Duke Energy (DUK) 10-Q 5 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 30, 2016
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	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		688,903,766
Duke Energy Carolinas [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Carolinas, LLC
Entity Central Index Key	30,371
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Progress Energy [Member]
Document Information [Line Items]
Entity Registrant Name	Progress Energy, Inc
Entity Central Index Key	1,094,093
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Progress [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Progress, LLC
Entity Central Index Key	17,797
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Florida [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Florida, LLC
Entity Central Index Key	37,637
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Ohio [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Ohio, Inc.
Entity Central Index Key	20,290
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Duke Energy Indiana [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Indiana, LLC
Entity Central Index Key	81,020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Revenues
Regulated electric	$ 5,053	$ 5,457
Nonregulated electric and other	400	377
Regulated natural gas	169	231
Total operating revenues	5,622	6,065
Operating Expenses
Fuel used in electric generation and purchased power – regulated	1,577	1,941
Fuel used in electric generation and purchased power – nonregulated	58	104
Cost of natural gas	60	111
Operation, maintenance and other	1,489	1,426
Depreciation and amortization	814	777
Property and other taxes	297	264
Impairment charges	3
Total operating expenses	4,298	4,623
Gains (Losses) on Sales of Other Assets and Other, net	9	14
Operating Income	1,333	1,456
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	8	13
Other income and expenses, net	79	74
Total other income and expenses	87	87
Interest Expense	511	403
Income From Continuing Operations Before Income Taxes	909	1,140
Income Tax Expense from Continuing Operations	213	364
Income from Continuing Operations	696	776
Income From Discontinued Operations, net of tax	3	91
Net income	699	867
Less: Net Income Attributable to Noncontrolling Interests	5	3
Net Income (Loss) Attributable to Parent	694	864
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments		(5)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(14)	(7)
Reclassification into earnings from cash flow hedges	2	4
Unrealized gains (losses) on available-for-sale securities	4
Other Comprehensive Income, net of tax	41	(133)
Comprehensive Income	740	734
Less: Comprehensive Income Attributable to Noncontrolling Interests	6	(1)
Comprehensive Income Attributable to Parent	$ 734	$ 735
Income from continuing operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	$ 1	$ 1.09
Diluted (usd per share)	1	1.09
Income from discontinued operations attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	0.01	0.13
Diluted (usd per share)	0.01	0.13
Net income attributable to Duke Energy Corporation common stockholders
Basic (usd per share)	1.01	1.22
Diluted (usd per share)	$ 1.01	$ 1.22
Weighted average shares outstanding
Basic (shares)	689	708
Diluted (shares)	689	708
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	$ 1,740	$ 1,901
Operating Expenses
Fuel used in electric generation and purchased power – regulated	421	578
Operation, maintenance and other	512	489
Depreciation and amortization	259	249
Property and other taxes	67	70
Total operating expenses	1,259	1,386
Operating Income	481	515
Other Income and Expenses
Other income and expenses, net	37	42
Interest Expense	107	102
Income From Continuing Operations Before Income Taxes	411	455
Income Tax Expense from Continuing Operations	140	163
Net Income (Loss) Attributable to Parent	271	292
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	272	292
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,332	2,536
Operating Expenses
Fuel used in electric generation and purchased power – regulated	860	1,032
Operation, maintenance and other	592	565
Depreciation and amortization	290	287
Property and other taxes	119	111
Impairment charges	2
Total operating expenses	1,863	1,995
Gains (Losses) on Sales of Other Assets and Other, net	6	8
Operating Income	475	549
Other Income and Expenses
Other income and expenses, net	20	27
Interest Expense	160	168
Income From Continuing Operations Before Income Taxes	335	408
Income Tax Expense from Continuing Operations	123	144
Income from Continuing Operations	212	264
Income From Discontinued Operations, net of tax		(1)
Net income	212	263
Less: Net Income Attributable to Noncontrolling Interests	3	3
Net Income (Loss) Attributable to Parent	209	260
Other Comprehensive Income (Loss), net of tax
Pension and OPEB adjustments	1	1
Reclassification into earnings from cash flow hedges	1	(2)
Unrealized gains (losses) on available-for-sale securities	1
Other Comprehensive Income, net of tax	3	(1)
Comprehensive Income	215	262
Less: Comprehensive Income Attributable to Noncontrolling Interests	3	3
Comprehensive Income Attributable to Parent	212	259
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,307	1,449
Operating Expenses
Fuel used in electric generation and purchased power – regulated	448	575
Operation, maintenance and other	386	375
Depreciation and amortization	175	152
Property and other taxes	41	32
Total operating expenses	1,050	1,134
Gains (Losses) on Sales of Other Assets and Other, net	1	1
Operating Income	258	316
Other Income and Expenses
Other income and expenses, net	17	20
Interest Expense	63	60
Income From Continuing Operations Before Income Taxes	212	276
Income Tax Expense from Continuing Operations	75	93
Net Income (Loss) Attributable to Parent	137	183
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,024	1,086
Operating Expenses
Fuel used in electric generation and purchased power – regulated	412	457
Operation, maintenance and other	205	188
Depreciation and amortization	114	134
Property and other taxes	78	80
Impairment charges	2
Total operating expenses	811	859
Operating Income	213	227
Other Income and Expenses
Other income and expenses, net	5	6
Interest Expense	41	49
Income From Continuing Operations Before Income Taxes	177	184
Income Tax Expense from Continuing Operations	67	71
Net Income (Loss) Attributable to Parent	110	113
Other Comprehensive Income (Loss), net of tax
Unrealized gains (losses) on available-for-sale securities	1	0
Other Comprehensive Income, net of tax	1
Comprehensive Income Attributable to Parent	111	113
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	340	339
Nonregulated electric and other	6	14
Regulated natural gas	170	233
Total operating revenues	516	586
Operating Expenses
Fuel used in electric generation and purchased power – regulated	111	115
Fuel used in electric generation and purchased power – nonregulated	10	14
Cost of natural gas	49	97
Operation, maintenance and other	119	128
Depreciation and amortization	61	57
Property and other taxes	71	70
Total operating expenses	421	481
Gains (Losses) on Sales of Other Assets and Other, net	1	6
Operating Income	96	111
Other Income and Expenses
Other income and expenses, net	2	3
Interest Expense	20	20
Income From Continuing Operations Before Income Taxes	78	94
Income Tax Expense from Continuing Operations	21	35
Income from Continuing Operations	57	59
Income From Discontinued Operations, net of tax	2	90
Net income		149
Net Income (Loss) Attributable to Parent	59	149
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	714	788
Operating Expenses
Fuel used in electric generation and purchased power – regulated	228	294
Operation, maintenance and other	162	181
Depreciation and amortization	125	104
Property and other taxes	23	(1)
Total operating expenses	538	578
Operating Income	176	210
Other Income and Expenses
Other income and expenses, net	4	5
Interest Expense	44	45
Income From Continuing Operations Before Income Taxes	136	170
Income Tax Expense from Continuing Operations	41	62
Net Income (Loss) Attributable to Parent	95	108
Other Comprehensive Income (Loss), net of tax
Reclassification into earnings from cash flow hedges	(1)	(1)
Other Comprehensive Income, net of tax	(1)	(1)
Comprehensive Income Attributable to Parent	$ 94	$ 107

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income (loss)	$ 699	$ 867
Other Comprehensive Income (Loss), net of tax
Foreign currency translation adjustments	49	(125)
Pension and OPEB adjustments		(5)
Net unrealized losses on cash flow hedges	(14)	(7)
Reclassification into earnings from cash flow hedges	2	4
Unrealized gains on available-for-sale securities	4
Other Comprehensive Income (Loss), net of tax	41	(133)
Comprehensive Income	740	734
Less: Comprehensive Income (Loss) Attributable to Noncontrolling Interests	6	(1)
Comprehensive Income Attributable to Parent	$ 734	$ 735

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 778	$ 857
Receivables (net of allowance for doubtful accounts)	609	703
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	1,714	1,748
Inventory	3,721	3,810
Regulatory assets	813	877
Other	308	327
Total current assets	7,943	8,322
Investments and Other Assets
Investments in equity method unconsolidated affiliates	547	499
Nuclear decommissioning trust funds	5,880	5,825
Goodwill	16,349	16,343
Other	3,036	3,042
Total investments and other assets	25,812	25,709
Property, Plant and Equipment
Cost	113,942	112,826
Accumulated depreciation and amortization	(38,154)	(37,665)
Generation facilities to be retired, net	644	548
Net property, plant and equipment	76,432	75,709
Regulatory Assets and Deferred Debits
Regulatory assets	11,483	11,373
Other	39	43
Total regulatory assets and deferred debits	11,522	11,416
Total Assets	121,709	121,156
Current Liabilities
Accounts payable	2,086	2,400
Notes payable and commercial paper	3,486	3,633
Taxes accrued	394	348
Interest accrued	481	430
Current maturities of long-term debt	2,075	2,074
Regulatory liabilities	404	400
Other	1,965	2,115
Total current liabilities	10,891	11,400
Long-Term Debt	38,232	37,495
Deferred Credits and Other Liabilities
Deferred income taxes	12,825	12,705
Investment tax credits	493	472
Accrued pension and other post-retirement benefit costs	1,077	1,088
Asset retirement obligations	10,269	10,264
Regulatory liabilities	6,278	6,255
Other	1,703	1,706
Total deferred credits and other liabilities	$ 32,645	$ 32,490
Commitments and Contingencies
Equity
Common stock	$ 1	$ 1
Additional paid-in capital	37,969	37,968
Retained earnings	2,688	2,564
Accumulated other comprehensive income (loss)	(766)	(806)
Total Duke Energy Corporation stockholders' equity	39,892	39,727
Noncontrolling interests	49	44
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	39,941	39,771
Total Liabilities and Equity	121,709	121,156
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	17	13
Receivables (net of allowance for doubtful accounts)	129	142
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	615	596
Receivables from affiliated companies	74	107
Notes receivable from affiliated companies	854	163
Inventory	1,236	1,276
Regulatory assets	269	305
Other	32	128
Total current assets	3,226	2,730
Investments and Other Assets
Nuclear decommissioning trust funds	3,081	3,050
Other	1,003	999
Total investments and other assets	4,084	4,049
Property, Plant and Equipment
Cost	39,833	39,398
Accumulated depreciation and amortization	(13,769)	(13,521)
Net property, plant and equipment	26,064	25,877
Regulatory Assets and Deferred Debits
Regulatory assets	2,801	2,766
Other	4	4
Total regulatory assets and deferred debits	2,805	2,770
Total Assets	36,179	35,426
Current Liabilities
Accounts payable	597	753
Accounts payable to affiliated companies	250	229
Taxes accrued	76	25
Interest accrued	134	95
Current maturities of long-term debt	468	356
Regulatory liabilities	48	39
Other	452	519
Total current liabilities	2,025	2,016
Long-Term Debt	8,592	7,711
Long-Term Debt Payable to Affiliated Companies	300	300
Deferred Credits and Other Liabilities
Deferred income taxes	6,298	6,146
Investment tax credits	197	199
Accrued pension and other post-retirement benefit costs	105	107
Asset retirement obligations	3,913	3,918
Regulatory liabilities	2,829	2,802
Other	642	621
Total deferred credits and other liabilities	$ 13,984	$ 13,793
Commitments and Contingencies
Equity
Member's equity	$ 11,288	$ 11,617
Accumulated other comprehensive income (loss)	(10)	(11)
Members' Equity	11,278	11,606
Total Liabilities and Equity	36,179	35,426
Progress Energy [Member]
Current Assets
Cash and cash equivalents	41	44
Receivables (net of allowance for doubtful accounts)	110	151
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	627	658
Receivables from affiliated companies	37	375
Inventory	1,748	1,751
Regulatory assets	333	362
Other	237	156
Total current assets	3,133	3,497
Investments and Other Assets
Nuclear decommissioning trust funds	2,798	2,775
Goodwill	3,655	3,655
Other	876	834
Total investments and other assets	7,329	7,264
Property, Plant and Equipment
Cost	43,166	42,666
Accumulated depreciation and amortization	(15,008)	(14,867)
Generation facilities to be retired, net	531	548
Net property, plant and equipment	28,689	28,347
Regulatory Assets and Deferred Debits
Regulatory assets	5,498	5,435
Other	5	5
Total regulatory assets and deferred debits	5,503	5,440
Total Assets	44,654	44,548
Current Liabilities
Accounts payable	666	722
Accounts payable to affiliated companies	256	311
Notes payable to affiliated companies	1,436	1,308
Taxes accrued	95	53
Interest accrued	185	195
Current maturities of long-term debt	265	315
Regulatory liabilities	279	286
Other	861	891
Total current liabilities	4,043	4,081
Long-Term Debt	13,795	13,999
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	4,937	4,790
Accrued pension and other post-retirement benefit costs	533	536
Asset retirement obligations	5,372	5,369
Regulatory liabilities	2,386	2,387
Other	371	383
Total deferred credits and other liabilities	$ 13,599	$ 13,465
Commitments and Contingencies
Equity
Additional paid-in capital	$ 8,092	$ 8,092
Retained earnings	5,040	4,831
Accumulated other comprehensive income (loss)	(45)	(48)
Total Duke Energy Corporation stockholders' equity	13,087	12,875
Noncontrolling interests	(20)	(22)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	13,067	12,853
Total Liabilities and Equity	44,654	44,548
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	11	15
Receivables (net of allowance for doubtful accounts)	47	87
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	372	349
Receivables from affiliated companies	6	16
Inventory	1,074	1,088
Regulatory assets	222	264
Other	51	121
Total current assets	1,783	1,940
Investments and Other Assets
Nuclear decommissioning trust funds	2,068	2,035
Other	521	486
Total investments and other assets	2,589	2,521
Property, Plant and Equipment
Cost	27,503	27,313
Accumulated depreciation and amortization	(10,266)	(10,141)
Generation facilities to be retired, net	531	548
Net property, plant and equipment	17,768	17,720
Regulatory Assets and Deferred Debits
Regulatory assets	2,768	2,710
Other	2	3
Total regulatory assets and deferred debits	2,770	2,713
Total Assets	24,910	24,894
Current Liabilities
Accounts payable	295	399
Accounts payable to affiliated companies	176	190
Notes payable to affiliated companies	108	209
Taxes accrued	33	15
Interest accrued	80	96
Current maturities of long-term debt	252	2
Regulatory liabilities	93	85
Other	382	412
Total current liabilities	1,419	1,408
Long-Term Debt	6,163	6,366
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	3,089	3,027
Investment tax credits	154	132
Accrued pension and other post-retirement benefit costs	261	262
Asset retirement obligations	4,573	4,567
Regulatory liabilities	1,876	1,878
Other	29	45
Total deferred credits and other liabilities	$ 9,982	$ 9,911
Commitments and Contingencies
Equity
Member's equity	$ 7,196	$ 7,059
Members' Equity	7,196	7,059
Total Liabilities and Equity	24,910	24,894
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	12	8
Receivables (net of allowance for doubtful accounts)	61	60
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	256	308
Receivables from affiliated companies	27	84
Inventory	674	663
Regulatory assets	111	98
Other	52	21
Total current assets	1,193	1,242
Investments and Other Assets
Nuclear decommissioning trust funds	730	740
Other	301	292
Total investments and other assets	1,031	1,032
Property, Plant and Equipment
Cost	15,652	15,343
Accumulated depreciation and amortization	(4,734)	(4,720)
Net property, plant and equipment	10,918	10,623
Regulatory Assets and Deferred Debits
Regulatory assets	2,730	2,725
Other	2	2
Total regulatory assets and deferred debits	2,732	2,727
Total Assets	15,874	15,624
Current Liabilities
Accounts payable	371	322
Accounts payable to affiliated companies	76	116
Notes payable to affiliated companies	948	813
Taxes accrued	62	132
Interest accrued	59	43
Current maturities of long-term debt	13	13
Regulatory liabilities	186	200
Other	451	452
Total current liabilities	2,166	2,091
Long-Term Debt	4,252	4,253
Deferred Credits and Other Liabilities
Deferred income taxes	2,544	2,460
Accrued pension and other post-retirement benefit costs	240	242
Asset retirement obligations	799	802
Regulatory liabilities	509	509
Other	132	146
Total deferred credits and other liabilities	$ 4,224	$ 4,159
Commitments and Contingencies
Equity
Member's equity	$ 5,231	$ 5,121
Accumulated other comprehensive income (loss)	1
Members' Equity	5,232	5,121
Total Liabilities and Equity	15,874	15,624
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	19	14
Receivables (net of allowance for doubtful accounts)	85	66
Receivables from affiliated companies	93	84
Notes receivable from affiliated companies	19
Inventory	105	105
Regulatory assets	26	36
Other	32	110
Total current assets	379	415
Investments and Other Assets
Goodwill	920	920
Other	20	20
Total investments and other assets	940	940
Property, Plant and Equipment
Cost	7,803	7,750
Accumulated depreciation and amortization	(2,515)	(2,507)
Net property, plant and equipment	5,288	5,243
Regulatory Assets and Deferred Debits
Regulatory assets	503	497
Other	2	2
Total regulatory assets and deferred debits	505	499
Total Assets	7,112	7,097
Current Liabilities
Accounts payable	211	207
Accounts payable to affiliated companies	53	53
Notes payable to affiliated companies	8	103
Taxes accrued	141	171
Interest accrued	29	18
Current maturities of long-term debt	55	106
Regulatory liabilities	18	12
Other	151	153
Total current liabilities	666	823
Long-Term Debt	1,562	1,467
Long-Term Debt Payable to Affiliated Companies	25	25
Deferred Credits and Other Liabilities
Deferred income taxes	1,427	1,407
Accrued pension and other post-retirement benefit costs	55	56
Asset retirement obligations	125	125
Regulatory liabilities	245	245
Other	164	165
Total deferred credits and other liabilities	$ 2,016	$ 1,998
Commitments and Contingencies
Equity
Common stock	$ 762	$ 762
Additional paid-in capital	2,720	2,720
Retained earnings	(639)	(698)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,843	2,784
Total Liabilities and Equity	7,112	7,097
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	17	9
Receivables (net of allowance for doubtful accounts)	82	96
Receivables from affiliated companies	64	71
Notes receivable from affiliated companies	102	83
Inventory	525	570
Regulatory assets	114	102
Other	16	15
Total current assets	920	946
Investments and Other Assets
Total investments and other assets	208	212
Property, Plant and Equipment
Cost	13,864	14,007
Accumulated depreciation and amortization	(4,472)	(4,484)
Generation facilities to be retired, net	113
Net property, plant and equipment	9,505	9,523
Regulatory Assets and Deferred Debits
Regulatory assets	766	716
Other	2	2
Total regulatory assets and deferred debits	768	718
Total Assets	11,401	11,399
Current Liabilities
Accounts payable	124	189
Accounts payable to affiliated companies	61	83
Taxes accrued	119	89
Interest accrued	51	56
Current maturities of long-term debt	547	547
Regulatory liabilities	60	62
Other	78	97
Total current liabilities	1,040	1,123
Long-Term Debt	3,071	3,071
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	1,650	1,657
Investment tax credits	138	138
Accrued pension and other post-retirement benefit costs	78	80
Asset retirement obligations	525	525
Regulatory liabilities	759	754
Other	60	65
Total deferred credits and other liabilities	$ 3,210	$ 3,219
Commitments and Contingencies
Equity
Member's equity	$ 3,930
Common stock		$ 1
Additional paid-in capital		1,384
Retained earnings		2,450
Accumulated other comprehensive income (loss)		1
Members' Equity	3,930
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		3,836
Total Liabilities and Equity	$ 11,401	$ 11,399

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Receivables, allowance for doubtful accounts	$ 18	$ 18
Restricted receivables, allowance for doubtful accounts	$ 55	$ 53
Common stock, par or stated value	$ 0.001	$ 0.001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	689,000,000	688,000,000
Duke Energy Carolinas [Member]
Receivables, allowance for doubtful accounts	$ 2	$ 3
Restricted receivables, allowance for doubtful accounts	7	7
Progress Energy [Member]
Receivables, allowance for doubtful accounts	6	6
Restricted receivables, allowance for doubtful accounts	$ 8	$ 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	$ 4
Restricted receivables, allowance for doubtful accounts	5	5
Duke Energy Florida [Member]
Receivables, allowance for doubtful accounts	2	2
Restricted receivables, allowance for doubtful accounts	3	3
Duke Energy Ohio [Member]
Receivables, allowance for doubtful accounts	$ 2	$ 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	$ 1	$ 1
Common stock, par or stated value		$ 0.01
Common stock, shares authorized		60,000,000
Common stock, shares outstanding		53,913,701

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 699	$ 867
Net Income (Loss) Attributable to Parent	694	864
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	931	883
Equity component of AFUDC	(42)	(42)
Gains on sales of other assets	(9)	(16)
Impairment charges	3	43
Deferred income taxes	181	368
Equity in earnings of unconsolidated affiliates	(8)	(13)
Accrued pension and other post-retirement benefit costs	4	18
Contributions to pension plans		(132)
Payments for asset retirement obligations	(112)	(26)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	102	(47)
Receivables	121	(41)
Inventory	89	57
Other current assets	13	(63)
Increase (decrease) in
Accounts payable	(210)	(201)
Taxes accrued	40	(63)
Other current liabilities	(81)	(85)
Other assets	45	30
Other liabilities	(102)	(97)
Net cash provided by operating activities	1,664	1,440
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,645)	(1,411)
Investment expenditures	(59)	(14)
Acquisitions		(29)
Purchases of available-for-sale securities	(1,347)	(1,035)
Proceeds from sales and maturities of available-for-sale securities	1,362	1,069
Net proceeds from the sales of other assets	1	1
Change in restricted cash	(32)	(36)
Other	(38)	(1)
Net cash used in investing activities	(1,758)	(1,456)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,140	497
Proceeds from the issuance of common stock related to employee benefit plans	7	15
Payments for the redemption of long-term debt	(389)	(403)
Proceeds from issuance of short-term debt with original maturities greater than 90 days		187
Payments for the redemption of short-term debt with original maturities greater than 90 days	(92)	(643)
Notes payable and commercial paper	(66)	1,727
Distributions to noncontrolling interests	(1)
Dividends paid	(570)	(564)
Other	(14)	(15)
Net cash provided by financing activities	15	801
Net (decrease) increase in cash and cash equivalents	(79)	785
Cash and cash equivalents at beginning of period	857	2,036
Cash and cash equivalents at end of period	778	2,821
Significant non-cash transactions:
Accrued capital expenditures	576	438
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	271	292
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	330	324
Equity component of AFUDC	(23)	(24)
Deferred income taxes	145	113
Accrued pension and other post-retirement benefit costs	1	4
Contributions to pension plans		(42)
Payments for asset retirement obligations	(52)	(6)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	3
Receivables	2	16
Receivable from affiliated companies	33	(16)
Inventory	40	7
Other current assets	102	2
Increase (decrease) in
Accounts payable	(165)	(133)
Accounts payable to affiliated companies	21	50
Taxes accrued	52	(17)
Other current liabilities	21	(27)
Other assets	26	44
Other liabilities	(26)	(11)
Net cash provided by operating activities	781	576
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(459)	(448)
Purchases of available-for-sale securities	(785)	(643)
Proceeds from sales and maturities of available-for-sale securities	785	643
Notes receivable from affiliated companies payments	(691)	(605)
Other	(18)	4
Net cash used in investing activities	(1,168)	(1,049)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	992	496
Payments for the redemption of long-term debt	(1)
Distributions to parent	(600)
Other		(6)
Net cash provided by financing activities	391	490
Net (decrease) increase in cash and cash equivalents	4	17
Cash and cash equivalents at beginning of period	13	13
Cash and cash equivalents at end of period	17	30
Significant non-cash transactions:
Accrued capital expenditures	179	102
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	212	263
Net Income (Loss) Attributable to Parent	209	260
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	342	329
Equity component of AFUDC	(14)	(14)
Gains on sales of other assets	(7)	(8)
Impairment charges	2
Deferred income taxes	182	196
Accrued pension and other post-retirement benefit costs	(6)	(1)
Contributions to pension plans		(42)
Payments for asset retirement obligations	(54)	(20)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	6	(22)
Receivables	70	(66)
Receivable from affiliated companies	295	(21)
Inventory	3	47
Other current assets	(76)	302
Increase (decrease) in
Accounts payable	9	(107)
Accounts payable to affiliated companies	(55)	83
Taxes accrued	42	47
Other current liabilities	(64)	(10)
Other assets	(46)	(21)
Other liabilities	(7)	(28)
Net cash provided by operating activities	834	907
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(750)	(563)
Purchases of available-for-sale securities	(533)	(298)
Proceeds from sales and maturities of available-for-sale securities	548	367
Proceeds from Insurance	43
Notes receivable from affiliated companies		42
Other	(15)	(20)
Net cash used in investing activities	(707)	(472)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	53
Payments for the redemption of long-term debt	(310)	(245)
Notes payable to affiliated companies	128	(185)
Distributions to noncontrolling interests	(1)
Other		(3)
Net cash provided by financing activities	(130)	(433)
Net (decrease) increase in cash and cash equivalents	(3)	2
Cash and cash equivalents at beginning of period	44	42
Cash and cash equivalents at end of period	41	44
Significant non-cash transactions:
Accrued capital expenditures	228	176
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	137	183
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	223	193
Equity component of AFUDC	(10)	(13)
Gains on sales of other assets	(2)	(1)
Deferred income taxes	100	138
Accrued pension and other post-retirement benefit costs	(8)	(4)
Contributions to pension plans		(21)
Payments for asset retirement obligations	(42)	(6)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(1)	(4)
Receivables	18	(92)
Receivable from affiliated companies	10	6
Inventory	15	37
Other current assets	83	170
Increase (decrease) in
Accounts payable	(16)	(52)
Accounts payable to affiliated companies	(14)	63
Taxes accrued	18	14
Other current liabilities	(39)	(28)
Other assets	(17)	(2)
Other liabilities	(4)	(17)
Net cash provided by operating activities	451	564
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(379)	(338)
Purchases of available-for-sale securities	(390)	(149)
Proceeds from sales and maturities of available-for-sale securities	384	144
Notes receivable from affiliated companies		32
Other	(13)	(12)
Net cash used in investing activities	(398)	(323)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	53
Payments for the redemption of long-term debt	(8)	(243)
Notes payable to affiliated companies	(101)
Other	(1)	(1)
Net cash provided by financing activities	(57)	(244)
Net (decrease) increase in cash and cash equivalents	(4)	(3)
Cash and cash equivalents at beginning of period	15	9
Cash and cash equivalents at end of period	11	6
Significant non-cash transactions:
Accrued capital expenditures	55	82
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	110	113
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	116	136
Equity component of AFUDC	(4)	(1)
Impairment charges	2
Deferred income taxes	83	39
Accrued pension and other post-retirement benefit costs	1	1
Contributions to pension plans		(21)
Payments for asset retirement obligations	(12)	(14)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	7	(20)
Receivables	52	24
Receivable from affiliated companies	14	(20)
Inventory	(12)	10
Other current assets	(44)	143
Increase (decrease) in
Accounts payable	25	(54)
Accounts payable to affiliated companies	(40)	15
Taxes accrued	(70)	61
Other current liabilities	(14)	24
Other assets	(30)	(17)
Other liabilities	(6)	(15)
Net cash provided by operating activities	178	404
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(370)	(224)
Purchases of available-for-sale securities	(143)	(149)
Proceeds from sales and maturities of available-for-sale securities	164	223
Proceeds from Insurance	43
Other	(1)	(7)
Net cash used in investing activities	(307)	(157)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	(2)	(2)
Notes payable to affiliated companies	135	108
Dividends to parent		(350)
Other		(1)
Net cash provided by financing activities	133	(245)
Net (decrease) increase in cash and cash equivalents	4	2
Cash and cash equivalents at beginning of period	8	8
Cash and cash equivalents at end of period	12	10
Significant non-cash transactions:
Accrued capital expenditures	173	94
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)		149
Net Income (Loss) Attributable to Parent	59	149
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	62	58
Equity component of AFUDC	(1)	(1)
Gains on sales of other assets	(1)	(6)
Impairment charges		40
Deferred income taxes	11	25
Accrued pension and other post-retirement benefit costs	1	2
Contributions to pension plans		(1)
Payments for asset retirement obligations	(1)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	2	(28)
Receivables	(18)	(8)
Receivable from affiliated companies	(9)	16
Inventory	1	(3)
Other current assets	78	80
Increase (decrease) in
Accounts payable	(1)	20
Accounts payable to affiliated companies		49
Taxes accrued	(31)	(4)
Other current liabilities	14	24
Other assets	(2)	15
Other liabilities		(74)
Net cash provided by operating activities	164	353
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(85)	(81)
Net proceeds from the sales of other assets	1
Notes receivable from affiliated companies payments	(19)
Notes receivable from affiliated companies		105
Other	(5)
Net cash used in investing activities	(108)	24
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	95
Payments for the redemption of long-term debt	(51)	(151)
Notes payable to affiliated companies	(95)	(193)
Other		(1)
Net cash provided by financing activities	(51)	(345)
Net (decrease) increase in cash and cash equivalents	5	32
Cash and cash equivalents at beginning of period	14	20
Cash and cash equivalents at end of period	19	52
Significant non-cash transactions:
Accrued capital expenditures	31	15
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	95	108
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	127	105
Equity component of AFUDC	(3)	(3)
Deferred income taxes	(16)	140
Accrued pension and other post-retirement benefit costs	2	3
Contributions to pension plans		(9)
Payments for asset retirement obligations	(5)
(Increase) decrease in
Receivables	16	3
Receivable from affiliated companies	7	1
Inventory	45	(5)
Other current assets	(19)	9
Increase (decrease) in
Accounts payable	(44)	21
Accounts payable to affiliated companies	(22)	1
Taxes accrued	30	13
Other current liabilities	(18)	6
Other assets	(4)	(8)
Other liabilities	(11)	(24)
Net cash provided by operating activities	180	361
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(151)	(188)
Purchases of available-for-sale securities	(5)	(3)
Proceeds from sales and maturities of available-for-sale securities	4	2
Notes receivable from affiliated companies payments	(19)	(106)
Other	(1)	16
Net cash used in investing activities	(172)	(279)
CASH FLOWS FROM FINANCING ACTIVITIES
Notes payable to affiliated companies		(71)
Other		(1)
Net cash provided by financing activities		(72)
Net (decrease) increase in cash and cash equivalents	8	10
Cash and cash equivalents at beginning of period	9	6
Cash and cash equivalents at end of period	17	16
Significant non-cash transactions:
Accrued capital expenditures	$ 42	$ 60

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Foreign Currency Translation Adjustments [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]	Net Gains (Losses) on Available for Sale Securities [Member]	Pension and OPEB Related Adjustments [Member]	Common Stockholders' Equity [Member]	Noncontrolling Interest [Member]		Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member]Members Equity [Member]	Duke Energy Carolinas [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Duke Energy Carolinas [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]	Progress Energy [Member]Additional Paid-in Capital [Member]	Progress Energy [Member]Retained Earnings [Member]	Progress Energy [Member]Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Progress Energy [Member]Pension and OPEB Related Adjustments [Member]	Progress Energy [Member]Common Stockholders' Equity [Member]	Progress Energy [Member]Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Progress [Member]Common Stock [Member]	Duke Energy Progress [Member]Retained Earnings [Member]	Duke Energy Progress [Member]Members Equity [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]Common Stock [Member]	Duke Energy Florida [Member]Retained Earnings [Member]	Duke Energy Florida [Member]Members Equity [Member]	Duke Energy Florida [Member]Net Gains (Losses) on Available for Sale Securities [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]Common Stock [Member]	Duke Energy Ohio [Member]Additional Paid-in Capital [Member]	Duke Energy Ohio [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]Common Stock [Member]	Duke Energy Indiana [Member]Additional Paid-in Capital [Member]	Duke Energy Indiana [Member]Retained Earnings [Member]	Duke Energy Indiana [Member]Members Equity [Member]	Duke Energy Indiana [Member]Net Gains (Losses) on Cash Flow Hedges [Member]
Balance at Dec. 31, 2014	$ 40,899	$ 1	$ 39,405	$ 2,012	$ (439)	$ (59)	$ 3	$ (48)	$ 40,875	$ 24						$ 11,176	$ 7,467	$ 3,782	$ (35)	$ 1	$ (7)	$ 11,208	$ (32)	$ 5,867	$ 2,159	$ 3,708		$ 5,222	$ 1,762	$ 3,460			$ 4,674	$ 762	$ 4,782	$ (870)	$ 3,848	$ 1	$ 1,384	$ 2,460		$ 3
Balance, in shares at Dec. 31, 2014		707,000,000
Beginning member's equity at Dec. 31, 2014												$ 10,924	$ 10,937	$ (12)	$ (1)
Net Income	867			864					864	3						263		260				260	3										149
Net Income Attributable to Parent	864											292	292			260								183		183		113		113			149			149	108			108
Other comprehensive (loss) income, net of tax	(133)				(121)	(3)		(5)	(129)	(4)						(1)			(2)		1	(1)															(1)					(1)
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	8		8						8
Common stock dividends	(564)			(564)					(564)																			(350)		(350)
Other	10			(3)					(3)	13	[1]							(3)				(3)	3
Balance at Mar. 31, 2015	41,087	$ 1	39,413	2,309	(560)	(62)	3	(53)	41,051	36						11,438	7,467	4,039	(37)	1	(6)	11,464	(26)	6,050	$ 2,159	$ 3,891		4,985	$ 1,762	$ 3,223			4,823	762	4,782	(721)	3,955	1	1,384	2,568		2
Balance, in shares at Mar. 31, 2015		708,000,000
Ending member's equity at Mar. 31, 2015												11,216	11,229	(12)	$ (1)
Balance at Dec. 31, 2015	$ 39,771	$ 1	37,968	2,564	(692)	(50)	(3)	(61)	39,727	44						$ 12,853	8,092	4,831	(31)		(17)	12,875	(22)										$ 2,784	762	2,720	(698)	$ 3,836	1	1,384	2,450		1
Balance, in shares at Dec. 31, 2015	688,000,000	688,000,000														100																	89,663,086				53,913,701
Beginning member's equity at Dec. 31, 2015												11,606	11,617	(11)										7,059			$ 7,059	5,121			$ 5,121
Net Income	$ 699			694					694	5						$ 212		209				209	3
Net Income Attributable to Parent	694											271	271			209								137			137	110			110		$ 59			59	$ 95				$ 95
Other comprehensive (loss) income, net of tax	41				48	(12)	4		40	1		1		1		3			1	1	1	3						1				$ 1					(1)					$ (1)
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	1		1						1
Common stock dividends	(570)			(570)					(570)
Distributions to parent												(600)	(600)
Distributions to noncontrolling interest in subsidiaries	(1)									(1)						(1)							(1)
Other																																						$ (1)	$ (1,384)	$ (2,450)	3,835
Balance at Mar. 31, 2016	$ 39,941	$ 1	$ 37,969	$ 2,688	$ (644)	$ (62)	$ 1	$ (61)	$ 39,892	$ 49						$ 13,067	$ 8,092	$ 5,040	$ (30)	$ 1	$ (16)	$ 13,087	$ (20)										$ 2,843	$ 762	$ 2,720	$ (639)
Balance, in shares at Mar. 31, 2016	689,000,000	689,000,000														100																	89,663,086
Ending member's equity at Mar. 31, 2016												$ 11,278	$ 11,288	$ (10)										$ 7,196			$ 7,196	$ 5,232			$ 5,231	$ 1					$ 3,930				$ 3,930
[1]	The $13 million change in Noncontrolling Interests is primarily related to an acquisition of majority interest in a solar company for an insignificant amount of cash consideration.

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Organization and Basis of Presentation	Index to Combined Notes to Condensed Consolidated Financial Statements The unaudited notes to the condensed consolidated financial statements that follow are a combined presentation. The following list indicates the registrants to which the footnotes apply. Tables within the notes may not sum across due to Progress Energy's consolidation of Duke Energy Progress, Duke Energy Florida and other subsidiaries that are not registrants as the Duke Energy amounts include balances from subsidiaries that are not registrants. Applicable Notes Registrant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Duke Energy Corporation • • • • • • • • • • • • • • • • • Duke Energy Carolinas, LLC • • • • • • • • • • • • • Progress Energy, Inc. • • • • • • • • • • • • • • • Duke Energy Progress, LLC • • • • • • • • • • • • • • Duke Energy Florida, LLC • • • • • • • • • • • • • Duke Energy Ohio, Inc. • • • • • • • • • • • • • • Duke Energy Indiana, LLC • • • • • • • • • • • • • ORGANIZATION AND BASIS OF PRESENTATION NATURE OF OPERATIONS AND BASIS OF CONSOLIDATION Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) and Latin America primarily through its direct and indirect subsidiaries. Duke Energy’s subsidiaries include its subsidiary registrants, Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, LLC (Duke Energy Progress); Duke Energy Florida, LLC (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, LLC (Duke Energy Indiana, formerly Duke Energy Indiana, Inc.). 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. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the Florida Public Service Commission (FPSC), NRC and FERC. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky, and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers and recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). See Note 2 for additional information. Substantially all of Duke Energy Ohio’s operations that remain after the sale qualify for regulatory accounting. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and FERC. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company. BASIS OF PRESENTATION Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales (collectively, the Disposal Group), a retail sales business owned by Duke Energy, to Dynegy on April 2, 2015. The results of operations of these businesses prior to the date of sale have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations, assets held for sale and liabilities associated with assets held for sale. See Note 2 for additional information. These Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP in the U.S. for annual financial statements. Since the interim Condensed Consolidated Financial Statements and Notes do not include all information and notes required by GAAP in the U.S. for annual financial statements, the Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the Consolidated Financial Statements and Notes in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2015 . The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors. In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform to the current year presentation. UNBILLED REVENUE Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills and meter reading schedules. Unbilled revenues, which are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets, are presented in the following table. (in millions) March 31, 2016 December 31, 2015 Duke Energy $ 715 $ 748 Duke Energy Carolinas 288 283 Progress Energy 158 172 Duke Energy Progress 85 102 Duke Energy Florida 73 70 Duke Energy Ohio 2 3 Duke Energy Indiana 33 31 Additionally, Duke Energy Ohio and Duke Energy Indiana sell nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 for further information. These receivables for unbilled revenues are shown in the table below. (in millions) March 31, 2016 December 31, 2015 Duke Energy Ohio $ 61 $ 71 Duke Energy Indiana 88 97 AMOUNTS ATTRIBUTABLE TO CONTROLLING INTERESTS Income from Discontinued Operations, net of tax presented on the respective Condensed Consolidated Statements of Operations for Duke Energy and Progress Energy is attributable only to controlling interests for all periods presented. 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 months ended March 31, 2016 and 2015 , 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 accounted for on a gross basis as both operating revenues and property and other taxes on the Condensed Consolidated Statements of Operations were as follows. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy $ 91 $ 100 Duke Energy Carolinas 8 9 Progress Energy 47 49 Duke Energy Progress 5 4 Duke Energy Florida 42 45 Duke Energy Ohio 28 32 Duke Energy Indiana 8 10 NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2016 and 2015 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. The following accounting standards were adopted by the Duke Energy Registrants during 2015. 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. Duke Energy has not reported any discontinued operations under the revised accounting guidance. Balance Sheet Classification of Deferred Taxes . In November 2015, the FASB issued revised accounting guidance for the Balance Sheet classification of deferred taxes. The core principle of this revised accounting guidance is that all deferred tax assets and liabilities should be classified as noncurrent. For Duke Energy, this revised accounting guidance was adopted prospectively for December 31, 2015. Balance Sheet Presentation of Debt Issuance Costs. In April and August of 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 was adopted retrospectively. The implementation of this accounting standard resulted in a reduction of Other within Regulatory Assets and Deferred Debits and in Long-Term Debt of $ 173 million and $ 170 million on the Condensed Consolidated Balance Sheets as of March 31, 2016 and December 31, 2015, respectively. Fair Value Disclosures for Certain Investments. In May 2015, the FASB issued revised accounting guidance for investments in certain entities that use net asset value per share (or its equivalent) as a practical expedient to determine fair value. The core principle of this revised accounting guidance is that the valuation of investments using the practical expedient should not be categorized within the fair value hierarchy (i.e., as Level 1, 2 or 3). The practical expedient applies to investments in investment companies for which there is not a readily determinable fair value (market quote) or the investment is not in a mutual fund with a publicly available net asset value. For Duke Energy, this revised accounting guidance was adopted retrospectively. The implementation of this guidance is reflected in Note 11 , "Fair Value Measurements." The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of March 31, 2016 . Revenue from Contracts with Customers. In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. 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 January 1, 2017. The guidance can be applied retrospectively to all prior reporting periods presented or retrospectively with a cumulative effect as of the initial date of application. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined. Financial Instruments Classification and Measurement. In January 2016, the FASB issued revised accounting guidance for the classification and measurement of financial instruments. Changes in the fair value of all equity securities will be required to be recorded in net income. Current GAAP allows some changes in fair value for available-for-sale equity securities to be recorded in AOCI. Additional disclosures will be required to present separately the financial assets and financial liabilities by measurement category and form of financial asset. Investments accounted for using the equity method of accounting are not included within the scope of this revised guidance. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, by recording a cumulative effect to the balance sheet as of January 1, 2018. This guidance is expected to have a minimal impact on Duke Energy's Condensed Consolidated Statements of Comprehensive Income as changes in the fair value of most of Duke Energy's available-for-sale equity securities are deferred as regulatory assets or liabilities. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2019, although it can be early adopted. The guidance is applied using a modified retrospective approach. Duke Energy is currently evaluating the requirements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Stock-Based Compensation and Income Taxes. In March 2016, the FASB issued revised accounting guidance for stock-based compensation and the associated income taxes. This is a simplification initiative of the FASB. This standard changes certain aspects of accounting for share-based payment awards to employees including the accounting for income taxes, statutory tax withholding requirements, as well as the classification on the Condensed Consolidated Statements of Cash Flows. This guidance will be applied prospectively, retrospectively, or using a modified retrospective transition method depending on the item changed. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2017, although it can be early adopted. Duke Energy is currently evaluating the requirements. The primary change expected is an increase in the volatility of income tax expense.

Acquisitions and Dispositions

Acquisitions and Dispositions	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS ACQUISITIONS The Duke Energy Registrants consolidate assets and liabilities from acquisitions as of the purchase date, and include earnings from acquisitions in consolidated earnings after the purchase date. Acquisition of Piedmont Natural Gas 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 and Piedmont will become a wholly owned subsidiary of Duke Energy. In addition, Duke Energy will assume Piedmont's existing debt, which was approximately $2.0 billion at January 31, 2016, the end of Piedmont's most recent quarter. Duke Energy expects to finance the transaction with a combination of debt, equity issuances and other cash sources. As of March 31, 2016, Duke Energy entered into $1.4 billion of forward-starting interest rate swaps to manage interest rate exposure for the expected financing of the Piedmont acquisition. For additional information on the forward-starting swaps, see Note 9 . In March, 2016, Duke Energy marketed an equity offering of 10.6 million shares of Duke Energy common stock. In lieu of issuing equity at the time of the offering, Duke Energy entered into equity forward sale agreements (the Equity Forwards) with Barclays Capital, Inc. (Barclays). Duke Energy expects to settle the Equity Forwards on or around the closing date of the Piedmont acquisition. The net proceeds received upon settlement are expected to be used to finance a portion of the acquisition of Piedmont. For additional information regarding the Equity Forwards, see Note 13. In connection with the Merger Agreement with Piedmont, Duke Energy entered into a $4.9 billion senior unsecured bridge financing facility (Bridge Facility) with Barclays. The Bridge Facility, if drawn upon, may be used to (i) fund the cash consideration for the transaction and (ii) pay certain fees and expenses in connection with the transaction. In November 2015, Barclays syndicated its commitment under the Bridge Facility to a broader group of lenders. Duke Energy does not expect to draw upon the Bridge Facility. The amount of the Bridge Facility is reduced by any financings related to the Piedmont acquisition entered into by Duke Energy, and has accordingly been reduced to $4.2 billion as a result of the Equity Forwards. Piedmont's shareholders have approved the company's acquisition by Duke Energy and the Federal Trade Commission (FTC) has granted early termination of the 30-day waiting period under the federal Hart-Scott-Rodino Antitrust Improvements Act of 1976. On January 15, 2016, Duke Energy and Piedmont filed an application with the NCUC for approval of the proposed business combination and associated financing transactions. On January 29, 2016, the NCUC approved Duke Energy's proposed financing transactions. The NCUC issued its Scheduling Order on March 2, 2016, setting a public and evidentiary hearing to begin on July 18, 2016. On March 7, 2016, the KPSC granted Duke Energy's declaratory request that the transaction does not constitute a change in control and does not require KPSC approval. The Tennessee Regulatory Authority approved Duke Energy's and Piedmont's request of the change in control resulting from the transaction at its March 14, 2016 meeting. Subject to receipt of required regulatory approvals and meeting closing conditions, Duke Energy and Piedmont expect to close the transaction by the end of 2016. 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 . 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. 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 was recognized as an acquisition adjustment, and recorded in property, plant and equipment. Duke Energy Progress established a rider in North Carolina to recover the costs to acquire, operate and maintain interests in the assets purchased as allocated to its North Carolina retail operations, including the purchase acquisition adjustment, and included the purchase acquisition adjustment in wholesale power formula rates. Duke Energy Progress received an order from the PSCSC to defer the recovery of the South Carolina retail allocated costs of the asset purchased until the Company's next general rate case. DISPOSITIONS Potential Sale of International Energy In February 2016, Duke Energy announced it had initiated a process to divest the International Energy business segment, excluding the equity method investment in National Methanol Company (NMC). Duke Energy is in the early stages and there have been no binding or non-binding offers submitted. Duke Energy can provide no assurance that this process will result in a transaction and there is no specific timeline for execution of a potential transaction. Proceeds from a successful exit would be used by Duke Energy to fund the operations and growth of domestic businesses. If the potential of a sale were to progress, it could result in classification of International Energy as assets held for sale and as a discontinued operation. As of March 31, 2016, the International Energy segment had a carrying value of approximately $2.6 billion , adjusted for $644 million of cumulative foreign currency translation losses currently classified as accumulated other comprehensive loss. Midwest Generation Exit Duke Energy, through indirect subsidiaries, completed the sale of the Disposal Group to a subsidiary of Dynegy on April 2, 2015, for approximately $2.8 billion in cash. The nonregulated Midwest generation business included generation facilities with approximately 5,900 MW of owned capacity located in Ohio, Pennsylvania, and Illinois. On April 1, 2015, prior to the sale, Duke Energy Ohio distributed its indirect ownership interest in the nonregulated Midwest generation business to a subsidiary of Duke Energy Corporation. The Disposal Group's results of operations are classified as discontinued operations in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Income. Current-year activity primarily relates to tax adjustments related to the Disposal Group. The following table presents the results of discontinued operations for the three months ended March 31, 2015. Duke Duke Energy (in millions) Energy Ohio Operating Revenues $ 543 $ 412 Loss on disposition (43 ) (44 ) Income before income taxes $ 147 $ 140 Income tax expense 51 50 Income from discontinued operations of the Disposal Group 96 90 Other, net of tax (a) (5 ) — Income from Discontinued Operations, net of tax $ 91 $ 90 (a) Relates to discontinued operations of businesses not related to the Disposal Group and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments. Commercial Portfolio utilized a revolving credit agreement (RCA) to support the operations of the nonregulated Midwest generation business. Interest expense associated with the RCA was allocated to discontinued operations. No other interest expense related to corporate level debt was allocated to discontinued operations. Duke Energy Ohio had a power purchase agreement with the Disposal Group for a portion of its standard service offer (SSO) supply requirement. The agreement and the SSO expired in May 2015.

Business Segments

Business Segments	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income, as discussed below, includes intercompany revenues and expenses that are eliminated in the Condensed Consolidated Financial Statements. Certain governance costs are allocated to each segment. In addition, direct interest expense and income taxes are included in segment income. During the first quarter of 2016, the Duke Energy chief operating decision-maker began to evaluate interim period segment performance based on financial information that includes the impact of income tax levelization within segment income. This represents a change from the previous measure, where the interim period impacts of income tax levelization were included within Other, and therefore excluded from segment income. As a result, prior period segment results presented have been recast to conform to this change. 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. Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets as presented in the tables that follow exclude all intercompany assets. DUKE ENERGY Duke Energy has the following reportable operating segments: Regulated Utilities, International Energy and Commercial Portfolio. Regulated Utilities conducts electric and natural gas operations that are substantially all regulated and, accordingly, qualify for regulatory accounting treatment. These operations are primarily conducted through the Subsidiary Registrants and are subject to the rules and regulations of the FERC, NRC, NCUC, PSCSC, FPSC, PUCO, IURC and KPSC. International Energy 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 target power generation in Latin America. Additionally, International Energy owns a 25 percent interest in NMC, a large regional producer of methyl tertiary butyl ether (MTBE) located in Saudi Arabia. The investment in NMC is accounted for under the equity method of accounting. In February 2016, Duke Energy announced it had initiated a process to potentially divest its International Energy business segment, excluding the investment in NMC. See Note 2 for further information. Commercial Portfolio builds, develops and operates wind and solar renewable generation and energy transmission projects throughout the U.S. For periods subsequent to the sale of the Disposal Group, beginning in the second quarter of 2015, certain immaterial results of operations and related assets previously presented in the Commercial Portfolio segment are presented in Regulated Utilities and Other. The remainder of Duke Energy’s operations is presented as Other, which is primarily comprised of unallocated corporate interest expense, unallocated corporate costs, contributions to the Duke Energy Foundation and the operations of Duke Energy’s wholly owned captive insurance subsidiary, Bison Insurance Company Limited (Bison). Three Months Ended March 31, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,250 $ 246 $ 114 $ 5,610 $ 12 $ — $ 5,622 Intersegment revenues 9 — — 9 17 (26 ) — Total revenues $ 5,259 $ 246 $ 114 $ 5,619 $ 29 $ (26 ) $ 5,622 Segment income (loss) (a) $ 695 $ 123 $ 27 $ 845 $ (154 ) $ — $ 691 Add back noncontrolling interests 5 Income from discontinued operations, net of tax 3 Net income $ 699 Segment assets $ 111,838 $ 3,247 $ 4,183 $ 119,268 $ 2,263 $ 178 $ 121,709 (a) Other includes $74 million of after-tax costs to achieve mergers and a $12 million after-tax charge related to cost savings initiatives. Three Months Ended March 31, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,713 $ 273 $ 73 $ 6,059 $ 6 $ — $ 6,065 Intersegment revenues 10 — — 10 21 (31 ) — Total revenues $ 5,723 $ 273 $ 73 $ 6,069 $ 27 $ (31 ) $ 6,065 Segment income (loss) (a) $ 774 $ 36 $ 7 $ 817 $ (43 ) $ (1 ) $ 773 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 91 Net income $ 867 Segment assets $ 106,642 $ 4,892 $ 6,202 $ 117,736 $ 4,230 $ 176 $ 122,142 (a) Other includes after-tax costs to achieve the 2012 Progress Energy merger of $13 million . DUKE ENERGY CAROLINAS, PROGRESS ENERGY, DUKE ENERGY PROGRESS, DUKE ENERGY FLORIDA, DUKE ENERGY OHIO AND DUKE ENERGY INDIANA The Subsidiary Registrants each have one reportable operating segment, Regulated Utilities, which generates, transmits, distributes and sells electricity, and for Duke Energy Ohio, also transports and sells natural gas. The remainder of 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. Other for Progress Energy also includes interest expense on corporate debt instruments of $56 million and $60 million for the three months ended March 31, 2016 and 2015, respectively. Other for Duke Energy Ohio also includes amounts related to Duke Energy Ohio's contractual arrangement to buy power from Ohio Valley Electric Corporations (OVEC's) power plants. The following table summarizes the net loss for Other for each of these entities. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas $ (17 ) $ (8 ) Progress Energy (49 ) (42 ) Duke Energy Progress (8 ) (4 ) Duke Energy Florida (4 ) (3 ) Duke Energy Ohio (9 ) (2 ) Duke Energy Indiana (2 ) (2 ) The assets at Duke Energy Carolinas, Progress Energy, Duke Energy Progress, Duke Energy Florida, Duke Energy Ohio and Duke Energy Indiana are substantially all included within the Regulated Utilities segment at March 31, 2016. 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. The following table summarizes segment information prior to the sale of the nonregulated Midwest generation business. Three Months Ended March 31, 2015 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Total revenues $ 572 $ 14 $ 586 $ — $ — $ 586 Segment income (loss) $ 70 $ (9 ) $ 61 $ (2 ) $ — $ 59 Income from discontinued operations, net of tax 90 Net income $ 149 Segment assets $ 6,782 $ 2,984 $ 9,766 $ 43 $ (13 ) $ 9,796

Regulatory Matters

Regulatory Matters	3 Months Ended
	Mar. 31, 2016
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS RATE RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio, Kentucky and Indiana), as well as sales of transmission service. Duke Energy Carolinas and Duke Energy Progress FERC Transmission Return on Equity Complaints On January 7, 2016, a group of transmission service customers filed a complaint with the FERC that the rate of return on equity of 10.2 percent in Duke Energy Carolinas' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On the same date a similar complaint was filed with the FERC claiming that the rate of return on equity of 10.8 percent in Duke Energy Progress' transmission formula rates is excessive and should be reduced to no higher than 8.49 percent , effective upon the complaint date. On April 21, 2016, the FERC issued an order which consolidated the cases, set a refund effective date of January 7, 2016, and set the consolidated case for settlement and hearing. Duke Energy Carolinas and Duke Energy Progress do not expect the potential impact on results of operations, cash flows or financial position to be material. It is not possible to predict the outcome of this matter. 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 AFUDC. The project is expected to be commercially available in late 2017. NCEMC will own approximately 13 percent of the project. On July 3, 2014, the South Carolina Coastal Conservation League (SCCL) and Southern Alliance for Clean Energy (SACE) jointly filed a Notice of Appeal with the Court of Appeals of South Carolina (S.C. Court of Appeals) seeking the court's review of the PSCSC's decision, claiming the PSCSC did not properly consider a request related to a proposed solar facility prior to granting approval of the CECPCN. The S.C. Court of Appeals affirmed the PSCSC's decision on February 10, 2016, and on March 24, 2016, denied a request for rehearing filed by SCCL and SACE. On April 21, 2016, SCCL and SACE petitioned the South Carolina Supreme Court for review of the S.C. Court of Appeals decision. Duke Energy Carolinas has 30 days to respond. Duke Energy Carolinas cannot predict the outcome of this matter. Duke Energy Progress Western Carolinas Modernization Plan On November 4, 2015, in response to community feedback, Duke Energy Progress announced a revised Western Carolinas Modernization Plan with an estimated cost of $1.1 billion . The revised plan includes retirement of the existing Asheville coal-fired plant, the construction of two 280 MW combined-cycle natural gas plants having dual fuel capability, with the option to build a third natural gas simple cycle unit in 2023 based upon the outcome of initiatives to reduce the region's power demand. The revised plan includes upgrades to existing transmission lines and substations, but eliminates the need for a new transmission line and a new substation associated with the project in South Carolina. The revised plan has the same overall project cost as the original plan and the plans to install solar generation remain unchanged. Duke Energy Progress has also proposed to add a pilot battery storage project. These investments will be made within the next seven years. Duke Energy Progress is also working with the local natural gas distribution company to upgrade an existing natural gas pipeline to serve the natural gas plant. The plan requires various approvals including regulatory approvals in North Carolina. Duke Energy Progress filed for a Certificate of Public Convenience and Necessity (CPCN) with the NCUC for the new natural gas units on January 15, 2016. On March 28, 2016, the NCUC issued an order approving the CPCN for the new combined-cycle natural gas plants, but denying the CPCN for the contingent simple cycle unit without prejudice to Duke Energy Progress to refile for approval in the future. Construction of these plants is scheduled to begin in 2016 and the plants are expected to be in service by late 2019. Duke Energy Progress plans to file for future approvals related to the proposed solar generation and pilot battery storage project. On April 26, 2016, the NCUC granted a motion from North Carolina Waste Awareness and Reduction Network (NC WARN) and The Climate Times to extend the deadline for parties to appeal the CPCN order until May 27, 2016. On April 27, 2016, the NCUC issued an order to establish the procedure to set the appeal bond related to this motion. The carrying value of the 376 MW Asheville coal-fired plant, including associated ash basin closure costs, of $531 million and $548 million are included in Generation facilities to be retired, net on Duke Energy Progress' Condensed Consolidated Balance Sheet as of March 31, 2016 and December 31, 2015 , respectively. Duke Energy Florida Purchase of Osprey Energy Center In December 2014, Duke Energy Florida and Osprey Energy Center, LLC, a wholly owned subsidiary of Calpine Corporation (Calpine), entered into an Asset Purchase and Sale Agreement for the purchase of a 599 MW combined-cycle natural gas plant in Auburndale, Florida (Osprey Plant acquisition) for approximately $166 million . In July 2015, the FERC and the FPSC issued separate orders of approval for the Osprey Plant acquisition. 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. On March 31, 2016, Duke Energy Florida and Calpine made Hart-Scott-Rodino filings with the Federal Trade Commission and the Department of Justice. 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 Nuclear Plant (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 . On April 5, 2016, the FPSC granted Duke Energy Florida’s motion to reduce the value of the Crystal River Unit 3 regulatory asset by $36 million and allow recovery of this amount, including carrying costs, through the capacity cost recovery clause over the years 2017 and 2018. In June 2015, the governor of Florida signed legislation to allow utilities to issue nuclear asset-recovery bonds to finance the recovery of certain retired nuclear generation assets, with approval of the FPSC. On November 19, 2015, the FPSC issued a financing order approving Duke Energy Florida’s request to issue nuclear asset-recovery bonds to finance its unrecovered regulatory asset related to Crystal River Unit 3 through a wholly owned special purpose entity. Nuclear asset-recovery bonds would replace the base rate recovery methodology authorized by the 2013 Agreement and result in a lower rate impact to customers with an approximately 20‑year recovery period. On March 31, 2016, Duke Energy Florida filed its Second Amendment to the registration statement for the proposed initial public offering of the bonds. The registration statement is subject to review and declaration of its effectiveness by the Securities and Exchange Commission. Duke Energy Florida expects to issue nuclear asset-recovery bonds in mid-2016. Duke Energy Ohio Accelerated Natural Gas Service Line Replacement Rider On January 20, 2015, Duke Energy Ohio filed an application for approval of an accelerated natural gas service line replacement program (ASRP). Under the ASRP, Duke Energy Ohio proposes to replace certain natural gas service lines on an accelerated basis. The program is proposed to last 10 years. Through the ASRP, Duke Energy Ohio also proposes to complete preliminary survey and investigation work related to natural gas service lines that are customer owned and for which it does not have valid records and, further, to relocate interior natural gas meters to suitable exterior locations where such relocation can be accomplished. Duke Energy Ohio projects total capital and operations and maintenance expenditures under the ASRP to approximate $320 million . The filing also seeks approval of Rider ASRP to recover related expenditures. Duke Energy Ohio proposes to update Rider ASRP on an annual basis. Duke Energy Ohio’s application is pending before the PUCO and it is uncertain when an order will be issued. Intervenors oppose the ASRP, primarily because they believe the program is neither required nor necessary under federal pipeline regulation. The hearing concluded on November 19, 2015, and initial and reply briefs were filed, with briefing complete on December 23, 2015. Duke Energy Ohio cannot predict the outcome of this matter. Energy Efficiency Cost Recovery On March 28, 2014, Duke Energy Ohio filed an application for recovery of program costs, lost distribution revenue and performance incentives related to its energy efficiency and peak demand reduction programs. These programs are undertaken to comply with environmental mandates set forth in Ohio law. After a comment period, the PUCO approved Duke Energy Ohio’s application, but found that Duke Energy Ohio was not permitted to use banked energy savings from previous years in order to calculate the amount of allowed incentive. This conclusion represented a change to the cost recovery mechanism that had been agreed to by intervenors and approved by the PUCO in previous cases. The PUCO granted the applications for rehearing filed by Duke Energy Ohio and an intervenor on July 8, 2015. Substantive ruling on the application for rehearing is pending. On January 6, 2016, Duke Energy Ohio and PUCO Staff entered into a stipulation pending PUCO approval, resolving the issues related to, among other things, performance incentives and the PUCO Staff audit of 2013 costs. Based on the stipulation, in December 2015, Duke Energy Ohio re-established approximately $20 million of revenues that had been reversed in the second quarter of 2015. A hearing on the stipulation commenced on March 10, 2016 and the post-hearing briefing schedule will conclude by May 13, 2016. Duke Energy Ohio cannot predict the outcome 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. The PUCO approved a settlement 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. The KPSC also approved a request to effect the RTO realignment, subject to a commitment not to seek double recovery in a future rate case of the transmission expansion fees that may be charged by MISO and PJM in the same period or overlapping periods. Duke Energy Ohio had a recorded liability for its exit obligation and share of MTEP costs, excluding MVP, of $91 million and $92 million , respectively, at March 31, 2016 and December 31, 2015 , within Other in Current liabilities and Other in Deferred credits and other liabilities on Duke Energy Ohio’s Condensed Consolidated Balance Sheets. MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. As of March 31, 2016 and December 31, 2015, Duke Energy Ohio had $72 million recorded in Regulatory assets on the Condensed Consolidated Balance Sheets. MVP. MISO approved 17 MVP proposals prior to Duke Energy Ohio’s exit from MISO on December 31, 2011. Construction of these projects is expected to continue through 2020. Costs of these projects, including operating and maintenance costs, property and income taxes, depreciation and an allowed return, are allocated and billed to MISO transmission owners. On December 29, 2011, MISO filed a tariff with the FERC providing for the allocation of MVP costs to a withdrawing owner based on monthly energy usage. The FERC set for hearing (i) whether MISO’s proposed cost allocation methodology to transmission owners who withdrew from MISO prior to January 1, 2012, is consistent with the tariff at the time of their withdrawal from MISO and, (ii) if not, what the amount of and methodology for calculating any MVP cost responsibility should be. In 2012, MISO estimated Duke Energy Ohio’s MVP obligation over the period from 2012 to 2071 at $2.7 billion , on an undiscounted basis. On July 16, 2013, a FERC Administrative Law Judge (ALJ) issued an initial decision. Under this initial decision, Duke Energy Ohio would be liable for MVP costs. Duke Energy Ohio filed exceptions to the initial decision, requesting FERC to overturn the ALJ’s decision. On October 29, 2015, the FERC issued an order reversing the ALJ's decision. The FERC ruled the cost allocation methodology is not consistent with the MISO tariff and that Duke Energy Ohio has no liability for MVP costs after its withdrawal from MISO. On November 30, 2015, MISO filed with the FERC a request for rehearing. Duke Energy Ohio cannot predict the outcome of this matter. Duke Energy Indiana Coal Combustion Residual (CCR) Plan On March 17, 2016, Duke Energy Indiana filed for approval of its first group of federally mandated CCR rule compliance projects (Phase I CCR Compliance Projects) to comply with the U.S. Environmental Protection Agency's (EPA) CCR rule. The projects in this Phase I filing are CCR compliance projects, including the conversion of Cayuga and Gibson Stations to dry bottom ash handling and related water treatment. Duke Energy Indiana has requested timely recovery of costs under a federal mandate tracker which provides for timely recovery of 80 percent of such costs and deferral with carrying costs of 20 percent of such costs for recovery in a subsequent retail base rate case. A procedural schedule has not been set for this matter. Duke Energy Indiana cannot predict the outcome of this matter. 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. The ninth semi-annual IGCC rider order was appealed by the Joint Intervenors. The proceeding will be remanded to the IURC for further proceedings and additional findings on the tax in-service issue. An evidentiary hearing has been set for August 31, 2016. The 11th through 15th semi-annual IGCC riders and a subdocket to Duke Energy Indiana's fuel adjustment clause remain pending at the IURC. 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 Office of Utility Consumer Counselor, the Industrial Group and Nucor Steel Indiana reached a settlement agreement to resolve these pending issues. On January 15, 2016, The Citizens Action Coalition of Indiana, Inc., Sierra Club, Save the Valley and Valley Watch joined a revised settlement (IGCC settlement). The IGCC settlement will result in customers not being billed for previously incurred operating costs of $87.5 million , and for additional Duke Energy Indiana payments and commitments of $5.5 million for attorneys’ fees and amounts to fund consumer programs. Attorneys’ fees and expenses for the new settling parties will be addressed in a separate proceeding. Duke Energy Indiana recognized pretax impairment and related charges of $93 million in the third quarter of 2015. Additionally, under the IGCC 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. The IGCC settlement also includes a commitment to either retire or stop burning coal by December 31, 2022, at the Gallagher Station. Pursuant to the IGCC settlement, the in-service date used for accounting and ratemaking will remain as June 2013. Remaining deferred costs will be recovered over eight years and not earn a carrying cost. The IGCC settlement, which is opposed by a residential customer and his spouse, is subject to IURC approval. An evidentiary hearing on the IGCC settlement was held on April 18, 2016, and a decision is expected in the third quarter of 2016. As of March 31, 2016 , deferred costs related to the project are approximately $147 million . Under the IGCC settlement, future IGCC riders will be filed annually, rather than every six months, with the next filing scheduled for first quarter 2017. Duke Energy Indiana cannot predict the outcome 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. The motion to consolidate complaints was denied. 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. On December 22, 2015, the presiding FERC ALJ issued an Initial Decision in which he set the base rate of return on equity at 10.32 percent . The Initial Decision will be reviewed by the FERC. Duke Energy Indiana currently believes these matters will have an immaterial impact on its results of operations, cash flows and financial position. Grid Infrastructure Improvement Plan On August 29, 2014, pursuant to a new statute, Duke Energy Indiana filed a seven-year grid infrastructure improvement plan with the IURC with an estimated cost of $1.9 billion , focusing on the reliability, integrity and modernization of the transmission and distribution system. The plan also provided for cost recovery through a transmission and distribution rider (T&D Rider). In May 2015, the IURC denied the original proposal due to an insufficient level of detailed projects and cost estimates in the plan. On December 7, 2015, Duke Energy Indiana filed a revised infrastructure improvement plan with an estimated cost of $1.8 billion in response to guidance from IURC orders and the Indiana Court of Appeals decisions related to this new statute. The revised plan uses a combination of advanced technology and infrastructure upgrades to improve service to customers and provide them with better information about their energy use. It also provides for cost recovery through a T&D rider. In March 2016, Duke Energy Indiana entered into a settlement with all parties to the proceeding except the Indiana Citizens Action Coalition, Inc. The settlement agreement decreased the capital expenditures eligible for timely recovery of costs in the seven-year plan to approximately $1.4 billion , including the removal of an automated metering infrastructure (AMI) project. The settlement provides for deferral accounting for depreciation and post-in-service carrying costs for AMI projects outside the seven-year plan. Duke Energy Indiana withdrew its request for a regulatory asset for current meters and retains the savings associated with AMI prior to the next retail base rate case, which is required to be filed prior to the end of the seven-year plan. Under the settlement, the return on equity to be used in the T&D Rider is 10 percent . The settlement is subject to approval of the IURC. An order is expected in August 2016. Duke Energy Indiana cannot predict the outcome of this matter. 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. 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. FERC approval of the application is expected in early 2017 and construction is projected to begin in summer of 2017, with a targeted in-service date of late 2018. ACP is working with various agencies to develop the final pipeline route. 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 (FP&L), have each contracted to buy pipeline capacity for 25-year initial terms. On February 3, 2016, the FERC issued an order granting the request for a CPCN to construct and operate the Sabal Trail pipeline. The Sabal Trail pipeline requires additional regulatory approvals and is scheduled to begin service in 2017. 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 Florida and Indiana earlier than their current estimated useful lives. These facilities do not have the requisite emission control equipment, primarily to meet 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 as of March 31, 2016. Remaining Net Capacity Book Value (a) (in MW) (in millions) Duke Energy Florida (b) Crystal River Units 1 and 2 873 128 Duke Energy Indiana Wabash River Unit 6 (c) 318 35 Gallagher Units 2 and 4 (d) 280 137 Total Duke Energy 1,471 300 (a) Remaining net book value amounts exclude any capitalized asset retirement costs. (b) Progress Energy amounts are equal to Duke Energy Florida amounts. (c) In April 2016, Wabash River 6 terminated coal burning operations and is targeted for retirement by the end of 2016. The total net book value of $113 million for the retail portion of Wabash River Unit 6 and the retail portion of capitalized asset retirement costs for Wabash River Units 2 through 6 is classified as Generation facilities to be retired, net on Duke Energy Indiana's Condensed Consolidated Balance Sheet at March 31, 2016. (d) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the proposed settlement of Edwardsport IGCC matters. 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 generating units (EGUs). The CPP establishes CO 2 emission rates and mass cap goals that apply to fossil fuel-fired generation. Under the CPP, states are required to develop and submit a final compliance plan, or an initial plan with an extension request, to the EPA by September 6, 2016, or no later than September 6, 2018, with an approved extension. These state plans are subject to EPA approval, with a federal plan applied to states that fail to submit a plan to the EPA or if a state plan is not approved. Legal challenges to the CPP have been filed by stakeholders and motions to stay the requirements of the rule pending the outcome of the litigation were granted by the U.S. Supreme Court in February 2016. Final resolution of these legal challenges could take several years. Compliance with CPP could cause the industry to replace coal generation with natural gas and renewables, especially in states that have significant CO 2 reduction targets under the rule. Costs to operate coal-fired generation plants continue to grow due to increasing environmental compliance requirements, including ash management costs unrelated to CPP, and this may result in the retirement of coal-fired generation plants earlier than the current useful lives. Duke Energy continues to evaluate the need to retire generating facilities and plans to seek regulatory recovery, where appropriate, for amounts that have not been recovered upon asset retirements. However, recovery is subject to future regulatory approval, including the recovery of carrying costs on remaining book values, and therefore cannot be assured. Refer to the "Western Carolinas Modernization Plan" discussion above for details of Duke Energy Progress' planned retirements.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES ENVIRONMENTAL Duke Energy is subject to international, federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. The Subsidiary Registrants are subject to federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. These regulations can be changed from time to time, imposing new obligations on the Duke Energy Registrants. The following environmental matters impact all of the Duke Energy Registrants. Remediation Activities In addition to Asset Retirement Obligations recorded as a result of various environmental regulations, the Duke Energy Registrants are responsible for environmental remediation at various sites. These include certain properties that are part of ongoing operations and sites formerly owned or used by Duke Energy entities. These sites are in various stages of investigation, remediation and monitoring. Managed in conjunction with relevant federal, state and local agencies, remediation activities vary based upon site conditions and location, remediation requirements, complexity and sharing of responsibility. If remediation activities involve joint and several liability provisions, strict liability or cost recovery or contribution actions, the Duke Energy Registrants could potentially be held responsible for environmental impacts caused by other potentially responsible parties, and may also benefit from insurance policies or contractual indemnities that cover some or all cleanup costs. Liabilities are recorded when losses become probable and are reasonably estimable. The total costs that may be incurred cannot be estimated because the extent of environmental impact, allocation among potentially responsible parties, remediation alternatives and/or regulatory decisions have not yet been determined. 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. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 Provisions/adjustments 10 2 1 — 1 — 6 Cash reductions (3 ) (1 ) (2 ) (1 ) (1 ) — — Balance at end of period $ 104 $ 11 $ 16 $ 2 $ 14 $ 54 $ 18 Three Months Ended March 31, 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 2 — — — — 1 2 Cash reductions (3 ) — — — — (1 ) (1 ) Balance at end of period $ 96 $ 10 $ 17 $ 5 $ 12 $ 54 $ 11 Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 83 Duke Energy Carolinas 22 Duke Energy Ohio 42 Duke Energy Indiana 15 North Carolina and South Carolina Ash Basins On February 2, 2014, a break in a stormwater pipe beneath an ash basin at Duke Energy Carolinas’ retired Dan River Steam Station caused a release of ash basin water and ash into the Dan River. On February 8, 2014, a permanent plug was installed in the stormwater pipe, stopping the release of materials into the river. Duke Energy Carolinas estimates 30,000 to 39,000 tons of ash and 24 million to 27 million gallons of basin water were released into the river. In July 2014, Duke Energy completed remediation work identified by the EPA and continues to cooperate with the EPA's civil enforcement process. Future costs related to the Dan River release, including pending or future state or federal civil enforcement proceedings, future regulatory directives, natural resources damages, additional pending litigation, future claims or litigation and long-term environmental impact costs, cannot be reasonably estimated at this time. North Carolina Department of Environmental Quality (NCDEQ), formerly the North Carolina Department of Environment and Natural Resources, has historically assessed Duke Energy Carolinas and Duke Energy Progress with Notice of Violations (NOV) for violations that were most often resolved through satisfactory corrective actions and minor, if any, fines or penalties. Subsequent to the Dan River matter discussed above, Duke Energy Carolinas and Duke Energy Progress have been served with a higher level of NOVs, including for violations at L.V. Sutton Plant and Dan River Steam Station. 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 groundwater contamination at the L.V. Sutton Plant. On February 8, 2016, NCDEQ assessed a penalty of approximately $6.8 million , including enforcement costs, against Duke Energy Carolinas related to stormwater pipes and associated discharges at the Dan River Steam Station. Duke Energy Carolinas recorded a charge in December 2015 for this penalty. See "Litigation" section below for additional discussion of matters related to these penalties. These fines and penalties are unprecedented and were not consistent with historic enforcement practices of NCDEQ. Based on historic practices the expected liability of any existing notice of violations would not be material. Duke Energy Carolinas and Duke Energy Progress cannot predict whether the NCDEQ will assess future penalties related to existing NOVs and if such penalties would be material. Asset retirement obligations recorded on the Duke Energy Carolinas and Duke Energy Progress Condensed Consolidated Balance Sheets at March 31, 2016 and December 31, 2015 , include the legal obligation for closure of coal ash basins and the disposal of related ash as a result of the North Carolina Coal Ash Management Act of 2014 (Coal Ash Act) and other agreements. In January 2016, NCDEQ published draft proposed risk classifications for sites not specifically delineated by the Coal Ash Act as high priority. These risk rankings were generally determined based on three primary criteria: structural integrity of the impoundments and impact to both surface and groundwaters. NCDEQ categorized 12 basins at four sites as intermediate risk and four basins at three plants as low risk. NCDEQ also categorized nine basins at six plants as “low-to-intermediate” risk, thereby not assigning a definitive risk ranking at that time. The risk rankings of these sites will be based upon receipt of additional data primarily related to groundwater quality and the completion of specific modifications and repairs to the impoundments. NCDEQ is expected to finalize proposed classifications in May 2016, based on results of the public comment period which ended in April 2016. Duke Energy cannot predict the final classifications. Per the Coal Ash Act, final proposed classifications are subject to Coal Ash Management Commission (Coal Ash Commission) adjustments and approval but may become law if the Commission fails to act within 60 days of receiving the final proposed classifications. In March 2016, the Coal Ash Commission originally created by the Coal Ash Act was disbanded by the Governor of North Carolina based on a North Carolina Supreme Court ruling regarding the constitutionality of the body. As a result, the finality of NCDEQ's classifications may be subject to challenge. Estimated asset retirement obligations have been recognized based on the assigned risk categories or, if not assigned, based on a probability weighting of potential closure methods. Actual closure costs incurred could be materially different from current estimates that form the basis of the recorded asset retirement obligations. 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. 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, which became effective in October 2015, classifies CCR as nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act and allows for beneficial use of CCR 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. Various industry and environmental parties have appealed the EPA's CCR rule in the D.C. Circuit Court of Appeals. On April 18, 2016, the EPA filed a motion with the federal court to settle five issues raised in litigation. The Duke Energy Registrants cannot predict the court's response to the proposed settlement, but would not expect a material impact from the settlement if approved as proposed by the EPA. Duke Energy is reviewing the proposed settlement to determine if additional asset retirement obligation adjustments will be required. 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, the Subsidiary Registrants recorded asset retirement obligation amounts during 2015. 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 which was lifted on March 24, 2016. On April 22, 2016, plaintiffs filed an Amended Verified Consolidated Shareholder Derivative Complaint (Amended Complaint) making the same allegations as in the Consolidated Complaint. The Duke Energy Defendants anticipate filing a Motion to Dismiss the Amended Complaint. 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. On December 7, 2015, the Duke Energy Defendants filed a Motion to Stay the proceedings. The proceedings are currently stayed until July 1, 2016, after which the Duke Energy Defendants may seek an additional stay. In addition to the above derivative complaints, in 2014, Duke Energy also received two shareholder litigation demand letters. The letters alleged that the members of the Board of Directors and certain officers breached their fiduciary duties by allowing the company to illegally dispose of and store coal ash pollutants. One of the letters also alleged a breach of fiduciary duty in the decision-making relating to the leadership changes following the close of the Progress Energy merger in July 2012. By letter dated September 4, 2015, attorneys for the shareholders were informed that, on the recommendation of the Demand Review Committee formed to consider such matters, the Board of Directors concluded not to pursue potential claims against individuals. One of the shareholders, Mitchell Pinsly, sent a formal demand for records and Duke Energy responded to this request. On October 30, 2015, shareholder Saul Bresalier filed a shareholder derivative complaint in the U.S. District Court for the District of Delaware. The lawsuit alleges that several current and former Duke Energy officers and directors (Bresalier Defendants) breached their fiduciary duties in connection with coal ash environmental issues, the post-merger change in Chief Executive Officer and oversight of political contributions. Duke Energy is named as a nominal defendant. The Bresalier Complaint contends that the Demand Review Committee failed to appropriately consider the shareholder’s earlier demand for litigation and improperly decided not to pursue claims against the Bresalier Defendants. The Bresalier Defendants filed a Motion to Dismiss the Bresalier litigation on January 15, 2016. In lieu of a response to the Motion to Dismiss, the plaintiff filed a Motion to Convert the Bresalier Defendants' Motion to Dismiss into a Motion for Summary Judgment and also for limited discovery. Briefing on the Motion to Convert is complete. It is not possible to predict whether Duke Energy will incur any liability or to estimate the damages, if any, it might incur in connection with these matters. Progress Energy Merger Shareholder Litigation On May 31, 2013, the Delaware Chancery Court consolidated four shareholder derivative lawsuits filed in 2012. The Court also appointed a lead plaintiff and counsel for plaintiffs and designated the case as In Re Duke Energy Corporation Derivative Litigation . The lawsuit names as defendants the 11 members of the Board of Directors who were also members of the pre-merger Board of 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. On December 10, 2015, the Duke Energy defendants filed a Motion to Dismiss the litigation. Oral argument on the motion is scheduled for May 9, 2016. 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. On December 21, 2015, Plaintiff filed a Consolidated Amended Complaint asserting the same claims contained in the original complaints. Duke Energy filed a Motion to Dismiss on February 19, 2016. On March 18, 2016, the Chancery Court Plaintiffs moved to intervene in the Tansey proceeding, asking the federal district court to stay the federal litigation in favor of the Delaware Chancery litigation. 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 Duke Energy Trading and Marketing, LLC (DETM), a non-operating Duke Energy affiliate, was a defendant, along with numerous other energy companies, in four class-action lawsuits and a fifth single-plaintiff lawsuit pending in a consolidated federal court proceeding in Nevada. Each of these lawsuits contains similar claims that defendants allegedly manipulated natural gas markets by various means, including providing false information to natural gas trade publications and entering into unlawful arrangements and agreements in violation of the antitrust laws of the respective states. Plaintiffs seek damages in unspecified amounts. In February 2016, DETM reached agreements in principle to settle all of the pending lawsuits. Settlement of the single-plaintiff settlement was finalized and paid in March 2016. Settlement of the class-action lawsuits are currently being finalized and will be subject to court approval. The settlement amounts are not material to Duke Energy. Brazil Expansion Lawsuit On August 9, 2011, the State of São Paulo sued Duke Energy International Geracao Paranapenema S.A. (DEIGP) in Brazilian state court. The lawsuit claims DEIGP is under a continuing obligation to expand installed generation capacity in the State of São Paulo by 15 percent pursuant to a stock purchase agreement under which DEIGP purchased generation assets from the state. On August 10, 2011, a judge granted an injunction ordering DEIGP to present a detailed expansion plan in satisfaction of the 15 percent obligation. DEIGP has previously taken a position that the expansion obligation is no longer viable given changes that have occurred in the electric energy sector since privatization. DEIGP submitted its proposed expansion plan on November 11, 2011, but reserved objections regarding enforceability. In January 2013, DEIGP filed appeals in the federal courts, which are still pending, regarding various procedural issues. A decision on the merits in the first instance court is also pending. It is not possible to predict whether Duke Energy will incur any liability or to estimate the damages, if any, it might incur in connection with this matter. Brazil Generation Record drought conditions in Brazil during 2014 and 2015 negatively impacted DEIGP. A number of electric generators have filed lawsuits seeking relief in the Brazilian courts to mitigate hydrological exposure and diminishing dispatch levels. Some courts have granted injunction orders to limit the financial exposure of certain generators. The implication of these orders is that other electricity market participants not covered by the injunctions may be required to compensate for the financial impact of the liability limitations. The Independent Power Producer Association (APINE) filed one such lawsuit on behalf of DEIGP and other hydroelectric generators against the Brazilian electric regulatory agency (ANEEL). On July 2, 2015, an injunction was granted in favor of APINE limiting the financial exposure of DEIGP and the other plaintiff generators, until the merits of the lawsuit are determined. ANEEL's appeal of the injunction was denied on December 18, 2015. The outcome of these lawsuits is uncertain. It is not possible to predict the impact to Duke Energy from the outcome of these matters. 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 penalties at all Duke Energy Carolinas and Duke Energy Progress coal facilities in North Carolina. Under the agreement, Duke Energy Progress paid approximately $6 million and Duke Energy Carolinas paid approximately $1 million . In addition to these payments, Duke Energy Progress and Duke Energy Carolinas will accelerate remediation actions at the Sutton, Asheville, Belews Creek and H.F. Lee plants. The ALJ entered a consent order resolving the contested case relating to the Sutton Plant and NCDEQ rescinded the NOVs relating to alleged groundwater violations at both the Sutton and Asheville plants. On October 13, 2015, the Southern Environmental Law Center (SELC), representing multiple conservation groups, filed a lawsuit in North Carolina Superior Court seeking judicial review of the order approving the settlement agreement with NCDEQ. The conservation groups contend that the ALJ exceeded his statutory authority in approving a settlement that provided for past, present, and future resolution of groundwater issues at facilities which were not at issue in the penalty appeal. On December 18, 2015, Duke Energy Carolinas and Duke Energy Progress filed a Motion to Dismiss the complaint. On February 12, 2016, the ALJ entered a new order clarifying that the dismissal of the contested case only applied to the specific issues before the ALJ in the Petition for Contested Case. On March 10, 2016, the court dismissed the SELC lawsuit based on the ALJ's entry of the new order. On February 8, 2016, NCDEQ assessed a penalty of approximately $6.8 million , including enforcement costs, against Duke Energy Carolinas related to storm-water pipes and associated discharges at the Dan River Steam Station. Duke Energy Carolinas recorded a charge in December 2015 for this penalty. In March 2016, Duke Energy Carolinas filed an appeal of this penalty. Trial date is set for August 22, 2016, for this proceeding. Duke Energy Carolinas cannot predict the outcome of this matter. NCDEQ State Enforcement Actions In the first quarter of 2013, SELC sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged CWA violations from coal ash basins at two of their coal-fired power plants in North Carolina. NCDEQ filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The cases have been consolidated and are being heard before a single judge. On August 16, 2013, NCDEQ filed an enforcement action against Duke Energy Carolinas and Duke Energy Progress related to their remaining plants in North Carolina, alleging violations of the CWA and violations of the North Carolina groundwater standards. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. SELC is representing several environmental groups who have been permitted to intervene in these cases. On July 10, 2015, Duke Energy Carolinas and Duke Energy Progress filed two Motions for Partial Summary Judgment in the case on the basis that there is no longer either a genuine controversy or disputed material facts about the relief for seven of the 14 North Carolina plants with coal ash basins. On September 14, 2015, the court granted the Motions for Partial Summary Judgment pending court approval of the terms through an order. In November 2015, NCDEQ submitted a proposed order. On November 23, 2015, Duke Energy Carolinas, Duke Energy Progress and SELC filed separate objections to portions of the NCDEQ filing. Following a hearing held on February 12, 2016, Duke Energy Carolinas and Duke Energy Progress submitted a revised proposed order to comply with rulings made by the judge at the hearing. On April 4, 2016, the court issued an order granting Duke Energy Progress' motion for partial summary judgment for cases involving the H.F. Lee, Cape Fear and Weatherspoon plants, thus concluding the litigation for those plants. Duke Energy Carolinas and Duke Energy Progress have submitted a proposed order relating to the remaining plants for which summary judgment has been granted. A ruling related to the proposed order for the remaining plants is pending. It is not possible to predict any liability or estimate any damages Duke Energy Carolinas or Duke Energy Progress might incur in connection with these matters. Federal Citizens Suits There are currently five cases filed in various North Carolina federal courts 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. 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 motion filed by the SELC, on August 1, 2014, the court modified the original June 9 order to dismiss only the plaintiff's federal law claim based on hydrologic connections at Sutton Lake. The claims related to the alleged state court violations of the permits are back in the case. On August 26, 2015, the court suspended the proceedings until further order from the court. On September 3, 2014, three citizen suits were filed by various environmental groups: (i) a citizen suit in the United States Court for the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Cape Fear Plant; (ii) in the United States Court for the Eastern District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the H.F. Lee Plant; and (iii) in the United States Court for the Middle District of North Carolina alleging unpermitted discharges to surface water and groundwater violations at the Buck Steam Station. Motions to Stay or Dismiss the proceedings were filed in each of the three cases. The proceedings related to Cape Fear and H.F. Lee have been stayed. On October 20, 2015, the court issued an order denying the motions in the Buck proceedings. Duke Energy Carolinas' motion seeking appellate review of the District Court's decision was denied on January 29, 2016. On April 11, 2016, the Roanoke River Basin Association served a Notice of Intent to Sue under the CWA, alleging unpermitted discharges to surface water and groundwater violations at the Mayo Plant. A federal citizen suit may be filed 60 days after service of the Notice of Intent to Sue. It is not possible to predict whether Duke Energy Carolinas or Duke Energy Progress will incur any liability or to estimate the damages, if any, they might incur in connection with these matters. Potential Groundwater Contamination Claims Beginning in May 2015, a number of residents living in the vicinity of the North Carolina facilities with ash basins received letters from NCDEQ advising them not to drink water from the private wells on their land tested by NCDEQ as the samples were found to have certain substances at levels higher than the criteria set by the North Carolina Department of Health and Human Services (DHHS). The criteria, in some cases, are considerably more stringent than federal drinking water standards established to protect human health and welfare. The Coal Ash Act requires additional groundwater monitoring and assessments for each of the 14 coal-fired plants in North Carolina, including sampling of private water supply wells. The data gathered through these Comprehensive Site Assessments (CSAs) will be used by NCDEQ to determine whether the water quality of these private water supply wells has been adversely impacted by the ash basins. Duke Energy has submitted CSAs documenting the results of extensive groundwater monitoring around coal ash basins at all 14 of the plants with coal ash basins. Generally, the data gathered through the installation of new monitoring wells and soil and water samples across the state have been consistent with historical data provided to state regulators over many years. The DHHS and NCDEQ sent follow-up letters on October 15, 2015, to residents near coal ash basins who have had their wells tested, stating that private well samplings at a considerable distance from coal ash impoundments, as well as some municipal water supplies, contain similar levels of vanadium and hexavalent chromium which leads investigators to believe these constituents are naturally occurring. In March 2016, DHHS rescinded the advisories. It is not possible to estimate the maximum exposure of loss, if any, that may occur in connection with claims which might be made by these residents. Asbestos-related Injuries and Damages Claims Duke Energy Carolinas has experienced numerous claims for indemnification and medical cost reimbursement related to asbestos exposure. These claims relate to damages for bodily injuries alleged to have arisen from exposure to or use of asbestos in connection with construction and maintenance activities conducted on its electric generation plants prior to 1985. As of March 31, 2016 , there were 118 asserted claims for non-malignant cases with the cumulative relief sought of up to $30 million , and 68 asserted claims for malignant cases with the cumulative relief sought of up to $10 million . Based on Duke Energy Carolinas’ experience, it is expected that the ultimate resolution of most of these claims likely will be less than the amount claimed. Duke Energy Carolinas has recognized asbestos-related reserves of $527 million at March 31, 2016 and $536 million at December 31, 2015 . These reserves are classified in Other within Deferred Credits and Other Liabilities and Other within Current Liabilities on the Condensed Consolidated Balance Sheets. These reserves are based upon the minimum amount of the range of loss for current and future asbestos claims through 2033, are recorded on an undiscounted basis and incorporate anticipated inflation. In light of the uncertainties inherent in a longer-term forecast, man

Debt and Credit Facilities

Debt and Credit Facilities	3 Months Ended
	Mar. 31, 2016
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). Three Months Ended March 31, 2016 Duke Maturity Interest Duke Energy Issuance Date Date Rate Energy Carolinas First Mortgage Bonds March 2016 (a) March 2023 2.500 % $ 500 $ 500 March 2016 (a) March 2046 3.875 % 500 500 Total issuances $ 1,000 $ 1,000 (a) Proceeds will be used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes. In April 2016, Duke Energy issued $350 million principal amount of senior unsecured notes with a fixed interest rate of 2.875% and maturity date of April 2023. Proceeds will be used to pay down outstanding commercial paper and for general corporate purposes. CURRENT MATURITIES OF LONG-TERM DEBT The following table shows the significant components of Current maturities of long-term debt on the Condensed Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings. (in millions) Maturity Date Interest Rate March 31, 2016 Unsecured Debt Duke Energy Indiana June 2016 6.050 % $ 325 Duke Energy (Parent) November 2016 2.150 % 500 First Mortgage Bonds Duke Energy Indiana July 2016 0.937 % 150 Duke Energy Carolinas December 2016 1.750 % 350 Duke Energy Progress March 2017 0.836 % 250 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Duke Energy Ohio (a) August 2027 1.266 % 50 Other 373 Current maturities of long-term debt $ 2,075 (a) Represents Duke Energy Kentucky's bonds with a mandatory put in December 2016. AVAILABLE CREDIT FACILITIES Master Credit Facility Duke Energy has a Master Credit Facility with a capacity of $7.5 billion through January 2020. The Duke Energy Registrants, excluding Progress Energy (Parent), have borrowing capacity under the Master Credit Facility up to a specified sublimit for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower. The amount available under the Master Credit Facility has been reduced to backstop issuances of commercial paper, certain letters of credit and variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder. Duke Energy Carolinas and Duke Energy Progress are also required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet obligations under plea agreements reached with the U.S. Department of Justice in 2015 related to violations at North Carolina facilities with ash basins. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. March 31, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Facility size (a) $ 7,500 $ 3,475 $ 800 $ 1,000 $ 1,200 $ 425 $ 600 Reduction to backstop issuances Commercial paper (b) (2,980 ) (1,816 ) (300 ) (205 ) (480 ) (29 ) (150 ) Outstanding letters of credit (79 ) (72 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 3,825 $ 1,587 $ 211 $ 543 $ 719 $ 396 $ 369 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Condensed Consolidated Balance Sheets. Piedmont Bridge Facility In connection with the Merger Agreement with Piedmont, Duke Energy entered into a $4.9 billion Bridge Facility with Barclays. The Bridge Facility, if drawn upon, may be used (i) to fund the cash consideration for the transaction and (ii) to pay certain fees and expenses in connection with the transaction. In November 2015, Barclays syndicated its commitment under the Bridge Facility to a broader group of lenders. Duke Energy does not expect to draw upon the Bridge Facility. The amount of the Bridge Facility is reduced by any financings related to the Piedmont acquisition entered into by Duke Energy, and has accordingly been reduced to $4.2 billion as a result of the Equity Forwards described in Note 13 , "Common Stock." Refer to Note 2 for additional information on the Piedmont acquisition. Short-Term Loan Facility On April 7, 2016, Duke Energy borrowed $500 million under a delayed-draw term loan facility (Term Loan) arranged on February 22, 2016. The Term Loan borrowing is due on or before August 19, 2016 and will bear interest at 30-day LIBOR plus 75 basis points. The Term Loan is pre-payable at par and the terms are generally consistent with those governing the Master Credit Facility.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL AND INTANGIBLE ASSETS GOODWILL The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Regulated International Commercial (in millions) Utilities Energy Portfolio Total Goodwill at December 31, 2015 $ 15,950 $ 271 $ 122 $ 16,343 Foreign exchange and other changes — 6 — 6 Goodwill at March 31, 2016 $ 15,950 $ 277 $ 122 $ 16,349 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 March 31, 2016 and December 31, 2015 . Progress Energy Progress Energy's Goodwill is included in the Regulated Utilities operating segment and there are no accumulated impairment charges.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Subsidiary Registrants engage in related party transactions in accordance with applicable state and federal commission regulations. Refer to the Condensed Consolidated Balance Sheets of the Subsidiary Registrants for balances due to or due from related parties. Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income. In addition to the amounts presented above, the Subsidiary Registrants record the impact on net income of other affiliate transactions, including rental of office space, participation in a money pool arrangement, other operational transactions and their proportionate share of certain charged expenses. See Note 6 to the Consolidated Financial Statements in the Annual Report on Form 10-K for more information regarding money pool. The net impact of these transactions was not material for the three months ended March 31, 2016 and 2015 for the Subsidiary Registrants. As discussed in Note 12 , certain trade receivables have been sold by Duke Energy Ohio and Duke Energy Indiana to CRC, an affiliate formed by a subsidiary of Duke Energy. The proceeds obtained from the sales of receivables are largely cash but also include a subordinated note from the affiliate for a portion of the purchase price. 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 . Refer to Note 2 for further information on the sale of the Disposal Group. Intercompany Income Taxes Duke Energy and its subsidiaries file a consolidated federal income tax return and other state and jurisdictional returns. The Subsidiary Registrants have a tax sharing agreement with Duke Energy for the allocation of consolidated tax liabilities and benefits. Income taxes recorded represent amounts the Subsidiary Registrants would incur as separate C-Corporations. The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price risk and interest rate risk. The primary use of commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Interest rate swaps are used to manage interest rate risk associated with borrowings. All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the Condensed Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting arrangements is offset against the collateralized derivatives on the Condensed Consolidated Balance Sheets. The cash impacts of settled derivatives are recorded as operating activities on the Condensed Consolidated Statements of Cash Flows. INTEREST RATE RISK The Duke Energy Registrants are exposed to changes in interest rates as a result of their issuance or anticipated issuance of variable-rate and fixed-rate debt and commercial paper. Interest rate risk is managed by limiting variable-rate exposures to a percentage of total debt and by monitoring changes in interest rates. To manage risk associated with changes in interest rates, the Duke Energy Registrants may enter into interest rate swaps, U.S. Treasury lock agreements and other financial contracts. In anticipation of certain fixed-rate debt issuances, a series of forward-starting interest rate swaps may be executed to lock in components of current market interest rates. These instruments are later terminated prior to or upon the issuance of the corresponding debt. Cash Flow Hedges For a derivative designated as hedging the exposure to variable cash flows of a future transaction, referred to as a cash flow hedge, the effective portion of the derivative's gain or loss is initially reported as a component of other comprehensive income and subsequently reclassified into earnings once the future transaction affects earnings. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. Gains and losses reclassified out of AOCI for the three months ended March 31, 2016 , were not material. Duke Energy's interest rate derivatives designated as hedges include interest rate swaps used to hedge existing debt within the International Energy and Renewables' businesses. Undesignated Contracts Undesignated contracts include contracts not designated as a hedge because they are accounted for under regulatory accounting and contracts that do not qualify for hedge accounting. Duke Energy’s interest rate swaps for its Regulated Utilities operations employ regulatory accounting. With regulatory accounting, the mark-to-market gains or losses on the swaps are deferred as regulatory liabilities or regulatory assets, respectively. Regulatory assets and liabilities are amortized consistent with the treatment of the related costs in the ratemaking process. The accrual of interest on the swaps is recorded as Interest Expense. During the three months ended March 31, 2016, Duke Energy entered into an additional $500 million of forward-starting interest rate swaps to manage interest rate exposure for the expected financing of the Piedmont acquisition, bringing the total outstanding to $1.4 billion . The swaps do not qualify for hedge accounting and are marked-to-market, with any gains or losses included within earnings. For the three months ended March 31, 2016 , unrealized losses on the swaps of $93 million were included within Interest Expense on the Condensed Consolidated Statements of Operations. The swaps will be terminated in conjunction with the acquisition financing. See Note 2 for additional information related to the Piedmont acquisition. The following table shows notional amounts for derivatives related to interest rate risk. March 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 2,327 400 500 250 250 27 Total notional amount $ 3,027 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,527 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $497 million at March 31, 2016 and December 31, 2015 . COMMODITY PRICE RISK The Duke Energy Registrants are exposed to the impact of changes in the 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 commissions, can be used to manage the risk of price volatility. At March 31, 2016 , all of Duke Energy's open commodity derivative instruments were undesignated because they are accounted for under regulatory accounting. Mark-to-market gains or losses on contracts that use regulatory accounting are deferred as regulatory liabilities or regulatory assets, respectively. Undesignated contracts expire as late as 2048 . 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 Condensed Consolidated Statements of Operations, with an offsetting impact on regulatory assets or liabilities. Therefore, due to the regulatory accounting followed by the Subsidiary Registrants for undesignated derivatives, realized and unrealized gains and losses on undesignated commodity derivatives do not have an immediate impact on reported net income. 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. March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 183 — — — — 144 39 Natural gas (millions of decatherms) 470 92 378 131 247 — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of decatherms) 398 66 332 117 215 — — LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED IN THE CONDENSED CONSOLIDATED BALANCE SHEETS The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 4 $ 1 $ 1 $ — $ — $ — $ 2 Noncurrent 7 3 4 2 2 — — Total Derivative Assets – Commodity Contracts $ 11 $ 4 $ 5 $ 2 $ 2 $ — $ 2 Interest Rate Contracts Not Designated as Hedging Instruments Current $ 3 $ — $ 3 $ — $ 3 $ — $ — Noncurrent 19 9 9 3 6 — — Total Derivative Assets – Interest Rate Contracts $ 22 $ 9 $ 12 $ 3 $ 9 $ — $ — Total Derivative Assets $ 33 $ 13 $ 17 $ 5 $ 11 $ — $ 2 Derivative Liabilities March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 270 $ 37 $ 232 $ 78 $ 154 $ — $ — Noncurrent 71 5 66 9 52 — — Total Derivative Liabilities – Commodity Contracts $ 341 $ 42 $ 298 $ 87 $ 206 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — Noncurrent 45 — — — — — — Not Designated as Hedging Instruments Current (a) 94 — — — — 1 — Noncurrent 45 39 — — — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 196 $ 39 $ — $ — $ — $ 7 $ — Total Derivative Liabilities $ 537 $ 81 $ 298 $ 87 $ 206 $ 7 $ — (a) Duke Energy amount includes $93 million of forward-starting interest rate swaps related to the Piedmont acquisition. Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 4 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 10 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 26 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 11 $ — $ — $ — $ — $ — $ — Noncurrent 33 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 63 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 419 $ 45 $ 322 $ 98 $ 216 $ 7 $ — OFFSETTING ASSETS AND LIABILITIES The following tables present the line items on the Condensed Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position, and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 7 $ 1 $ 4 $ — $ 3 $ — $ 2 Gross amounts offset (1 ) (1 ) (1 ) — — — — Net amounts presented in Current Assets: Other $ 6 $ — $ 3 $ — $ 3 $ — $ 2 Noncurrent Gross amounts recognized $ 26 $ 12 $ 13 $ 5 $ 8 $ — $ — Gross amounts offset (15 ) (12 ) (3 ) (2 ) (1 ) — — Net amounts presented in Investments and Other Assets: Other $ 11 $ — $ 10 $ 3 $ 7 $ — $ — Derivative Liabilities March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 376 $ 37 $ 232 $ 78 $ 154 $ 1 $ — Gross amounts offset (16 ) (1 ) (15 ) — (15 ) — — Net amounts presented in Current Liabilities: Other $ 360 $ 36 $ 217 $ 78 $ 139 $ 1 $ — Noncurrent Gross amounts recognized $ 161 $ 44 $ 66 $ 9 $ 52 $ 6 $ — Gross amounts offset (23 ) (12 ) (11 ) (2 ) (9 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 138 $ 32 $ 55 $ 7 $ 43 $ 6 $ — Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 8 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 4 $ — $ — $ — $ — $ — $ — Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 271 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 249 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 148 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 132 $ 13 $ 82 $ 21 $ 56 $ 6 $ — OBJECTIVE CREDIT CONTINGENT FEATURES Certain derivative contracts contain objective credit contingent features. These features include the requirement to post cash collateral or letters of credit if specific events occur, such as a credit rating downgrade below investment grade. The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio and Duke Energy Indiana were not material. March 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 453 $ 81 $ 279 $ 83 $ 196 Fair value of collateral already posted 23 — 23 — 23 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 430 81 256 83 173 December 31, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting arrangement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral under master netting arrangements. All receivables presented below were offset against net derivative positions on the Condensed Consolidated Balance Sheets. March 31, 2016 December 31, 2015 (in millions) Receivables Receivables Duke Energy $ 23 $ 30 Progress Energy 23 30 Duke Energy Florida 23 30

Investments in Debt and Equity

Investments in Debt and Equity Securities	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments In Debt And Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES AVAILABLE-FOR-SALE SECURITIES The Duke Energy Registrants classify their investments in debt and equity securities as available-for-sale. Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the nuclear decommissioning fund (NDTF) at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to OPEB plans, and (iii) Duke Energy’s captive insurance 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 investments and the Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana grantor trusts (Investment Trusts) are managed by independent investment managers with discretion to buy, sell, and invest pursuant to the objectives set forth by the trust agreements. The Duke Energy Registrants have limited oversight of the day-to-day management of these investments. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt and equity securities within the Investment Trusts are considered other-than-temporary impairments and are recognized immediately. Investments within the Investment Trusts generally qualify for regulatory accounting, and accordingly realized and unrealized gains and losses are deferred as a regulatory asset or liability. Certain investments held in Duke Energy Florida's NDTF were acquired in a settlement with Florida Municipal Joint Owners (FMJO) and do not qualify for regulatory accounting. Unrealized gains and losses on these assets are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired, and realized gains and losses are included within Other income and expense, net on the Condensed Consolidated Statements of Operations. The value of these assets has not materially changed since the assets were acquired from FMJO. As a result, there is no material impact on earnings of the Duke Energy Registrants. Other Available-for-Sale Securities Unrealized gains and losses on all other available-for-sale securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. 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 March 31, 2016 and December 31, 2015 . DUKE ENERGY The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 201 $ — $ — $ 179 Equity securities 1,823 64 3,592 1,823 58 3,590 Corporate debt securities 16 3 454 7 8 432 Municipal bonds 6 — 211 5 1 185 U.S. government bonds 33 — 1,288 11 5 1,254 Other debt securities 1 4 148 — 4 177 Total NDTF $ 1,879 $ 71 $ 5,894 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 29 $ — $ — $ 29 Equity securities 33 1 97 32 1 95 Corporate debt securities 1 2 91 1 3 92 Municipal bonds 3 1 76 3 1 74 U.S. government bonds 2 — 56 — — 45 Other debt securities — 2 55 — 2 62 Total Other Investments (a) $ 39 $ 6 $ 404 $ 36 $ 7 $ 397 Total Investments $ 1,918 $ 77 $ 6,298 $ 1,882 $ 83 $ 6,214 (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. The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 136 Due after one through five years 769 Due after five through 10 years 559 Due after 10 years 915 Total $ 2,379 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 March 31, (in millions) 2016 2015 Realized gains $ 54 $ 102 Realized losses 50 14 DUKE ENERGY CAROLINAS The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 50 $ — $ — $ 34 Equity securities 1,022 31 2,088 1,021 27 2,094 Corporate debt securities 8 2 257 3 5 292 Municipal bonds 1 — 53 1 — 33 U.S. government bonds 12 — 502 3 3 438 Other debt securities 1 4 138 — 4 147 Total NDTF $ 1,044 $ 37 $ 3,088 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,044 $ 38 $ 3,091 $ 1,028 $ 40 $ 3,041 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 14 Due after one through five years 195 Due after five through 10 years 224 Due after 10 years 520 Total $ 953 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 March 31, (in millions) 2016 2015 Realized gains $ 34 $ 90 Realized losses 37 12 PROGRESS ENERGY The following table presents the estimated fair value investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 151 $ — $ — $ 145 Equity securities 801 33 1,504 802 31 1,496 Corporate debt securities 8 1 197 4 3 140 Municipal bonds 5 — 158 4 1 152 U.S. government bonds 21 — 786 8 2 816 Other debt securities — — 10 — — 30 Total NDTF $ 835 $ 34 $ 2,806 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 17 $ — $ — $ 18 Municipal bonds 3 — 46 3 — 45 Total Other Investments (a) $ 3 $ — $ 63 $ 3 $ — $ 63 Total Investments $ 838 $ 34 $ 2,869 $ 821 $ 37 $ 2,842 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 101 Due after one through five years 486 Due after five through 10 years 264 Due after 10 years 346 Total $ 1,197 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 March 31, (in millions) 2016 2015 Realized gains $ 19 $ 12 Realized losses 13 1 DUKE ENERGY PROGRESS The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 100 $ — $ — $ 110 Equity securities 595 27 1,184 596 25 1,178 Corporate debt securities 6 1 145 3 2 96 Municipal bonds 5 — 158 4 1 150 U.S. government bonds 15 — 479 6 2 486 Other debt securities — — 6 — — 18 Total NDTF $ 621 $ 28 $ 2,072 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (a) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 621 $ 28 $ 2,073 $ 609 $ 30 $ 2,039 (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. The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 37 Due after one through five years 282 Due after five through 10 years 219 Due after 10 years 250 Total $ 788 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 March 31, (in millions) 2016 2015 Realized gains $ 15 $ 9 Realized losses 11 1 DUKE ENERGY FLORIDA The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 35 Equity securities 206 6 320 206 6 318 Corporate debt securities 2 — 52 1 1 44 Municipal bonds — — — — — 2 U.S. government bonds 6 — 307 2 — 330 Other debt securities — — 4 — — 12 Total NDTF (c) $ 214 $ 6 $ 734 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 6 Municipal bonds 3 — 46 3 — 45 Total Other Investments (a) $ 3 $ — $ 47 $ 3 $ — $ 51 Total Investments $ 217 $ 6 $ 781 $ 212 $ 7 $ 792 (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 decrease in estimated fair value of the NDTF as of March 31, 2016, is primarily due to reimbursements from the NDTF for Duke Energy Florida's cost 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) March 31, 2016 Due in one year or less $ 64 Due after one through five years 204 Due after five through 10 years 45 Due after 10 years 96 Total $ 409 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 March 31, (in millions) 2016 2015 Realized gains $ 4 $ 3 Realized losses 2 — DUKE ENERGY INDIANA The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 2 Equity securities 27 — 72 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds — 1 27 — 1 26 Total Other Investments (a) $ 27 $ 1 $ 102 $ 27 $ 1 $ 101 Total Investments $ 27 $ 1 $ 102 $ 27 $ 1 $ 101 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset. The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 2 Due after one through five years 14 Due after five through 10 years 9 Due after 10 years 4 Total $ 29 Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were insignificant for the three months ended March 31, 2016 and 2015 .

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data, or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient. Fair value measurements are classified in three levels based on the fair value hierarchy: Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. An active market is one in which transactions for an asset or liability occur with sufficient frequency and volume to provide ongoing pricing information. Level 2 – A fair value measurement utilizing inputs other than quoted prices included in Level 1 that are observable, either directly or indirectly, for an asset or liability. Inputs include (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active, (iii) and inputs other than quoted market prices that are observable for the asset or liability, such as interest rate curves and yield curves observable at commonly quoted intervals, volatilities and credit spreads. A Level 2 measurement cannot have more than an insignificant portion of its valuation based on unobservable inputs. Instruments in this category include non-exchange-traded derivatives, such as over-the-counter forwards, swaps and options; certain marketable debt securities; and financial instruments traded in less than active markets. Level 3 – Any fair value measurement which includes unobservable inputs for more than an insignificant portion of the valuation. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value. Level 3 measurements may include longer-term instruments that extend into periods in which observable inputs are not available. Not Categorized – As discussed in Note 1 , certain investments are not categorized within the Fair Value hierarchy. These investments are measured based on the fair value of the underlying investments but may not be readily redeemable at that fair value. Fair value accounting guidance permits entities to elect to measure certain financial instruments that are not required to be accounted for at fair value, such as equity method investments or the company’s own debt, at fair value. The Duke Energy Registrants have not elected to record any of these items at fair value. Transfers between levels represent assets or liabilities that were previously (i) categorized at a higher level for which the inputs to the estimate became less observable or (ii) classified at a lower level for which the inputs became more observable during the period. The Duke Energy Registrant’s policy is to recognize transfers between levels of the fair value hierarchy at the end of the period. There were no transfers between levels during the three months ended March 31, 2016 and 2015 . Valuation methods of the primary fair value measurements disclosed below are as follows. Investments in equity securities The majority of investments in equity securities are valued using Level 1 measurements. Investments in equity securities are typically valued at the closing price in the principal active market as of the last business day of the quarter. Principal active markets for equity prices include published exchanges such as Nasdaq Composite (NASDAQ) and New York Stock Exchange (NYSE). Foreign equity prices are translated from their trading currency using the currency exchange rate in effect at the close of the principal active market. There was no after-hours market activity that was required to be reflected in the reported fair value measurements. Investments in debt securities Most investments in debt securities are valued using Level 2 measurements because the valuations use interest rate curves and credit spreads applied to the terms of the debt instrument (maturity and coupon interest rate) and consider the counterparty credit rating. If the market for a particular fixed income security is relatively inactive or illiquid, the measurement is Level 3. Commodity derivatives Commodity derivatives with clearinghouses are classified as Level 1. Other commodity derivatives are primarily valued using internally developed discounted cash flow models which incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or non-performance risk (after reflecting credit enhancements such as collateral), and are discounted to present value. Pricing inputs are derived from published exchange transaction prices and other observable data sources. In the absence of an active market, the last available price may be used. If forward price curves are not observable for the full term of the contract and the unobservable period had more than an insignificant impact on the valuation, the commodity derivative is classified as Level 3. In isolation, increases (decreases) in natural gas forward prices result in favorable (unfavorable) fair value adjustments for natural gas purchase contracts; and increases (decreases) in electricity forward prices result in unfavorable (favorable) fair value adjustments for electricity sales contracts. Duke Energy regularly evaluates and validates pricing inputs used to estimate the fair value of natural gas commodity contracts by a market participant price verification procedure. This procedure provides a comparison of internal forward commodity curves to market participant generated curves. Interest rate derivatives Most over-the-counter interest rate contract derivatives are valued using financial models which utilize observable inputs for similar instruments and are classified as Level 2. Inputs include forward interest rate curves, notional amounts, interest rates and credit quality of the counterparties. DUKE ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,592 $ 3,426 $ 1 $ — $ 165 Nuclear decommissioning trust fund debt securities 2,302 935 1,367 — Other available-for-sale equity securities 97 97 — — — Other available-for-sale debt securities 307 85 218 4 Derivative assets 33 — 31 2 Total assets 6,331 4,543 1,617 6 165 Derivative liabilities (537 ) (6 ) (531 ) — Net assets $ 5,794 $ 4,537 $ 1,086 $ 6 $ 165 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 Derivative assets 26 — 16 10 Total assets 6,240 4,260 1,793 15 172 Derivative liabilities (419 ) — (419 ) — Net assets $ 5,821 $ 4,260 $ 1,374 $ 15 $ 172 The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues. Three Months Ended March 31, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Purchases, sales, issuances and settlements: Sales (1 ) — (1 ) Settlements — (7 ) (7 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (1 ) (1 ) Balance at end of period $ 4 $ 2 $ 6 Three Months Ended March 31, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains included in earnings — 24 24 Purchases, sales, issuances and settlements: Settlements — (10 ) (10 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 1 Balance at end of period $ 5 $ 14 $ 19 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 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,088 $ 1,922 $ 1 $ — $ 165 Nuclear decommissioning trust fund debt securities 1,000 264 736 — Other available-for-sale debt securities 3 — — 3 Derivative assets 13 — 13 — Total assets 3,104 2,186 750 3 165 Derivative liabilities (81 ) — (81 ) — Net assets $ 3,023 $ 2,186 $ 669 $ 3 $ 165 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — Other available-for-sale debt securities 3 — — 3 Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172 There was no change to the Level 3 balance during the three months ended March 31, 2016 and March 31, 2015 . PROGRESS ENERGY The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,504 $ 1,504 $ — Nuclear decommissioning trust fund debt securities 1,302 671 631 Other available-for-sale debt securities 63 17 46 Derivative assets 17 — 17 Total assets 2,886 2,192 694 Derivative liabilities (298 ) — (298 ) Net assets $ 2,588 $ 2,192 $ 396 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591 DUKE ENERGY PROGRESS The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,184 $ 1,184 $ — Nuclear decommissioning trust fund debt securities and other 888 389 499 Other available-for-sale debt securities and other 1 1 — Derivative assets 5 — 5 Total assets 2,078 1,574 504 Derivative liabilities (87 ) — (87 ) Net assets $ 1,991 $ 1,574 $ 417 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623 DUKE ENERGY FLORIDA The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 320 $ 320 $ — Nuclear decommissioning trust fund debt securities and other 414 282 132 Other available-for-sale debt securities and other 47 1 46 Derivative assets 11 — 11 Total assets 792 603 189 Derivative liabilities (206 ) — (206 ) Net assets (liabilities) $ 586 $ 603 $ (17 ) December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 ) DUKE ENERGY OHIO The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which are disclosed in Note 9 . March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative liabilities $ (7 ) $ — $ (7 ) $ — Net liabilities $ (7 ) $ — $ (7 ) $ — December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended March 31, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains included in earnings — 25 Purchases, sales, issuances and settlements: Settlements (2 ) — Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (1 ) — Balance at end of period $ — $ 7 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 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 72 $ 72 $ — $ — Other available-for-sale debt securities and other 30 1 29 — Derivative assets 2 — — 2 Net assets $ 104 $ 73 $ 29 $ 2 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7 The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended March 31, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Total pretax realized or unrealized losses included in earnings — (3 ) Purchases, sales, issuances and settlements: Settlements (5 ) (9 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 Balance at end of period $ 2 $ 3 QUANTITATIVE INFORMATION ABOUT UNOBSERVABLE INPUTS The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. As of March 31, 2016 and December 31, 2015 all Level 3 derivatives were financial transmission rights (FTRs). March 31, 2016 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 2 RTO auction pricing FTR price – per Megawatt-Hour (MWh) $ (1.67 ) - $ 5.29 Duke Energy Indiana 2 RTO auction pricing FTR price – per MWh (1.67 ) - 5.29 December 31, 2015 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29 OTHER FAIR VALUE DISCLOSURES The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. March 31, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 40,307 $ 44,785 $ 39,569 $ 42,537 Duke Energy Carolinas 9,360 10,567 8,367 9,156 Progress Energy 14,210 16,245 14,464 15,856 Duke Energy Progress 6,565 7,134 6,518 6,757 Duke Energy Florida 4,265 5,109 4,266 4,908 Duke Energy Ohio 1,642 1,836 1,598 1,724 Duke Energy Indiana 3,768 4,362 3,768 4,219 At both March 31, 2016 and December 31, 2015 , fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and non-recourse notes payable of VIEs are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2016
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES A VIE is an entity that is evaluated for consolidation using more than a simple analysis of voting control. The analysis to determine whether an entity is a VIE considers contracts with an entity, credit support for an entity, the adequacy of the equity investment of an entity and the relationship of voting power to the amount of equity invested in an entity. This analysis is performed either upon the creation of a legal entity or upon the occurrence of an event requiring reevaluation, such as a significant change in an entity’s assets or activities. A qualitative analysis of control determines the party that consolidates a VIE. This assessment is based on (i) what party has the power to direct the activities of the VIE that most significantly impact its economic performance and (ii) what party has rights to receive benefits or is obligated to absorb losses that could potentially be significant to the VIE. The analysis of the party that consolidates a VIE is a continual reassessment. No financial support was provided to any of the consolidated VIEs during the three months ended March 31, 2016 and the year ended December 31, 2015 , 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. March 31, 2016 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress (c) Florida (c) (in millions) DERF DEPR DEFR 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) 615 372 256 437 20 14 1,714 Other — — — — 149 2 151 Investments and Other Assets Other — — — — 58 — 58 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 2,027 20 2,047 Accumulated depreciation and amortization — — — — (340 ) (6 ) (346 ) Total assets $ 615 $ 372 $ 256 $ 437 $ 1,914 $ 32 $ 3,626 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 23 $ — $ 23 Taxes accrued — — — — 4 — 4 Current maturities of long-term debt — — — — 82 12 94 Other — — — — 22 — 22 Long-Term Debt (b) 425 300 225 325 995 — 2,270 Deferred Credits and Other Liabilities Deferred income taxes — — — — 240 — 240 Asset retirement obligations — — — — 37 — 37 Other — — — — 42 — 42 Total liabilities $ 425 $ 300 $ 225 $ 325 $ 1,445 $ 12 $ 2,732 Net assets of consolidated variable interest entities $ 190 $ 72 $ 31 $ 112 $ 469 $ 20 $ 894 December 31, 2015 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress (c) Florida (c) (in millions) DERF DEPR DEFR 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) 596 349 309 454 19 21 1,748 Other — — — — 138 4 142 Investments and Other Assets Other — — — — 70 — 70 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 2,015 20 2,035 Accumulated depreciation and amortization — — — — (321 ) (6 ) (327 ) Total assets $ 596 $ 349 $ 309 $ 454 $ 1,921 $ 41 $ 3,670 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 35 $ — $ 35 Taxes accrued 5 3 — — 5 1 14 Current maturities of long-term debt — — — — 108 17 125 Other — — — — 15 2 17 Long-Term Debt (b) 425 254 225 325 968 — 2,197 Deferred Credits and Other Liabilities Deferred income taxes — — — — 289 — 289 Asset retirement obligations — — — — 35 — 35 Other — — — — 33 — 33 Total liabilities $ 430 $ 257 $ 225 $ 325 $ 1,488 $ 20 $ 2,745 Net assets of consolidated variable interest entities $ 166 $ 92 $ 84 $ 129 $ 433 $ 21 $ 925 (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 total amount for Duke Energy Progress and Duke Energy Florida. 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), Duke Energy Progress Receivables, LLC (DEPR) and Duke Energy Florida Receivables, LLC (DEFR) are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. On a daily basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and related services from their parent companies. DERF, DEPR and DEFR are wholly owned limited liability companies with separate legal existence from their parent companies, and their assets are not generally available to creditors of their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy the receivables from their parents companies. 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 most significant activity that impacts the economic performance of DERF, DEPR and DEFR are the decisions made to manage delinquent receivables. Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida consolidate DERF, DEPR and DEFR, respectively, as they make those decisions. 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) $ 425 $ 300 $ 225 Expiration date December 2018 February 2019 April 2019 CRC CRC is a bankruptcy remote, special purpose entity indirectly owned by Duke Energy. On a revolving basis, Duke Energy Ohio and Duke Energy Indiana sell to CRC certain accounts receivable arising from the sale of electricity and related services. The receivables sold are securitized by CRC through a credit facility managed by two unrelated third parties. Borrowing availability from the credit facility is limited to the amount of qualified receivables sold to CRC. The sole source of funds to satisfy the related debt obligation is cash collections from the receivables. The credit facility expires in December 2018 and is reflected on Duke Energy's Condensed Consolidated Balance Sheets as Long-Term Debt. The proceeds Duke Energy Ohio and Duke Energy Indiana receive from the sale of receivables to CRC are typically 75 percent cash and 25 percent in the form of a subordinated note from CRC. The subordinated note is a retained interest in the receivables sold. Depending on collection experience, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million . CRC is considered a VIE because (i) equity capitalization is insufficient to support its operations, (ii) power to direct the activities that most significantly impact the economic performance of the entity are not performed by the equity holder, Cinergy, and (iii) deficiencies in net worth of CRC are not funded by Cinergy, but by Duke Energy. The most significant activities that impact the economic performance of CRC are decisions made to manage delinquent receivables. Duke Energy consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC. Renewables Certain Duke Energy renewable energy facilities are VIEs due to long-term fixed-price power purchase agreements. These fixed-price agreements effectively transfer commodity price risk to the buyer of the power. Certain other Duke Energy renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. For certain VIEs, assets are restricted and cannot be pledged as collateral or sold to third parties without prior approval of debt holders. The activities that most significantly impact the economic performance of these renewable energy facilities were decisions associated with siting, negotiating purchase power agreements, engineering, procurement and construction, and decisions associated with ongoing operations and maintenance-related activities. Duke Energy consolidates the entities as it 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. March 31, 2016 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 39 $ 50 Investments in equity method unconsolidated affiliates 227 186 413 — — Total assets $ 227 $ 186 $ 413 $ 39 $ 50 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 16 $ 16 $ — $ — Net assets $ 227 $ 170 $ 397 $ 39 $ 50 December 31, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 235 152 387 — — Total assets $ 235 $ 152 $ 387 $ 47 $ 60 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 235 $ 135 $ 370 $ 47 $ 60 The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the power purchase agreement with 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 rulemaking could increase the costs of OVEC, which would be passed through to Duke Energy Ohio. CRC See discussion under Consolidated VIEs for additional information related to CRC. Amounts included in Receivables from affiliated companies in the above table for Duke Energy Ohio and Duke Energy Indiana reflect their retained interest in receivables sold to CRC. These subordinated notes held by Duke Energy Ohio and Duke Energy Indiana are stated at fair value. Carrying values of retained interests are determined by allocating carrying value of the receivables between assets sold and interests retained based on relative fair value. The allocated bases of the subordinated notes are not materially different than their face value because (i) the receivables generally turn over in less than two months, (ii) credit losses are reasonably predictable due to the broad customer base and lack of significant concentration, and (iii) the equity in CRC is subordinate to all retained interests and thus would absorb losses first. The hypothetical effect on fair value of the retained interests assuming both a 10 percent and a 20 percent unfavorable variation in credit losses or discount rates is not material due to the short turnover of receivables and historically low credit loss history. Interest accrues to Duke Energy Ohio and Duke Energy Indiana on the retained interests using the acceptable yield method. This method generally approximates the stated rate on the notes since the allocated basis and the face value are nearly equivalent. An impairment charge is recorded against the carrying value of both retained interests and purchased beneficial interest whenever it is determined that an other-than-temporary impairment has occurred. Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2016 2015 2016 2015 Anticipated credit loss ratio 0.6 % 0.6 % 0.3 % 0.3 % Discount rate 1.4 % 1.2 % 1.4 % 1.2 % Receivable turnover rate 13.2 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) March 31, 2016 December 31, 2015 March 31, 2016 December 31, 2015 Receivables sold $ 225 $ 233 $ 253 $ 260 Less: Retained interests 39 47 50 60 Net receivables sold $ 186 $ 186 $ 203 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Three Months Ended March 31, March 31, (in millions) 2016 2015 2016 2015 Sales Receivables sold $ 532 $ 644 $ 635 $ 716 Loss recognized on sale 3 3 3 3 Cash flows Cash proceeds from receivables sold 537 640 643 722 Return received on retained interests 1 1 1 2 Cash flows from sales of receivables are reflected within Operating Activities on Duke Energy Ohio’s and Duke Energy Indiana’s Condensed Consolidated Statements of Cash Flows. Collection fees received in connection with servicing transferred accounts receivable are included in Operation, maintenance and other on Duke Energy Ohio’s and Duke Energy Indiana’s Condensed Consolidated Statements of Operations and Comprehensive Income. The loss recognized on sales of receivables is calculated monthly by multiplying receivables sold during the month by the required discount. The required discount is derived monthly utilizing a three-year weighted average formula that considers charge-off history, late charge history and turnover history on the sold receivables, as well as a component for the time value of money. The discount rate, or component for the time value of money, is the prior month-end London Interbank Offered Rate (LIBOR) plus a fixed rate of 1.00 percent .

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Common Stock	COMMON STOCK Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common stockholders, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted average number of common stock outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common stockholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted average number of common stock outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options and the Equity Forwards, were exercised or settled. Duke Energy’s participating securities are restricted stock units that are entitled to dividends declared on Duke Energy common stock during the restricted stock unit’s vesting periods. The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common stock outstanding to the diluted weighted average number of common shares outstanding. Three Months Ended March 31, (in millions, except per share amounts) 2016 2015 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 691 $ 772 Weighted average shares outstanding – basic 689 708 Weighted average shares outstanding – diluted 689 708 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 1.00 $ 1.09 Diluted $ 1.00 $ 1.09 Potentially dilutive items excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.825 $ 0.795 (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. Equity Forwards In March 2016, Duke Energy marketed an equity offering of 10.6 million shares of common stock. In lieu of issuing equity at the time of the offering, Duke Energy entered into Equity Forwards with Barclays. No amounts have or will be recorded in Duke Energy’s Condensed Consolidated Financial Statements with respect to the equity offering until settlements of the Equity Forwards occur. The Equity Forwards require Duke Energy to, at its election prior to June 30, 2017, either physically settle the transactions by issuing the total of 10.6 million of its common stock to Barclays in exchange for net proceeds at the then-applicable forward sale price specified by the agreements (initially $69.84 per share) or Duke Energy can net settle the transactions in whole or in part through the delivery or receipt of cash or shares. The forward sale price is subject to adjustment on a daily basis based on a floating interest rate factor and will decrease by other fixed amounts specified in the agreements. The net proceeds received upon settlement are expected to be used to finance a portion of the acquisition of Piedmont. Until settlement of the Equity Forwards, earnings per share dilution resulting from the agreements, if any, will be determined under the treasury stock method. If Duke Energy had elected to net share settle the contract as of March 31, 2016, Duke Energy would have been required to deliver 1.4 million shares. Accelerated Stock Repurchase Program On April 6, 2015, Duke Energy entered into agreements with each of Goldman, Sachs & Co. and JPMorgan Chase Bank, National Association (the Dealers) to repurchase a total of $1.5 billion of Duke Energy common stock under an accelerated stock repurchase program (the ASR). Duke Energy made payments of $750 million to each of the Dealers and was delivered 16.6 million shares, with a total fair value of $1.275 billion , which represented approximately 85 percent of the total number of shares of Duke Energy common stock expected to be repurchased under the ASR. The $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	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION For employee awards, equity classified stock-based compensation cost is measured at the service inception date or the grant date, based on the estimated achievement of certain performance metrics or the fair value of the award, and is recognized as expense or capitalized as a component of property, plant and equipment over the requisite service period. Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense, and stock-based compensation costs capitalized are included in the following table. Three Months Ended March 31, (in millions) 2016 2015 Restricted stock unit awards $ 7 $ 9 Performance awards 5 5 Pretax stock-based compensation cost $ 12 $ 14 Tax benefit associated with stock-based compensation expense $ 4 $ 5 Stock-based compensation costs capitalized 1 1

Employee Benefit Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS DEFINED BENEFIT RETIREMENT PLANS Duke Energy maintains, and the Subsidiary Registrants participate in, qualified, non-contributory defined benefit retirement plans. The plans cover most U.S. employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits equal to a percentage of current eligible earnings based on age or the combination of age and years of service, and interest credits. Certain employees are covered under plans that use a final average earnings formula. Under these average earnings formulas, a plan participant 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 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’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. Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the three months ended March 31, 2016 . Three Months Ended March 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Contributions $ 132 $ 42 $ 42 $ 21 $ 21 $ 1 $ 9 Net periodic benefit costs disclosed in the tables below represent the cost of the respective benefit plan for the periods presented. However, portions of the net periodic benefit costs disclosed in the tables below have been capitalized as a component of property, plant and equipment. Amounts presented in the tables below for the Subsidiary Registrants represent the amounts of pension and other post-retirement benefit costs allocated by Duke Energy for employees of the Subsidiary Registrants. Additionally, the Subsidiary Registrants are allocated their proportionate share of pension and post-retirement benefit costs for employees of Duke Energy’s shared services affiliate that provides support to the Subsidiary Registrants. These allocated amounts are included in the governance and shared service costs discussed in Note 8 . Duke Energy uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. QUALIFIED PENSION PLANS The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 36 $ 12 $ 11 $ 6 $ 5 $ 1 $ 2 Interest cost on projected benefit obligation 83 21 26 12 14 5 7 Expected return on plan assets (129 ) (35 ) (42 ) (21 ) (21 ) (7 ) (10 ) Amortization of actuarial loss 33 8 14 6 7 1 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 3 1 1 — — — — Net periodic pension costs $ 22 $ 5 $ 9 $ 3 $ 5 $ — $ 2 Three Months Ended March 31, 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 82 21 26 12 14 5 7 Expected return on plan assets (129 ) (36 ) (43 ) (20 ) (22 ) (6 ) (10 ) Amortization of actuarial loss 43 10 17 8 8 2 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 2 1 1 — — — — Net periodic pension costs $ 34 $ 7 $ 11 $ 6 $ 5 $ 2 $ 3 NON-QUALIFIED PENSION PLANS Net periodic pension costs for non-qualified pension plans were not material for the three months ended March 31, 2016 and 2015. OTHER POST-RETIREMENT BENEFIT PLANS Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as set forth in the plans. The health care benefits include medical, dental, vision, and prescription drug coverage and are subject to certain limitations, such as deductibles and co-payments. The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 1 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 8 2 4 2 2 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss (gain) 1 (1 ) 5 3 2 — (1 ) Amortization of prior service credit (35 ) (3 ) (26 ) (17 ) (9 ) — — Net periodic other post-retirement benefit costs $ (28 ) $ (4 ) $ (17 ) $ (12 ) $ (5 ) $ — $ — Three Months Ended March 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 2 — — 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 $ (21 ) $ (4 ) $ (15 ) $ (10 ) $ (4 ) $ — $ — EMPLOYEE SAVINGS PLAN Duke Energy sponsors, and the Subsidiary Registrants participate in, an employee savings plan that covers substantially all U.S. employees. Most employees participate in a matching contribution formula where Duke Energy provides a matching contribution generally equal to 100 percent of employee before-tax and Roth 401(k) contributions of up to 6 percent of eligible pay per pay period. Dividends on Duke Energy shares held by the savings plan are charged to retained earnings when declared and shares held in the 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 a three-year vesting requirement, is provided to the employee’s savings plan account. The following table presents employer contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Three Months Ended March 31, 2016 $ 52 $ 18 $ 15 $ 11 $ 4 $ 1 $ 2 2015 49 16 14 11 4 1 2

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES TAXES ON FOREIGN EARNINGS As of December 31, 2015, the Company’s intention was to indefinitely reinvest foreign earnings of International Energy earned after December 31, 2014. In February 2016, Duke Energy announced it had initiated a process to divest the International Energy business segment, excluding the investment in NMC. Accordingly, Duke Energy no longer intends to indefinitely reinvest the undistributed earnings of International Energy. The Company recorded U.S. income taxes of approximately $ 12 million in the first quarter of 2016 related to such earnings and will prospectively provide U.S. income taxes on future foreign earnings. This change in the Company's intent, combined with the extension of bonus depreciation by Congress in late 2015, allows Duke Energy to more efficiently utilize foreign tax credits and reduce U.S. deferred tax liabilities associated with historic unremitted foreign earnings by approximately $ 95 million . 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 March 31, 2016 2015 Duke Energy 23.4 % 31.9 % Duke Energy Carolinas 34.1 % 35.8 % Progress Energy 36.7 % 35.4 % Duke Energy Progress 35.4 % 33.8 % Duke Energy Florida 37.9 % 38.6 % Duke Energy Ohio 26.9 % 36.7 % Duke Energy Indiana 30.2 % 36.6 % The decrease in the effective tax rate for Duke Energy for the three months ended March 31, 2016, is primarily due to lower income taxes on foreign earnings as a result of the Company's intent to no longer indefinitely reinvest the foreign earnings of the International Energy segment combined with more efficient utilization of foreign tax credits. Refer to "Taxes on Foreign Earnings" above for additional information. The decrease in the effective tax rate for Duke Energy Carolinas for the three months ended March 31, 2016, is primarily due to a favorable state resolution related to prior-year tax returns. The increase in the effective tax rate for Progress Energy for the three months ended March 31, 2016, is primarily due to an unfavorable tax levelization in 2016 compared to a favorable tax levelization in 2015. The increase in the effective tax rate for Duke Energy Progress for the three months ended March 31, 2016, is primarily due to an unfavorable tax levelization in 2016 compared to a favorable tax levelization in 2015. The decrease in the effective tax rate for Duke Energy Ohio for the three months ended March 31, 2016, is primarily due to a favorable prior-period adjustment for depreciation and other property, plant and equipment. The decrease in the effective tax rate for Duke Energy Indiana for the three months ended March 31, 2016, is primarily due to a favorable prior-period adjustment for depreciation and other property, plant and equipment.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS For information on subsequent events related to regulatory matters, commitments and contingencies, and debt and credit facilities see Notes 4, 5 and 6, respectively.

Organization and Basis of Pre25

Organization and Basis of Presentation (Policy)	3 Months Ended
	Mar. 31, 2016
Policy Text Block [Line Items]
Nature of Operations and Basis of Consolidation	NATURE OF OPERATIONS AND BASIS OF CONSOLIDATION Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) and Latin America primarily through its direct and indirect subsidiaries. Duke Energy’s subsidiaries include its subsidiary registrants, Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, LLC (Duke Energy Progress); Duke Energy Florida, LLC (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, LLC (Duke Energy Indiana, formerly Duke Energy Indiana, Inc.). 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. Duke Energy Florida is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Florida. Duke Energy Florida is subject to the regulatory provisions of the Florida Public Service Commission (FPSC), NRC and FERC. Substantially all of Duke Energy Florida’s operations qualify for regulatory accounting. Duke Energy Ohio is a regulated public utility primarily engaged in the transmission and distribution of electricity in portions of Ohio and Kentucky, the generation and sale of electricity in portions of Kentucky, and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers and recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. On April 2, 2015, Duke Energy completed the sale of its nonregulated Midwest generation business, which sold power into wholesale energy markets, to a subsidiary of Dynegy Inc. (Dynegy). See Note 2 for additional information. Substantially all of Duke Energy Ohio’s operations that remain after the sale qualify for regulatory accounting. Duke Energy Indiana is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of Indiana. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and FERC. Substantially all of Duke Energy Indiana’s operations qualify for regulatory accounting. On January 1, 2016, Duke Energy Indiana, an Indiana corporation, converted into an Indiana limited liability company.
Basis of Accounting	BASIS OF PRESENTATION Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales (collectively, the Disposal Group), a retail sales business owned by Duke Energy, to Dynegy on April 2, 2015. The results of operations of these businesses prior to the date of sale have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations, assets held for sale and liabilities associated with assets held for sale. See Note 2 for additional information. These Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Condensed Consolidated Financial Statements do not include all information and notes required by GAAP in the U.S. for annual financial statements. Since the interim Condensed Consolidated Financial Statements and Notes do not include all information and notes required by GAAP in the U.S. for annual financial statements, the Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the Consolidated Financial Statements and Notes in the Duke Energy Registrants’ combined Annual Report on Form 10-K for the year ended December 31, 2015 . The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants make any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. These Condensed Consolidated Financial Statements, in the opinion of the respective companies’ management, reflect all normal recurring adjustments necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors.
Use of Estimates	In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Unbilled Revenue	UNBILLED REVENUE Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes, timing of rendering customer bills and meter reading schedules.
Excise Taxes	EXCISE TAXES Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Otherwise, excise taxes are accounted for net. Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes on the Condensed Consolidated Statements of Operations were as follows.
New Accounting Standards	NEW ACCOUNTING STANDARDS The new accounting standards adopted for 2016 and 2015 had no material impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants. The following accounting standards were adopted by the Duke Energy Registrants during 2015. 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. Duke Energy has not reported any discontinued operations under the revised accounting guidance. Balance Sheet Classification of Deferred Taxes . In November 2015, the FASB issued revised accounting guidance for the Balance Sheet classification of deferred taxes. The core principle of this revised accounting guidance is that all deferred tax assets and liabilities should be classified as noncurrent. For Duke Energy, this revised accounting guidance was adopted prospectively for December 31, 2015. Balance Sheet Presentation of Debt Issuance Costs. In April and August of 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 was adopted retrospectively. The implementation of this accounting standard resulted in a reduction of Other within Regulatory Assets and Deferred Debits and in Long-Term Debt of $ 173 million and $ 170 million on the Condensed Consolidated Balance Sheets as of March 31, 2016 and December 31, 2015, respectively. Fair Value Disclosures for Certain Investments. In May 2015, the FASB issued revised accounting guidance for investments in certain entities that use net asset value per share (or its equivalent) as a practical expedient to determine fair value. The core principle of this revised accounting guidance is that the valuation of investments using the practical expedient should not be categorized within the fair value hierarchy (i.e., as Level 1, 2 or 3). The practical expedient applies to investments in investment companies for which there is not a readily determinable fair value (market quote) or the investment is not in a mutual fund with a publicly available net asset value. For Duke Energy, this revised accounting guidance was adopted retrospectively. The implementation of this guidance is reflected in Note 11 , "Fair Value Measurements." The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by Duke Energy, as of March 31, 2016 . Revenue from Contracts with Customers. In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. 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 January 1, 2017. The guidance can be applied retrospectively to all prior reporting periods presented or retrospectively with a cumulative effect as of the initial date of application. Duke Energy is currently evaluating the requirements. The ultimate impact of the new standard has not yet been determined. Financial Instruments Classification and Measurement. In January 2016, the FASB issued revised accounting guidance for the classification and measurement of financial instruments. Changes in the fair value of all equity securities will be required to be recorded in net income. Current GAAP allows some changes in fair value for available-for-sale equity securities to be recorded in AOCI. Additional disclosures will be required to present separately the financial assets and financial liabilities by measurement category and form of financial asset. Investments accounted for using the equity method of accounting are not included within the scope of this revised guidance. For Duke Energy, the revised accounting guidance is effective for interim and annual periods beginning January 1, 2018, by recording a cumulative effect to the balance sheet as of January 1, 2018. This guidance is expected to have a minimal impact on Duke Energy's Condensed Consolidated Statements of Comprehensive Income as changes in the fair value of most of Duke Energy's available-for-sale equity securities are deferred as regulatory assets or liabilities. Leases. In February 2016, the FASB issued revised accounting guidance for leases. The core principle of this guidance is that a lessee should recognize the assets and liabilities that arise from leases on the balance sheet. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2019, although it can be early adopted. The guidance is applied using a modified retrospective approach. Duke Energy is currently evaluating the requirements. Other than an expected increase in assets and liabilities, the ultimate impact of the new standard has not yet been determined. Stock-Based Compensation and Income Taxes. In March 2016, the FASB issued revised accounting guidance for stock-based compensation and the associated income taxes. This is a simplification initiative of the FASB. This standard changes certain aspects of accounting for share-based payment awards to employees including the accounting for income taxes, statutory tax withholding requirements, as well as the classification on the Condensed Consolidated Statements of Cash Flows. This guidance will be applied prospectively, retrospectively, or using a modified retrospective transition method depending on the item changed. For Duke Energy, this guidance is effective for interim and annual periods beginning January 1, 2017, although it can be early adopted. Duke Energy is currently evaluating the requirements. The primary change expected is an increase in the volatility of income tax expense.
Duke Energy Ohio [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 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 nearly all of their retail accounts receivable to an affiliate, Cinergy Receivables Company, LLC (CRC), on a revolving basis. These transfers of receivables are accounted for as sales and include receivables for unbilled revenues. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 for further information. These receivables for unbilled revenues are shown in the table below.

Organization and Basis of Pre26

Organization and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2016
Organization And Basis Of Presentation [Line Items]
Schedule of Excise Taxes	Excise taxes accounted for on a gross basis as both operating revenues and property and other taxes on the Condensed Consolidated Statements of Operations were as follows. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy $ 91 $ 100 Duke Energy Carolinas 8 9 Progress Energy 47 49 Duke Energy Progress 5 4 Duke Energy Florida 42 45 Duke Energy Ohio 28 32 Duke Energy Indiana 8 10
Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues, which are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets, are presented in the following table. (in millions) March 31, 2016 December 31, 2015 Duke Energy $ 715 $ 748 Duke Energy Carolinas 288 283 Progress Energy 158 172 Duke Energy Progress 85 102 Duke Energy Florida 73 70 Duke Energy Ohio 2 3 Duke Energy Indiana 33 31
Duke Energy Ohio [Member] | Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below. (in millions) March 31, 2016 December 31, 2015 Duke Energy Ohio $ 61 $ 71 Duke Energy Indiana 88 97
Duke Energy Indiana [Member] | Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below. (in millions) March 31, 2016 December 31, 2015 Duke Energy Ohio $ 61 $ 71 Duke Energy Indiana 88 97

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Income Statement Disclosures	The following table presents the results of discontinued operations for the three months ended March 31, 2015. Duke Duke Energy (in millions) Energy Ohio Operating Revenues $ 543 $ 412 Loss on disposition (43 ) (44 ) Income before income taxes $ 147 $ 140 Income tax expense 51 50 Income from discontinued operations of the Disposal Group 96 90 Other, net of tax (a) (5 ) — Income from Discontinued Operations, net of tax $ 91 $ 90 (a) Relates to discontinued operations of businesses not related to the Disposal Group and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments.

Business Segments (Tables)

Business Segments (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting Information [Line Items]
Business Segment Data	Three Months Ended March 31, 2016 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,250 $ 246 $ 114 $ 5,610 $ 12 $ — $ 5,622 Intersegment revenues 9 — — 9 17 (26 ) — Total revenues $ 5,259 $ 246 $ 114 $ 5,619 $ 29 $ (26 ) $ 5,622 Segment income (loss) (a) $ 695 $ 123 $ 27 $ 845 $ (154 ) $ — $ 691 Add back noncontrolling interests 5 Income from discontinued operations, net of tax 3 Net income $ 699 Segment assets $ 111,838 $ 3,247 $ 4,183 $ 119,268 $ 2,263 $ 178 $ 121,709 (a) Other includes $74 million of after-tax costs to achieve mergers and a $12 million after-tax charge related to cost savings initiatives. Three Months Ended March 31, 2015 Total Regulated International Commercial Reportable (in millions) Utilities Energy Portfolio Segments Other Eliminations Consolidated Unaffiliated revenues $ 5,713 $ 273 $ 73 $ 6,059 $ 6 $ — $ 6,065 Intersegment revenues 10 — — 10 21 (31 ) — Total revenues $ 5,723 $ 273 $ 73 $ 6,069 $ 27 $ (31 ) $ 6,065 Segment income (loss) (a) $ 774 $ 36 $ 7 $ 817 $ (43 ) $ (1 ) $ 773 Add back noncontrolling interests 3 Income from discontinued operations, net of tax 91 Net income $ 867 Segment assets $ 106,642 $ 4,892 $ 6,202 $ 117,736 $ 4,230 $ 176 $ 122,142 (a) Other includes after-tax costs to achieve the 2012 Progress Energy merger of $13 million . The following table summarizes the net loss for Other for each of these entities. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas $ (17 ) $ (8 ) Progress Energy (49 ) (42 ) Duke Energy Progress (8 ) (4 ) Duke Energy Florida (4 ) (3 ) Duke Energy Ohio (9 ) (2 ) Duke Energy Indiana (2 ) (2 )
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data	The following table summarizes segment information prior to the sale of the nonregulated Midwest generation business. Three Months Ended March 31, 2015 Total Regulated Commercial Reportable (in millions) Utilities Portfolio Segments Other Eliminations Consolidated Total revenues $ 572 $ 14 $ 586 $ — $ — $ 586 Segment income (loss) $ 70 $ (9 ) $ 61 $ (2 ) $ — $ 59 Income from discontinued operations, net of tax 90 Net income $ 149 Segment assets $ 6,782 $ 2,984 $ 9,766 $ 43 $ (13 ) $ 9,796

Regulatory Matters (Tables)

Regulatory Matters (Tables)	3 Months Ended
	Mar. 31, 2016
Public Utilities, General Disclosures [Line Items]
Schedule of Potential Plant Retirements	The table below contains the net carrying value of generating facilities planned for retirement or included in recent IRPs as evaluated for potential retirement due to a lack of requisite environmental control equipment. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets as of March 31, 2016. Remaining Net Capacity Book Value (a) (in MW) (in millions) Duke Energy Florida (b) Crystal River Units 1 and 2 873 128 Duke Energy Indiana Wabash River Unit 6 (c) 318 35 Gallagher Units 2 and 4 (d) 280 137 Total Duke Energy 1,471 300 (a) Remaining net book value amounts exclude any capitalized asset retirement costs. (b) Progress Energy amounts are equal to Duke Energy Florida amounts. (c) In April 2016, Wabash River 6 terminated coal burning operations and is targeted for retirement by the end of 2016. The total net book value of $113 million for the retail portion of Wabash River Unit 6 and the retail portion of capitalized asset retirement costs for Wabash River Units 2 through 6 is classified as Generation facilities to be retired, net on Duke Energy Indiana's Condensed Consolidated Balance Sheet at March 31, 2016. (d) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the proposed settlement of Edwardsport IGCC matters.

Commitments and Contingencies (

Commitments and Contingencies (Table)	3 Months Ended
	Mar. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Additional Possible Losses in Excess of Recorded Environmental Reserves	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are not material except as presented in the table below. (in millions) Duke Energy $ 83 Duke Energy Carolinas 22 Duke Energy Ohio 42 Duke Energy Indiana 15
Schedule of Loss Contingencies	The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters, excluding asbestos related reserves and the exit obligation discussed above related to the termination of an EPC contract. Reserves are classified on the Condensed Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss in excess of recorded reserves is not material, other than as described above. (in millions) March 31, 2016 December 31, 2015 Reserves for Legal Matters Duke Energy $ 181 $ 166 Duke Energy Carolinas 11 11 Progress Energy 54 54 Duke Energy Progress 6 6 Duke Energy Florida 31 31 Duke Energy Ohio 80 80
Reserve for Environmental Costs [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Loss Contingencies	The following tables contain information regarding reserves for probable and estimable costs related to the various environmental sites. These reserves are recorded in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Balance at beginning of period $ 97 $ 10 $ 17 $ 3 $ 14 $ 54 $ 12 Provisions/adjustments 10 2 1 — 1 — 6 Cash reductions (3 ) (1 ) (2 ) (1 ) (1 ) — — Balance at end of period $ 104 $ 11 $ 16 $ 2 $ 14 $ 54 $ 18 Three Months Ended March 31, 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 2 — — — — 1 2 Cash reductions (3 ) — — — — (1 ) (1 ) Balance at end of period $ 96 $ 10 $ 17 $ 5 $ 12 $ 54 $ 11

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016 Unsecured Debt Duke Energy Indiana June 2016 6.050 % $ 325 Duke Energy (Parent) November 2016 2.150 % 500 First Mortgage Bonds Duke Energy Indiana July 2016 0.937 % 150 Duke Energy Carolinas December 2016 1.750 % 350 Duke Energy Progress March 2017 0.836 % 250 Tax-exempt Bonds Duke Energy Carolinas February 2017 3.600 % 77 Duke Energy Ohio (a) August 2027 1.266 % 50 Other 373 Current maturities of long-term debt $ 2,075 (a) Represents Duke Energy Kentucky's bonds with a mandatory put in December 2016.
Schedule Of Line Of Credit Facilities	The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility. March 31, 2016 Duke Duke Duke Duke Duke Duke Duke Energy Energy Energy Energy Energy Energy (in millions) Energy (Parent) Carolinas Progress Florida Ohio Indiana Facility size (a) $ 7,500 $ 3,475 $ 800 $ 1,000 $ 1,200 $ 425 $ 600 Reduction to backstop issuances Commercial paper (b) (2,980 ) (1,816 ) (300 ) (205 ) (480 ) (29 ) (150 ) Outstanding letters of credit (79 ) (72 ) (4 ) (2 ) (1 ) — — Tax-exempt bonds (116 ) — (35 ) — — — (81 ) Coal ash set-aside (500 ) — (250 ) (250 ) — — — Available capacity $ 3,825 $ 1,587 $ 211 $ 543 $ 719 $ 396 $ 369 (a) Represents the sublimit of each borrower. (b) Duke Energy issued $625 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Condensed Consolidated Balance Sheets.
Schedule of Long-term Debt Instruments [Table Text Block]	The following table summarizes significant debt issuances (in millions). Three Months Ended March 31, 2016 Duke Maturity Interest Duke Energy Issuance Date Date Rate Energy Carolinas First Mortgage Bonds March 2016 (a) March 2023 2.500 % $ 500 $ 500 March 2016 (a) March 2046 3.875 % 500 500 Total issuances $ 1,000 $ 1,000 (a) Proceeds will be used to fund capital expenditures for ongoing construction, capital maintenance and for general corporate purposes.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2016
Goodwill [Line Items]
Goodwill By Reportable Operating Segment	The following table presents goodwill by reportable operating segment for Duke Energy. Duke Energy Regulated International Commercial (in millions) Utilities Energy Portfolio Total Goodwill at December 31, 2015 $ 15,950 $ 271 $ 122 $ 16,343 Foreign exchange and other changes — 6 — 6 Goodwill at March 31, 2016 $ 15,950 $ 277 $ 122 $ 16,349

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2016
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Progress Energy [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table. Three Months Ended March 31, (in millions) 2016 2015 Duke Energy Carolinas Corporate governance and shared service expenses (a) $ 217 $ 219 Indemnification coverages (b) 5 6 Joint Dispatch Agreement (JDA) revenue (c) 9 26 JDA expense (c) 41 57 Progress Energy Corporate governance and shared service expenses (a) $ 174 $ 167 Indemnification coverages (b) 9 10 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Progress Corporate governance and shared service expenses (a) $ 100 $ 101 Indemnification coverages (b) 4 4 JDA revenue (c) 41 57 JDA expense (c) 9 26 Duke Energy Florida Corporate governance and shared service expenses (a) $ 74 $ 66 Indemnification coverages (b) 5 6 Duke Energy Ohio Corporate governance and shared service expenses (a) $ 85 $ 85 Indemnification coverages (b) 1 3 Duke Energy Indiana Corporate governance and shared service expenses (a) $ 94 $ 89 Indemnification coverages (b) 2 2 (a) The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources and employee benefits, information technology, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (b) The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income. (c) Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Intercompany Income Tax Receivable/Payable	The following table includes the balance of intercompany income tax receivables and payables for the Subsidiary Registrants. Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Carolinas Energy Progress Florida Ohio Indiana March 31, 2016 Intercompany income tax receivable $ — $ 170 $ 22 $ 16 $ — $ — Intercompany income tax payable 6 — — — 9 60 December 31, 2015 Intercompany income tax receivable $ 122 $ 120 $ 104 $ — $ 54 $ — Intercompany income tax payable — — — 96 — 47

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2016
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. March 31, 2016 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 2,327 400 500 250 250 27 Total notional amount $ 3,027 $ 400 $ 500 $ 250 $ 250 $ 27 December 31, 2015 Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Cash flow hedges (a) $ 700 $ — $ — $ — $ — $ — Undesignated contracts 1,827 400 500 250 250 27 Total notional amount $ 2,527 $ 400 $ 500 $ 250 $ 250 $ 27 (a) Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $497 million at March 31, 2016 and December 31, 2015 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. March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 183 — — — — 144 39 Natural gas (millions of decatherms) 470 92 378 131 247 — — December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy Energy Carolinas Energy Progress Florida Ohio Indiana Electricity (gigawatt-hours) 70 — — — — 34 36 Natural gas (millions of decatherms) 398 66 332 117 215 — —
Location And Fair Value Of Derivatives Recognized in the Condensed Consolidated Balance Sheets	The following tables show the fair value and balance sheet location of derivative instruments. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below are shown gross and cash collateral on the derivatives has not been netted against the fair values shown. Derivative Assets March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 4 $ 1 $ 1 $ — $ — $ — $ 2 Noncurrent 7 3 4 2 2 — — Total Derivative Assets – Commodity Contracts $ 11 $ 4 $ 5 $ 2 $ 2 $ — $ 2 Interest Rate Contracts Not Designated as Hedging Instruments Current $ 3 $ — $ 3 $ — $ 3 $ — $ — Noncurrent 19 9 9 3 6 — — Total Derivative Assets – Interest Rate Contracts $ 22 $ 9 $ 12 $ 3 $ 9 $ — $ — Total Derivative Assets $ 33 $ 13 $ 17 $ 5 $ 11 $ — $ 2 Derivative Liabilities March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 270 $ 37 $ 232 $ 78 $ 154 $ — $ — Noncurrent 71 5 66 9 52 — — Total Derivative Liabilities – Commodity Contracts $ 341 $ 42 $ 298 $ 87 $ 206 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 12 $ — $ — $ — $ — $ — $ — Noncurrent 45 — — — — — — Not Designated as Hedging Instruments Current (a) 94 — — — — 1 — Noncurrent 45 39 — — — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 196 $ 39 $ — $ — $ — $ 7 $ — Total Derivative Liabilities $ 537 $ 81 $ 298 $ 87 $ 206 $ 7 $ — (a) Duke Energy amount includes $93 million of forward-starting interest rate swaps related to the Piedmont acquisition. Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 12 $ — $ 1 $ — $ 1 $ 3 $ 7 Noncurrent 4 — 4 — 4 — — Total Derivative Assets – Commodity Contracts $ 16 $ — $ 5 $ — $ 5 $ 3 $ 7 Interest Rate Contracts Designated as Hedging Instruments Noncurrent $ 4 $ — $ — $ — $ — $ — $ — Not Designated as Hedging Instruments Current 6 — 6 2 2 — — Total Derivative Assets – Interest Rate Contracts $ 10 $ — $ 6 $ 2 $ 2 $ — $ — Total Derivative Assets $ 26 $ — $ 11 $ 2 $ 7 $ 3 $ 7 Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Commodity Contracts Not Designated as Hedging Instruments Current $ 256 $ 32 $ 222 $ 77 $ 145 $ — $ — Noncurrent 100 8 92 16 71 — — Total Derivative Liabilities – Commodity Contracts $ 356 $ 40 $ 314 $ 93 $ 216 $ — $ — Interest Rate Contracts Designated as Hedging Instruments Current $ 11 $ — $ — $ — $ — $ — $ — Noncurrent 33 — — — — — — Not Designated as Hedging Instruments Current 4 — 3 — — 1 — Noncurrent 15 5 5 5 — 6 — Total Derivative Liabilities – Interest Rate Contracts $ 63 $ 5 $ 8 $ 5 $ — $ 7 $ — Total Derivative Liabilities $ 419 $ 45 $ 322 $ 98 $ 216 $ 7 $ —
Offsetting Assets	Derivative Assets December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 18 $ — $ 7 $ 2 $ 3 $ 3 $ 7 Gross amounts offset (3 ) — (2 ) — (2 ) — — Net amounts presented in Current Assets: Other $ 15 $ — $ 5 $ 2 $ 1 $ 3 $ 7 Noncurrent Gross amounts recognized $ 8 $ — $ 4 $ — $ 4 $ — $ — Gross amounts offset (4 ) — (4 ) — (4 ) — — Net amounts presented in Investments and Other Assets: Other $ 4 $ — $ — $ — $ — $ — $ — The following tables present the line items on the Condensed Consolidated Balance Sheets where derivatives are reported. Substantially all of Duke Energy's outstanding derivative contracts are subject to enforceable master netting arrangements. The Gross amounts offset in the tables below show the effect of these netting arrangements on financial position, and include collateral posted to offset the net position. The amounts shown are calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below. Derivative Assets March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 7 $ 1 $ 4 $ — $ 3 $ — $ 2 Gross amounts offset (1 ) (1 ) (1 ) — — — — Net amounts presented in Current Assets: Other $ 6 $ — $ 3 $ — $ 3 $ — $ 2 Noncurrent Gross amounts recognized $ 26 $ 12 $ 13 $ 5 $ 8 $ — $ — Gross amounts offset (15 ) (12 ) (3 ) (2 ) (1 ) — — Net amounts presented in Investments and Other Assets: Other $ 11 $ — $ 10 $ 3 $ 7 $ — $ —
Offsetting Liabilities	Derivative Liabilities March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 376 $ 37 $ 232 $ 78 $ 154 $ 1 $ — Gross amounts offset (16 ) (1 ) (15 ) — (15 ) — — Net amounts presented in Current Liabilities: Other $ 360 $ 36 $ 217 $ 78 $ 139 $ 1 $ — Noncurrent Gross amounts recognized $ 161 $ 44 $ 66 $ 9 $ 52 $ 6 $ — Gross amounts offset (23 ) (12 ) (11 ) (2 ) (9 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 138 $ 32 $ 55 $ 7 $ 43 $ 6 $ — Derivative Liabilities December 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Current Gross amounts recognized $ 271 $ 32 $ 225 $ 77 $ 145 $ 1 $ — Gross amounts offset (22 ) — (21 ) (1 ) (20 ) — — Net amounts presented in Current Liabilities: Other $ 249 $ 32 $ 204 $ 76 $ 125 $ 1 $ — Noncurrent Gross amounts recognized $ 148 $ 13 $ 97 $ 21 $ 71 $ 6 $ — Gross amounts offset (16 ) — (15 ) — (15 ) — — Net amounts presented in Deferred Credits and Other Liabilities: Other $ 132 $ 13 $ 82 $ 21 $ 56 $ 6 $ —
Derivative Contracts with Contingent Credit Features	The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Ohio and Duke Energy Indiana were not material. March 31, 2016 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 453 $ 81 $ 279 $ 83 $ 196 Fair value of collateral already posted 23 — 23 — 23 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 430 81 256 83 173 December 31, 2015 Duke Duke Duke Duke Energy Progress Energy Energy (in millions) Energy Carolinas Energy Progress Florida Aggregate fair value of derivatives in a net liability position $ 334 $ 45 $ 290 $ 93 $ 194 Fair value of collateral already posted 30 — 30 — 30 Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered 304 45 260 93 164 The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting arrangement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral under master netting arrangements. All receivables presented below were offset against net derivative positions on the Condensed Consolidated Balance Sheets. March 31, 2016 December 31, 2015 (in millions) Receivables Receivables Duke Energy $ 23 $ 30 Progress Energy 23 30 Duke Energy Florida 23 30

Investments in Debt and Equit35

Investments in Debt and Equity Securities (Tables)	3 Months Ended
	Mar. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in available-for-sale securities. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 201 $ — $ — $ 179 Equity securities 1,823 64 3,592 1,823 58 3,590 Corporate debt securities 16 3 454 7 8 432 Municipal bonds 6 — 211 5 1 185 U.S. government bonds 33 — 1,288 11 5 1,254 Other debt securities 1 4 148 — 4 177 Total NDTF $ 1,879 $ 71 $ 5,894 $ 1,846 $ 76 $ 5,817 Other Investments Cash and cash equivalents $ — $ — $ 29 $ — $ — $ 29 Equity securities 33 1 97 32 1 95 Corporate debt securities 1 2 91 1 3 92 Municipal bonds 3 1 76 3 1 74 U.S. government bonds 2 — 56 — — 45 Other debt securities — 2 55 — 2 62 Total Other Investments (a) $ 39 $ 6 $ 404 $ 36 $ 7 $ 397 Total Investments $ 1,918 $ 77 $ 6,298 $ 1,882 $ 83 $ 6,214 (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.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 136 Due after one through five years 769 Due after five through 10 years 559 Due after 10 years 915 Total $ 2,379
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 March 31, (in millions) 2016 2015 Realized gains $ 54 $ 102 Realized losses 50 14
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. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 50 $ — $ — $ 34 Equity securities 1,022 31 2,088 1,021 27 2,094 Corporate debt securities 8 2 257 3 5 292 Municipal bonds 1 — 53 1 — 33 U.S. government bonds 12 — 502 3 3 438 Other debt securities 1 4 138 — 4 147 Total NDTF $ 1,044 $ 37 $ 3,088 $ 1,028 $ 39 $ 3,038 Other Investments Other debt securities $ — $ 1 $ 3 $ — $ 1 $ 3 Total Other Investments (a) $ — $ 1 $ 3 $ — $ 1 $ 3 Total Investments $ 1,044 $ 38 $ 3,091 $ 1,028 $ 40 $ 3,041 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 14 Due after one through five years 195 Due after five through 10 years 224 Due after 10 years 520 Total $ 953
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 March 31, (in millions) 2016 2015 Realized gains $ 34 $ 90 Realized losses 37 12
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. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 151 $ — $ — $ 145 Equity securities 801 33 1,504 802 31 1,496 Corporate debt securities 8 1 197 4 3 140 Municipal bonds 5 — 158 4 1 152 U.S. government bonds 21 — 786 8 2 816 Other debt securities — — 10 — — 30 Total NDTF $ 835 $ 34 $ 2,806 $ 818 $ 37 $ 2,779 Other Investments Cash and cash equivalents $ — $ — $ 17 $ — $ — $ 18 Municipal bonds 3 — 46 3 — 45 Total Other Investments (a) $ 3 $ — $ 63 $ 3 $ — $ 63 Total Investments $ 838 $ 34 $ 2,869 $ 821 $ 37 $ 2,842 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 101 Due after one through five years 486 Due after five through 10 years 264 Due after 10 years 346 Total $ 1,197
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 March 31, (in millions) 2016 2015 Realized gains $ 19 $ 12 Realized losses 13 1
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. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 100 $ — $ — $ 110 Equity securities 595 27 1,184 596 25 1,178 Corporate debt securities 6 1 145 3 2 96 Municipal bonds 5 — 158 4 1 150 U.S. government bonds 15 — 479 6 2 486 Other debt securities — — 6 — — 18 Total NDTF $ 621 $ 28 $ 2,072 $ 609 $ 30 $ 2,038 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 1 Total Other Investments (a) $ — $ — $ 1 $ — $ — $ 1 Total Investments $ 621 $ 28 $ 2,073 $ 609 $ 30 $ 2,039 (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.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 37 Due after one through five years 282 Due after five through 10 years 219 Due after 10 years 250 Total $ 788
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 March 31, (in millions) 2016 2015 Realized gains $ 15 $ 9 Realized losses 11 1
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. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value NDTF Cash and cash equivalents $ — $ — $ 51 $ — $ — $ 35 Equity securities 206 6 320 206 6 318 Corporate debt securities 2 — 52 1 1 44 Municipal bonds — — — — — 2 U.S. government bonds 6 — 307 2 — 330 Other debt securities — — 4 — — 12 Total NDTF (c) $ 214 $ 6 $ 734 $ 209 $ 7 $ 741 Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 6 Municipal bonds 3 — 46 3 — 45 Total Other Investments (a) $ 3 $ — $ 47 $ 3 $ — $ 51 Total Investments $ 217 $ 6 $ 781 $ 212 $ 7 $ 792 (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 decrease in estimated fair value of the NDTF as of March 31, 2016, is primarily due to reimbursements from the NDTF for Duke Energy Florida's cost 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) March 31, 2016 Due in one year or less $ 64 Due after one through five years 204 Due after five through 10 years 45 Due after 10 years 96 Total $ 409
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 March 31, (in millions) 2016 2015 Realized gains $ 4 $ 3 Realized losses 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. March 31, 2016 December 31, 2015 Gross Gross Gross Gross Unrealized Unrealized Estimated Unrealized Unrealized Estimated Holding Holding Fair Holding Holding Fair (in millions) Gains Losses (b) Value Gains Losses (b) Value Other Investments Cash and cash equivalents $ — $ — $ 1 $ — $ — $ 2 Equity securities 27 — 72 27 — 71 Corporate debt securities — — 2 — — 2 Municipal bonds — 1 27 — 1 26 Total Other Investments (a) $ 27 $ 1 $ 102 $ 27 $ 1 $ 101 Total Investments $ 27 $ 1 $ 102 $ 27 $ 1 $ 101 (a) These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. (b) Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities. (in millions) March 31, 2016 Due in one year or less $ 2 Due after one through five years 14 Due after five through 10 years 9 Due after 10 years 4 Total $ 29

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,592 $ 3,426 $ 1 $ — $ 165 Nuclear decommissioning trust fund debt securities 2,302 935 1,367 — Other available-for-sale equity securities 97 97 — — — Other available-for-sale debt securities 307 85 218 4 Derivative assets 33 — 31 2 Total assets 6,331 4,543 1,617 6 165 Derivative liabilities (537 ) (6 ) (531 ) — Net assets $ 5,794 $ 4,537 $ 1,086 $ 6 $ 165 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 3,590 $ 3,418 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 2,227 672 1,555 — Other available-for-sale equity securities 95 95 — — — Other available-for-sale debt securities 302 75 222 5 Derivative assets 26 — 16 10 Total assets 6,240 4,260 1,793 15 172 Derivative liabilities (419 ) — (419 ) — Net assets $ 5,821 $ 4,260 $ 1,374 $ 15 $ 172
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues. Three Months Ended March 31, 2016 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ 10 $ 15 Purchases, sales, issuances and settlements: Sales (1 ) — (1 ) Settlements — (7 ) (7 ) Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — (1 ) (1 ) Balance at end of period $ 4 $ 2 $ 6 Three Months Ended March 31, 2015 (in millions) Investments Derivatives (net) Total Balance at beginning of period $ 5 $ (1 ) $ 4 Total pretax realized or unrealized gains included in earnings — 24 24 Purchases, sales, issuances and settlements: Settlements — (10 ) (10 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 1 Balance at end of period $ 5 $ 14 $ 19
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3. As of March 31, 2016 and December 31, 2015 all Level 3 derivatives were financial transmission rights (FTRs). March 31, 2016 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 2 RTO auction pricing FTR price – per Megawatt-Hour (MWh) $ (1.67 ) - $ 5.29 Duke Energy Indiana 2 RTO auction pricing FTR price – per MWh (1.67 ) - 5.29 December 31, 2015 Fair Value of FTRs (in millions) Valuation Technique Unobservable Input Range Duke Energy $ 10 RTO auction pricing FTR price – per MWh $ (0.74 ) - $ 7.29 Duke Energy Ohio 3 RTO auction pricing FTR price – per MWh 0.67 - 2.53 Duke Energy Indiana 7 RTO auction pricing FTR price – per MWh (0.74 ) - 7.29
Schedule Of Long Term Debt Fair Value [Table Text Block]	The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements. March 31, 2016 December 31, 2015 (in millions) Book Value Fair Value Book Value Fair Value Duke Energy $ 40,307 $ 44,785 $ 39,569 $ 42,537 Duke Energy Carolinas 9,360 10,567 8,367 9,156 Progress Energy 14,210 16,245 14,464 15,856 Duke Energy Progress 6,565 7,134 6,518 6,757 Duke Energy Florida 4,265 5,109 4,266 4,908 Duke Energy Ohio 1,642 1,836 1,598 1,724 Duke Energy Indiana 3,768 4,362 3,768 4,219
Duke Energy Carolinas [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,088 $ 1,922 $ 1 $ — $ 165 Nuclear decommissioning trust fund debt securities 1,000 264 736 — Other available-for-sale debt securities 3 — — 3 Derivative assets 13 — 13 — Total assets 3,104 2,186 750 3 165 Derivative liabilities (81 ) — (81 ) — Net assets $ 3,023 $ 2,186 $ 669 $ 3 $ 165 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Not categorized Nuclear decommissioning trust fund equity securities $ 2,094 $ 1,922 $ — $ — $ 172 Nuclear decommissioning trust fund debt securities 944 246 698 — Other available-for-sale debt securities 3 — — 3 Total assets 3,041 2,168 698 3 172 Derivative liabilities (45 ) — (45 ) — Net assets $ 2,996 $ 2,168 $ 653 $ 3 $ 172
Progress Energy [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,504 $ 1,504 $ — Nuclear decommissioning trust fund debt securities 1,302 671 631 Other available-for-sale debt securities 63 17 46 Derivative assets 17 — 17 Total assets 2,886 2,192 694 Derivative liabilities (298 ) — (298 ) Net assets $ 2,588 $ 2,192 $ 396 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,496 $ 1,496 $ — Nuclear decommissioning trust fund debt securities 1,283 426 857 Other available-for-sale debt securities 63 18 45 Derivative assets 11 — 11 Total assets 2,853 1,940 913 Derivative liabilities (322 ) — (322 ) Net assets $ 2,531 $ 1,940 $ 591
Duke Energy Progress [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,184 $ 1,184 $ — Nuclear decommissioning trust fund debt securities and other 888 389 499 Other available-for-sale debt securities and other 1 1 — Derivative assets 5 — 5 Total assets 2,078 1,574 504 Derivative liabilities (87 ) — (87 ) Net assets $ 1,991 $ 1,574 $ 417 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 1,178 $ 1,178 $ — Nuclear decommissioning trust fund debt securities and other 860 141 719 Other available-for-sale debt securities and other 1 1 — Derivative assets 2 — 2 Total assets 2,041 1,320 721 Derivative liabilities (98 ) — (98 ) Net assets $ 1,943 $ 1,320 $ 623
Duke Energy Florida [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral which is disclosed in Note 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 320 $ 320 $ — Nuclear decommissioning trust fund debt securities and other 414 282 132 Other available-for-sale debt securities and other 47 1 46 Derivative assets 11 — 11 Total assets 792 603 189 Derivative liabilities (206 ) — (206 ) Net assets (liabilities) $ 586 $ 603 $ (17 ) December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Nuclear decommissioning trust fund equity securities $ 318 $ 318 $ — Nuclear decommissioning trust fund debt securities and other 423 285 138 Other available-for-sale debt securities and other 51 6 45 Derivative assets 7 — 7 Total assets 799 609 190 Derivative liabilities (216 ) — (216 ) Net assets (liabilities) $ 583 $ 609 $ (26 )
Duke Energy Ohio [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which are disclosed in Note 9 . March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative liabilities $ (7 ) $ — $ (7 ) $ — Net liabilities $ (7 ) $ — $ (7 ) $ — December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Derivative assets $ 3 $ — $ — $ 3 Derivative liabilities (7 ) — (7 ) — Net (liabilities) assets $ (4 ) $ — $ (7 ) $ 3
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended March 31, (in millions) 2016 2015 Balance at beginning of period $ 3 $ (18 ) Total pretax realized or unrealized gains included in earnings — 25 Purchases, sales, issuances and settlements: Settlements (2 ) — Total losses included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities (1 ) — Balance at end of period $ — $ 7
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 9 . See Note 10 for additional information related to investments by major security type. March 31, 2016 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 72 $ 72 $ — $ — Other available-for-sale debt securities and other 30 1 29 — Derivative assets 2 — — 2 Net assets $ 104 $ 73 $ 29 $ 2 December 31, 2015 (in millions) Total Fair Value Level 1 Level 2 Level 3 Other available-for-sale equity securities $ 71 $ 71 $ — $ — Other available-for-sale debt securities and other 30 2 28 — Derivative assets 7 — — 7 Net assets $ 108 $ 73 $ 28 $ 7
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following table provides a reconciliation of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Derivatives (net) Three Months Ended March 31, (in millions) 2016 2015 Balance at beginning of period $ 7 $ 14 Total pretax realized or unrealized losses included in earnings — (3 ) Purchases, sales, issuances and settlements: Settlements (5 ) (9 ) Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities — 1 Balance at end of period $ 2 $ 3

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2016
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	The following tables summarize the impact of VIEs consolidated by Duke Energy and the Subsidiary Registrants on the Condensed Consolidated Balance Sheets. March 31, 2016 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress (c) Florida (c) (in millions) DERF DEPR DEFR 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) 615 372 256 437 20 14 1,714 Other — — — — 149 2 151 Investments and Other Assets Other — — — — 58 — 58 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 2,027 20 2,047 Accumulated depreciation and amortization — — — — (340 ) (6 ) (346 ) Total assets $ 615 $ 372 $ 256 $ 437 $ 1,914 $ 32 $ 3,626 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 23 $ — $ 23 Taxes accrued — — — — 4 — 4 Current maturities of long-term debt — — — — 82 12 94 Other — — — — 22 — 22 Long-Term Debt (b) 425 300 225 325 995 — 2,270 Deferred Credits and Other Liabilities Deferred income taxes — — — — 240 — 240 Asset retirement obligations — — — — 37 — 37 Other — — — — 42 — 42 Total liabilities $ 425 $ 300 $ 225 $ 325 $ 1,445 $ 12 $ 2,732 Net assets of consolidated variable interest entities $ 190 $ 72 $ 31 $ 112 $ 469 $ 20 $ 894 December 31, 2015 Duke Energy Duke Duke Duke Energy Energy Energy Carolinas Progress (c) Florida (c) (in millions) DERF DEPR DEFR 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) 596 349 309 454 19 21 1,748 Other — — — — 138 4 142 Investments and Other Assets Other — — — — 70 — 70 Property, Plant and Equipment Property, plant and equipment, cost (a) — — — — 2,015 20 2,035 Accumulated depreciation and amortization — — — — (321 ) (6 ) (327 ) Total assets $ 596 $ 349 $ 309 $ 454 $ 1,921 $ 41 $ 3,670 LIABILITIES AND EQUITY Current Liabilities Accounts payable $ — $ — $ — $ — $ 35 $ — $ 35 Taxes accrued 5 3 — — 5 1 14 Current maturities of long-term debt — — — — 108 17 125 Other — — — — 15 2 17 Long-Term Debt (b) 425 254 225 325 968 — 2,197 Deferred Credits and Other Liabilities Deferred income taxes — — — — 289 — 289 Asset retirement obligations — — — — 35 — 35 Other — — — — 33 — 33 Total liabilities $ 430 $ 257 $ 225 $ 325 $ 1,488 $ 20 $ 2,745 Net assets of consolidated variable interest entities $ 166 $ 92 $ 84 $ 129 $ 433 $ 21 $ 925 (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 total amount for Duke Energy Progress and Duke Energy Florida. 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) $ 425 $ 300 $ 225 Expiration date December 2018 February 2019 April 2019
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. March 31, 2016 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 39 $ 50 Investments in equity method unconsolidated affiliates 227 186 413 — — Total assets $ 227 $ 186 $ 413 $ 39 $ 50 Other current liabilities — 2 2 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 16 $ 16 $ — $ — Net assets $ 227 $ 170 $ 397 $ 39 $ 50 December 31, 2015 Duke Energy Duke Duke Energy Energy (in millions) Renewables Other Total Ohio Indiana Receivables from affiliated companies $ — $ — $ — $ 47 $ 60 Investments in equity method unconsolidated affiliates 235 152 387 — — Total assets $ 235 $ 152 $ 387 $ 47 $ 60 Other current liabilities — 3 3 — — Deferred credits and other liabilities — 14 14 — — Total liabilities $ — $ 17 $ 17 $ — $ — Net assets $ 235 $ 135 $ 370 $ 47 $ 60
Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	Key assumptions used in estimating fair value are detailed in the following table. Duke Energy Ohio Duke Energy Indiana 2016 2015 2016 2015 Anticipated credit loss ratio 0.6 % 0.6 % 0.3 % 0.3 % Discount rate 1.4 % 1.2 % 1.4 % 1.2 % Receivable turnover rate 13.2 % 12.9 % 10.6 % 10.6 % The following table shows the gross and net receivables sold. Duke Energy Ohio Duke Energy Indiana (in millions) March 31, 2016 December 31, 2015 March 31, 2016 December 31, 2015 Receivables sold $ 225 $ 233 $ 253 $ 260 Less: Retained interests 39 47 50 60 Net receivables sold $ 186 $ 186 $ 203 $ 200 The following table shows sales and cash flows related to receivables sold. Duke Energy Ohio Duke Energy Indiana Three Months Ended Three Months Ended March 31, March 31, (in millions) 2016 2015 2016 2015 Sales Receivables sold $ 532 $ 644 $ 635 $ 716 Loss recognized on sale 3 3 3 3 Cash flows Cash proceeds from receivables sold 537 640 643 722 Return received on retained interests 1 1 1 2

Common Stock (Tables)

Common Stock (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted average number of common stock outstanding to the diluted weighted average number of common shares outstanding. Three Months Ended March 31, (in millions, except per share amounts) 2016 2015 Income from continuing operations attributable to Duke Energy common stockholders excluding impact of participating securities $ 691 $ 772 Weighted average shares outstanding – basic 689 708 Weighted average shares outstanding – diluted 689 708 Earnings per share from continuing operations attributable to Duke Energy common stockholders Basic $ 1.00 $ 1.09 Diluted $ 1.00 $ 1.09 Potentially dilutive items excluded from the calculation (a) 2 2 Dividends declared per common share $ 0.825 $ 0.795 (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)	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule Of Stock-Based Compensation Expense	Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense, and stock-based compensation costs capitalized are included in the following table. Three Months Ended March 31, (in millions) 2016 2015 Restricted stock unit awards $ 7 $ 9 Performance awards 5 5 Pretax stock-based compensation cost $ 12 $ 14 Tax benefit associated with stock-based compensation expense $ 4 $ 5 Stock-based compensation costs capitalized 1 1

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employee Savings Plan Matching Contributions	The following table presents employer contributions made by Duke Energy and expensed by the Subsidiary Registrants. Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Three Months Ended March 31, 2016 $ 52 $ 18 $ 15 $ 11 $ 4 $ 1 $ 2 2015 49 16 14 11 4 1 2
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. Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the three months ended March 31, 2016 . Three Months Ended March 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Contributions $ 132 $ 42 $ 42 $ 21 $ 21 $ 1 $ 9
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 36 $ 12 $ 11 $ 6 $ 5 $ 1 $ 2 Interest cost on projected benefit obligation 83 21 26 12 14 5 7 Expected return on plan assets (129 ) (35 ) (42 ) (21 ) (21 ) (7 ) (10 ) Amortization of actuarial loss 33 8 14 6 7 1 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 3 1 1 — — — — Net periodic pension costs $ 22 $ 5 $ 9 $ 3 $ 5 $ — $ 2 Three Months Ended March 31, 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 82 21 26 12 14 5 7 Expected return on plan assets (129 ) (36 ) (43 ) (20 ) (22 ) (6 ) (10 ) Amortization of actuarial loss 43 10 17 8 8 2 3 Amortization of prior service credit (4 ) (2 ) (1 ) — — — — Other 2 1 1 — — — — Net periodic pension costs $ 34 $ 7 $ 11 $ 6 $ 5 $ 2 $ 3
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Pension Costs	The following tables include the components of net periodic other post-retirement benefit costs. Three Months Ended March 31, 2016 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 1 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 8 2 4 2 2 — 1 Expected return on plan assets (3 ) (2 ) — — — — — Amortization of actuarial loss (gain) 1 (1 ) 5 3 2 — (1 ) Amortization of prior service credit (35 ) (3 ) (26 ) (17 ) (9 ) — — Net periodic other post-retirement benefit costs $ (28 ) $ (4 ) $ (17 ) $ (12 ) $ (5 ) $ — $ — Three Months Ended March 31, 2015 Duke Duke Duke Duke Duke Duke Energy Progress Energy Energy Energy Energy (in millions) Energy Carolinas Energy Progress Florida Ohio Indiana Service cost $ 2 $ — $ — $ — $ — $ — $ — Interest cost on accumulated post-retirement benefit obligation 9 2 4 2 2 — — 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 $ (21 ) $ (4 ) $ (15 ) $ (10 ) $ (4 ) $ — $ —

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rates	The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table. Three Months Ended March 31, 2016 2015 Duke Energy 23.4 % 31.9 % Duke Energy Carolinas 34.1 % 35.8 % Progress Energy 36.7 % 35.4 % Duke Energy Progress 35.4 % 33.8 % Duke Energy Florida 37.9 % 38.6 % Duke Energy Ohio 26.9 % 36.7 % Duke Energy Indiana 30.2 % 36.6 %

Organization and Basis of Pre42

Organization and Basis of Presentation Organization and Basis of Presentation (Narrative)(Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 173	$ 170

Organization and Basis of Pre43

Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 715	$ 748
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	288	283
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	158	172
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	85	102
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	73	70
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	2	3
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	33	31
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	61	71
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 88	$ 97

Organization and Basis of Pre44

Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 91	$ 100
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	8	9
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	47	49
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	5	4
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	42	45
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	28	32
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 8	$ 10

Acquisitions and Dispositions45

Acquisitions and Dispositions (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2015
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses		$ 29
Piedmont Natural Gas [Member]
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses	$ 4,900
Long-term debt assumed	2,000
Forward starting interest rate swaps, notional	$ 1,400
Shares offered	10.6
Bridge Facility	$ 4,900
Bridge Facility, Remaining Borrowing Capacity	4,200
Acquirer Termination Fee	250
Acquiree Termination Fee	125
Duke Energy Progress [Member] | NCEMPA Generating Assets [Member]
Significant Acquisitions and Disposals [Abstract]
Payments to acquire businesses	1,250
Acquisition adjustment, recorded within property, plant and equipment	350
Duke Energy Ohio [Member] | Midwest Generation Business [Member]
Significant Acquisitions and Disposals [Abstract]
Proceeds from sale of business			$ 2,800
International Energy [Member]
Significant Acquisitions and Disposals [Abstract]
Segment Carrying Value	2,600
Currency Translation Adjustment	$ 644

Acquisitions and Dispositions46

Acquisitions and Dispositions (Assets Held For Sale) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax	$ 3	$ 91
Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax	$ 2	90
Midwest Generation Business [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues		543
Loss on disposition		(43)
Income before income taxes		147
Income tax expense		51
Income From Discontinued Operations, net of tax		96
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues		412
Loss on disposition		(44)
Income before income taxes		140
Income tax expense		50
Income From Discontinued Operations, net of tax		90
Other Disposal Groups [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income From Discontinued Operations, net of tax		$ (5)

Business Segments (Narrative) (

Business Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Interest Expense	$ 511	$ 403
Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	160	168
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Interest Expense	20	20
Other [Member] | Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	$ 56	$ 60
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
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 5,622	$ 6,065
Segment income	691	773
Add back noncontrolling interests	5	3
Income From Discontinued Operations, net of tax	3	91
Net income (loss)	699	867
Segment assets	121,709	122,142	$ 121,156
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,250	5,713
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	246	273
Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	114	73
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	12	6
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,610	6,059
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,259	5,723
Segment income	695	774
Segment assets	111,838	106,642
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	246	273
Segment income	123	36
Segment assets	3,247	4,892
Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	114	73
Segment income	27	7
Segment assets	4,183	6,202
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,619	6,069
Segment income	845	817
Segment assets	119,268	117,736
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(26)	(31)
Segment income		(1)
Segment assets	178	176
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(10)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(17)	(21)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(10)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	29	27
Segment income	(154)	(43)
Segment assets	2,263	4,230
Costs to achieve Progress Energy merger	74	13
Cost Savings Initiative, Net of tax	12
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	516	586
Segment income		59
Income From Discontinued Operations, net of tax	2	90
Net income (loss)		149
Segment assets	7,112	9,796	$ 7,097
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	$ (9)	(2)
Duke Energy Ohio [Member] | Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		572
Segment income		70
Segment assets		6,782
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		14
Segment income		(9)
Segment assets		2,984
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		586
Segment income		61
Segment assets		9,766
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment assets		(13)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income		(2)
Segment assets		$ 43

Business Segments (Schedule of

Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Segment income	$ 691	$ 773
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(17)	(8)
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(49)	(42)
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(8)	(4)
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(4)	(3)
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Segment income		59
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(9)	(2)
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (2)	$ (2)

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2015USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)MW	Sep. 30, 2015USD ($)	Mar. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	$ 11,373		$ 11,483
Electric Domestic Regulated Revenue			5,053		$ 5,457
Payments to Acquire Businesses, Gross					29
Property, Plant and Equipment, Net	75,709		$ 76,432
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW			1,471
Property, Plant and Equipment, Net			$ 300
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			40.00%
Atlantic Coast Pipeline (ACP) [Member] | Dominion Resources [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			45.00%
Atlantic Coast Pipeline (ACP) [Member] | Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			10.00%
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			7.50%
Sabal Trail Transmission Pipeline [Member] | Spectra Energy [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			59.50%
Sabal Trail Transmission Pipeline [Member] | NextEra [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			33.00%
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	2,766		$ 2,801
Property, Plant and Equipment, Net	25,877		$ 26,064
Duke Energy Carolinas [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission			10.20%
Duke Energy Carolinas [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage			8.49%
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC			$ 600
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member] | NCEMC [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage			13.00%
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	5,435		$ 5,498
Property, Plant and Equipment, Net	28,347		$ 28,689
Progress Energy [Member] | Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW			873
Property, Plant and Equipment, Net			$ 128
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	2,710		2,768
Property, Plant and Equipment, Net	17,720		17,768
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost			$ 1,100
Duke Energy Progress [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission			10.80%
Duke Energy Progress [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage			8.49%
Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW			376
Property, Plant and Equipment, Net	548		$ 531
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	2,725		2,730
Property, Plant and Equipment, Net	10,623		$ 10,918
Duke Energy Florida [Member] | Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Payments to Acquire Businesses, Gross		$ 166
Duke Energy Florida [Member] | Crystal River Units 1 and 2 [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW			873
Property, Plant and Equipment, Net			$ 128
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement[Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Regulatory Costs Not yet Approved	1,298
Regulatory assets, noncurrent	1,283
Public Utilities, Approved Rate Increase (Decrease), Amount			(36)
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	497		503
Electric Domestic Regulated Revenue			340		$ 339
Property, Plant and Equipment, Net	5,243		5,288
Duke Energy Ohio [Member] | Accelerated Natural Gas Service Line Replacement Rider [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital and operations and maintenance cost			320
Duke Energy Ohio [Member] | Energy Efficiency and Peak Demand Reduction Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Electric Domestic Regulated Revenue	20
Duke Energy Ohio [Member] | Regional Transmission Organization [Member]
Public Utilities, General Disclosures [Line Items]
Exit obligation	92		91
Regulatory assets, noncurrent			$ 72
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Approved MVP Proposals			17
MISO estimate of Duke Energy Ohio's MVP obligation			$ 2,700
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	716		766
Property, Plant and Equipment, Net	$ 9,523		$ 9,505
Duke Energy Indiana [Member] | Coal Combustion Residual Plan [Member]
Public Utilities, General Disclosures [Line Items]
Federal Mandate Costs Recovered Through Tracker Mechanism			80.00%
Federally Mandated Costs Recovered In Future Rate Case			20.00%
Duke Energy Indiana [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission			12.38%
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission			0.50%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage			8.67%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage			10.32%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost			$ 1,900
Duke Energy Indiana [Member] | Revised Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage			10.00%
Estimated capital cost			$ 1,800
Public Utilities, Requested Rate Increase (Decrease), Amount			1,400
Duke Energy Indiana [Member] | Edwardsport Igcc Plant [Member] | IGCC Rider Proceeding [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount			87.5
Legal Fees			$ 5.5
Utilities Operating Expense, Other				$ 93
Regulatory Asset, Amortization Period			8 years
Regulatory Assets			$ 147

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)MW	Dec. 31, 2015USD ($)
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 76,432	$ 75,709
Generation Facilities To Be Retired Net	$ 644	548
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,471
Remaining net book value (in millions)	$ 300
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	26,064	25,877
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	28,689	28,347
Generation Facilities To Be Retired Net	$ 531	548
Progress Energy [Member] | Generation Facilities To Be Retired [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 128
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	17,768	17,720
Generation Facilities To Be Retired Net	531	548
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$ 10,918	10,623
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member] | Crystal River Units 1 and 2 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	873
Remaining net book value (in millions)	$ 128
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	5,288	5,243
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	9,505	$ 9,523
Generation Facilities To Be Retired Net	113
Duke Energy Indiana [Member] | Wabash River Unit 6 [Member]
Public Utilities, General Disclosures [Line Items]
Generation Facilities To Be Retired Net	$ 113
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member] | Wabash River Unit 6 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	318
Remaining net book value (in millions)	$ 35
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member] | Gallagher Units 2 and 4 [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Remaining net book value (in millions)	$ 137

Commitments and Contingencies52

Commitments and Contingencies (Narrative) (Details) $ in Millions	Feb. 08, 2016USD ($)	Mar. 10, 2015USD ($)	Feb. 02, 2014Tgal	Aug. 10, 2011	Aug. 09, 2011	Mar. 31, 2014USD ($)	Mar. 31, 2016USD ($)Claims	Dec. 31, 2015USD ($)	Aug. 18, 2014gal
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							$ 181	$ 166
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent				15.00%	15.00%
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							11	11
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed	$ 6.8
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] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves							527	536
Reinsurance retention policy, excess retention, amount reinsured							847
Probable insurance recoveries							$ 600	599
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims							118
Asbestos-related injuries and damages reserves							$ 30
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims							68
Asbestos-related injuries and damages reserves							$ 10
Duke Energy Carolinas [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement							1
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							54	54
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							6	6
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed		$ 25
Duke Energy Progress [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement							6
Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed		$ 25
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							31	31
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount							54
Loss contingency, damages sought, value						$ 510
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual							80	$ 80
Duke Energy Ohio [Member] | W.C. Beckjord Station [Member]
Valuation and Qualifying Accounts [Abstract]
Gallons of Fuel Released | gal									9,000
Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement Amount							$ 81

Commitments and Contingencies53

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 83
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	97	$ 97
Provisions/adjustments	10	2
Cash reductions	(3)	(3)
Ending balance	104	96
Duke Energy Carolinas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	22
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	10
Provisions/adjustments	2
Cash reductions	(1)
Ending balance	11	10
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	17
Provisions/adjustments	1
Cash reductions	(2)
Ending balance	16	17
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	3	5
Provisions/adjustments	0
Cash reductions	(1)
Ending balance	2	5
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	14	12
Provisions/adjustments	1
Cash reductions	(1)
Ending balance	14	12
Duke Energy Ohio [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	42
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	54	54
Provisions/adjustments		1
Cash reductions	0	(1)
Ending balance	54	54
Duke Energy Indiana [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	15
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	12	10
Provisions/adjustments	6	2
Cash reductions	0	(1)
Ending balance	$ 18	$ 11

Commitments and Contingencies54

Commitments and Contingencies (Schedule of Legal Reserves) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Reserves for legal matters	$ 181	$ 166
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	11	11
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	54	54
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	6	6
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	31	31
Duke Energy Ohio [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 80	$ 80

Debt and Credit Facilities Debt

Debt and Credit Facilities Debt and Credit Facilities (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Debt issuances		$ 1,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility size		4,900
Available capacity		4,200
Subsequent Event [Member] | Unsecured Debt [Member] | April 2016 Unsecured note maturing April 2023 [Member]
Debt Instrument [Line Items]
Debt issuances	$ 350
Interest rate	2.875%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		7,500
Available capacity		3,825
Term Loan Facility [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Short-term Debt, Maximum Amount Outstanding During Period	$ 500
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		1,000
Available capacity		543
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances		1,000
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility size		800
Available capacity		211
USDOJ [Member] | Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required		250
USDOJ [Member] | Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance Required		$ 250

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) $ in Millions	Mar. 31, 2016USD ($)
Debt Instrument [Line Items]
Debt issuances	$ 1,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances	$ 1,000
First Mortgage [Member] | March 2016 2.500% First Mortgage Bond Maturing March 2023 [Member]
Debt Instrument [Line Items]
Interest rate	2.50%
Debt issuances	$ 500
First Mortgage [Member] | March 2016 3.875% First Mortgage Bond Maturing March 2046 [Member]
Debt Instrument [Line Items]
Interest rate	3.875%
Debt issuances	$ 500
First Mortgage [Member] | Duke Energy Carolinas [Member] | March 2016 2.500% First Mortgage Bond Maturing March 2023 [Member]
Debt Instrument [Line Items]
Interest rate	2.50%
Debt issuances	$ 500
First Mortgage [Member] | Duke Energy Carolinas [Member] | March 2016 3.875% First Mortgage Bond Maturing March 2046 [Member]
Debt Instrument [Line Items]
Interest rate	3.875%
Debt issuances	$ 500

Debt and Credit Facilities (S57

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,075	$ 2,074
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 373
Parent Company [Member] | Unsecured Debt [Member] | 2.150% Unsecured Debt Maturing November 2016 [Member]
Debt Instrument [Line Items]
Interest rate	2.15%
Current maturities of long-term debt	$ 500
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 468	356
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 1.750% First Mortgage bonds Maturing December 2016 [Member]
Debt Instrument [Line Items]
Interest rate	1.75%
Current maturities of long-term debt	$ 350
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member] | February 2017 Debt Maturity [Member]
Debt Instrument [Line Items]
Interest rate	3.60%
Current maturities of long-term debt	$ 77
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 252	2
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 0.836% First Mortgage Bonds Maturing March 2017 [Member]
Debt Instrument [Line Items]
Interest rate	0.836%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	13	13
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 55	106
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member] | August 2027 Debt Maturity [Member]
Debt Instrument [Line Items]
Interest rate	1.266%
Current maturities of long-term debt	$ 50
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 547	$ 547
Duke Energy Indiana [Member] | Unsecured Debt [Member] | 6.050% 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] | 0.937% First Mortgage Bonds Maturing July 2016 [Member]
Debt Instrument [Line Items]
Interest rate	0.937%
Current maturities of long-term debt	$ 150

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member] $ in Millions	Mar. 31, 2016USD ($)
Line of Credit Facility [Line Items]
Facility size	$ 7,500
Commercial paper	(2,980)
Outstanding letters of credit	(79)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	3,825
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	3,475
Commercial paper	(1,816)
Outstanding letters of credit	(72)
Available capacity	1,587
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member]
Line of Credit Facility [Line Items]
Commercial paper	(625)
Duke Energy Carolinas [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 Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,000
Commercial paper	(205)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	543
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	1,200
Commercial paper	(480)
Outstanding letters of credit	(1)
Available capacity	719
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	425
Commercial paper	(29)
Available capacity	396
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600
Commercial paper	(150)
Tax exempt bonds	(81)
Available capacity	$ 369

Goodwill and Intangible Asset59

Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill	$ 16,349	$ 16,343
Foreign exchange and other changes	6
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill	15,950	15,950
International [Member]
Goodwill [Roll Forward]
Goodwill	277	271
Foreign exchange and other changes	6
Commercial Portfolio [Member]
Goodwill [Roll Forward]
Goodwill	122	122
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	920	920
Accumulated impairment charges	$ 216	$ 216

Related Party Transactions (Oth

Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 217	$ 219
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	9	26
Related party transaction, expenses from transactions with related party	41	57
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	174	167
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	10
Progress Energy [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	41	57
Related party transaction, expenses from transactions with related party	9	26
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	100	101
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	4
Duke Energy Progress [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	41	57
Related party transaction, expenses from transactions with related party	9	26
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	74	66
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6
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	85	85
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	1	3
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	94	89
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 2	$ 2

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - Duke Energy Ohio [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Apr. 01, 2015
Related Party Transaction [Line Items]
Intercompany loan payable	$ 8	$ 103
DECAM [Member]
Related Party Transaction [Line Items]
Intercompany loan payable			$ 294

Related Party Transactions Rela

Related Party Transactions Related Party Transactions (Intercompany Income Taxes) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Duke Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	$ 74	$ 107
Due to Related Parties, Current	250	229
Duke Energy Carolinas [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current		122
Due to Related Parties, Current	6
Progress Energy [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	37	375
Due to Related Parties, Current	256	311
Progress Energy [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	170	120
Duke Energy Progress [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	6	16
Due to Related Parties, Current	176	190
Duke Energy Progress [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	22	104
Duke Energy Florida [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	27	84
Due to Related Parties, Current	76	116
Duke Energy Florida [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	16
Due to Related Parties, Current		96
Duke Energy Ohio [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	93	84
Due to Related Parties, Current	53	53
Duke Energy Ohio [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current		54
Due to Related Parties, Current	9
Duke Energy Indiana [Member]
Income Tax Disclosure [Line Items]
Due from Related Parties, Current	64	71
Due to Related Parties, Current	61	83
Duke Energy Indiana [Member] | Income Taxes [Member]
Income Tax Disclosure [Line Items]
Due to Related Parties, Current	$ 60	$ 47

Derivatives and Hedging (Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Bcf in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)GWhBcf	Dec. 31, 2015USD ($)GWhBcf
Derivative [Line Items]
Undesignated Commodity Contracts Latest Expiration Year	2,048
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	183	70
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	470	398
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 3,027	$ 2,527
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	700	700
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	2,327	1,827
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	497	$ 497
Piedmont Natural Gas [Member]
Derivative [Line Items]
Notional amount	1,400
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	93
Piedmont Natural Gas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Derivative, Contract Entered Into During The Period, Notional Amount	500
Notional amount	$ 1,400
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	92	66
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 400	$ 400
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 400	$ 400
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	378	332
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 500	$ 500
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 500	$ 500
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	131	117
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 250
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms | Bcf	247	215
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 250
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 250	$ 250
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	144	34
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	$ 27	$ 27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	39	36

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	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 33	$ 26
Location and fair value amounts of derivatives (Liability)	537	419
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	18
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	26	8
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	376	271
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	161	148
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	16
Location and fair value amounts of derivatives (Liability)	341	356
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	10
Location and fair value amounts of derivatives (Liability)	196	63
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	12	11
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	45	33
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	12
Location and fair value amounts of derivatives (Liability)	270	256
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	4
Location and fair value amounts of derivatives (Liability)	71	100
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Location and fair value amounts of derivatives (Liability)	94	4
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	19
Location and fair value amounts of derivatives (Liability)	45	15
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13
Location and fair value amounts of derivatives (Liability)	81	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	32
Duke Energy Carolinas [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	44	13
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4
Location and fair value amounts of derivatives (Liability)	42	40
Duke Energy Carolinas [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9
Location and fair value amounts of derivatives (Liability)	39	5
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	37	32
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	5	8
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9
Location and fair value amounts of derivatives (Liability)	39	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	11
Location and fair value amounts of derivatives (Liability)	298	322
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	7
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	4
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	232	225
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	66	97
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	5
Location and fair value amounts of derivatives (Liability)	298	314
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	6
Location and fair value amounts of derivatives (Liability)		8
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	1
Location and fair value amounts of derivatives (Liability)	232	222
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	4
Location and fair value amounts of derivatives (Liability)	66	92
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Location and fair value amounts of derivatives (Liability)		3
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Location and fair value amounts of derivatives (Liability)	87	98
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] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	78	77
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	9	21
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	87	93
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	78	77
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	9	16
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	7
Location and fair value amounts of derivatives (Liability)	206	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	3
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	4
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	154	145
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	52	71
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	5
Location and fair value amounts of derivatives (Liability)	206	216
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Location and fair value amounts of derivatives (Liability)	154	145
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	4
Location and fair value amounts of derivatives (Liability)	52	71
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	7	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	6
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	7
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Noncurrent [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	6
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	7
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	7
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	$ 7
Piedmont Natural Gas [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 93

Derivatives and Hedging (Schedu

Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 33	$ 26
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	26
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	537	419
Net amounts recognized on the Condensed Consolidated Balance Sheet	537	419
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	18
Gross amounts offset	(1)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	26	8
Gross amounts offset	(15)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	4
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	376	271
Gross amounts offset	(16)	(22)
Net amounts recognized on the Condensed Consolidated Balance Sheet	360	249
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	161	148
Gross amounts offset	(23)	(16)
Net amounts recognized on the Condensed Consolidated Balance Sheet	138	132
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	13
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	81	45
Net amounts recognized on the Condensed Consolidated Balance Sheet	81	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1
Gross amounts offset	(1)
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12
Gross amounts offset	(12)
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	37	32
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	36	32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	44	13
Gross amounts offset	(12)
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	17	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	298	322
Net amounts recognized on the Condensed Consolidated Balance Sheet	298	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	7
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	4
Gross amounts offset	(3)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	232	225
Gross amounts offset	(15)	(21)
Net amounts recognized on the Condensed Consolidated Balance Sheet	217	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	66	97
Gross amounts offset	(11)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	87	98
Net amounts recognized on the Condensed Consolidated Balance Sheet	87	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	78	77
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	78	76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	21
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	206	216
Net amounts recognized on the Condensed Consolidated Balance Sheet	206	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Gross amounts offset	(1)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	154	145
Gross amounts offset	(15)	(20)
Net amounts recognized on the Condensed Consolidated Balance Sheet	139	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	52	71
Gross amounts offset	(9)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	43	56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 2	$ 7

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	$ 453	$ 334
Fair value of collateral already posted	23	30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	430	304
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability	23	30
Duke Energy Carolinas [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	81	45
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	81	45
Progress Energy [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	279	290
Fair value of collateral already posted	23	30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	256	260
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability	23	30
Duke Energy Progress [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	83	93
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	83	93
Duke Energy Florida [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	196	194
Fair value of collateral already posted	23	30
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	173	164
Information Regarding Cash Collateral Under Master Netting Arrangements
Amount of right to receive cash collateral, offset against derivative liability	$ 23	$ 30

Investments in Debt and Equit67

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Gains	$ 1,918	$ 1,882
Gross Unrealized Holding Losses	77	83
Estimated Fair Value	6,298	6,214
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1,879	1,846
Gross Unrealized Holding Losses	71	76
Estimated Fair Value	5,894	5,817
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	201	179
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1,823	1,823
Gross Unrealized Holding Losses	64	58
Estimated Fair Value	3,592	3,590
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	16	7
Gross Unrealized Holding Losses	3	8
Estimated Fair Value	454	432
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	6	5
Gross Unrealized Holding Losses		1
Estimated Fair Value	211	185
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	33	11
Gross Unrealized Holding Losses		5
Estimated Fair Value	1,288	1,254
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1
Gross Unrealized Holding Losses	4	4
Estimated Fair Value	148	177
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	39	36
Gross Unrealized Holding Losses	6	7
Estimated Fair Value	404	397
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	29	29
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	33	32
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	97	95
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1	1
Gross Unrealized Holding Losses	2	3
Estimated Fair Value	91	92
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	3	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	76	74
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	2
Estimated Fair Value	56	45
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	55	62
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1,044	1,028
Gross Unrealized Holding Losses	38	40
Estimated Fair Value	3,091	3,041
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1,044	1,028
Gross Unrealized Holding Losses	37	39
Estimated Fair Value	3,088	3,038
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	50	34
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1,022	1,021
Gross Unrealized Holding Losses	31	27
Estimated Fair Value	2,088	2,094
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	8	3
Gross Unrealized Holding Losses	2	5
Estimated Fair Value	257	292
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1	1
Gross Unrealized Holding Losses	0
Estimated Fair Value	53	33
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	12	3
Gross Unrealized Holding Losses	0	3
Estimated Fair Value	502	438
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	1
Gross Unrealized Holding Losses	4	4
Estimated Fair Value	138	147
Duke Energy Carolinas [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	838	821
Gross Unrealized Holding Losses	34	37
Estimated Fair Value	2,869	2,842
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	835	818
Gross Unrealized Holding Losses	34	37
Estimated Fair Value	2,806	2,779
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	151	145
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	801	802
Gross Unrealized Holding Losses	33	31
Estimated Fair Value	1,504	1,496
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	8	4
Gross Unrealized Holding Losses	1	3
Estimated Fair Value	197	140
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	5	4
Gross Unrealized Holding Losses		1
Estimated Fair Value	158	152
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	21	8
Gross Unrealized Holding Losses		2
Estimated Fair Value	786	816
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	10	30
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	3	3
Estimated Fair Value	63	63
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	17	18
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	3	3
Estimated Fair Value	46	45
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	621	609
Gross Unrealized Holding Losses	28	30
Estimated Fair Value	2,073	2,039
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	621	609
Gross Unrealized Holding Losses	28	30
Estimated Fair Value	2,072	2,038
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	100	110
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	595	596
Gross Unrealized Holding Losses	27	25
Estimated Fair Value	1,184	1,178
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	6	3
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	145	96
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	5	4
Gross Unrealized Holding Losses		1
Estimated Fair Value	158	150
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	15	6
Gross Unrealized Holding Losses		2
Estimated Fair Value	479	486
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	6	18
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	1
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	217	212
Gross Unrealized Holding Losses	6	7
Estimated Fair Value	781	792
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	214	209
Gross Unrealized Holding Losses	6	7
Estimated Fair Value	734	741
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	51	35
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	206	206
Gross Unrealized Holding Losses	6	6
Estimated Fair Value	320	318
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	2	1
Gross Unrealized Holding Losses		1
Estimated Fair Value	52	44
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	0	2
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	6	2
Estimated Fair Value	307	330
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	4	12
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	3	3
Estimated Fair Value	47	51
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	6
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	3	3
Estimated Fair Value	46	45
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	27	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	102	101
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	27	27
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	102	101
Duke Energy Indiana [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	2
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains	27	27
Estimated Fair Value	72	71
Duke Energy Indiana [Member] | Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	2
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	$ 27	$ 26

Investments in Debt and Equit68

Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Mar. 31, 2016USD ($)
Debt Instrument [Line Items]
Due in one year or less	$ 136
Due after one through five years	769
Due after five through 10 years	559
Due after 10 years	915
Total	2,379
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	14
Due after one through five years	195
Due after five through 10 years	224
Due after 10 years	520
Total	953
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	101
Due after one through five years	486
Due after five through 10 years	264
Due after 10 years	346
Total	1,197
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	37
Due after one through five years	282
Due after five through 10 years	219
Due after 10 years	250
Total	788
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	64
Due after one through five years	204
Due after five through 10 years	45
Due after 10 years	96
Total	409
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	2
Due after one through five years	14
Due after five through 10 years	9
Due after 10 years	4
Total	$ 29

Investments in Debt and Equit69

Investments in Debt and Equity Securities (Realized Gains and Losses)(Details) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$ 54	$ 102
Realized losses	50	14
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	34	90
Realized losses	37	12
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	19	12
Realized losses	13	1
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	15	9
Realized losses	11	1
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	4	$ 3
Realized losses	$ 2

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$ 33	$ 26
Total assets	6,331	6,240
Derivative liabilities	(537)	(419)
Net assets	5,794	5,821
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0
Total assets	4,543	4,260
Derivative liabilities	(6)
Net assets	4,537	4,260
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	31	16
Total assets	1,617	1,793
Derivative liabilities	(531)	(419)
Net assets	1,086	1,374
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	10
Total assets	6	15
Net assets	6	15
Fair Value, Inputs, Not Categorized [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	165	172
Net assets	165	172
Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,592	3,590
Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,426	3,418
Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1
Equity Securities [Member] | Ndtf [Member] | Fair Value, Inputs, Not Categorized [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	165	172
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	97	95
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	97	95
Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,302	2,227
Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	935	672
Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,367	1,555
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	307	302
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	85	75
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	218	222
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	4	5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	13
Total assets	3,104	3,041
Derivative liabilities	(81)	(45)
Net assets	3,023	2,996
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,186	2,168
Net assets	2,186	2,168
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	13
Total assets	750	698
Derivative liabilities	(81)	(45)
Net assets	669	653
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3	3
Net assets	3	3
Duke Energy Carolinas [Member] | Fair Value, Inputs, Not Categorized [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	165	172
Net assets	165	172
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,088	2,094
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,922	1,922
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Fair Value, Inputs, Not Categorized [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	165	172
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,000	944
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	264	246
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	736	698
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	3
Duke Energy Carolinas [Member] | Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	3
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	17	11
Total assets	2,886	2,853
Derivative liabilities	(298)	(322)
Net assets	2,588	2,531
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,192	1,940
Derivative liabilities	0
Net assets	2,192	1,940
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	17	11
Total assets	694	913
Derivative liabilities	(298)	(322)
Net assets	396	591
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,504	1,496
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,504	1,496
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,302	1,283
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	671	426
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	631	857
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	63	63
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	17	18
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	46	45
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	2
Total assets	2,078	2,041
Derivative liabilities	(87)	(98)
Net assets	1,991	1,943
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	1,574	1,320
Net assets	1,574	1,320
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	2
Total assets	504	721
Derivative liabilities	(87)	(98)
Net assets	417	623
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,184	1,178
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,184	1,178
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	888	860
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	389	141
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	499	719
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	1
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	11	7
Total assets	792	799
Derivative liabilities	(206)	(216)
Net assets	586	583
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	603	609
Net assets	603	609
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	11	7
Total assets	189	190
Derivative liabilities	(206)	(216)
Net assets	(17)	(26)
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	320	318
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	320	318
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	414	423
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	282	285
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	132	138
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	47	51
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	6
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	46	45
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		3
Derivative liabilities	(7)	(7)
Net assets	(7)	(4)
Duke Energy Ohio [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(7)	(7)
Net assets	(7)	(7)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets		3
Net assets		3
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	7
Net assets	104	108
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets	73	73
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets	29	28
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	7
Net assets	2	7
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	72	71
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	72	71
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	30	30
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1	2
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 29	$ 28

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Investments
Beginning balance	$ 15	$ 4
Total pretax gains (losses) included in earnings		24
Sales	(1)
Settlements	(7)	(10)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(1)	1
Ending balance	6	19
Derivatives (net)
Beginning balance	10	(1)
Total pretax gains (losses) included in earnings		24
Settlements	(7)	(10)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(1)	1
Ending balance	2	14
Investments [Member]
Investments
Beginning balance	5	5
Sales	(1)
Ending balance	4	5
Duke Energy Ohio [Member]
Derivatives (net)
Beginning balance	3	(18)
Total pretax gains (losses) included in earnings		25
Settlements	2
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	(1)
Ending balance		7
Duke Energy Indiana [Member]
Derivatives (net)
Beginning balance	7	14
Total pretax gains (losses) included in earnings		(3)
Settlements	(5)	(9)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	0	1
Ending balance	$ 2	$ 3

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)$ / MWh	Dec. 31, 2015USD ($)$ / MWh	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 2	$ 10	$ 14	$ (1)
Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 2	$ 10
Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	(1.67)	(0.74)
Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	5.29	7.29
Duke Energy Ohio [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $		$ 3	7	(18)
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $		$ 3
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh		0.67
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh		2.53
Duke Energy Indiana [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 2	$ 7	$ 3	$ 14
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability) | $	$ 2	$ 7
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	(1.67)	(0.74)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Financial Transmission Rights | $ / MWh	5.29	7.29

Fair Value Measurements (Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 40,307	$ 39,569
Long-term debt, fair value	44,785	42,537
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	9,360	8,367
Long-term debt, fair value	10,567	9,156
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	14,210	14,464
Long-term debt, fair value	16,245	15,856
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	6,565	6,518
Long-term debt, fair value	7,134	6,757
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,265	4,266
Long-term debt, fair value	5,109	4,908
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,642	1,598
Long-term debt, fair value	1,836	1,724
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,768	3,768
Long-term debt, fair value	$ 4,362	$ 4,219

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Minimum equity balance required by Cinergy Receivables	$ 3
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Percent of proceeds received as cash	75.00%
Percent of proceeds received as subordinated note	25.00%
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 Ohio [Member] | Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Duke Energy Indiana [Member] | 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	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 778	$ 857	$ 2,821	$ 2,036
Restricted receivables of VIEs	1,714	1,748
Other current assets	308	327
Investments and other assets	3,036	3,042
Property, plant and equipment, cost	113,942	112,826
Accumulated depreciation and amortization	(38,154)	(37,665)
Other deferred debits	39	43
Accounts payable	2,086	2,400
Current maturities of long-term debt	2,075	2,074
Other current liabilities	1,965	2,115
Long-Term Debt	38,232	37,495
Deferred income taxes	12,825	12,705
Asset retirement obligation	10,269	10,264
Other liabilities	1,703	1,706
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	2
Restricted receivables of VIEs	1,714	1,748
Other current assets	151	142
Investments and other assets	58	70
Property, plant and equipment, cost	2,047	2,035
Accumulated depreciation and amortization	(346)	(327)
Total assets	3,626	3,670
Accounts payable	23	35
Taxes accrued	4	14
Current maturities of long-term debt	94	125
Other current liabilities	22	17
Long-Term Debt	2,270	2,197
Deferred income taxes	240	289
Asset retirement obligation	37	35
Other liabilities	42	33
Total liabilities	2,732	2,745
Net assets of consolidated VIEs	894	925
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	17	13	30	13
Restricted receivables of VIEs	615	596
Other current assets	32	128
Investments and other assets	1,003	999
Property, plant and equipment, cost	39,833	39,398
Accumulated depreciation and amortization	(13,769)	(13,521)
Other deferred debits	4	4
Accounts payable	597	753
Current maturities of long-term debt	468	356
Other current liabilities	452	519
Long-Term Debt	8,592	7,711
Deferred income taxes	6,298	6,146
Asset retirement obligation	3,913	3,918
Other liabilities	642	621
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	11	15	6	9
Restricted receivables of VIEs	372	349
Other current assets	51	121
Investments and other assets	521	486
Property, plant and equipment, cost	27,503	27,313
Accumulated depreciation and amortization	(10,266)	(10,141)
Other deferred debits	2	3
Accounts payable	295	399
Current maturities of long-term debt	252	2
Other current liabilities	382	412
Long-Term Debt	6,163	6,366
Deferred income taxes	3,089	3,027
Asset retirement obligation	4,573	4,567
Other liabilities	29	45
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	12	8	$ 10	$ 8
Restricted receivables of VIEs	256	308
Other current assets	52	21
Investments and other assets	301	292
Property, plant and equipment, cost	15,652	15,343
Accumulated depreciation and amortization	(4,734)	(4,720)
Other deferred debits	2	2
Accounts payable	371	322
Current maturities of long-term debt	13	13
Other current liabilities	451	452
Long-Term Debt	4,252	4,253
Deferred income taxes	2,544	2,460
Asset retirement obligation	799	802
Other liabilities	132	146
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	615	596
Total assets	615	596
Taxes accrued		5
Long-Term Debt	425	425
Total liabilities	425	430
Net assets of consolidated VIEs	190	166
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	372	349
Total assets	372	349
Taxes accrued		3
Long-Term Debt	300	254
Total liabilities	300	257
Net assets of consolidated VIEs	72	92
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	256	309
Total assets	256	309
Long-Term Debt	225	225
Total liabilities	225	225
Net assets of consolidated VIEs	31	84
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	437	454
Total assets	437	454
Long-Term Debt	325	325
Total liabilities	325	325
Net assets of consolidated VIEs	112	129
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	20	19
Other current assets	149	138
Investments and other assets	58	70
Property, plant and equipment, cost	2,027	2,015
Accumulated depreciation and amortization	(340)	(321)
Total assets	1,914	1,921
Accounts payable	23	35
Taxes accrued	4	5
Current maturities of long-term debt	82	108
Other current liabilities	22	15
Long-Term Debt	995	968
Deferred income taxes	240	289
Asset retirement obligation	37	35
Other liabilities	42	33
Total liabilities	1,445	1,488
Net assets of consolidated VIEs	469	433
Other VIEs [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	2
Restricted receivables of VIEs	14	21
Other current assets	2	4
Property, plant and equipment, cost	20	20
Accumulated depreciation and amortization	(6)	(6)
Total assets	32	41
Taxes accrued		1
Current maturities of long-term debt	12	17
Other current liabilities		2
Total liabilities	12	20
Net assets of consolidated VIEs	$ 20	$ 21

Variable Interest Entities (S76

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 1,000
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	1,000
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 425
Line of Credit Facility, Expiration Date	Dec. 1, 2018
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 300
Line of Credit Facility, Expiration Date	Feb. 1, 2019
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$ 225
Line of Credit Facility, Expiration Date	Apr. 1, 2019

Variable Interest Entities (S77

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 547	$ 499
Investments and other assets	3,036	3,042
Other current liabilities	1,965	2,115
Deferred credits and other liabilities	32,645	32,490
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	413	387
Total assets	413	387
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets	397	370
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	227	235
Total assets	227	235
Net assets	227	235
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	186	152
Total assets	186	152
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets	170	135
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	93	84
Investments and other assets	20	20
Other current liabilities	151	153
Deferred credits and other liabilities	2,016	1,998
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	39	47
Total assets	39	47
Net assets	39	47
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	64	71
Other current liabilities	78	97
Deferred credits and other liabilities	3,210	3,219
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables from affiliated companies	50	60
Total assets	50	60
Net assets	$ 50	$ 60

Variable Interest Entities (Fai

Variable Interest Entities (Fair Value Assumptions)(Details) - Cinergy Receivables [Member]	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.60%	0.60%
Discount rate	1.40%	1.20%
Receivable turnover rate	13.20%	12.90%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.40%	1.20%
Receivable turnover rate	10.60%	10.60%

Variable Interest Entities (Rec

Variable Interest Entities (Receivables Sold)(Details) - Cinergy Receivables [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 225	$ 233
Less: Retained interests	39	47
Net receivables sold	186	186
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	253	260
Less: Retained interests	50	60
Net receivables sold	$ 203	$ 200

Variable Interest Entities (Sal

Variable Interest Entities (Sales and Cash Flows)(Details) - Cinergy Receivables [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$ 532	$ 644
Loss recognized on sale	3	3
Cash proceeds from receivables sold	537	640
Return received on retained interests	1	1
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	635	716
Loss recognized on sale	3	3
Cash proceeds from receivables sold	643	722
Return received on retained interests	$ 1	$ 2

Common Stock (Earnings Per Shar

Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 691	$ 773
Average shares, basic	689	708
Average shares, diluted	689	708
EPS, basic (usd per share)	$ 1	$ 1.09
EPS, diluted (usd per share)	$ 1	$ 1.09
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 691	$ 772
Average shares, basic	689	708
Average shares, diluted	689	708
EPS, basic (usd per share)	$ 1	$ 1.09
EPS, diluted (usd per share)	$ 1	$ 1.09
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

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		3 Months Ended
	Jun. 30, 2015	Apr. 30, 2015	Jun. 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
Delivered Shares from Dealers	3.2	16.6	19.8
Fair Market Value of Delivered Shares	$ 225	$ 1,275
Percentage of ASR common stock received				85.00%
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

Common Stock Common Stock (Equi

Common Stock Common Stock (Equity Securities Offering) (Details) - Piedmont Natural Gas [Member] shares in Millions	Mar. 31, 2016$ / sharesshares
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered	10.6
Then Forward Price | $ / shares	$ 69.84
Shares required to net settle	1.4

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$ 12	$ 14
Tax benefit associated with stock-based compensation expense	4	5
Stock-based compensation costs capitalized	1	1
Restricted Stock Units Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	7	9
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$ 5	$ 5

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details)	3 Months Ended
	Mar. 31, 2016
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%

Employee Benefit Plans Employee

Employee Benefit Plans Employee Benefit Plans (Plan Contributions) (Details) - Pension Plan [Member] $ in Millions	3 Months Ended
	Mar. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	$ 132
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	42
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	42
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	21
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	21
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	1
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	$ 9

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 36	$ 40
Interest cost on projected benefit obligation	83	82
Expected return on plan assets	(129)	(129)
Amortization of actuarial loss (gain)	33	43
Amortization of prior service cost (credit)	(4)	(4)
Other	3	2
Net periodic costs	22	34
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	12	13
Interest cost on projected benefit obligation	21	21
Expected return on plan assets	(35)	(36)
Amortization of actuarial loss (gain)	8	10
Amortization of prior service cost (credit)	(2)	(2)
Other	1	1
Net periodic costs	5	7
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11	11
Interest cost on projected benefit obligation	26	26
Expected return on plan assets	(42)	(43)
Amortization of actuarial loss (gain)	14	17
Amortization of prior service cost (credit)	(1)	(1)
Other	1	1
Net periodic costs	9	11
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	6	6
Interest cost on projected benefit obligation	12	12
Expected return on plan assets	(21)	(20)
Amortization of actuarial loss (gain)	6	8
Net periodic costs	3	6
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5	5
Interest cost on projected benefit obligation	14	14
Expected return on plan assets	(21)	(22)
Amortization of actuarial loss (gain)	7	8
Net periodic costs	5	5
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1
Interest cost on projected benefit obligation	5	5
Expected return on plan assets	(7)	(6)
Amortization of actuarial loss (gain)	1	2
Net periodic costs		2
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	3
Interest cost on projected benefit obligation	7	7
Expected return on plan assets	(10)	(10)
Amortization of actuarial loss (gain)	3	3
Net periodic costs	2	3
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	2
Interest cost on projected benefit obligation	8	9
Expected return on plan assets	(3)	(3)
Amortization of actuarial loss (gain)	1	6
Amortization of prior service cost (credit)	(35)	(35)
Net periodic costs	(28)	(21)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2
Expected return on plan assets	(2)	(2)
Amortization of actuarial loss (gain)	(1)
Amortization of prior service cost (credit)	(3)	(4)
Net periodic costs	(4)	(4)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	4	4
Amortization of actuarial loss (gain)	5	7
Amortization of prior service cost (credit)	(26)	(26)
Net periodic costs	(17)	(15)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2
Amortization of actuarial loss (gain)	3	5
Amortization of prior service cost (credit)	(17)	(17)
Net periodic costs	(12)	(10)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2
Amortization of actuarial loss (gain)	2	3
Amortization of prior service cost (credit)	(9)	(9)
Net periodic costs	(5)	$ (4)
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
Amortization of actuarial loss (gain)	$ (1)

Employee Benefit Plans (Employe

Employee Benefit Plans (Employee Savings Plans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Employee Savings Plans [Abstract]
Employer contributions	$ 52	$ 49
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Employer contributions	18	16
Progress Energy [Member]
Employee Savings Plans [Abstract]
Employer contributions	15	14
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Employer contributions	11	11
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Employer contributions	4	4
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Employer contributions	1	1
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Employer contributions	$ 2	$ 2

Income Taxes Income Taxes (Taxe

Income Taxes Income Taxes (Taxes on Foreign Earnings) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Unremitted Earnings [Member] | International Energy [Member]
Income Tax Disclosure [Line Items]
U.S. Income Taxes on Foreign Earnings	$ 12
Previously Remitted Earnings [Member]
Income Tax Disclosure [Line Items]
U.S. Income Taxes on Foreign Earnings	$ 95

Income Taxes (Effective Tax Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	23.40%	31.90%
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	34.10%	35.80%
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	36.70%	35.40%
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	35.40%	33.80%
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	37.90%	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	26.90%	36.70%
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	30.20%	36.60%