	(71)
Net periodic costs	(15)	(7)	(44)	(20)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				1
Interest cost on projected benefit obligation	2	3	6	8
Amortization of actuarial loss (gain)	5	8	14	23
Amortization of prior service cost (credit)	(17)	(19)	(50)	(55)
Net periodic costs	(10)	(8)	(30)	(23)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				2
Interest cost on projected benefit obligation	2	3	5	9
Amortization of actuarial loss (gain)	3	3	8	8
Amortization of prior service cost (credit)	(9)	(5)	(25)	(16)
Net periodic costs	(4)	1	(12)	3
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)
Net periodic costs			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	4
Expected return on plan assets				(1)
Amortization of actuarial loss (gain)			(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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Employee Savings Plans [Abstract]
Employer matching contributions	$ 34	$ 30	$ 120	$ 110
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Employer matching contributions	11	10	40	36
Progress Energy [Member]
Employee Savings Plans [Abstract]
Employer matching contributions	10	10	36	33
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Employer matching contributions	7	7	26	23
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Employer matching contributions	3	3	10	10
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Employer matching contributions			2	2
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Employer matching contributions	$ 1	$ 1	$ 5	$ 5

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	30.90%	34.00%	32.50%	31.40%
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	36.50%	33.90%	36.30%	33.70%
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	25.00%	37.10%	31.80%	37.30%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	34.40%	36.30%	35.30%	36.60%
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	30.10%	38.50%	35.20%	38.60%
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	39.30%	38.30%	37.60%	34.90%
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	37.00%	31.60%	36.60%	35.20%