Duke Energy (DUK) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	5-May-15
Document Information [Line Items]
Entity Registrant Name	Duke Energy Corporation
Entity Central Index Key	1326160
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		691,537,400
Duke Energy Carolinas [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Carolinas, LLC
Entity Central Index Key	30371
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Progress Energy [Member]
Document Information [Line Items]
Entity Registrant Name	Progress Energy, Inc
Entity Central Index Key	1094093
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Duke Energy Progress [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Progress, Inc.
Entity Central Index Key	17797
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Duke Energy Florida [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Florida, Inc.
Entity Central Index Key	37637
Current Fiscal Year End Date	-19
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	20290
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Duke Energy Indiana [Member]
Document Information [Line Items]
Entity Registrant Name	Duke Energy Indiana, Inc.
Entity Central Index Key	81020
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Revenues
Regulated electric	$5,457	$5,550
Nonregulated electric and other	377	491
Regulated natural gas	231	222
Total operating revenues	6,065	6,263
Operating Expenses
Fuel used in electric generation and purchased power – regulated	1,941	2,000
Fuel used in electric generation and purchased power – nonregulated	104	136
Cost of natural gas and other	111	116
Operation, maintenance and other	1,426	1,449
Depreciation and amortization	777	755
Property and other taxes	264	350
Impairment charges	0	96
Total operating expenses	4,623	4,902
Gains on Sales of Other Assets and Other, net	14	1
Operating Income (Loss)	1,456	1,362
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	13	36
Other income and expenses, net	74	95
Total other income and expenses	87	131
Interest Expense	403	404
Income (Loss) From Continuing Operations Before Income Taxes	1,140	1,089
Income Tax Expense (Benefit) from Continuing Operations	364	339
Income (Loss) From Continuing Operations	776	750
Income (Loss) From Discontinued Operations, net of tax	91	-843
Net income (loss)	867	-93
Less: Net Income Attributable to Noncontrolling Interests	3	4
Net Income (Loss) Attributable to Parent	864	-97
Other Comprehensive (Loss) Income, net of tax
Pension and OPEB adjustments	-5	-1
Net unrealized gain (loss) on cash flow hedges	-7
Reclassification into earnings from cash flow hedges	4
Other Comprehensive (Loss) Income, net of tax	-133	23
Comprehensive Income (Loss)	734	-70
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	-1	5
Comprehensive Income Attributable to Parent	735	-75
Income from continuing operations attributable to Duke Energy Corporation common shareholders
Basic (usd per share)	$1.09	$1.05
Diluted (usd per share)	$1.09	$1.05
Income (Loss) from discontinued operations attributable to Duke Energy Corporation common shareholders
Basic (usd per share)	$0.13	($1.19)
Diluted (usd per share)	$0.13	($1.19)
Net Income (Loss) attributable to Duke Energy Corporation common shareholders
Basic (usd per share)	$1.22	($0.14)
Diluted (usd per share)	$1.22	($0.14)
Weighted-average shares outstanding
Basic (shares)	708	706
Diluted (shares)	708	706
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	1,901	2,000
Operating Expenses
Fuel used in electric generation and purchased power – regulated	578	658
Operation, maintenance and other	489	487
Depreciation and amortization	249	242
Property and other taxes	70	104
Total operating expenses	1,386	1,491
Operating Income (Loss)	515	509
Other Income and Expenses
Other income and expenses, net	42	49
Interest Expense	102	101
Income (Loss) From Continuing Operations Before Income Taxes	455	457
Income Tax Expense (Benefit) from Continuing Operations	163	171
Net Income (Loss) Attributable to Parent	292	286
Other Comprehensive (Loss) Income, net of tax
Reclassification into earnings from cash flow hedges		1
Other Comprehensive (Loss) Income, net of tax		1
Comprehensive Income Attributable to Parent	292	287
Progress Energy [Member]
Operating Revenues
Total operating revenues	2,536	2,541
Operating Expenses
Fuel used in electric generation and purchased power – regulated	1,032	1,043
Operation, maintenance and other	565	595
Depreciation and amortization	287	276
Property and other taxes	111	151
Total operating expenses	1,995	2,065
Gains on Sales of Other Assets and Other, net	8	1
Operating Income (Loss)	549	477
Other Income and Expenses
Other income and expenses, net	27	15
Interest Expense	168	169
Income (Loss) From Continuing Operations Before Income Taxes	408	323
Income Tax Expense (Benefit) from Continuing Operations	144	119
Income (Loss) From Continuing Operations	264	204
Income (Loss) From Discontinued Operations, net of tax	-1	-1
Net income (loss)	263	203
Less: Net Income Attributable to Noncontrolling Interests	3	1
Net Income (Loss) Attributable to Parent	260	202
Other Comprehensive (Loss) Income, net of tax
Pension and OPEB adjustments	1	1
Net unrealized gain (loss) on cash flow hedges		1
Reclassification into earnings from cash flow hedges	-2	0
Other Comprehensive (Loss) Income, net of tax	-1	2
Comprehensive Income (Loss)	262	205
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	3	1
Comprehensive Income Attributable to Parent	259	204
Duke Energy Progress [Member]
Operating Revenues
Total operating revenues	1,449	1,422
Operating Expenses
Fuel used in electric generation and purchased power – regulated	575	573
Operation, maintenance and other	375	381
Depreciation and amortization	152	144
Property and other taxes	32	67
Total operating expenses	1,134	1,165
Gains on Sales of Other Assets and Other, net	1	1
Operating Income (Loss)	316	258
Other Income and Expenses
Other income and expenses, net	20	9
Interest Expense	60	57
Income (Loss) From Continuing Operations Before Income Taxes	276	210
Income Tax Expense (Benefit) from Continuing Operations	93	77
Net Income (Loss) Attributable to Parent	183	133
Duke Energy Florida [Member]
Operating Revenues
Total operating revenues	1,086	1,116
Operating Expenses
Fuel used in electric generation and purchased power – regulated	457	470
Operation, maintenance and other	188	211
Depreciation and amortization	134	132
Property and other taxes	80	84
Total operating expenses	859	897
Operating Income (Loss)	227	219
Other Income and Expenses
Other income and expenses, net	6	5
Interest Expense	49	49
Income (Loss) From Continuing Operations Before Income Taxes	184	175
Income Tax Expense (Benefit) from Continuing Operations	71	67
Net Income (Loss) Attributable to Parent	113	108
Other Comprehensive (Loss) Income, net of tax
Net unrealized gain (loss) on cash flow hedges		1
Other Comprehensive (Loss) Income, net of tax		1
Comprehensive Income Attributable to Parent	113	109
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	339	339
Nonregulated electric and other	14	13
Regulated natural gas	233	223
Total operating revenues	586	575
Operating Expenses
Fuel used in electric generation and purchased power – regulated	115	124
Fuel used in electric generation and purchased power – nonregulated	14	13
Cost of natural gas and other	97	99
Operation, maintenance and other	128	127
Depreciation and amortization	57	57
Property and other taxes	70	68
Impairment charges		94
Total operating expenses	481	582
Gains on Sales of Other Assets and Other, net	6
Operating Income (Loss)	111	-7
Other Income and Expenses
Other income and expenses, net	3	3
Interest Expense	20	20
Income (Loss) From Continuing Operations Before Income Taxes	94	-24
Income Tax Expense (Benefit) from Continuing Operations	35	-9
Income (Loss) From Continuing Operations	59	-15
Income (Loss) From Discontinued Operations, net of tax	90	-875
Net Income (Loss) Attributable to Parent	149	-890
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	788	845
Operating Expenses
Fuel used in electric generation and purchased power – regulated	294	339
Operation, maintenance and other	181	166
Depreciation and amortization	104	102
Property and other taxes	-1	23
Total operating expenses	578	630
Operating Income (Loss)	210	215
Other Income and Expenses
Other income and expenses, net	5	7
Interest Expense	45	43
Income (Loss) From Continuing Operations Before Income Taxes	170	179
Income Tax Expense (Benefit) from Continuing Operations	62	66
Net Income (Loss) Attributable to Parent	108	113
Other Comprehensive (Loss) Income, net of tax
Reclassification into earnings from cash flow hedges	-1	1
Other Comprehensive (Loss) Income, net of tax	-1	1
Comprehensive Income Attributable to Parent	$107	$114

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income (loss)	$867	($93)
Other Comprehensive (Loss) Income, net of tax
Foreign currency translation adjustments	-125	24
Pension and OPEB adjustments	-5	-1
Net unrealized gain (loss) on cash flow hedges	-7
Reclassification into earnings from cash flow hedges	4
Other Comprehensive (Loss) Income, net of tax	-133	23
Comprehensive Income (Loss)	734	-70
Less: Comprehensive (Loss) Income Attributable to Noncontrolling Interests	-1	5
Comprehensive Income Attributable to Parent	$735	($75)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Current Assets
Cash and cash equivalents	$2,821	$2,036
Receivables (net of allowance for doubtful accounts)	750	791
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	2,016	1,973
Inventory	3,413	3,459
Assets held for sale	354	364
Regulatory assets	960	1,115
Other	2,008	1,837
Total current assets	12,322	11,575
Investments and Other Assets
Investments in equity method unconsolidated affiliates	343	358
Nuclear decommissioning trust funds	5,576	5,546
Goodwill	16,329	16,321
Assets held for sale	2,603	2,642
Other	3,207	3,008
Total investments and other assets	28,058	27,875
Property, Plant and Equipment
Cost	105,692	104,861
Accumulated depreciation and amortization	-35,400	-34,824
Generation Facilities To Be Retired Net	9	9
Net property, plant and equipment	70,301	70,046
Regulatory Assets and Deferred Debits
Regulatory assets	11,279	11,042
Other	182	171
Total regulatory assets and deferred debits	11,461	11,213
Total Assets	122,142	120,709
Current Liabilities
Accounts payable	1,920	2,271
Notes payable and commercial paper	3,790	2,514
Taxes accrued	508	569
Interest accrued	490	418
Current maturities of long-term debt	2,800	2,807
Liabilities associated with assets held for sale	146	262
Regulatory liabilities	235	204
Other	2,014	2,188
Total current liabilities	11,903	11,233
Long-Term Debt	37,173	37,213
Deferred Credits and Other Liabilities
Deferred income taxes	13,914	13,423
Investment tax credits	424	427
Accrued pension and other post-retirement benefit costs	1,170	1,145
Liabilities associated with assets held for sale	26	35
Asset retirement obligations	8,541	8,466
Regulatory liabilities	6,237	6,193
Other	1,667	1,675
Total deferred credits and other liabilities	31,979	31,364
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	39,413	39,405
Retained earnings	2,309	2,012
Accumulated other comprehensive income (loss)	-672	-543
Total Duke Energy Corporation stockholders' equity	41,051	40,875
Noncontrolling interests	36	24
Total equity	41,087	40,899
Total Liabilities and Equity	122,142	120,709
Duke Energy Carolinas [Member]
Current Assets
Cash and cash equivalents	30	13
Receivables (net of allowance for doubtful accounts)	106	129
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	658	647
Receivables from affiliated companies	91	75
Notes receivable from affiliated companies	755	150
Inventory	1,117	1,124
Regulatory assets	376	399
Other	41	77
Total current assets	3,174	2,614
Investments and Other Assets
Nuclear decommissioning trust funds	3,118	3,042
Other	996	959
Total investments and other assets	4,114	4,001
Property, Plant and Equipment
Cost	37,682	37,372
Accumulated depreciation and amortization	-12,935	-12,700
Net property, plant and equipment	24,747	24,672
Regulatory Assets and Deferred Debits
Regulatory assets	2,460	2,465
Other	45	42
Total regulatory assets and deferred debits	2,505	2,507
Total Assets	34,540	33,794
Current Liabilities
Accounts payable	504	709
Accounts payable to affiliated companies	204	154
Taxes accrued	129	146
Interest accrued	135	95
Current maturities of long-term debt	506	507
Regulatory liabilities	26	34
Other	398	434
Total current liabilities	1,902	2,079
Long-Term Debt	8,079	7,584
Long-Term Debt Payable to Affiliated Companies	300	300
Deferred Credits and Other Liabilities
Deferred income taxes	5,901	5,812
Investment tax credits	203	204
Accrued pension and other post-retirement benefit costs	109	111
Asset retirement obligations	3,460	3,428
Regulatory liabilities	2,730	2,710
Other	640	642
Total deferred credits and other liabilities	13,043	12,907
Commitments and Contingencies
Equity
Member's equity	11,229	10,937
Accumulated other comprehensive income (loss)	-13	-13
Total member's equity	11,216	10,924
Total Liabilities and Equity	34,540	33,794
Progress Energy [Member]
Current Assets
Cash and cash equivalents	44	42
Receivables (net of allowance for doubtful accounts)	129	129
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	779	741
Receivables from affiliated companies	80	59
Notes receivable from affiliated companies	178	220
Inventory	1,543	1,590
Regulatory assets	392	491
Other	793	1,285
Total current assets	3,938	4,557
Investments and Other Assets
Nuclear decommissioning trust funds	2,458	2,503
Goodwill	3,655	3,655
Other	777	670
Total investments and other assets	6,890	6,828
Property, Plant and Equipment
Cost	39,067	38,650
Accumulated depreciation and amortization	-13,714	-13,506
Net property, plant and equipment	25,353	25,144
Regulatory Assets and Deferred Debits
Regulatory assets	5,687	5,408
Other	90	91
Total regulatory assets and deferred debits	5,777	5,499
Total Assets	41,958	42,028
Current Liabilities
Accounts payable	667	847
Accounts payable to affiliated companies	286	203
Notes payable to affiliated companies	650	835
Taxes accrued	161	114
Interest accrued	203	184
Current maturities of long-term debt	1,564	1,507
Regulatory liabilities	125	106
Other	961	1,021
Total current liabilities	4,617	4,817
Long-Term Debt	12,946	13,247
Deferred Credits and Other Liabilities
Deferred income taxes	4,834	4,759
Accrued pension and other post-retirement benefit costs	561	533
Asset retirement obligations	4,738	4,711
Regulatory liabilities	2,413	2,379
Other	411	406
Total deferred credits and other liabilities	12,957	12,788
Commitments and Contingencies
Equity
Common stock	0	0
Additional paid-in capital	7,467	7,467
Retained earnings	4,039	3,782
Accumulated other comprehensive income (loss)	-42	-41
Total Duke Energy Corporation stockholders' equity	11,464	11,208
Noncontrolling interests	-26	-32
Total equity	11,438	11,176
Total Liabilities and Equity	41,958	42,028
Duke Energy Progress [Member]
Current Assets
Cash and cash equivalents	6	9
Receivables (net of allowance for doubtful accounts)	49	43
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	479	436
Receivables from affiliated companies	4	10
Notes receivable from affiliated companies	205	237
Inventory	929	966
Regulatory assets	267	287
Other	99	384
Total current assets	2,038	2,372
Investments and Other Assets
Nuclear decommissioning trust funds	1,738	1,701
Other	450	412
Total investments and other assets	2,188	2,113
Property, Plant and Equipment
Cost	24,444	24,207
Accumulated depreciation and amortization	-9,162	-9,021
Net property, plant and equipment	15,282	15,186
Regulatory Assets and Deferred Debits
Regulatory assets	2,857	2,675
Other	34	34
Total regulatory assets and deferred debits	2,891	2,709
Total Assets	22,399	22,380
Current Liabilities
Accounts payable	363	481
Accounts payable to affiliated companies	183	120
Taxes accrued	61	47
Interest accrued	87	81
Current maturities of long-term debt	702	945
Regulatory liabilities	80	71
Other	359	409
Total current liabilities	1,835	2,154
Long-Term Debt	5,255	5,256
Deferred Credits and Other Liabilities
Deferred income taxes	2,978	2,908
Accrued pension and other post-retirement benefit costs	287	290
Asset retirement obligations	3,936	3,905
Regulatory liabilities	1,883	1,832
Other	175	168
Total deferred credits and other liabilities	9,259	9,103
Commitments and Contingencies
Equity
Common stock	2,159	2,159
Retained earnings	3,891	3,708
Total equity	6,050	5,867
Total Liabilities and Equity	22,399	22,380
Duke Energy Florida [Member]
Current Assets
Cash and cash equivalents	10	8
Receivables (net of allowance for doubtful accounts)	77	84
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	301	305
Receivables from affiliated companies	60	40
Inventory	614	623
Regulatory assets	124	203
Other	333	521
Total current assets	1,519	1,784
Investments and Other Assets
Nuclear decommissioning trust funds	720	803
Other	270	204
Total investments and other assets	990	1,007
Property, Plant and Equipment
Cost	14,613	14,433
Accumulated depreciation and amortization	-4,545	-4,478
Net property, plant and equipment	10,068	9,955
Regulatory Assets and Deferred Debits
Regulatory assets	2,830	2,733
Other	39	39
Total regulatory assets and deferred debits	2,869	2,772
Total Assets	15,446	15,518
Current Liabilities
Accounts payable	302	365
Accounts payable to affiliated companies	85	70
Notes payable to affiliated companies	192	84
Taxes accrued	126	65
Interest accrued	68	47
Current maturities of long-term debt	562	562
Regulatory liabilities	45	35
Other	577	586
Total current liabilities	1,957	1,814
Long-Term Debt	4,296	4,298
Deferred Credits and Other Liabilities
Deferred income taxes	2,465	2,452
Accrued pension and other post-retirement benefit costs	254	221
Asset retirement obligations	803	806
Regulatory liabilities	529	547
Other	157	158
Total deferred credits and other liabilities	4,208	4,184
Commitments and Contingencies
Equity
Common stock	1,762	1,762
Retained earnings	3,223	3,460
Total equity	4,985	5,222
Total Liabilities and Equity	15,446	15,518
Duke Energy Ohio [Member]
Current Assets
Cash and cash equivalents	52	20
Receivables (net of allowance for doubtful accounts)	98	93
Receivables from affiliated companies	91	107
Notes receivable from affiliated companies	40	145
Inventory	109	97
Assets held for sale	295	316
Regulatory assets	21	49
Other	97	167
Total current assets	803	994
Investments and Other Assets
Goodwill	920	920
Assets held for sale	2,565	2,605
Other	35	23
Total investments and other assets	3,520	3,548
Property, Plant and Equipment
Cost	7,208	7,141
Accumulated depreciation and amortization	-2,264	-2,213
Generation Facilities To Be Retired Net	9	9
Net property, plant and equipment	4,953	4,937
Regulatory Assets and Deferred Debits
Regulatory assets	512	512
Other	8	8
Total regulatory assets and deferred debits	520	520
Total Assets	9,796	9,999
Current Liabilities
Accounts payable	221	209
Accounts payable to affiliated companies	123	74
Notes payable to affiliated companies	298	491
Taxes accrued	181	163
Interest accrued	29	19
Current maturities of long-term debt	56	157
Liabilities associated with assets held for sale	129	246
Regulatory liabilities	24	10
Other	64	66
Total current liabilities	1,125	1,435
Long-Term Debt	1,525	1,584
Long-Term Debt Payable to Affiliated Companies	25	25
Deferred Credits and Other Liabilities
Deferred income taxes	1,790	1,765
Accrued pension and other post-retirement benefit costs	48	48
Liabilities associated with assets held for sale	25	34
Asset retirement obligations	26	27
Regulatory liabilities	243	241
Other	166	166
Total deferred credits and other liabilities	2,298	2,281
Commitments and Contingencies
Equity
Common stock	762	762
Additional paid-in capital	4,782	4,782
Retained earnings	-721	-870
Total equity	4,823	4,674
Total Liabilities and Equity	9,796	9,999
Duke Energy Indiana [Member]
Current Assets
Cash and cash equivalents	16	6
Receivables (net of allowance for doubtful accounts)	83	87
Receivables from affiliated companies	114	115
Notes receivable from affiliated companies	106
Inventory	542	537
Regulatory assets	88	93
Other	240	326
Total current assets	1,189	1,164
Investments and Other Assets
Other	257	251
Total investments and other assets	257	251
Property, Plant and Equipment
Cost	13,180	13,034
Accumulated depreciation and amortization	-4,314	-4,219
Net property, plant and equipment	8,866	8,815
Regulatory Assets and Deferred Debits
Regulatory assets	686	685
Other	23	24
Total regulatory assets and deferred debits	709	709
Total Assets	11,021	10,939
Current Liabilities
Accounts payable	173	179
Accounts payable to affiliated companies	59	58
Notes payable to affiliated companies		71
Taxes accrued	67	54
Interest accrued	51	56
Current maturities of long-term debt	5	5
Regulatory liabilities	60	54
Other	88	98
Total current liabilities	503	575
Long-Term Debt	3,636	3,636
Long-Term Debt Payable to Affiliated Companies	150	150
Deferred Credits and Other Liabilities
Deferred income taxes	1,656	1,591
Investment tax credits	139	139
Accrued pension and other post-retirement benefit costs	81	82
Asset retirement obligations	33	32
Regulatory liabilities	790	796
Other	78	90
Total deferred credits and other liabilities	2,777	2,730
Commitments and Contingencies
Equity
Common stock	1	1
Additional paid-in capital	1,384	1,384
Retained earnings	2,568	2,460
Accumulated other comprehensive income (loss)	2	3
Total equity	3,955	3,848
Total Liabilities and Equity	$11,021	$10,939

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Share data, unless otherwise specified
Receivables, allowance for doubtful accounts	$16	$17
Restricted receivables, allowance for doubtful accounts	54	51
Common stock, par or stated value	$0.00	$0.00
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	708,000,000	707,000,000
Duke Energy Carolinas [Member]
Receivables, allowance for doubtful accounts	3	3
Restricted receivables, allowance for doubtful accounts	6	6
Progress Energy [Member]
Receivables, allowance for doubtful accounts	7	8
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	6	7
Restricted receivables, allowance for doubtful accounts	4	5
Common stock, par or stated value	$0	$0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares outstanding	160,000,000	160,000,000
Duke Energy Florida [Member]
Receivables, allowance for doubtful accounts	2	2
Restricted receivables, allowance for doubtful accounts	3	3
Common stock, par or stated value	$0	$0
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares outstanding	100	100
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	$0.01
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares outstanding	53,913,701	53,913,701

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$867	($93)
Net Income (Loss) Attributable to Parent	864	-97
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	883	884
Equity component of AFUDC	-42	-28
Gains on sales of other assets	-16
Impairment charges	43	1,382
Deferred income taxes	368	-178
Equity in earnings of unconsolidated affiliates	-13	-36
Accrued pension and other post-retirement benefit costs	18	27
Contributions to pension plans	-132
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	-47	45
Receivables	-41	29
Inventory	57	272
Other current assets	-63	-297
Increase (decrease) in
Accounts payable	-201	-97
Taxes accrued	-63	-175
Other current liabilities	-85	-346
Other assets	30	-22
Other liabilities	-123	6
Net cash provided by operating activities	1,440	1,373
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-1,411	-1,232
Investment expenditures	-14	-36
Acquisitions	-29
Purchases of available-for-sale securities	-1,035	-967
Proceeds from sales and maturities of available-for-sale securities	1,069	1,004
Net proceeds from the sales of equity investments and other assets	1	4
Change in restricted cash	-36	-27
Other	-1	-32
Net cash used in investing activities	-1,456	-1,286
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	497	875
Proceeds from the issuance of common stock related to employee benefit plans	15	19
Payments for the redemption of long-term debt	-403	-1,287
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	-643
Notes payable and commercial paper	1,727	898
Distributions to noncontrolling interests		-3
Dividends paid	-564	-553
Other	-15	-6
Net cash provided by (used in) financing activities	801	-57
Net increase in cash and cash equivalents	785	30
Cash and cash equivalents at beginning of period	2,036	1,501
Cash and cash equivalents at end of period	2,821	1,531
Significant non-cash transactions:
Accrued capital expenditures	438	361
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	292	286
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	324	309
Equity component of AFUDC	-24	-22
Deferred income taxes	113	87
Accrued pension and other post-retirement benefit costs	4	6
Contributions to pension plans	-42
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions		3
Receivables	16	11
Receivable from affiliated companies	-16	-27
Inventory	7	181
Other current assets	2	-59
Increase (decrease) in
Accounts payable	-133	-100
Accounts payable to affiliated companies	50	21
Taxes accrued	-17	-3
Other current liabilities	-27	-26
Other assets	44	14
Other liabilities	-17	-9
Net cash provided by operating activities	576	672
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-448	-426
Purchases of available-for-sale securities	-643	-584
Proceeds from sales and maturities of available-for-sale securities	643	579
Notes receivable from affiliated companies	-605	-115
Other	4	-6
Net cash used in investing activities	-1,049	-552
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	496
Dividends or distributions to parent		-126
Other	-6
Net cash provided by (used in) financing activities	490	-126
Net increase in cash and cash equivalents	17	-6
Cash and cash equivalents at beginning of period	13	23
Cash and cash equivalents at end of period	30	17
Significant non-cash transactions:
Accrued capital expenditures	102	133
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	263	203
Net Income (Loss) Attributable to Parent	260	202
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	329	316
Equity component of AFUDC	-14	-1
Gains on sales of other assets	-8	-1
Deferred income taxes	196	183
Accrued pension and other post-retirement benefit costs	-1	7
Contributions to pension plans	-42
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	-22	13
Receivables	-66	-45
Receivable from affiliated companies	-21
Inventory	47	72
Other current assets	302	-134
Increase (decrease) in
Accounts payable	-107	-53
Accounts payable to affiliated companies	83	114
Taxes accrued	47	3
Other current liabilities	-10	-116
Other assets	-21	-52
Other liabilities	-48	-6
Net cash provided by operating activities	907	503
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-563	-475
Purchases of available-for-sale securities	-298	-266
Proceeds from sales and maturities of available-for-sale securities	367	269
Notes receivable from affiliated companies	42	-101
Other	-20	-25
Net cash used in investing activities	-472	-598
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		875
Payments for the redemption of long-term debt	-245	-469
Notes payable to affiliated companies	-185	-291
Distributions to noncontrolling interests		-3
Other	-3	-39
Net cash provided by (used in) financing activities	-433	73
Net increase in cash and cash equivalents	2	-22
Cash and cash equivalents at beginning of period	42	58
Cash and cash equivalents at end of period	44	36
Significant non-cash transactions:
Accrued capital expenditures	176	158
Duke Energy Progress [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	183	133
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	193	183
Equity component of AFUDC	-13	-2
Gains on sales of other assets	-1	-1
Deferred income taxes	138	117
Accrued pension and other post-retirement benefit costs	-4	-2
Contributions to pension plans	-21
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	-4	6
Receivables	-92	10
Receivable from affiliated companies	6	-5
Inventory	37	53
Other current assets	170	-183
Increase (decrease) in
Accounts payable	-52	-37
Accounts payable to affiliated companies	63	139
Taxes accrued	14
Other current liabilities	-28	-41
Other assets	-2	-13
Other liabilities	-23	-1
Net cash provided by operating activities	564	356
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-338	-299
Purchases of available-for-sale securities	-149	-151
Proceeds from sales and maturities of available-for-sale securities	144	149
Notes receivable from affiliated companies	32	-65
Other	-12	-18
Net cash used in investing activities	-323	-384
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		650
Payments for the redemption of long-term debt	-243	-168
Notes payable to affiliated companies		-462
Other	-1	-4
Net cash provided by (used in) financing activities	-244	16
Net increase in cash and cash equivalents	-3	-12
Cash and cash equivalents at beginning of period	9	21
Cash and cash equivalents at end of period	6	9
Significant non-cash transactions:
Accrued capital expenditures	82	116
Duke Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	113	108
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	136	133
Equity component of AFUDC	-1
Deferred income taxes	39	60
Accrued pension and other post-retirement benefit costs	1	7
Contributions to pension plans	-21
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	-20	5
Receivables	24	21
Receivable from affiliated companies	-20	-7
Inventory	10	20
Other current assets	143	68
Increase (decrease) in
Accounts payable	-54	24
Accounts payable to affiliated companies	15	28
Taxes accrued	61	10
Other current liabilities	24	-63
Other assets	-17	-36
Other liabilities	-29	-13
Net cash provided by operating activities	404	365
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-224	-176
Purchases of available-for-sale securities	-149	-115
Proceeds from sales and maturities of available-for-sale securities	223	120
Notes receivable from affiliated companies		-110
Other	-7	-8
Net cash used in investing activities	-157	-289
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt		225
Payments for the redemption of long-term debt	-2	-1
Notes payable to affiliated companies	108	-181
Dividends or distributions to parent	-350	-124
Other	-1	-1
Net cash provided by (used in) financing activities	-245	-82
Net increase in cash and cash equivalents	2	-6
Cash and cash equivalents at beginning of period	8	16
Cash and cash equivalents at end of period	10	10
Significant non-cash transactions:
Accrued capital expenditures	94	42
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	149	-890
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	58	92
Equity component of AFUDC	-1	-1
Gains on sales of other assets	-6
Impairment charges	40	1,417
Deferred income taxes	25	-501
Accrued pension and other post-retirement benefit costs	2	1
Contributions to pension plans	-1
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	-28	39
Receivables	-8	-16
Receivable from affiliated companies	16	-6
Inventory	-3	29
Other current assets	80	-92
Increase (decrease) in
Accounts payable	20	21
Accounts payable to affiliated companies	49	-13
Taxes accrued	-4	-38
Other current liabilities	24	-7
Other assets	15	-9
Other liabilities	-74	7
Net cash provided by operating activities	353	33
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-81	-83
Notes receivable from affiliated companies	105	-110
Net cash used in investing activities	24	-193
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt	-151	-1
Notes payable to affiliated companies	-193	263
Dividends or distributions to parent		-100
Other	-1
Net cash provided by (used in) financing activities	-345	162
Net increase in cash and cash equivalents	32	2
Cash and cash equivalents at beginning of period	20	36
Cash and cash equivalents at end of period	52	38
Significant non-cash transactions:
Accrued capital expenditures	15	24
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income (Loss) Attributable to Parent	108	113
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion (including amortization of nuclear fuel)	105	103
Equity component of AFUDC	-3	-4
Deferred income taxes	140	-39
Accrued pension and other post-retirement benefit costs	3	4
Contributions to pension plans	-9
(Increase) decrease in
Receivables	3	-23
Receivable from affiliated companies	1	10
Inventory	-5	-10
Other current assets	9	-41
Increase (decrease) in
Accounts payable	21	-36
Accounts payable to affiliated companies	1	12
Taxes accrued	13	110
Other current liabilities	6	-6
Other assets	-8	-3
Other liabilities	-24	50
Net cash provided by operating activities	361	240
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-188	-133
Purchases of available-for-sale securities	-3	-3
Proceeds from sales and maturities of available-for-sale securities	2	3
Notes receivable from affiliated companies	-106	-94
Other	16
Net cash used in investing activities	-279	-227
CASH FLOWS FROM FINANCING ACTIVITIES
Payments for the redemption of long-term debt		-1
Notes payable to affiliated companies	-71
Other	-1	-1
Net cash provided by (used in) financing activities	-72	-2
Net increase in cash and cash equivalents	10	11
Cash and cash equivalents at beginning of period	6	15
Cash and cash equivalents at end of period	16	26
Significant non-cash transactions:
Accrued capital expenditures	$60	$32

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Changes in Equity (USD $)	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]	Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Progress Energy [Member]	Duke Energy Progress [Member]	Duke Energy Progress [Member]	Duke Energy Progress [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]	Duke Energy Ohio [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]	Duke Energy Indiana [Member]
In Millions, except Share data												Members Equity [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]	Net Gains (Losses) on Available for Sale Securities [Member]		Additional Paid In Capital [Member]	Retained Earnings [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]		Common Stock [Member]	Retained Earnings [Member]		Common Stock [Member]	Retained Earnings [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]		Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]		Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]
Beginning member's equity at Dec. 31, 2013											$10,350	$10,365	($14)	($1)
Balance at Dec. 31, 2013	41,408	1	39,365	2,363	-307	-40		-52	41,330	78					10,864	7,467	3,452	-43		-16	10,860	4	5,625	2,159	3,466	4,797	1,762	3,036	-1	5,269	762	4,882	-375	3,939	1	1,384	2,551	3
Balance, in shares at Dec. 31, 2013		706,000,000
Net income (loss)	-93			-97					-97	4					203		202				202	1
Net Income (Loss) Attributable to Parent	-97										286	286			202								133		133	108		108		-890			-890	113			113
Other comprehensive income (loss), net of tax	23				23			-1	22	1	1		1		2			1		1	2					1			1					1				1
Distributions to parent											-126	-126
Common stock issuances, including dividend reinvestment and employee benefits	7		7						7
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock dividends	-553			-553					-553																	-124		-124		-100		-100
Distributions to noncontrolling interest in subsidiaries	-3									-3					-3							-3
Transfer of service company net assets to Duke Energy															-539		-542	3			-539
Ending member's equity at Mar. 31, 2014											10,511	10,525	-13	-1
Balance at Mar. 31, 2014	40,789	1	39,372	1,713	-284	-40		-53	40,709	80					10,527	7,467	3,112	-39		-15	10,525	2	5,758	2,159	3,599	4,782	1,762	3,020		4,279	762	4,782	-1,265	4,053	1	1,384	2,664	4
Balance, in shares at Mar. 31, 2014		707,000,000
Beginning member's equity at Dec. 31, 2014											10,924	10,937	-12	-1
Balance at Dec. 31, 2014	40,899	1	39,405	2,012	-439	-59	3	-48	40,875	24					11,176	7,467	3,782	-35	1	-7	11,208	-32	5,867	2,159	3,708	5,222	1,762	3,460		4,674	762	4,782	-870	3,848	1	1,384	2,460	3
Balance, in shares at Dec. 31, 2014	707,000,000	707,000,000													100								160,000,000			100				89,663,086				53,913,701
Net income (loss)	867			864					864	3					263		260				260	3
Net Income (Loss) Attributable to Parent	864										292	292			260								183		183	113		113		149			149	108			108
Other comprehensive income (loss), net of tax	-133				-121	-3		-5	-129	-4					-1			-2		1	-1													-1				-1
Common stock issuances, including dividend reinvestment and employee benefits	8		8						8
Common stock issuances, including dividend reinvestment and employee benefits, shares		1,000,000
Common stock dividends	-564			-564					-564																	-350		-350
Other	10			-3					-3	13							-3				-3	3
Ending member's equity at Mar. 31, 2015											11,216	11,229	-12	-1
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	708,000,000													100								160,000,000			100				89,663,086				53,913,701

Organization_and_Basis_of_Pres

Organization and Basis of Presentation

3 Months Ended

Mar. 31, 2015

Accounting Policies [Abstract]

Organization and Basis of Presentation

Index to Combined Notes to Condensed Consolidated Financial Statements

The unaudited notes to the condensed consolidated financial statements that follow are a combined presentation. The following list indicates the registrants to which the footnotes apply.

Applicable Notes

Registrant

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

Duke Energy Corporation

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Duke Energy Carolinas, LLC

•

•

•

•

•

•

•

•

•

•

•

•

•

Progress Energy, Inc.

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Duke Energy Progress, Inc.

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Duke Energy Florida, Inc.

•

•

•

•

•

•

•

•

•

•

•

•

•

Duke Energy Ohio, Inc.

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Duke Energy Indiana, Inc.

•

•

•

•

•

•

•

•

•

•

•

•

•

ORGANIZATION AND BASIS OF PRESENTATION

NATURE OF OPERATIONS AND BASIS OF CONSOLIDATION

Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) and Latin America primarily through its direct and indirect subsidiaries. Duke Energy’s subsidiaries include its subsidiary registrants, Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, Inc. (Duke Energy Progress); Duke Energy Florida, Inc. (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, Inc. (Duke Energy Indiana). When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its six separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants).

These Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities.

Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), Public Service Commission of South Carolina (PSCSC), U.S. Nuclear Regulatory Commission (NRC) and FERC. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting.

Progress Energy is a public utility holding company headquartered in Raleigh, North Carolina, subject to regulation by the FERC. Progress Energy conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Substantially all of Progress Energy’s operations qualify for regulatory accounting.

Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting.

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, in the generation and sale of electricity in portions of Kentucky, and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. Duke Energy Ohio applied regulatory accounting to a portion of its operations. 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.

BASIS OF PRESENTATION

Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales LLC to Dynegy on April 2, 2015. The results of operations of these businesses have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations for all periods presented. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations for all periods presented, assets held for sale and liabilities associated with assets held for sale as of March 31, 2015. 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, 2014.

The information in these combined notes relate to each of the Duke Energy Registrants as noted in the Index to the Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants makes any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself.

These Condensed Consolidated Financial Statements reflect all normal recurring adjustments in the opinion of the respective companies’ management, necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors.

In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.

Certain prior year amounts have been reclassified to conform to the current year presentation.

UNBILLED REVENUE

Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes and meter reading schedules.

Unbilled revenues are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets as shown in the following table.

(in millions)

March 31, 2015

December 31, 2014

Duke Energy

$

710

$

827

Duke Energy Carolinas

257

295

Progress Energy

188

217

Duke Energy Progress

114

135

Duke Energy Florida

74

82

Duke Energy Ohio

1

—

Duke Energy Indiana

28

27

Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 for further information. These receivables for unbilled revenues are shown in the table below.

(in millions)

March 31, 2015

December 31, 2014

Duke Energy Ohio

$

62

$

79

Duke Energy Indiana

91

112

AMOUNTS ATTRIBUTABLE TO CONTROLLING INTERESTS

Loss From Discontinued Operations, net of tax presented on the respective Condensed Consolidated Statements of Operations for Duke Energy and Progress Energy, is attributable only to controlling interests for all periods presented. 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, 2015 and 2014, reclassifications out of accumulated other comprehensive income (AOCI) for the Duke Energy Registrants were not material. Changes in AOCI for the Duke Energy Registrants are presented in their respective Condensed Consolidated Statements of Equity.

EXCISE TAXES

Certain excise taxes levied by state or local governments are required to be paid even if not collected from the customer. These taxes are recognized on a gross basis. Otherwise, excise taxes are accounted for net.

Excise taxes recognized on a gross basis are recorded as Operating Revenues and Property and other taxes on the Condensed Consolidated Statements of Operations. The following table provides the amount of excise taxes accounted for on a gross basis.

Three Months Ended March 31,

(in millions)

2015

2014

Duke Energy

$

100

$

167

Duke Energy Carolinas

9

46

Progress Energy

49

77

Duke Energy Progress

4

32

Duke Energy Florida

45

45

Duke Energy Ohio

32

34

Duke Energy Indiana

10

10

NEW ACCOUNTING STANDARDS

The new accounting standards adopted for 2015 and 2014 had no significant impact on the presentation or results of operations, cash flows or financial position of the Duke Energy Registrants.

ASC 205 — Reporting Discontinued Operations. In April 2014, the Financial Accounting Standards Board (FASB) issued revised accounting guidance for reporting discontinued operations. A discontinued operation would be either (i) a component of an entity or a group of components of an entity that represents a separate major line of business or major geographical area of operations that either has been disposed of or is part of a single coordinated plan to be classified as held for sale or (ii) a business that, on acquisition, meets the criteria to be classified as held for sale.

For the Duke Energy Registrants, this revised accounting guidance is effective on a prospective basis for interim and annual periods beginning January 1, 2015. Duke Energy has not reported any discontinued operations under the revised accounting guidance.

The following new Accounting Standards Updates (ASUs) have been issued, but have not yet been adopted by the Duke Energy Registrants, as of March 31, 2015.

ASC 606 — Revenue from Contracts with Customers. In May 2014, the FASB issued revised accounting guidance for revenue recognition from contracts with customers. The core principle of this revised accounting guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this update also require disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers.

For the Duke Energy Registrants, this revised accounting guidance is effective for interim and annual periods beginning January 1, 2017. However, the FASB is considering allowing companies to delay implementation for one year. Duke Energy is currently evaluating requirements, and the ultimate impact of the revised accounting guidance has not yet been determined.

ASC 835 — Presentation of Debt Issuance Costs. In April 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.

This revised accounting guidance would be effective retroactively beginning January 1, 2016 for Duke Energy, but can be adopted earlier. Based on the amount of debt issuance costs reported as of December 31, 2014 in the Consolidated Balance Sheets, Duke Energy would record a reduction of $137 million in Regulatory Assets and Deferred Debits and Long-Term Debt. Duke Energy is currently evaluating whether implementation will occur prior to the first quarter of 2016.

Acquisitions_and_Dispositions

Acquisitions and Dispositions	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONS
	ACQUISITIONS
	Purchase of NCEMPA's Generation
	On September 5, 2014, Duke Energy Progress executed an agreement to purchase North Carolina Eastern Municipal Power Agency’s (NCEMPA) ownership interests in certain generating assets jointly owned with and operated by Duke Energy Progress. The agreement provides for the acquisition of a total of approximately 700 megawatts (MW) at Brunswick Nuclear Station, Shearon Harris Nuclear Station (Harris), Mayo Steam Station and Roxboro Steam Station. The purchase price for the ownership interest and fuel and spare parts inventory is approximately $1.2 billion. On December 9, 2014, the FERC approved Duke Energy Progress' request to purchase NCEMPA's interests in the generation assets, approved Duke Energy Progress' 30-year wholesale power supply agreement with NCEMPA and approved Duke Energy Progress' inclusion of the acquisition adjustment resulting from the asset purchase in wholesale power formula rates. On December 22, 2014, Duke Energy Progress and NCEMPA filed a request with the NRC to transfer the Brunswick Nuclear Station and Harris operating licenses from NCEMPA to Duke Energy Progress. On April 2, 2015, North Carolina legislation was passed that, among other things, allows Duke Energy Progress to recover its retail investment, including the acquisition adjustment, and operating costs associated with the acquisition through a rider mechanism. On April 13, 2015, Duke Energy Progress and NCEMPA filed a Joint Notice of Transfer and Request for Approval of Certificate of Public Convenience and Necessity (CPCN) with the NCUC, seeking to transfer the CPCN for NCEMPA's ownership interests to Duke Energy Progress. Closing of the transaction is conditioned on approval from the NCUC, the NRC and all municipality members of NCEMPA. The transaction is expected to close by the end of 2015.
	DISPOSITIONS
	Midwest Generation Exit
	Duke Energy, through indirect subsidiaries, completed the sale of the nonregulated Midwest generation business and Duke Energy Retail Sales LLC (Disposal Group) to a subsidiary of Dynegy on April 2, 2015, for approximately $2.8 billion in cash. 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 on April 1, 2015.
	The assets and liabilities of the Disposal Group were included in the Commercial Power segment and are classified as held for sale in Duke Energy's and Duke Energy Ohio's Condensed Consolidated Balance Sheet. The following table presents information related to the Duke Energy Ohio generation plants included in the Disposal Group.
	Facility	Plant Type		Primary Fuel		Location		Total MW Capacity(d)		Owned MW Capacity(d)	Ownership Interest
	Stuart(a)(c)	Fossil Steam		Coal		OH		2,308		900	39	%
	Zimmer(a)	Fossil Steam		Coal		OH		1,300		605	46.5	%
	Hanging Rock	Combined Cycle		Natural Gas		OH		1,226		1,226	100	%
	Miami Fort (Units 7 and 8) (b)	Fossil Steam		Coal		OH		1,020		652	64	%
	Conesville(a)(c)	Fossil Steam		Coal		OH		780		312	40	%
	Washington	Combined Cycle		Natural Gas		OH		617		617	100	%
	Fayette	Combined Cycle		Natural Gas		PA		614		614	100	%
	Killen(b)(c)	Fossil Steam		Coal		OH		600		198	33	%
	Lee	Combustion Turbine		Natural Gas		IL		568		568	100	%
	Dick's Creek	Combustion Turbine		Natural Gas		OH		136		136	100	%
	Miami Fort	Combustion Turbine		Oil		OH		56		56	100	%
	Total Midwest Generation							9,225		5,884
	(a)	Jointly owned with America Electric Power Generation Resources and The Dayton Power & Light Company.
	(b)	Jointly owned with The Dayton Power & Light Company.
	(c)	Facility is not operated by Duke Energy Ohio.
	(d)	Total MW capacity is based on summer capacity.
	The Disposal Group also includes a retail sales business owned by Duke Energy.
	The results of operations of the Disposal Group are classified as discontinued operations in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Income. Certain immaterial costs that may be eliminated as a result of the sale have remained in continuing operations. The following table presents the results of discontinued operations.
	Duke Energy
			Three Months Ended March 31,
	(in millions)		2015				2014
	Operating Revenues		$	543			$	368
	Estimated loss on disposition		(43		)		(1,287		)
	Income (loss) before income taxes		$	147			$	(1,303	)
	Income tax expense (benefit)		51				(466		)
	Income (loss) from discontinued operations of the Disposal Group		96				(837		)
	Other, net of tax(a)		(5		)		(6		)
	Income (Loss) from Discontinued Operations, net of tax		$	91			$	(843	)
	(a)	Other discontinued operations relates to prior sales of businesses and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments.
	Duke Energy Ohio
		Three Months Ended March 31,
	(in millions)	2015				2014
	Operating Revenues	$	412			$	195
	Estimated loss on disposition	(44		)		(1,323		)
	Income (loss) before income taxes	$	140			$	(1,354	)
	Income tax expense (benefit)	50				(479		)
	Income (Loss) from Discontinued Operations, net of tax	$	90			$	(875	)
	The Duke Energy and Duke Energy Ohio held for sale assets include net pretax impairments of approximately $43 million and $44 million, respectively, for the three months ended March 31, 2015, and approximately $1,287 million and $1,323 million, respectively, for the three months ended March 31, 2014. The impairment was recorded to write down the carrying amount of the assets to the estimated fair value of the business, based on the expected selling price to Dynegy less cost to sell. These losses were included in Income (Loss) from Discontinued Operations, net of tax in the Condensed Consolidated Statements of Operations and Comprehensive Income. The final loss on disposition is not expected to result in a material impact on Duke Energy's or Duke Energy Ohio's operations in the second quarter of 2015.
	Commercial Power has a revolving credit agreement (RCA) to support the operations of the nonregulated Midwest generation business. Interest expense associated with the RCA has been allocated to discontinued operations. No other interest expense related to corporate level debt has been allocated to discontinued operations.
	The following table presents the Disposal Group's carrying values in the Condensed Consolidated Balance Sheets' major classes of Assets held for sale and Liabilities associated with assets held for sale.
		March 31, 2015
	(in millions)	Duke				Duke
		Energy				Energy
						Ohio
	Current assets	$	354			$	295
	Investments and other assets	50				45
	Property, plant and equipment	2,553				2,520
	Total Assets held for sale	$	2,957			$	2,860
	Current liabilities	$	146			$	129
	Deferred credits and other liabilities	26				25
	Total Liabilities associated with assets held for sale	$	172			$	154
	Duke Energy Ohio has a power purchase agreement with the Disposal Group for a portion of its standard service offer (SSO) supply requirement through May 2015. Duke Energy will also provide, and receive reimbursement for, transition services provided to Dynegy for a period of up to 12 months. The continuing cash flows are not considered direct cash flows and are not expected to be material. Duke Energy or Duke Energy Ohio will not significantly influence the operations of the Disposal Group during the transition service period.
	See Notes 4 and 5 for a discussion of contingencies related to the Disposal Group that will be retained by Duke Energy Ohio subsequent to the sale.

Business_Segments

Business Segments	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS
	Duke Energy evaluates segment performance based on segment income. Segment income is defined as income from continuing operations net of income attributable to noncontrolling interests. Segment income, as discussed below, includes intercompany revenues and expenses that are eliminated in the Condensed Consolidated Financial Statements. Certain governance costs are allocated to each segment. In addition, direct interest expense and income taxes are included in segment income.
	Operating segments are determined based on information used by the chief operating decision-maker in deciding how to allocate resources and evaluate the performance.
	Products and services are sold between affiliate companies and reportable segments of Duke Energy at cost. Segment assets as presented in the following tables exclude all intercompany assets.
	DUKE ENERGY
	Duke Energy has the following reportable operating segments: Regulated Utilities, International Energy and Commercial Power.
	Regulated Utilities conducts operations primarily through Duke Energy Carolinas, Duke Energy Progress, Duke Energy Florida, Duke Energy Indiana, and the regulated transmission and distribution operations of Duke Energy Ohio. These electric and natural gas operations are subject to the rules and regulations of the FERC, NRC, NCUC, PSCSC, FPSC, PUCO, IURC and KPSC. Substantially all of Regulated Utilities’ operations are regulated and, accordingly, these operations qualify for regulatory accounting treatment.
	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 National Methanol Company (NMC), a large regional producer of methyl tertiary butyl ether (MTBE) located in Saudi Arabia. The investment in NMC is accounted for under the equity method of accounting.
	Commercial Power builds, develops and operates wind and solar renewable generation and energy transmission projects throughout the continental U.S. As discussed in Note 2, Duke Energy completed the sale of Commercial Power's nonregulated Midwest generation business to Dynegy in a transaction that closed on April 2, 2015. The results of operations of the nonregulated Midwest generation business have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations for all periods presented. Certain costs such as interest and general and administrative expenses previously allocated to the Disposal Group were not reclassified to discontinued operations. As a result of the sale, Commercial Power will no longer qualify as a Duke Energy Ohio reportable operating segment. The remaining assets and related results of operations previously reported in Commercial Power will be presented as Other.
	The remainder of Duke Energy’s operations is presented as Other. While it is not an operating segment, Other primarily includes unallocated corporate interest expense, certain unallocated corporate costs, Bison Insurance Company Limited (Bison), Duke Energy’s wholly owned, captive insurance subsidiary, and contributions to The Duke Energy Foundation.
		Three Months Ended March 31, 2015
	(in millions)	Regulated Utilities			International			Commercial			Total			Other			Eliminations			Consolidated
					Energy			Power			Reportable
											Segments
	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		$	1		$	811		$	(37	)	$	(1	)	$	773
	Add back noncontrolling interests component																			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 Progress Energy merger of $13 million.
		Three Months Ended March 31, 2014
	(in millions)	Regulated Utilities			International			Commercial			Total			Other			Eliminations			Consolidated
					Energy			Power			Reportable
											Segments
	Unaffiliated revenues	$	5,795		$	382		$	81		$	6,258		$	5		$	—		$	6,263
	Intersegment revenues	10			—			—			10			20			(30		)	—
	Total revenues	$	5,805		$	382		$	81		$	6,268		$	25		$	(30	)	$	6,263
	Segment income (loss)(a)(b)	$	737		$	130		$	(32	)	$	835		$	(87	)	$	(2	)	$	746
	Add back noncontrolling interest																			4
	Loss from discontinued operations, net of tax																			(843		)
	Net loss																			$	(93	)
	(a)	Commercial Power recorded a pretax impairment charge of $94 million related to Ohio Valley Electric Corporation (OVEC). See Note 12 for additional information.
	(b)    Other includes after-tax costs to achieve the Progress Energy merger of $34 million.
	DUKE ENERGY OHIO
	Duke Energy Ohio has two reportable operating segments, Regulated Utilities and Commercial Power.
	Regulated Utilities transmits and distributes electricity in portions of Ohio and generates, distributes and sells electricity in portions of Kentucky. Regulated Utilities also transports and sells natural gas in portions of Ohio and Northern Kentucky. It conducts operations primarily through Duke Energy Ohio and its wholly owned subsidiary, Duke Energy Kentucky.
	As discussed in Note 2, Duke Energy completed the sale of Commercial Power's nonregulated Midwest generation business to Dynegy in a transaction that closed on April 2, 2015. The results of operations of the nonregulated Midwest generation business have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations and Comprehensive Income for all periods presented. Amounts remaining in Commercial Power relate to assets not included in the Disposal Group. Certain costs such as interest and general and administrative expenses previously allocated to the Disposal Group were not reclassified to discontinued operations. As a result of the sale, Commercial Power will no longer qualify as a Duke Energy Ohio reportable operating segment. The remaining assets and related results of operations previously reported in Commercial Power will be presented as Other.
	The remainder of Duke Energy Ohio’s operations is presented as Other. While it is not considered an operating segment, Other primarily includes certain governance costs allocated by its parent, Duke Energy. See Note 8 for additional information. All of Duke Energy Ohio’s revenues are generated domestically and its long-lived assets are all in the U.S.
		Three Months Ended March 31, 2015
	(in millions)	Regulated Utilities			Commercial Power			Total Reportable Segments			Other			Eliminations			Consolidated
	Unaffiliated revenues	$	572		$	14		$	586		$	—		$	—		$	586
	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
		Three Months Ended March 31, 2014
	(in millions)	Regulated Utilities			Commercial Power			Total Reportable Segments			Other			Eliminations			Consolidated
	Unaffiliated revenues	$	562		$	13		$	575		$	—		$	—		$	575
	Total revenues	$	562		$	13		$	575		$	—		$	—		$	575
	Segment income (loss)(a)	$	61		$	(74	)	$	(13	)	$	(2	)	$	—		$	(15	)
	Loss from discontinued operations, net of tax																(875		)
	Net loss																$	(890	)
	(a)    Commercial Power recorded a pretax impairment charge of $94 million related to OVEC. See Note 12 for additional information.
	DUKE ENERGY CAROLINAS, PROGRESS ENERGY, DUKE ENERGY PROGRESS, DUKE ENERGY FLORIDA AND DUKE ENERGY INDIANA
	The remaining Subsidiary Registrants each have one reportable operating segment, Regulated Utility, which generates, transmits, distributes and sells electricity. The remainder of each company’s operations is classified as Other. While not considered a reportable segment for any of these companies, Other consists of certain unallocated corporate costs. The following table summarizes the net loss for Other at each of these registrants.
		Three Months Ended March 31,
	(in millions)	2015			2014
	Duke Energy Carolinas	$	(8	)	$	(21	)
	Progress Energy(a)	(42		)	(52		)
	Duke Energy Progress	(4		)	(10		)
Duke Energy Florida	(3		)	(4		)
Duke Energy Indiana	(2		)	(3		)
(a)	Other for Progress Energy also includes interest expense on corporate debt instruments of $60 million and $63 million for the three months ended March 31, 2015 and 2014, respectively.
The respective Regulated Utility operating segments include substantially all of Duke Energy Carolinas’, Progress Energy’s, Duke Energy Progress’, Duke Energy Florida’s and Duke Energy Indiana’s assets at March 31, 2015 and 2014.

Regulatory_Matters

Regulatory Matters

3 Months Ended

Mar. 31, 2015

Regulated Operations [Abstract]

Regulatory Matters

REGULATORY MATTERS

RATE RELATED INFORMATION

The NCUC, PSCSC, FPSC, IURC, PUCO and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service.

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. On May 16, 2014, Duke Energy Carolinas announced its intention to begin construction in summer 2015 and estimates a cost to build of $600 million for its share of the facility, including allowance for funds used during construction (AFUDC). The project is expected to be commercially available in late 2017. NCEMC will own approximately 13 percent of the project. On July 3, 2014, the South Carolina Coastal Conservation League (SCCCL) and Southern Alliance for Clean Energy (SACE) jointly filed a Notice of Appeal with the Court of Appeals of South Carolina seeking the court's review of the PSCSC's decision. The case has been fully briefed and is pending in the Court of Appeals. Duke Energy Carolinas cannot predict the outcome of this matter.

Duke Energy Progress

Sutton Black Start Combustion Turbine CPCN

On April 15, 2015, Duke Energy Progress filed a CPCN application with the NCUC for approval to construct an 84 MW black start combustion turbine (CT) project at the existing Sutton plant (Sutton Black Start CT Project). The Sutton Black Start CT Project would replace three existing CTs with total capacity of 61 MW with two new 42 MW CT units with black start and fast start capability. In addition to peaking system capacity, the Sutton Black Start CT Project will provide regional black start capability and tertiary backup power services for the Brunswick Nuclear Plant. The NCUC has scheduled an evidentiary hearing on June 22, 2015 and a decision is expected by October 2015.

Duke Energy Florida

FERC Transmission Return on Equity Complaint

Seminole Electric Cooperative, Inc. and Florida Municipal Power Agency filed multiple complaints with the FERC alleging Duke Energy Florida's current rate of return on equity in transmission formula rates of 10.8 percent is unjust and unreasonable. The latest complaint, filed on August 12, 2014, claims the rate of return should be reduced to 8.69 percent. The FERC consolidated all complaints for the purposes of settlement, hearing and decision. The parties are engaged in settlement discussions. The outcome of this matter is not expected to be material.

Citrus County Combined Cycle Facility

On October 2, 2014, the FPSC granted Duke Energy Florida a Determination of Need for the construction of a 1,640 MW combined cycle natural gas plant in Citrus County, Florida. The facility is expected to be commercially available in 2018 at an estimated cost of $1.5 billion, including AFUDC. Additional environmental and governmental approvals will be sought for the Citrus County project.

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. Closing is subject to the approval of the FERC, FPSC and 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 January 30, 2015, Duke Energy Florida petitioned the FPSC requesting a determination that the Osprey Plant acquisition or, alternatively, the construction of a 320 MW combustion turbine at its existing Suwannee generating facility with an estimated cost of $197 million is the most cost-effective generation alternative to meet Duke Energy Florida's remaining generation need prior to 2018. A hearing with the FPSC is scheduled for June 2015. On March 13, 2015, Duke Energy Florida made a filing requesting FERC approval of the Osprey Plant acquisition by July 30, 2015. In the FERC proceeding, no protests were filed. Seminole Electric Cooperative intervened to request clarification concerning the transmission facilities to be constructed in connection with the Osprey Plant acquisition. If timely approval of the Osprey Plant acquisition is not received from the FERC, the Suwannee project would be constructed.

Duke Energy Ohio

2014 Electric Security Plan

In April 2015, the PUCO modified and approved Duke Energy Ohio's proposed ESP, with a three-year term and an effective date of June 1, 2015. The PUCO approved a competitive procurement process for SSO load, a distribution capital investment rider, and a tracking mechanism for incremental distribution expenses caused by major storms. The PUCO order also approved a placeholder tariff for a price stabilization rider, but denied Duke Energy Ohio's specific request to include OVEC in the rider at this time; however, the order allows Duke Energy Ohio to submit additional information to request recovery in the future. On May 4, 2015, Duke Energy Ohio filed an application for rehearing requesting the PUCO to modify or amend certain aspects of the order.

2012 Natural Gas Rate Case

On November 13, 2013, the PUCO issued an order approving a settlement among Duke Energy Ohio, the PUCO Staff and intervening parties (the Gas Settlement). The Gas Settlement provided for (i) no increase in base rates for natural gas distribution service and (ii) a return on equity of 9.84 percent. The Gas Settlement provided for a subsequent hearing on Duke Energy Ohio’s request for rider recovery of environmental remediation costs associated with its former manufactured gas plant (MGP) sites. After the conclusion of the evidentiary hearing and briefs, the PUCO authorized Duke Energy Ohio to recover $56 million, excluding carrying costs, of environmental remediation costs. The MGP rider became effective in April 2014 for a five-year period. On March 31, 2014, Duke Energy Ohio filed an application with the PUCO to adjust the MGP rider for investigation and remediation costs incurred in 2013.

Certain consumer groups appealed the PUCO’s decision to the Ohio Supreme Court and further asked the court to stay implementation of the PUCO’s order and collections under the MGP rider pending their appeal. The Ohio Supreme Court granted the motion to stay and subsequently required the posting of a bond to effectuate the stay. When the bond was not posted, the PUCO approved Duke Energy Ohio’s request, in January 2015, to reinstate collections under the MGP rider and Duke Energy Ohio resumed billings. Amounts collected prior to the suspension of the rider were immaterial. On March 31, 2015, Duke Energy Ohio filed an application to adjust the MGP rider to recover remediation costs incurred in 2014. Duke Energy Ohio cannot predict the outcome of the appeal of this matter.

Regional Transmission Organization (RTO) Realignment

Duke Energy Ohio, including Duke Energy Kentucky, transferred control of its transmission assets from Midcontinent Independent System Operator, Inc. (MISO) to PJM Interconnection, LLC (PJM), effective December 31, 2011.

On December 22, 2010, the KPSC approved Duke Energy Kentucky’s request to effect the RTO realignment, subject to a commitment not to seek double recovery in a future rate case of the transmission expansion fees that may be charged by MISO and PJM in the same period or overlapping periods.

On May 25, 2011, the PUCO approved a settlement between Duke Energy Ohio, Ohio Energy Group, the Office of Ohio Consumers’ Counsel and the PUCO Staff related to Duke Energy Ohio’s recovery of certain costs of the RTO realignment via a non-bypassable rider. Duke Energy Ohio is allowed to recover all MISO Transmission Expansion Planning (MTEP) costs, including but not limited to Multi-Value Project (MVP) costs, directly or indirectly charged to Ohio customers. Duke Energy Ohio also agreed to vigorously defend against any charges for MVP projects from MISO.

Upon its exit from MISO on December 31, 2011, Duke Energy Ohio recorded a liability for its exit obligation and share of MTEP costs, excluding MVP. This liability was recorded within Other in Current liabilities and Other in Deferred credits and other liabilities on Duke Energy Ohio’s Condensed Consolidated Balance Sheets.

The following table provides a reconciliation of the beginning and ending balances of Duke Energy Ohio’s recorded obligations related to its withdrawal from MISO. As of March 31, 2015, $73 million is recorded as a Regulatory asset on Duke Energy Ohio's Condensed Consolidated Balance Sheets.

(in millions)

31-Dec-14

Provision /

Cash

31-Mar-15

Adjustments

Reductions

Duke Energy Ohio

$

94

$

—

$

(1

)

$

93

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. On July 16, 2013, a FERC Administrative Law Judge (ALJ) issued an initial decision. Under this initial decision, Duke Energy Ohio would be liable for MVP costs. Duke Energy Ohio filed exceptions to the initial decision, requesting the FERC overturn the ALJ’s decision. After reviewing the initial decision, along with all exceptions and responses filed by the parties, the FERC will issue a final decision. Duke Energy Ohio fully intends to appeal to the federal court of appeals if the FERC affirms the ALJ’s decision. Duke Energy Ohio cannot predict the outcome of these proceedings.

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. The estimated obligation is subject to great uncertainty including the ultimate cost of the projects, the annual costs of operations and maintenance, taxes and return over the project lives, the number of years in service for the projects and the allocation to Duke Energy Ohio.

Any liability related to the MISO MVP matter attributable to the Disposal Group was not transferred to Dynegy upon the sale of the nonregulated Midwest generation business.

FERC Transmission Return on Equity and MTEP Cost Settlement

On October 14, 2011, Duke Energy Ohio and Duke Energy Kentucky submitted with the FERC proposed modifications to the PJM Interconnection Open Access Transmission Tariff pertaining to recovery of the transmission revenue requirement as PJM transmission owners. The filing was made in connection with Duke Energy Ohio's and Duke Energy Kentucky's move from MISO to PJM effective January 1, 2012. On April 24, 2012, the FERC issued an order accepting the proposed filing effective January 1, 2012, except that the order denied a request to recover certain costs associated with the move from MISO to PJM without prejudice to the right to submit another filing seeking such recovery and including certain additional evidence, and set the rate of return on equity of 12.38 percent for settlement and hearing. On April 16, 2015, the FERC approved a settlement agreement between Duke Energy Ohio, Duke Energy Kentucky and six PJM transmission customers with load in the Duke Energy Ohio and Duke Energy Kentucky zone. The principal terms of the settlement agreement are that, effective upon the date of FERC approval, (i) the return on equity for wholesale transmission service is reduced to 11.38 percent, (ii) the settling parties agreed not to seek a change in the return on equity that would be effective prior to June 1, 2017 and (iii) Duke Energy Ohio and Duke Energy Kentucky will recover 30 percent of the wholesale portion of costs arising from their obligation to pay any portion of the costs of projects included in any MTEP that was approved prior to the date of Duke Energy Ohio's and Duke Energy Kentucky's integration into PJM.

Duke Energy Indiana

Edwardsport Integrated Gasification Combined Cycle (IGCC) Plant

On November 20, 2007, the IURC granted Duke Energy Indiana a CPCN for the construction of the Edwardsport IGCC power plant. The Citizens Action Coalition of Indiana, Inc., Sierra Club, Inc., Save the Valley, Inc., and Valley Watch, Inc. (collectively, the Joint Intervenors) were intervenors in several matters related to the Edwardsport IGCC Plant.

The Edwardsport IGCC plant was placed in commercial operation in June 2013. Costs for the Edwardsport IGCC plant are recovered from retail electric customers via a tracking mechanism, the IGCC rider. Updates to the IGCC rider are filed semi-annually. An order on the eleventh semi-annual IGCC rider is currently pending. The twelfth and thirteenth semi-annual IGCC riders were combined for hearings which were held in February 2015. Issues in this proceeding include whether the IGCC plant was properly declared in service for ratemaking purposes in June 2013 and the operational performance of the plant during its initial ten months of operations.

The ninth and tenth semi-annual IGCC rider orders have been appealed by the Joint Intervenors. On August 21, 2014, the Indiana Court of Appeals affirmed the IURC order in the tenth IGCC rider proceeding and on October 29, 2014 denied Joint Intervenors' request for rehearing. The Joint Intervenors requested the Indiana Supreme Court to review the decision, which was denied on April 23, 2015, concluding the appeal. On September 8, 2014, the Indiana Court of Appeals remanded the IURC order in the ninth IGCC rider proceeding back to the IURC for further findings. On February 25, 2015, the IURC issued a new order upholding its prior decision and providing additional detailed findings. Joint Intervenors have appealed this remand order to the Indiana Court of Appeals.

On April 2, 2014, the IURC established a subdocket to Duke Energy Indiana’s current fuel adjustment clause proceeding. In this fuel adjustment subdocket, the IURC intends to review underlying causes for net negative generation amounts at the Edwardsport IGCC plant during the period September through November 2013. Duke Energy Indiana contends the net negative generation is related to the consumption of fuel and auxiliary power when the plant was in start-up or off line. In addition to the OUCC, the Duke Energy Indiana Industrial Group, Nucor Steel-Indiana, Steel Dynamics, Inc., and the Joint Intervenors are parties to the subdocket. The IURC has deferred the fuel adjustment subdocket until resolution of the twelfth and thirteenth semi-annual IGCC rider proceedings. In addition, although the IURC approved fuel adjustment clause recovery for the period December 2013 through March 2014, it determined such fuel costs reasonably related to the operational performance of the Edwardsport IGCC plant shall be subject to refund pending the outcome of the twelfth and thirteenth semi-annual IGCC riders.

Duke Energy Indiana cannot predict the outcome of the fuel adjustment clause proceedings or pending and 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 should be reduced to 8.67 percent and requests a consolidation of complaints. On January 5, 2015, the FERC issued an order accepting the MISO transmission owners 0.50 percent adder to the base rate of return on equity based on participation in an RTO subject to it being applied to a return on equity that is shown to be just and reasonable in the pending return on equity complaint. Settlement procedures in the base return on equity proceeding were terminated and a hearing is scheduled for August 17, 2015. Duke Energy Indiana cannot predict the outcome of this matter.

Grid Infrastructure Improvement Plan

On August 29, 2014, Duke Energy Indiana filed a seven-year grid infrastructure improvement plan with the IURC with an estimated cost of $1.9 billion, focusing on the reliability, integrity and modernization of the transmission and distribution system. If approved, 80 percent of the costs will be recovered through a rate tracker. The remaining 20 percent are subject to deferral and subsequent recovery through future rate case proceedings. Hearings were held in January 2015 and Duke Energy Indiana expects a decision in mid-2015.

OTHER REGULATORY MATTERS

Atlantic Coast Pipeline

On September 2, 2014, Duke Energy, Dominion Resources (Dominion), Piedmont Natural Gas and AGL Resources announced the formation of a company, Atlantic Coast Pipeline, LLC (ACP), to build and own the proposed Atlantic Coast Pipeline (the pipeline), a 550-mile interstate natural gas pipeline. The pipeline is designed to meet the needs identified in requests for proposals by Duke Energy Carolinas, Duke Energy Progress and Piedmont Natural Gas. Dominion will build and operate the pipeline and will own 45 percent. Duke Energy will have a 40 percent ownership interest in ACP through its Commercial Power segment. The remaining share will be owned by Piedmont Natural Gas and 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. The project will require FERC approval, which ACP will seek to secure by summer 2016. The estimated in-service date of the pipeline is late 2018.

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 pipeline and NextEra Energy will own the remaining 33 percent of the pipeline. The pipeline will traverse Alabama, Georgia and Florida to meet rapidly growing demand for natural gas in those states. The primary customers of the pipeline, Duke Energy Florida and Florida Power & Light Company, have each contracted to buy pipeline capacity for 25-year initial terms. The pipeline, scheduled to begin service in 2017, requires federal and other regulatory approvals.

NC WARN FERC Complaint

On December 16, 2014, NC WARN filed a complaint with the FERC against Duke Energy Carolinas and Duke Energy Progress that alleged (i) Duke Energy Carolinas and Duke Energy Progress manipulated the electricity market by constructing costly and unneeded generation facilities leading to unjust and unreasonable rates; (ii) Duke Energy Carolinas and Duke Energy Progress failed to comply with Order 1000 by not effectively connecting their transmission systems with neighboring utilities which also have excess capacity; (iii) the plans of Duke Energy Carolinas and Duke Energy Progress for unrealistic future growth lead to unnecessary and expensive generating plants; (iv) the FERC should investigate the practices of Duke Energy Carolinas and Duke Energy Progress and the potential benefits of having them enter into a regional transmission organization; and (v) the FERC should force Duke Energy Carolinas and Duke Energy Progress to purchase power from other utilities rather than construct wasteful and redundant power plants. A copy of the complaint was filed with the PSCSC on January 6, 2015. Duke Energy Carolinas and Duke Energy Progress have filed responses requesting dismissal of the complaint with the FERC and the PSCSC. In April 2015, the FERC and the PSCSC issued separate orders dismissing the NC WARN petition.

Planned and 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, Ohio and Indiana earlier than their current estimated useful lives. These facilities do not have the requisite emission control equipment, primarily to meet United States Environmental Protection Agency (EPA) regulations recently approved or proposed.

The table below contains the net carrying value of generating facilities planned for retirement or being evaluated for potential retirement included in recent IRPs. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets.

31-Mar-15

Duke Energy

Progress Energy(b)

Duke Energy Florida(b)

Duke Energy Ohio(c)

Duke Energy Indiana(d)

Capacity (in MW)

1,704

873

873

163

668

Remaining net book value (in millions)(a)

$

243

$

120

$

120

$

9

$

114

(a)

Included in Property, plant and equipment, net as of March 31, 2015, on the Condensed Consolidated Balance Sheets.

(b)

Includes Crystal River Units 1 and 2.

(c)

Includes Miami Fort Unit 6, which is expected to be retired by June 1, 2015.

(d)

Includes Wabash River Units 2 through 6. Wabash River Unit 6 is being evaluated for potential conversion to natural gas. Duke Energy Indiana committed to retire or convert the Wabash River Units 2 through 5 by June 2018 in conjunction with a settlement agreement associated with the Edwardsport air permit.

In addition to evaluations based on the extent facilities are equipped to comply with environmental regulations, Duke Energy continually monitors and evaluates the appropriate generation mix and fuel diversity for its generation fleet when making retirement decisions. Duke Energy Carolinas and Duke Energy Progress are evaluating the potential for coal-fired generating unit retirements with a net carrying value of approximately $110 million and $150 million, respectively, included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets.

Duke Energy continues to evaluate the potential need to retire generating facilities earlier than the current estimated useful lives, and plans to seek regulatory recovery, as necessary, for amounts that would not be otherwise recovered when any of these assets are retired. However, such recovery, including recovery of carrying costs on remaining book values, could be subject to future regulatory approvals and therefore cannot be assured.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES
	ENVIRONMENTAL
	Duke Energy is subject to international, federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal, and other environmental matters. The Subsidiary Registrants are subject to federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. These regulations can be changed from time to time, imposing new obligations on the Duke Energy Registrants.
	The following environmental matters impact all of the Duke Energy Registrants.
	Remediation Activities
	The Duke Energy Registrants are responsible for environmental remediation at various contaminated sites. These include some 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, activities vary with site conditions and locations, remediation requirements, complexity and sharing of responsibility. If remediation activities involve joint and several liability provisions, strict liability, or cost recovery or contribution actions, the Duke Energy Registrants could potentially be held responsible for contamination caused by other potentially responsible parties, and may also benefit from insurance policies or contractual indemnities that cover some or all cleanup costs. Liabilities are recorded when losses become probable and are reasonably estimable. The total costs that may be incurred cannot be estimated because the extent of environmental impact, allocation among potentially responsible parties, remediation alternatives and/or regulatory decisions have not yet been determined. Additional costs associated with remediation activities are likely to be incurred in the future and could be significant. Costs are typically expensed as Operation, maintenance and other in the 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, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas		Progress Energy			Duke Energy Progress		Duke Energy Florida			Duke Energy Ohio			Duke Energy 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
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas		Progress Energy			Duke Energy Progress		Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Balance at beginning of period	$	79		$	11	$	27		$	8	$	19		$	27		$	7
	Provisions/adjustments	3			—		3			2		1			—			—
	Cash reductions	(1		)	—		(1		)	—		(1		)	—			—
	Balance at end of period	$	81		$	11	$	29		$	10	$	19		$	27		$	7
	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are presented in the table below.
	(in millions)
	Duke Energy	$	89
	Duke Energy Carolinas	25
	Progress Energy	15
	Duke Energy Progress	1
	Duke Energy Florida	14
	Duke Energy Ohio	42
	Duke Energy Indiana	7
	North Carolina and South Carolina Ash Basins
	On February 2, 2014, a break in a stormwater pipe beneath an ash basin at Duke Energy Carolinas’ retired Dan River steam station caused a release of ash basin water and ash into the Dan River. On February 8, 2014, a permanent plug was installed in the stormwater pipe, stopping the release of materials into the river. Duke Energy Carolinas estimates 30,000 to 39,000 tons of ash and 24 million to 27 million gallons of basin water were released into the river. In July 2014, Duke Energy completed remediation work identified by the EPA and continues to cooperate with the EPA's civil enforcement process. Total repairs and remediation expenses incurred by Duke Energy Carolinas related to the release were approximately $24 million. No additional expenses were recorded in the first quarter of 2015. Duke Energy Carolinas will not seek recovery of these costs from ratepayers. See the "Litigation" section below for additional information on litigation, investigations and enforcement actions related to ash basins, including the Memorandum of Plea Agreement (Plea Agreements) in connection to the North Carolina Ash Basin Grand Jury Investigation. Other costs related to the Dan River release, including pending or future state or federal civil enforcement proceedings, future regulatory directives, natural resources damages, additional pending litigation, future claims or litigation, and long-term environmental impact costs cannot be reasonably estimated at this time.
	On September 20, 2014, the North Carolina Coal Ash Management Act of 2014 (Coal Ash Act) became law. The Coal Ash Act (i) establishes a Coal Ash Management Commission (Coal Ash Commission) to oversee handling of coal ash within the state; (ii) prohibits construction of new and expansion of existing ash impoundments and use of existing impoundments at retired facilities; (iii) requires closure of ash impoundments at Duke Energy Progress' Asheville and Sutton stations and Duke Energy Carolinas' Riverbend and Dan River stations no later than August 1, 2019; (iv) requires dry disposal of fly ash at active plants not retired by December 31, 2018; (v) requires dry disposal of bottom ash at active plants by December 31, 2019, or retirement of active plants; (vi) requires all remaining ash impoundments in North Carolina to be categorized as high-risk, intermediate-risk or low-risk no later than December 31, 2015 by the North Carolina Department of Environment and Natural Resources (DENR) with the method of closure and timing to be based upon the assigned risk, with closure no later than December 31, 2029; (vii) establishes requirements to deal with groundwater and surface water impacts from impoundments; and (viii) enhances the level of regulation for structural fills utilizing coal ash. The Coal Ash Act includes a variance procedure for compliance deadlines and modification of requirements regarding structural fills and compliance boundaries. Provisions of the Coal Ash Act prohibit cost recovery for unlawful discharge of ash basin waters occurring after January 1, 2014. The Coal Ash Act leaves the decision on cost recovery determinations related to closure of coal combustion residual (CCR) surface impoundments (ash basins or impoundments) to the normal ratemaking processes before utility regulatory commissions. Duke Energy has and will periodically submit to DENR site-specific coal ash impoundment closure plans. These plans and all associated permits must be approved by DENR before any excavation work can begin.
	In September 2014, Duke Energy Carolinas executed a consent agreement with the South Carolina Department of Health and Environmental Control (SCDHEC) requiring the excavation of an inactive ash basin and ash fill area at the W.S. Lee Steam Station. As part of this agreement, in December 2014, Duke Energy Carolinas filed an ash removal plan and schedule with SCDHEC.
	Asset retirement obligations are recorded on the Duke Energy Carolinas and Duke Energy Progress Condensed Consolidated Balance Sheets at March 31, 2015 based upon the legal obligation for closure of coal ash basins and the disposal of related ash as a result of the Coal Ash Act and the agreement with SCDHEC.
	Coal Combustion Residuals
	On April 17, 2015, the EPA published in the Federal Registry a rule to regulate the disposal of CCR from electric utilities as solid waste. The federal regulation classifies CCR as nonhazardous waste under the Resource Conservation and Recovery Act. The regulation applies to all new and existing landfills, new and existing surface impoundments, structural fills and CCR piles. The rule establishes requirements regarding landfill design, structural integrity design and assessment criteria for surface impoundments, groundwater monitoring and protection procedures and other operational and reporting procedures to ensure the safe disposal and management of CCR. In addition to the requirements of the federal CCR regulation, CCR landfills and surface impoundments will continue to be independently regulated by most states. Duke Energy records an asset retirement obligation when it has a legal obligation to incur retirement costs associated with the retirement of a long-lived asset and the obligation can be reasonably estimated. Duke Energy Registrants impacted by the rule will record additional asset retirement obligation amounts in the second quarter of 2015. 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.
	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 to the company 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 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 DENR to minimize regulation and by opposing previously anticipated citizen suit litigation. The Mesirov Complaint seeks corporate governance reforms and damages relating to costs associated with the Dan River release, remediation of ash basins that are out of compliance with the CWA and defending and payment of fines, penalties and settlements relating to criminal and civil investigations and lawsuits.
	In addition to the above derivative complaints, Duke Energy has also received two shareholder litigation demand letters. On May 28, 2014, Duke Energy received a shareholder litigation demand letter sent on behalf of shareholder Mitchell Pinsly. The letter alleges that the members of the Board of Directors and certain officers breached their fiduciary duties by allowing the company to illegally dispose of and store coal ash pollutants. The letter demands that the Board of Directors take action to recover damages associated with those breaches of fiduciary duty; otherwise, the attorney will file a shareholder derivative action. By letter dated July 3, 2014, counsel for the shareholder was informed that the Board of Directors appointed a Demand Review Committee to evaluate the allegations in the Demand Letter.
	On March 24, 2015, Duke Energy received a shareholder litigation demand letter sent on behalf of shareholder Saul Bresalier. The letter alleges that the members of the Board of Directors and certain officers breached their fiduciary duties in their management of the company's environmental practices, as well as in their decision-making relating to the leadership changes following the close of the Progress Energy merger in July 2012. The letter demands that the Board of Directors take action to recover damages associated with those alleged breaches of fiduciary duty; otherwise, the attorney will file a shareholder derivative action.
	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
	Duke Energy, the eleven members of the Board of Directors who were also members of the pre-merger Board of Directors (Legacy Duke Energy Directors) and certain Duke Energy officers are defendants in a purported securities class action lawsuit (Nieman v. Duke Energy Corporation, et al). This lawsuit consolidates three lawsuits originally filed in July 2012, and is pending in the United States District Court for the Western District of North Carolina. The plaintiffs allege federal Securities Act and Exchange Act claims based on allegations of materially false and misleading representations and omissions in the Registration Statement filed on July 7, 2011, and purportedly incorporated into other documents, all in connection with the post-merger change in Chief Executive Officer (CEO). On August 15, 2014, the parties reached an agreement in principle to settle the litigation for an amount which, net of the expected proceeds of insurance policies, is not anticipated to have a material effect on the results of operations, cash flows or financial position of Duke Energy. On March 10, 2015, the parties filed a Stipulation of Settlement and a Motion for Preliminary Approval of the Settlement. The court issued an order for preliminary approval of the settlement on March 25, 2015. Notice has been sent to members of the class and a final approval hearing is expected to occur in the second half of 2015.
	On May 31, 2013, the Delaware Chancery Court consolidated four shareholder derivative lawsuits filed in 2012. The Court also appointed a lead plaintiff and counsel for plaintiffs and designated the case as In Re Duke Energy Corporation Derivative Litigation. The lawsuit names as defendants the Legacy Duke Energy Directors. Duke Energy is named as a nominal defendant. The case alleges claims for breach of fiduciary duties of loyalty and care in connection with the post-merger change in CEO. The case is stayed pending resolution of the Nieman v. Duke Energy Corporation, et al. case in North Carolina.
	Two shareholder Derivative Complaints, filed in 2012 in federal district court in Delaware, were consolidated as Tansey v. Rogers, et al. The case alleges claims for breach of fiduciary duty and waste of corporate assets, as well as claims under Section 14(a) and 20(a) of the Exchange Act. Duke Energy is named as a nominal defendant. Pursuant to an order entered on September 2, 2014, the court administratively closed this consolidated derivative action. The parties filed a status report with the court on December 1, 2014, and will continue to do so every six months thereafter until the Nieman v. Duke Energy Corporation, et al. case in North Carolina has been resolved.
	It is not possible to estimate the maximum exposure of loss that may occur in connection with these lawsuits.
	Price Reporting Cases
	Five lawsuits were filed against a Duke Energy affiliate, Duke Energy Trading and Marketing, LLC, and other energy companies and remain pending in a consolidated, single federal court proceeding in Nevada. Each of these lawsuits contain similar claims that defendants allegedly manipulated natural gas markets by various means, including providing false information to natural gas trade publications and entering into unlawful arrangements and agreements in violation of the antitrust laws of the respective states. Plaintiffs seek damages in unspecified amounts.
	On July 18, 2011, the judge granted a defendant’s motion for summary judgment in two of five cases. The U.S. Court of Appeals for the Ninth Circuit subsequently reversed the lower court’s decision. On April 21, 2015, the Supreme Court affirmed the U.S. Court of Appeals decision. The case will be remanded to the federal district court for further proceedings.
	It is not possible to predict whether Duke Energy will incur any liability or to estimate the damages, if any, it might incur in connection with the remaining matters. However, based on Duke Energy’s past experiences with similar cases of this nature, it does not believe its exposure under these remaining matters is material.
	Brazil Expansion Lawsuit
	On August 9, 2011, the State of São Paulo sued Duke Energy International Geracao Paranapenema S.A. (DEIGP) in Brazilian state court. The lawsuit claims DEIGP is under a continuing obligation to expand installed generation capacity in the State of São Paulo by 15 percent pursuant to a stock purchase agreement under which DEIGP purchased generation assets from the state. On August 10, 2011, a judge granted an ex parte injunction ordering DEIGP to present a detailed expansion plan in satisfaction of the 15 percent obligation. DEIGP has previously taken a position 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 regarding various procedural issues. A decision on the merits in the first instance court is 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.
	Duke Energy Carolinas and Duke Energy Progress
	DENR State Enforcement Actions
	In the first quarter of 2013, environmental organizations sent notices of intent to sue Duke Energy Carolinas and Duke Energy Progress related to alleged groundwater violations and CWA violations from coal ash basins at two of their coal-fired power plants in North Carolina. DENR filed enforcement actions against Duke Energy Carolinas and Duke Energy Progress alleging violations of water discharge permits and North Carolina groundwater standards. The case against Duke Energy Carolinas was filed in Mecklenburg County Superior Court. The case against Duke Energy Progress was filed in Wake County Superior Court. The cases are being heard before a single judge.
	On October 4, 2013, Duke Energy Carolinas, Duke Energy Progress and DENR negotiated a proposed consent order covering these two plants. The consent order would have assessed civil penalties and imposed a compliance schedule requiring Duke Energy Carolinas and Duke Energy Progress to undertake monitoring and data collection activities toward making appropriate corrective action to address any substantiated violations. In light of the coal ash release that occurred at Dan River on February 2, 2014, on March 21, 2014, DENR withdrew its support of the consent orders and requested that the court proceed with the litigation.
	On August 16, 2013, DENR filed an enforcement action against Duke Energy Carolinas and Duke Energy Progress related to their remaining plants in North Carolina, alleging violations of the CWA and violations of the North Carolina groundwater standards. The case against Duke Energy Carolinas was filed in Mecklenburg County Superior Court. The case against Duke Energy Progress was filed in Wake County Superior Court. Both of these cases have been assigned to the judge handling the enforcement actions discussed above. The SELC, on behalf of several environmental groups, has been permitted to intervene in these cases.
	In August 2014, DENR issued a Notice of Violation (NOV) for alleged groundwater violations at Duke Energy Progress' L.V. Sutton plant. On March 10, 2015, DENR 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 station. On April 9, 2015, Duke Energy Progress filed a Petition for Contested Case hearing in the Office of Administrative Hearings, which has been assigned to an Administrative Judge. Duke Energy Progress has appealed the penalty on the basis that DENR exceeded its statutory authority. Hearing is set for August 24, 2015.
	In February 2015, DENR issued an NOV for alleged groundwater violations at Duke Energy Progress' Asheville plant. Duke Energy Progress has responded to DENR regarding this NOV. DENR has not taken any enforcement action for this NOV, but penalties may be assessed in the future.
	It is not possible to predict any liability or estimate any damages Duke Energy Carolinas or Duke Energy Progress might incur in connection with these matters.
	North Carolina Declaratory Judgment Action
On October 10, 2012, the SELC, on behalf of the same environmental groups that were permitted to challenge the consent decrees discussed above, filed a petition with the North Carolina Environmental Management Commission (EMC) asking for a declaratory ruling seeking to clarify the application of the state’s groundwater protection rules to coal ash basins. The petition sought to change the interpretation of regulations that permitted DENR to assess the extent, cause and significance of any groundwater contamination before ordering action to eliminate the source of contamination, among other issues. Duke Energy Carolinas and Duke Energy Progress were both permitted to intervene in the matter. On December 3, 2012, the EMC affirmed this interpretation of the regulations.
On March 6, 2014, the North Carolina State Court judge overturned the ruling of the EMC holding that in the case of groundwater contamination, DENR was required to issue an order to immediately eliminate the source of the contamination before an assessment of the nature, significance and extent of the contamination or the continuing damage to the groundwater was conducted. Duke Energy Carolinas, Duke Energy Progress and the EMC appealed the ruling in April 2014. On May 16, 2014, the North Carolina Court of Appeals denied a petition to stay the case during the appeal. On October 10, 2014, the parties were notified the case has been transferred to the NCSC. Oral argument was held on March 16, 2015.
Federal Citizens Suits
There are currently five cases filed in various North Carolina federal courts contending that the DENR state enforcement actions discussed above do not adequately address the issues raised in the notices of intent to sue related to the Riverbend, Sutton, Cape Fear, H.F. Lee and Buck plants.
On June 11, 2013, Catawba Riverkeeper Foundation, Inc. (Catawba Riverkeeper) filed a separate action in the United States Court for the Western District of North Carolina. The lawsuit contends the state enforcement action discussed above does not adequately address issues raised in Catawba Riverkeeper’s notice of intent to sue relating to the Riverbend plant. On April 11, 2014, the Court denied Catawba Riverkeeper’s objections to the Magistrate Judge’s recommendation that plaintiff’s case be dismissed as well as Duke Energy Carolinas’ motion to dismiss. The Court allowed limited discovery, after which Duke Energy Carolinas may file any renewed motions to dismiss.
On 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 September 3, 2014, three cases 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) a citizen suit 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) 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 Buck plant. Motions to Stay the proceedings were filed in each of the three cases.
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.
North Carolina Ash Basin Grand Jury Investigation
As a result of the Dan River ash basin water release discussed above, DENR issued a Notice of Violation and Recommendation of Assessment of Civil Penalties with respect to this matter on February 28, 2014, which the company responded to on March 13, 2014. Duke Energy and certain Duke Energy employees received subpoenas issued by the United States Attorney for the Eastern District of North Carolina in connection with a criminal investigation related to all 14 of the North Carolina facilities with ash basins and the nature of Duke Energy's contacts with DENR with respect to those facilities. This is a multidistrict investigation that also involves state law enforcement authorities.
On February 20, 2015, Duke Energy Carolinas, Duke Energy Progress and Duke Energy Business Services LLC (DEBS), a wholly owned subsidiary of Duke Energy, each entered into Plea Agreements in connection with the investigation initiated by the United States Department of Justice Environmental Crimes Section and the United States Attorneys for the Eastern District of North Carolina, the Middle District of North Carolina and the Western District of North Carolina (collectively, USDOJ). The Plea Agreements are subject to the approval of the United States District Court for the Eastern District of North Carolina and, if approved, will end the grand jury investigation related to the Dan River ash basin release and the management of coal ash basins at 14 plants in North Carolina with coal ash basins, as discussed above. A hearing on the Plea Agreements is scheduled for May 14, 2015.
Under the Plea Agreements, the USDOJ charged DEBS and Duke Energy Progress with four misdemeanor CWA violations related to violations at Duke Energy Progress’ H.F. Lee Steam Electric Plant, Cape Fear Steam Electric Plant and Asheville Steam Electric Generating Plant. The USDOJ charged Duke Energy Carolinas and DEBS with five misdemeanor CWA violations related to violations at Duke Energy Carolinas’ Dan River Steam Station and Riverbend Steam Station. DEBS, Duke Energy Carolinas and Duke Energy Progress also agreed (i) to a five-year probation period, (ii) to pay a total of approximately $68 million in fines and restitution and $34 million for community service and mitigation (the Payments), (iii) to fund and establish environmental compliance plans subject to the oversight of a court-appointed monitor in addition to certain other conditions set out in the Plea Agreements. Duke Energy Carolinas and Duke Energy Progress also agree to each maintain $250 million under their Master Credit Facility as security to meet their obligations under the Plea Agreements. Payments under the Plea Agreements will be borne by shareholders and are not tax deductible. Duke Energy Corporation has agreed to issue a guarantee of all payments and performance due from DEBS, Duke Energy Carolinas and Duke Energy Progress, including but not limited to payments for fines, restitution, community service, mitigation and the funding of, and obligations under, the environmental compliance plans. As a result of the Plea Agreements, Duke Energy Carolinas and Duke Energy Progress have liabilities of $72 million and $30 million, respectively, within Accounts payable on the Condensed Consolidated Balance Sheets.
The Plea Agreements do not cover pending civil claims related to the Dan River coal ash release and operations at other North Carolina coal plants. Duke Energy Corporation will continue to cooperate with government agencies and defend against remaining civil litigation associated with these matters.
Duke Energy Carolinas
New Source Review
In 1999-2000, the U.S. Department of Justice (DOJ) on behalf of the EPA filed a number of complaints and notices of violation against multiple utilities, including Duke Energy Carolinas, for alleged violations of the New Source Review (NSR) provisions of the Clean Air Act (CAA). The government alleges the utilities violated the CAA when undertaking certain maintenance and repair projects at certain coal plants without (i) obtaining NSR permits and (ii) installing the best available emission controls for sulfur dioxide, nitrogen oxide and particulate matter. The complaints seek the installation of pollution control technology on generating units that allegedly violated the CAA, and unspecified civil penalties in amounts of up to $37,500 per day for each violation. Duke Energy Carolinas asserts there were no CAA violations because the applicable regulations do not require NSR permitting in cases where the projects undertaken are “routine” or otherwise do not result in a net increase in emissions.
In 2000, the government sued Duke Energy Carolinas in the U.S. District Court in Greensboro, North Carolina, claiming NSR violations for 29 projects performed at 25 of Duke Energy Carolinas’ coal-fired units. Duke Energy Carolinas asserts the projects were routine and not projected to increase emissions. The parties subsequently filed a stipulation agreeing to dismiss with prejudice all but 13 claims at 13 generating units, 11 of which have since been retired. Trial date has been set for October 2015. It is not possible to predict whether Duke Energy Carolinas will incur any liability or to estimate the damages, if any, it might incur in connection with this matter. Ultimate resolution of these matters could have a material effect on the results of operations, cash flows or financial position of Duke Energy Carolinas. However, the appropriate regulatory recovery will be pursued for costs incurred in connection with such resolution.
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, 2015, there were 121 asserted claims for non-malignant cases with the cumulative relief sought of up to $26 million, and 32 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 $570 million at March 31, 2015 and $575 million at December 31, 2014. These reserves are classified in Other within Deferred Credits and Other Liabilities and Other within Current Liabilities on the Condensed Consolidated Balance Sheets. These reserves are based upon the minimum amount of the range of loss for current and future asbestos claims through 2033, are recorded on an undiscounted basis and incorporate anticipated inflation. In light of the uncertainties inherent in a longer-term forecast, management does not believe they can reasonably estimate the indemnity and medical costs that might be incurred after 2033 related to such potential claims. It is possible Duke Energy Carolinas may incur asbestos liabilities in excess of the recorded reserves.
Duke Energy Carolinas has third-party insurance to cover certain losses related to asbestos-related injuries and damages above an aggregate self-insured retention of $476 million. Duke Energy Carolinas’ cumulative payments began to exceed the self-insurance retention in 2008. Future payments up to the policy limit will be reimbursed by the third-party insurance carrier. The insurance policy limit for potential future insurance recoveries indemnification and medical cost claim payments is $864 million in excess of the self-insured retention. Receivables for insurance recoveries were $617 million at March 31, 2015, and $616 million at December 31, 2014. These amounts are classified in Other within Investments and Other Assets and Receivables on the Condensed Consolidated Balance Sheets. Duke Energy Carolinas is not aware of any uncertainties regarding the legal sufficiency of insurance claims. Duke Energy Carolinas believes the insurance recovery asset is probable of recovery as the insurance carrier continues to have a strong financial strength rating.
Duke Energy Florida
Westinghouse Contract Litigation
On March 28, 2014, Duke Energy Florida filed a lawsuit against Westinghouse in the U.S. District Court for the Western District of North Carolina. The lawsuit seeks recovery of $54 million in milestone payments in excess of work performed under the terminated engineering, procurement and construction agreement (EPC) for Levy as well as a determination by the court of the amounts due to Westinghouse as a result of the termination of the EPC.
On March 31, 2014, Westinghouse filed a lawsuit against Duke Energy Florida in U.S. District Court for the Western District of Pennsylvania. The Pennsylvania lawsuit alleged damages under the EPC in excess of $510 million for engineering and design work, costs to end supplier contracts and an alleged termination fee.
On June 9, 2014, the judge in the North Carolina case ruled that the litigation will proceed in the Western District of North Carolina. In November 2014, Westinghouse filed a Motion for Partial Judgment on the pleadings, which was denied on March 30, 2015. Trial is set for February 2016. It is not possible to predict the outcome of the litigation and whether Duke Energy Florida will incur any liability for terminating the EPC or to estimate the damages, if any, it might incur in connection with these matters. Ultimate resolution of these matters could have a material effect on the results of operations, financial position or cash flows of Duke Energy Florida. However, appropriate regulatory recovery will be pursued for the retail portion of any costs incurred in connection with such resolution.
Duke Energy Ohio
Antitrust Lawsuit
In January 2008, four plaintiffs, including individual, industrial and nonprofit customers, filed a lawsuit against Duke Energy Ohio in federal court in the Southern District of Ohio. Plaintiffs alleged Duke Energy Ohio conspired to provide inequitable and unfair price advantages for certain large business consumers by entering into non-public option agreements in exchange for their withdrawal of challenges to Duke Energy Ohio’s Rate Stabilization Plan implemented in early 2005. In March 2014, a federal judge certified this matter as a class action. Plaintiffs allege claims for antitrust violations under the federal Robinson Patman Act as well as fraud and conspiracy allegations under the federal Racketeer Influenced and Corrupt Organizations statute and the Ohio Corrupt Practices Act which could exceed $500 million. Plaintiffs also claim to be entitled to treble damages.
A March 31, 2015 mediation was unsuccessful. Duke Energy Ohio's motion for summary judgment is pending. Trial has been set to begin on July 27, 2015. It is not possible to predict whether Duke Energy Ohio will incur any liability or to estimate the damages, if any, that may be incurred in connection with this matter. Ultimate resolution of this matter could have a material effect on the results of operations, cash flows or financial position of Duke Energy Ohio.
Any liability related to the lawsuit attributable to the Disposal Group was not transferred to Dynegy upon the sale of the Disposal Group. See Note 2 for further discussion on the Midwest Generation Exit.
Duke Energy Indiana
Edwardsport IGCC
On December 11, 2012, Duke Energy Indiana filed an arbitration action against General Electric Company and Bechtel Corporation in connection with their work at the Edwardsport IGCC facility. Duke Energy Indiana is seeking damages equaling some or all of the additional costs incurred in the construction of the project not recovered at the IURC. The arbitration hearing concluded in December 2014. Post-hearing briefs have been submitted and a ruling is pending. Duke Energy Indiana cannot predict the outcome of this matter.
Other Litigation and Legal Proceedings
The Duke Energy Registrants are involved in other legal, tax and regulatory proceedings arising in the ordinary course of business, some of which involve significant amounts. The Duke Energy Registrants believe the final disposition of these proceedings will not have a material effect on their results of operations, cash flows or financial position.
The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters discussed above, excluding asbestos-related reserves. Reserves are classified on the Condensed Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss for all non-asbestos-related matters in excess of recorded reserves is not material.
(in millions)	March 31, 2015			December 31, 2014
Reserves for Legal Matters
Duke Energy	$	331		$	323
Duke Energy Carolinas	72			72
Progress Energy	93			93
Duke Energy Progress	37			37
Duke Energy Florida	34			36
Duke Energy Ohio	10			—
OTHER COMMITMENTS AND CONTINGENCIES
General
As part of their normal business, the Duke Energy Registrants are party to various financial guarantees, performance guarantees and other contractual commitments to extend guarantees of credit and other assistance to various subsidiaries, investees and other third parties. These guarantees involve elements of performance and credit risk, which are not fully recognized on the Condensed Consolidated Balance Sheets and have unlimited maximum potential payments. However, the Duke Energy Registrants do not believe these guarantees will have a material effect on their results of operations, cash flows or financial position.
In addition, the Duke Energy Registrants enter into various fixed-price, non-cancelable commitments to purchase or sell power, take-or-pay arrangements, transportation, or throughput agreements and other contracts that may or may not be recognized on their respective Condensed Consolidated Balance Sheets. Some of these arrangements may be recognized at fair value on their respective Condensed Consolidated Balance Sheets if such contracts meet the definition of a derivative and the normal purchase/normal sale (NPNS) exception does not apply. In most cases, the Duke Energy Registrants’ purchase obligation contracts contain provisions for price adjustments, minimum purchase levels and other financial commitments.

Debt_and_Credit_Facilities

Debt and Credit Facilities	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt And Credit Facilities	DEBT AND CREDIT FACILITIES
	SUMMARY OF SIGNIFICANT DEBT ISSUANCES
	The following table summarizes significant debt issuances (in millions).
						Three Months Ended March 31, 2015
	Issuance Date	Maturity Date		Interest Rate			Duke			Duke
							Energy			Energy
										Carolinas
	First Mortgage Bonds
	March 2015(a)	Jun-45		3.75	%		$	500		$	500
	Total issuances						$	500		$	500
	(a)	Proceeds will be used to redeem $500 million of first mortgage bonds due October 2015.
	CURRENT MATURITIES OF LONG-TERM DEBT
	The following table shows the significant components of Current maturities of long-term debt on the Condensed Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings.
	(in millions)	Maturity Date		Interest Rate			March 31, 2015
	Unsecured Debt
	Duke Energy (Parent)	Apr-15		3.35	%		$	450
	Progress Energy (Parent)	Jan-16		5.625	%		300
	First Mortgage Bonds
	Duke Energy Progress	Apr-15		5.15	%		300
	Duke Energy Carolinas	Oct-15		5.3	%		500
	Duke Energy Florida	Nov-15		0.65	%		250
	Duke Energy Florida	Dec-15		5.1	%		300
	Duke Energy Progress	Dec-15		5.25	%		400
	Other						300
	Current maturities of long-term debt						$	2,800
	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. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility.
		March 31, 2015
	(in millions)	Duke Energy				Duke Energy (Parent)			Duke Energy Carolinas			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Facility size(a)	$	7,500			$	3,200		$	1,200		$	1,000		$	900		$	600		$	600
	Reduction to backstop issuances
	Commercial paper(b)	(3,256		)		(2,764		)	(300		)	—			(17		)	(25		)	(150		)
	Outstanding letters of credit	(66		)		(60		)	(4		)	(1		)	(1		)	—			—
	Tax-exempt bonds	(116		)		—			(35		)	—			—			—			(81		)
	Available capacity	$	4,062			$	376		$	861		$	999		$	882		$	575		$	369
	(a)	Represents the sublimit of each borrower.
	(b)	Duke Energy issued $475 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Condensed Consolidated Balance Sheets.
	In April 2015, Duke Energy paid down its outstanding commercial paper by approximately $1.3 billion using a portion of the proceeds from the sale of the nonregulated Midwest generation business. See Note 2 for additional information.
	On February 20, 2015, Duke Energy Carolinas, Duke Energy Progress and DEBS, a wholly owned subsidiary of Duke Energy, each entered into Plea Agreements in connection with the investigation initiated by the USDOJ. Duke Energy Carolinas and Duke Energy Progress are required to each maintain $250 million of available capacity under the Master Credit Facility as security to meet their obligations under the Plea Agreements, in addition to certain other conditions. The Plea Agreements are subject to court approval. See Note 5 for further details.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL AND INTANGIBLE ASSETS
	GOODWILL
	The following tables present goodwill by reportable operating segment for Duke Energy and Duke Energy Ohio.
	Duke Energy
	(in millions)	Regulated Utilities			International Energy			Commercial Power			Total
	Balance at December 31, 2014
	Goodwill	$	15,950		$	307		$	935		$	17,192
	Accumulated impairment charges	—			—			(871		)	(871		)
	Balance at December 31, 2014, as adjusted for accumulated impairment charges	15,950			307			64			16,321
	Foreign exchange and other changes	—			(16		)	—			(16		)
	Acquisitions	—			—			24			24
	Balance at March 31, 2015
	Goodwill	15,950			291			959			17,200
	Accumulated impairment charges	—			—			(871		)	(871		)
	Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	15,950		$	291		$	88		$	16,329
	Duke Energy Ohio
	(in millions)	Regulated Utilities			Commercial Power			Total
	Balance at December 31, 2014
	Goodwill	$	1,136		$	1,188		$	2,324
	Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
	Balance at December 31, 2014, as adjusted for accumulated impairment charges	920			—			920
	Balance at March 31, 2015
	Goodwill	1,136			1,188			2,324
	Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
	Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	920		$	—		$	920
	Progress Energy
	Progress Energy's Goodwill is included in the Regulated Utilities operating segment and there are no accumulated impairment charges.
	INTANGIBLE ASSETS
	During 2014, Duke Energy Ohio reduced the carrying amount of OVEC to zero. A charge of $94 million is recorded in Impairment charges on Duke Energy Ohio's Condensed Consolidated Statement of Operations. See Note 12 for additional information.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS
	The Subsidiary Registrants engage in related party transactions, which are generally performed at cost and in accordance with the 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)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	In addition to the amounts presented above, the Subsidiary Registrants record the impact 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, 2015 and 2014 for the Subsidiary Registrants.
	See Note 12 for information relative to sale of receivables to an affiliate consolidated by Duke Energy.
	Duke Energy Commercial Asset Management (DECAM) was a nonregulated, indirect subsidiary of Duke Energy Ohio that owned generating plants included in the Disposal Group discussed in Note 2. DECAM's business activities included the execution of commodity transactions, third-party vendor and supply contracts, and service contracts for certain of Duke Energy’s nonregulated entities. The commodity contracts DECAM entered were accounted for as undesignated contracts or NPNS. Consequently, mark-to-market impacts of intercompany contracts with, and sales of power to, nonregulated entities are included in Income (Loss) From Discontinued Operations, net of tax in Duke Energy Ohio’s Condensed Consolidated Statements of Operations and Comprehensive Income. These amounts totaled net expense of $3 million and $54 million for the three months ended March 31, 2015 and 2014, respectively.
	DECAM, not a credit rated entity, received credit support from Duke Energy or its nonregulated subsidiaries and not from the regulated utility operations of Duke Energy Ohio. DECAM met its funding needs through an intercompany loan agreement with a subsidiary of Duke Energy. DECAM also had the ability to loan money to the subsidiary of Duke Energy. DECAM had an outstanding intercompany loan payable of $294 million and $459 million, respectively, as of March 31, 2015 and December 31, 2014. These amounts are recorded in Notes payable to affiliated companies on Duke Energy Ohio’s Condensed Consolidated Balance Sheets. The intercompany loan payable was repaid on April 2, 2015 with funds received from the sale of the Disposal Group. Refer to Note 2 for further information on this disposition.

Derivatives_and_Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING
	The Duke Energy Registrants use commodity and interest rate contracts to manage commodity price and interest rate risks. The primary use of energy commodity derivatives is to hedge the generation portfolio against changes in the prices of electricity and natural gas. Interest rate swaps are used to manage interest rate risk associated with borrowings.
	All derivative instruments not identified as NPNS are recorded at fair value as assets or liabilities on the Condensed Consolidated Balance Sheets. Cash collateral related to derivative instruments executed under master netting agreement is offset against the collateralized derivatives on the balance sheet.
	Changes in the fair value of derivative agreements that either do not qualify for or have not been designated as hedges are reflected in current earnings or as regulatory assets or liabilities.
	COMMODITY PRICE RISK
	The Duke Energy Registrants are exposed to the impact of changes in the future prices of electricity, coal and natural gas. Exposure to commodity price risk is influenced by a number of factors including the term of contracts, the liquidity of markets and delivery locations.
	Fair Value and Cash Flow Hedges
	At March 31, 2015, there were no open commodity derivative instruments designated as hedges.
	Undesignated Contracts
	Undesignated contracts may include contracts not designated as a hedge, contracts that do not qualify for hedge accounting, derivatives that do not or no longer qualify for the NPNS scope exception, and de-designated hedge contracts. These contracts expire as late as 2018.
	Volumes
	The tables below show information relating to volumes of outstanding commodity derivatives. Amounts disclosed represent the absolute value of notional volumes of commodity contracts excluding NPNS. Amounts disclosed represent the absolute value of notional amounts. 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, 2015
		Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Electricity (gigawatt-hours)(a)	22,810			—			—			—			—			17,734			571
	Natural gas (millions of decatherms)	666			57			333			111			222			276			—
		December 31, 2014
		Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Electricity (gigawatt-hours)(a)	25,370			—			—			—			—			19,141			—
	Natural gas (millions of decatherms)	676			35			328			116			212			313			—
	(a)	Amounts at Duke Energy Ohio include intercompany positions that eliminate at Duke Energy.
	INTEREST RATE RISK
	The Duke Energy Registrants are exposed to changes in interest rates as a result of their issuance or anticipated issuance of variable-rate and fixed-rate debt and commercial paper. Interest rate risk is managed by limiting variable-rate exposures to a percentage of total debt and by monitoring changes in interest rates. To manage risk associated with changes in interest rates, the Duke Energy Registrants may enter into interest rate swaps, U.S. Treasury lock agreements and other financial contracts. In anticipation of certain fixed-rate debt issuances, a series of forward starting interest rate swaps may be executed to lock in components of current market interest rates. These instruments are later terminated prior to or upon the issuance of the corresponding debt. Pretax gains or losses recognized from inception to termination of the hedges are amortized as a component of interest expense over the life of the debt.
	Duke Energy has a combination foreign exchange, pay fixed-receive floating interest rate swap to fix the US dollar equivalent payments on a floating-rate Chilean debt issue.
	In January 2015, Duke Energy Progress executed fixed-to-floating rate swaps. The swaps were issued to economically convert $250 million of fixed rate first mortgage bonds due September 15, 2021, to floating rate with an initial rate of approximately 1.75 percent.
	The following table shows notional amounts for derivatives related to interest rate risk.
		March 31, 2015																December 31, 2014
	(in millions)	Duke				Duke Energy Progress				Duke				Duke Energy Ohio				Duke				Duke				Duke Energy Ohio
		Energy								Energy								Energy				Energy
										Florida												Florida
	Cash flow hedges(a)	$	750			$	—			$	—			$	—			$	750			$	—			$	—
	Undesignated contracts	527				250				250				27				277				250				27
	Total notional amount	$	1,277			$	250			$	250			$	27			$	1,027			$	250			$	27
	(a)	Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $541 million at March 31, 2015 and December 31, 2014, respectively.
	LOCATION AND FAIR VALUE OF DERIVATIVE ASSETS AND LIABILITIES RECOGNIZED IN THE CONDENSED CONSOLIDATED BALANCE SHEETS
	The following tables show the fair value of derivatives and the line items in the Condensed Consolidated Balance Sheets where they are reported. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below show gross and cash collateral on the derivatives has not been netted against the fair values shown.
	Derivative Assets		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Commodity Contracts
	Not Designated as Hedging Instruments
	Current Assets: Other		$	4			$	—			$	—			$	—			$	—			$	—			$	3
	Current Assets: Assets held for sale		45				—				—				—				—				78				—
	Investments and Other Assets: Assets held for sale		21				—				—				—				—				48				—
	Current Liabilities: Other		1				—				1				—				1				—				—
	Current Liabilities: Assets held for sale		206				—				—				—				—				206				—
	Deferred Credits and Other Liabilities: Other		2				—				2				—				2				—				—
	Deferred Credits and Other Liabilities: Assets held for sale		123				—				—				—				—				123				—
	Total Derivative Assets - Commodity Contracts		$	402			$	—			$	3			$	—			$	3			$	455			$	3
	Interest Rate Contracts
	Designated as Hedging Instruments
	Investments and Other Assets: Other		$	3			$	—			$	—			$	—			$	—			$	—			$	—
	Not Designated as Hedging Instruments
	Current Assets: Other		5				—				5				2				3				—				—
	Investments and Other Assets: Other		1				—				1				—				1				—				—
	Total Derivative Assets - Interest Rate Contracts		9				—				6				2				4				—				—
	Total Derivative Assets		$	411			$	—			$	9			$	2			$	7			$	455			$	3
	Derivative Liabilities		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Commodity Contracts
	Not Designated as Hedging Instruments
	Current Assets: Assets held for sale		$	21			$	—			$	—			$	—			$	—			$	59			$	—
	Investments and Other Assets: Assets held for sale		7				—				—				—				—				23				—
	Current Liabilities: Other		308				19				289				100				189				—				—
	Current Liabilities: Assets held for sale		263				—				—				—				—				249				—
Deferred Credits and Other Liabilities: Other		112				8				104				26				78				—				—
Deferred Credits and Other Liabilities: Assets held for sale		209				—				—				—				—				207				—
Total Derivative Liabilities - Commodity Contracts		$	920			$	27			$	393			$	126			$	267			$	538			$	—
Interest Rate Contracts
Designated as Hedging Instruments
Current Liabilities: Other		$	14			$	—			$	—			$	—			$	—			$	1			$	—
Deferred Credits and Other Liabilities: Other		38				—				—				—				—				6				—
Not Designated as Hedging Instruments
Current Liabilities: Other		1				—				—				—				—				—				—
Deferred Credits and Other Liabilities: Other		11				—				5				5				—				—				—
Total Derivative Liabilities - Interest Rate Contracts		64				—				5				5				—				7				—
Total Derivative Liabilities		$	984			$	27			$	398			$	131			$	267			$	545			$	—
Derivative Assets		December 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Commodity Contracts
Not Designated as Hedging Instruments
Current Assets: Other		$	18			$	—			$	—			$	—			$	—			$	1			$	—
Current Assets: Assets Held for sale		15				—				—				—				—				28				—
Investments and Other Assets: Other		3				—				—				—				—				—				—
Investments and Other Assets: Assets held for sale		15				—				—				—				—				26				—
Current Liabilities: Other		1				—				—				—				—				—				—
Current Liabilities: Assets held for sale		174				—				—				—				—				175				—
Deferred Credits and Other Liabilities: Other		2				—				—				—				—				—				—
Deferred Credits and Other Liabilities: Assets held for sale		111				—				—				—				—				111				—
Total Derivative Assets - Commodity Contracts		$	339			$	—			$	—			$	—			$	—			$	341			$	—
Interest Rate Contracts
Designated as Hedging Instruments
Current Assets: Other		$	—			$	—			$	—			$	—			$	—			$	—			$	14
Investments and Other Assets: Other		10				—				—				—				—				—				—
Not Designated as Hedging Instruments
Current Assets: Other		2				—				2				—				2				—				—
Total Derivative Assets - Interest Rate Contracts		12				—				2				—				2				—				14
Total Derivative Assets		$	351			$	—			$	2			$	—			$	2			$	341			$	14
Derivative Liabilities		December 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Commodity Contracts
Designated as Hedging Instruments
Current Liabilities: Other		$	—			$	—			$	1			$	1			$	—			$	—			$	—
Not Designated as Hedging Instruments
Current Assets: Assets held for sale		—				—				—				—				—				4				—
Investments and Other Assets: Assets held for sale		—				—				—				—				—				4				—
Current Liabilities: Other		307				14				288				108				180				—				—
Current Liabilities: Assets held for sale		253				—				—				—				—				252				—
Deferred Credits and Other Liabilities: Other		91				5				80				23				57				—				—
Deferred Credits and Other Liabilities: Assets held for sale		208				—				—				—				—				207				—
Total Derivative Liabilities - Commodity Contracts		$	859			$	19			$	369			$	132			$	237			$	467			$	—
Interest Rate Contracts
Designated as Hedging Instruments
Current Liabilities: Other		$	13			$	—			$	—			$	—			$	—			$	1			$	—
Deferred Credits and Other Liabilities: Other		29				—				—				—				—				5				—
Not Designated as Hedging Instruments
Current Liabilities: Other		1				—				—				—				—				—				—
Deferred Credits and Other Liabilities: Other		7				—				2				—				2				—				—
Total Derivative Liabilities - Interest Rate Contracts		50				—				2				—				2				6				—
Total Derivative Liabilities		$	909			$	19			$	371			$	132			$	239			$	473			$	—
OFFSETTING ASSETS AND LIABILITIES
The following tables show the balance sheet location of derivative contracts subject to enforceable master netting agreements and include collateral posted to offset the net position. This disclosure is intended to enable users to evaluate the effect of netting arrangements on financial position. The amounts shown were calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below.
Derivative Assets		March 31, 2015
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Current(a)
Gross amounts recognized		$	261			$	—			$	6			$	2			$	4			$	284			$	3
Gross amounts offset		(227		)		—				(1		)		—				(1		)		(265		)		—
Net amounts subject to master netting		34				—				5				2				3				19				3
Amounts not subject to master netting		—				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	34			$	—			$	5			$	2			$	3			$	19			$	3
Non-Current(b)
Gross amounts recognized		$	150			$	—			$	3			$	—			$	3			$	171			$	—
Gross amounts offset		(131		)		—				(2		)		—				(2		)		(145		)		—
Net amounts subject to master netting		19				—				1				—				1				26				—
Amounts not subject to master netting		—				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	19			$	—			$	1			$	—			$	1			$	26			$	—
(a)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Current Assets on the Condensed Consolidated Balance Sheets.
(b)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
Derivative Liabilities		March 31, 2015
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Current(c)
Gross amounts recognized		$	607			$	19			$	289			$	100			$	189			$	309			$	—
Gross amounts offset		(293		)		—				(32		)		(1		)		(31		)		(300		)		—
Net amounts subject to master netting		314				19				257				99				158				9				—
Amounts not subject to master netting		—				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	314			$	19			$	257			$	99			$	158			$	9			$	—
Non-Current(d)
Gross amounts recognized		$	377			$	8			$	109			$	31			$	78			$	236			$	—
Gross amounts offset		(216		)		—				(14		)		—				(14		)		(218		)		—
Net amounts subject to master netting		161				8				95				31				64				18				—
Amounts not subject to master netting		—				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	161			$	8			$	95			$	31			$	64			$	18			$	—
(c)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Current Liabilities on the Condensed Consolidated Balance Sheets.
(d)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
Derivative Assets		December 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Current(a)
Gross amounts recognized		$	210			$	—			$	2			$	—			$	2			$	204			$	14
Gross amounts offset		(153		)		—				(2		)		—				(2		)		(179		)		—
Net amounts subject to master netting		57				—				—				—				—				25				14
Amounts not subject to master netting		—				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	57			$	—			$	—			$	—			$	—			$	25			$	14
Non-Current(b)
Gross amounts recognized		$	136			$	—			$	—			$	—			$	—			$	137			$	—
Gross amounts offset		(88		)		—				—				—				—				(114		)		—
Net amounts subject to master netting		48				—				—				—				—				23				—
Amounts not subject to master netting		5				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	53			$	—			$	—			$	—			$	—			$	23			$	—
(a)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Current Assets on the Condensed Consolidated Balance Sheets.
(b)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
Derivative Liabilities		December 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Current(c)
Gross amounts recognized		$	573			$	14			$	289			$	109			$	180			$	257			$	—
Gross amounts offset		(213		)		—				(17		)		—				(17		)		(222		)		—
Net amounts subject to master netting		360				14				272				109				163				35				—
Amounts not subject to master netting		1				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	361			$	14			$	272			$	109			$	163			$	35			$	—
Non-Current(d)
Gross amounts recognized		$	319			$	5			$	82			$	23			$	59			$	216			$	—
Gross amounts offset		(173		)		—				(8		)		—				(8		)		(193		)		—
Net amounts subject to master netting		146				5				74				23				51				23				—
Amounts not subject to master netting		16				—				—				—				—				—				—
Net amounts recognized on the Condensed Consolidated Balance Sheet		$	162			$	5			$	74			$	23			$	51			$	23			$	—
(c)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Current Liabilities on the Condensed Consolidated Balance Sheets.
(d)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
GAINS AND LOSSES RECOGNIZED ON CASH FLOW HEDGES
The following tables show the gains and losses recognized on cash flow hedges and the line items on the Condensed Consolidated Statements of Operations or Condensed Consolidated Balance Sheets where such gains and losses are included when reclassified from AOCI. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt.
There was no hedge ineffectiveness during the three months ended March 31, 2015 and 2014, and no gains or losses were excluded from the assessment of hedge effectiveness during the same periods.
		Three Months Ended March 31, 2015
(in millions)		Duke Energy(a)				Duke Energy Carolinas				Duke Energy Indiana
Pretax Gains (Losses) Recorded in AOCI
Interest rate contracts		$	(11	)		$	—			$	—
Total Pretax Gains (Losses) Recorded in AOCI		(11		)		—				—
Location of Pretax Gains (Losses) Reclassified from AOCI into Earnings
Interest rate contracts
Interest expense		(1		)		(1		)		1
Total Pretax Gains (Losses) Reclassified from AOCI into Earnings		$	(1	)		$	(1	)		$	1
(a)    A $5 million pretax gain is expected to be recognized in earnings during the next 12 months as interest expense.
		Three Months Ended March 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Duke Energy Indiana
Pretax Gains (Losses) Recorded in AOCI
Interest rate contracts		$	2			$	—			$	—
Total Pretax Gains (Losses) Recorded in AOCI		2				—				—
Location of Pretax Gains (Losses) Reclassified from AOCI into Earnings
Interest rate contracts
Interest expense		(1		)		—				—
Total Pretax Gains (Losses) Reclassified from AOCI into Earnings		$	(1	)		$	—			$	—
GAINS AND LOSSES RECOGNIZED ON UNDESIGNATED CONTRACTS
The following tables show the gains and losses during the year recognized on undesignated derivatives and the line items on the Condensed Consolidated Statements of Operations or the Condensed Consolidated Balance Sheets where the pretax gains and losses were reported. Amounts included in Regulatory Assets or Liabilities for commodity contracts are reclassified to earnings to match recovery through the fuel clause. Amounts included in Regulatory Assets or Liabilities for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. These amounts reclassified to earnings from Regulated Assets or Liabilities for commodity and interest rate contracts are excluded from the following tables.
		Three Months Ended March 31, 2015
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Location of Pretax Gains (Losses) Recognized in Earnings
Commodity contracts
Revenue: Regulated electric		$	1			$	—			$	—			$	—			$	—			$	—			$	1
Revenue: Nonregulated electric and other		17				—				—				—				—				13				—
Fuel used in electric generation and purchased power - nonregulated		37				—				—				—				—				37				—
Interest rate contracts
Interest expense		(1		)		—				(1		)		—				(1		)		—				—
Total Pretax Gains (Losses) Recognized in Earnings		$	54			$	—			$	(1	)		$	—			$	(1	)		$	50			$	1
Location of Pretax (Losses) Gains Recognized as Regulatory Assets or Liabilities
Commodity contracts
Regulatory assets		$	(340	)		$	(28	)		$	(314	)		$	(127	)		$	(187	)		$	—			$	2
Regulatory liabilities		(2		)		—				—				—				—				2				(4		)
Interest rate contracts
Regulatory assets		(5		)		—				(4		)		(5		)		1				(1		)		—
Regulatory liabilities		3				—				3				2				1				—				—
Total Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities		$	(344	)		$	(28	)		$	(315	)		$	(130	)		$	(185	)		$	1			$	(2	)
		Three Months Ended March 31, 2014
(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Location of Pretax Gains (Losses) Recognized in Earnings
Commodity contracts
Revenue: Regulated electric		$	(4	)		$	—			$	(3	)		$	(3	)		$	—			$	—			$	—
Revenue: Nonregulated electric and other		(397		)		—				—				—				—				(449		)		—
Fuel used in electric generation and purchased power - regulated		7				—				7				7				—				—				—
Fuel used in electric generation and purchased power - nonregulated		138				—				—				—				—				138				—
Interest rate contracts
Interest expense		(4		)		—				(4		)		(3		)		(1		)		—				—
Total Pretax Gains (Losses) Recognized in Earnings		$	(260	)		$	—			$	—			$	1			$	(1	)		$	(311	)		$	—
Location of Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities
Commodity contracts
Regulatory assets		$	(2	)		$	—			$	(2	)		$	17			$	(19	)		$	—			$	—
Regulatory liabilities		27				—				—				—				—				2				—
Interest rate contracts
Regulatory assets		4				—				4				3				1				—				—
Total Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities		$	29			$	—			$	2			$	20			$	(18	)		$	2			$	—
CREDIT RISK
Certain derivative contracts contain contingent credit features. These features may include (i) material adverse change clauses or payment acceleration clauses that could result in immediate payments or (ii) the posting of letters of credit or termination of the derivative contract before maturity if specific events occur, such as a credit rating downgrade below investment grade.
The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Indiana were not material.
	March 31, 2015
(in millions)	Duke				Duke Energy Carolinas				Progress Energy				Duke				Duke				Duke
	Energy												Energy				Energy				Energy
													Progress				Florida				Ohio
Aggregate fair value amounts of derivative instruments in a net liability position	$	834			$	11			$	344			$	110			$	234			$	479
Fair value of collateral already posted	219				—				43				1				42				176
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	326				11				301				109				192				14
	December 31, 2014
(in millions)	Duke				Duke Energy Carolinas				Progress Energy				Duke				Duke				Duke
	Energy												Energy				Energy				Energy
													Progress				Florida				Ohio
Aggregate fair value amounts of derivative instruments in a net liability position	$	845			$	19			$	370			$	131			$	239			$	456
Fair value of collateral already posted	209				—				23				—				23				186
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	407				19				347				131				216				41
The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting agreement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral and payables related to the obligation to return cash collateral under master netting arrangements. Amounts for Duke Energy Carolinas and Duke Energy Indiana were not material.
	March 31, 2015				December 31, 2014
(in millions)	Receivables				Receivables
Duke Energy
Amounts offset against net derivative positions	$	151			$	145
Amounts not offset against net derivative positions	68				64
Progress Energy
Amounts offset against net derivative positions	43				23
Duke Energy Progress
Amounts offset against net derivative positions	1				—
Duke Energy Florida
Amounts offset against net derivative positions	42				23
Duke Energy Ohio
Amounts offset against net derivative positions	108				122
Amounts not offset against net derivative positions	68				64

Investments_in_Debt_and_Equity

Investments in Debt and Equity Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments In Debt And Equity Securities	INVESTMENTS IN DEBT AND EQUITY SECURITIES
	The Duke Energy Registrants classify their investments in debt and equity securities as either trading or available-for-sale.
	TRADING SECURITIES
	Investments in debt and equity securities held in grantor trusts associated with certain deferred compensation plans and certain other investments are classified as trading securities. The fair value of these investments was $10 million at March 31, 2015 and $7 million at December 31, 2014.
	AVAILABLE-FOR-SALE SECURITIES
	All other investments in debt and equity securities are classified as available-for-sale securities.
	Duke Energy’s available-for-sale securities are primarily comprised of investments held in (i) the Nuclear Decommissioning Trust Fund (NDTF) at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, (ii) grantor trusts at Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana related to other post-retirement benefit obligations (OPEB) plans, (iii) Duke Energy’s captive insurance investment portfolio and (iv) Duke Energy’s foreign operations investment portfolio.
	Duke Energy classifies all other investments in debt and equity securities as long-term, unless otherwise noted.
	Investment Trusts
	The investments within the NDTF at Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida and the Duke Energy Progress, Duke Energy Florida and Duke Energy Indiana grantor trusts (Investment Trusts) are managed by independent investment managers with discretion to buy, sell and invest pursuant to the objectives set forth by the trust agreements. The Duke Energy Registrants have limited oversight of the day-to-day management of these investments. As a result, the ability to hold investments in unrealized loss positions is outside the control of the Duke Energy Registrants. Accordingly, all unrealized losses associated with debt and equity securities within the Investment Trusts are considered other-than-temporary impairments and are recognized immediately. Pursuant to regulatory accounting, substantially all realized and unrealized gains and losses associated with investments within the Investment Trusts are deferred as a regulatory asset or liability. As a result, there is no immediate impact on earnings of the Duke Energy Registrants.
	Other Available-for-Sale Securities
	Unrealized gains and losses on all other available-for-sale securities are included in other comprehensive income until realized, unless it is determined the carrying value of an investment is other-than-temporarily impaired. If an other-than-temporary impairment exists, the unrealized loss is included in earnings based on the criteria discussed below.
	The Duke Energy Registrants analyze all investment holdings each reporting period to determine whether a decline in fair value should be considered other-than-temporary. Criteria used to evaluate whether an impairment associated with equity securities is other-than-temporary includes, but is not limited to, (i) the length of time over which the market value has been lower than the cost basis of the investment, (ii) the percentage decline compared to the cost of the investment and (iii) management’s intent and ability to retain its investment for a period of time sufficient to allow for any anticipated recovery in market value. If a decline in fair value is determined to be other-than-temporary, the investment is written down to its fair value through a charge to earnings.
	If the entity does not have an intent to sell a debt security and it is not more likely than not management will be required to sell the debt security before the recovery of its cost basis, the impairment write-down to fair value would be recorded as a component of other comprehensive income, except for when it is determined a credit loss exists. In determining whether a credit loss exists, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than the amortized cost basis, (ii) changes in the financial condition of the issuer of the security, or in the case of an asset-backed security, the financial condition of the underlying loan obligors, (iii) consideration of underlying collateral and guarantees of amounts by government entities, (iv) ability of the issuer of the security to make scheduled interest or principal payments and (v) any changes to the rating of the security by rating agencies. If a credit loss exists, the amount of impairment write-down to fair value is split between credit loss and other factors. The amount related to credit loss is recognized in earnings. The amount related to other factors is recognized in other comprehensive income. There were no credit losses as of March 31, 2015 and December 31, 2014. There were no other-than-temporary impairments for debt or equity securities as of March 31, 2015 and December 31, 2014.
	DUKE ENERGY
	The following table presents the estimated fair value of investments in available-for-sale securities.
		March 31, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value(c)		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	106	$	—	$	—	$	136
	Equity securities	1,916		28		3,643		1,926		29		3,650
	Corporate debt securities	19		1		482		14		2		454
	Municipal bonds	7		2		227		5		—		184
	U.S. government bonds	24		1		864		19		2		978
	Other debt securities	2		2		148		1		2		147
	Total NDTF(d)	$	1,968	$	34	$	5,470	$	1,965	$	35	$	5,549
	Other Investments
	Cash and cash equivalents	$	—	$	—	$	29	$	—	$	—	$	15
	Equity securities	36		—		98		34		—		96
	Corporate debt securities	3		—		81		1		1		58
	Municipal bonds	3		1		75		3		1		76
	U.S. government bonds	—		—		45		—		—		27
	Other debt securities	1		2		83		1		1		80
	Total Other Investments(a)	$	43	$	3	$	411	$	39	$	3	$	352
	Total Investments	$	2,011	$	37	$	5,881	$	2,004	$	38	$	5,901
	(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
	(c)	These amounts exclude net pending trade receivables of $107 million as of March 31, 2015.
	(d)	The decrease in the estimated fair value of the NDTF for the three months ended March 31, 2015 is primarily due to reimbursement from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Station.
	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	110
	Due after one through five years	603
	Due after five through 10 years	488
	Due after 10 years	804
	Total	$	2,005
	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)	2015		2014
	Realized gains	$	102	$	31
	Realized losses	14		4
	DUKE ENERGY CAROLINAS
	The following table presents the estimated fair value of investments in available-for-sale securities.
		March 31, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value(c)		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	42	$	—	$	—	$	51
	Equity securities	1,076		16		2,127		1,102		17		2,162
	Corporate debt securities	11		1		329		8		2		316
	Municipal bonds	2		1		90		1		—		62
	U.S. government bonds	8		1		296		7		1		308
	Other debt securities	2		2		128		1		2		133
	Total NDTF	$	1,099	$	21	$	3,012	$	1,119	$	22	$	3,032
	Other Investments
Other debt securities	$	—	$	1	$	3	$	—	$	1	$	3
Total Other Investments(a)	$	—	$	1	$	3	$	—	$	1	$	3
Total Investments	$	1,099	$	22	$	3,015	$	1,119	$	23	$	3,035
(a)	These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
(c)	These amounts exclude net pending trade receivables of $107 million as of March 31, 2015.
The table below summarizes the maturity date for debt securities.
(in millions)	March 31, 2015
Due in one year or less	$	5
Due after one through five years	177
Due after five through 10 years	257
Due after 10 years	407
Total	$	846
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)	2015		2014
Realized gains	$	90	$	23
Realized losses	12		1
PROGRESS ENERGY
The following table presents the estimated fair value investments in available-for-sale securities.
	March 31, 2015						December 31, 2014
(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
NDTF
Cash and cash equivalents	$	—	$	—	$	64	$	—	$	—	$	85
Equity securities	840		12		1,516		824		12		1,488
Corporate debt securities	8		—		153		6		—		138
Municipal bonds	5		1		137		4		—		122
U.S. government bonds	16		—		568		12		1		670
Other debt securities	—		—		20		—		—		14
Total NDTF(c)	$	869	$	13	$	2,458	$	846	$	13	$	2,517
Other Investments
Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	15
Municipal bonds	3		—		42		3		—		43
Total Other Investments(a)	$	3	$	—	$	60	$	3	$	—	$	58
Total Investments	$	872	$	13	$	2,518	$	849	$	13	$	2,575
(a)    These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
(c)	The decrease in the estimated fair value of the NDTF for the three months ended March 31, 2015 is primarily due to reimbursement from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Station.
The table below summarizes the maturity date for debt securities.
(in millions)	March 31, 2015
Due in one year or less	$	84
Due after one through five years	350
Due after five through 10 years	160
Due after 10 years	326
Total	$	920
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)	2015		2014
Realized gains	$	12	$	7
Realized losses	1		2
DUKE ENERGY PROGRESS
The following table presents the estimated fair value of investments in available-for-sale securities.
	March 31, 2015						December 31, 2014
(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
NDTF
Cash and cash equivalents	$	—	$	—	$	40	$	—	$	—	$	50
Equity securities	626		10		1,194		612		10		1,171
Corporate debt securities	6		—		107		5		—		97
Municipal bonds	5		1		135		4		—		120
U.S. government bonds	10		—		251		9		1		265
Other debt securities	—		—		12		—		—		8
Total NDTF	$	647	$	11	$	1,739	$	630	$	11	$	1,711
Other Investments
Cash and cash equivalents	$	—	$	—	$	1	$	—	$	—	$	—
Total Other Investments(a)	$	—	$	—	$	1	$	—	$	—	$	—
Total Investments	$	647	$	11	$	1,740	$	630	$	11	$	1,711
(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
The table below summarizes the maturity date for debt securities.
(in millions)	March 31, 2015
Due in one year or less	$	12
Due after one through five years	147
Due after five through 10 years	113
Due after 10 years	233
Total	$	505
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)	2015		2014
Realized gains	$	9	$	6
Realized losses	1		2
DUKE ENERGY FLORIDA
The following table presents the estimated fair value of investments in available-for-sale securities.
	March 31, 2015						December 31, 2014
(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
NDTF
Cash and cash equivalents	$	—	$	—	$	24	$	—	$	—	$	35
Equity securities	214		2		322		212		2		317
Corporate debt securities	2		—		46		1		—		41
Municipal bonds	—		—		2		—		—		2
U.S. government bonds	6		—		317		3		—		405
Other debt securities	—		—		8		—		—		6
Total NDTF	$	222	$	2	$	719	$	216	$	2	$	806
Other Investments
Cash and cash equivalents	$	—	$	—	$	2	$	—	$	—	$	1
Municipal bonds	3		—		42		3		—		43
Total Other Investments(a)	$	3	$	—	$	44	$	3	$	—	$	44
Total Investments	$	225	$	2	$	763	$	219	$	2	$	850
(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
(c)	The decrease in the estimated fair value of the NDTF for the three months ended March 31, 2015 is primarily due to reimbursement from the NDTF for Duke Energy Florida's costs related to ongoing decommissioning activity of the Crystal River Unit 3 Nuclear Station.
The table below summarizes the maturity date for debt securities.
(in millions)	March 31, 2015
Due in one year or less	$	72
Due after one through five years	203
Due after five through 10 years	47
Due after 10 years	93
Total	$	415
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)	2015		2014
Realized gains	$	3	$	1
Realized losses	—		1
DUKE ENERGY INDIANA
The following table presents the estimated fair value of investments in available-for-sale securities.
	March 31, 2015						December 31, 2014
(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
Other Investments
Equity securities	$	30	$	—	$	73	$	28	$	—	$	71
Municipal bonds	—		1		30		—		1		30
Total Other Investments(a)	$	30	$	1	$	103	$	28	$	1	$	101
Total Investments	$	30	$	1	$	103	$	28	$	1	$	101
(a)    These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
The table below summarizes the maturity date for debt securities.
(in millions)	March 31, 2015
Due in one year or less	$	2
Due after one through five years	17
Due after five through 10 years	8
Due after 10 years	3
Total	$	30
Realized gains and losses, which were determined on a specific identification basis, from sales of available-for-sale securities were insignificant for the three months ended March 31, 2015 and 2014.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	Fair value is the exchange price to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date. The fair value definition focuses on an exit price versus the acquisition cost. Fair value measurements use market data or assumptions market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs may be readily observable, corroborated by market data or generally unobservable. Valuation techniques maximize the use of observable inputs and minimize use of unobservable inputs. A midmarket pricing convention (the midpoint price between bid and ask prices) is permitted for use as a practical expedient.
	Fair value measurements are classified in three levels based on the fair value hierarchy:
	Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. An active market is one in which transactions for an asset or liability occur with sufficient frequency and volume to provide ongoing pricing information.
	Level 2 – A fair value measurement utilizing inputs other than quoted prices included in Level 1 that are observable, either directly or indirectly, for an asset or liability. Inputs include (i) quoted prices for similar assets or liabilities in active markets, (ii) quoted prices for identical or similar assets or liabilities in markets that are not active and (iii) inputs other than quoted market prices that are observable for the asset or liability, such as interest rate curves and yield curves observable at commonly quoted intervals, volatilities and credit spreads. A Level 2 measurement cannot have more than an insignificant portion of its valuation based on unobservable inputs. Instruments in this category include non-exchange-traded derivatives, such as over-the-counter forwards, swaps and options; certain marketable debt securities; and financial instruments traded in less than active markets.
	Level 3 – Any fair value measurement which includes unobservable inputs for more than an insignificant portion of the valuation. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value. Level 3 measurements may include longer-term instruments that extend into periods in which observable inputs are not available.
	The 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 1 and 2 during the three months ended March 31, 2015 and 2014. Transfers out of Level 3 during the three months ended March 31, 2015 are the result of forward commodity prices becoming observable due to the passage of time.
	Valuation methods of the primary fair value measurements disclosed 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 equity securities that are Level 2 or 3 are typically ownership interests in commingled investment funds.
	Investments in debt securities
	With the exception of U.S. Treasuries which are classified as Level 1, most investments in debt securities are valued using Level 2 measurements because the valuations use interest rate curves and credit spreads applied to the terms of the debt instrument (maturity and coupon interest rate) and consider the counterparty credit rating. If the market for a particular fixed income security is relatively inactive or illiquid, the measurement is Level 3.
	Commodity derivatives
	Commodity derivatives with clearinghouses are classified as Level 1. Other commodity derivatives are primarily fair valued using internally developed discounted cash flow models which incorporate forward price, adjustments for liquidity (bid-ask spread) and credit or 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 fair value of natural gas commodity contracts by a market participant price verification procedure. This procedure provides a comparison of internal forward commodity curves to market participant generated curves.
	Interest rate derivatives
	Most over-the-counter interest rate contract derivatives are valued using financial models which utilize observable inputs for similar instruments and are classified as Level 2. Inputs include forward interest rate curves, notional amounts, interest rates and credit quality of the counterparties.
	Goodwill, Long-lived Assets and Assets Held for Sale
	See Note 7 for a discussion of the valuation of goodwill and long-lived assets and Note 2 related to the assets and related liabilities of the Disposal Group classified as held for sale.
	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, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	3,643			$	3,476			$	3			$	164
	Nuclear decommissioning trust fund debt securities	1,827				542				1,285				—
	Other trading and available-for-sale equity securities	98				98				—				—
	Other trading and available-for-sale debt securities	323				73				245				5
	Derivative assets	52				7				22				23
	Total assets	5,943				4,196				1,555				192
	Derivative liabilities	(625		)		(119		)		(497		)		(9		)
	Net assets	$	5,318			$	4,077			$	1,058			$	183
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	3,650			$	3,493			$	6			$	151
	Nuclear decommissioning trust fund debt securities	1,899				648				1,251				—
	Other trading and available-for-sale equity securities	96				96				—				—
	Other trading and available-for-sale debt securities	263				41				217				5
	Derivative assets	110				49				24				37
	Total assets	6,018				4,327				1,498				193
	Derivative liabilities	(668		)		(162		)		(468		)		(38		)
	Net assets	$	5,350			$	4,165			$	1,030			$	155
	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues.
		Three Months Ended March 31, 2015
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	156			$	(1	)		$	155
	Total pretax realized or unrealized gains (losses) included in earnings	—				24				24
	Purchases, sales, issuances and settlements:
	Purchases	9				—				9
	Sales	(1		)		—				(1		)
	Settlements	—				(10		)		(10		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5				1				6
	Balance at end of period	$	169			$	14			$	183
		Three Months Ended March 31, 2014
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	98			$	13			$	111
	Total pretax realized or unrealized gains (losses) included in earnings	—				18				18
	Purchases, sales, issuances and settlements:
	Purchases	1				—				1
	Sales	(1		)		—				(1		)
	Settlements	—				(39		)		(39		)
	Transfers out of Level 3 due to observability of inputs	—				(5		)		(5		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				(1		)		—
	Balance at end of period	$	99			$	(14	)		$	85
	Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding	$	—			$	7			$	7
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, 2015
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	2,127			$	1,960			$	3			$	164
Nuclear decommissioning trust fund debt securities	885				131				754				—
Other trading and available-for-sale debt securities	3				—				—				3
Total assets	3,015				2,091				757				167
Derivative liabilities	(27		)		—				(27		)		—
Net assets	$	2,988			$	2,091			$	730			$	167
	December 31, 2014
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	2,162			$	2,005			$	6			$	151
Nuclear decommissioning trust fund debt securities	870				138				732				—
Other trading and available-for-sale debt securities	3				—				—				3
Total assets	3,035				2,143				738				154
Derivative liabilities	(19		)		—				(19		)		—
Net assets	$	3,016			$	2,143			$	719			$	154
The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
	Three Months Ended March 31, 2015
(in millions)	Investments				Derivatives (net)				Total
Balance at beginning of period	$	154			$	—			$	154
Purchases, sales, issuances and settlements:
Purchases	9				—				9
Issuances	(1		)		—				(1		)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5				—				5
Balance at end of period	$	167			$	—			$	167
	Three Months Ended March 31, 2014
(in millions)	Investments				Derivatives (net)				Total
Balance at beginning of period	$	81			$	(2	)		$	79
Purchases, sales, issuances and settlements:
Purchases	1				—				1
Sales	(1		)		—				(1		)
Settlements	—				(2		)		(2		)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				—				1
Balance at end of period	$	82			$	(4	)		$	78
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, 2015
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	1,516			$	1,516			$	—			$	—
Nuclear decommissioning trust fund debt securities	942				411				531				—
Other trading and available-for-sale debt securities	60				16				44				—
Derivative assets	6				—				6				—
Total assets	2,524				1,943				581				—
Derivative liabilities	(395		)		—				(395		)		—
Net assets	$	2,129			$	1,943			$	186			$	—
	December 31, 2014
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	1,488			$	1,488			$	—			$	—
Nuclear decommissioning trust fund debt securities	1,029				510				519				—
Other trading and available-for-sale debt securities	58				15				43				—
Derivative assets	4				—				4				—
Total assets	2,579				2,013				566				—
Derivative liabilities	(373		)		—				(373		)		—
Net assets	$	2,206			$	2,013			$	193			$	—
The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
	Derivatives (net)
	Three Months Ended March 31,
(in millions)	2015				2014
Balance at beginning of period	$	—			$	—
Total pretax realized or unrealized gains included in earnings	—				(3		)
Balance at end of period	$	—			$	(3	)
Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			$	(3	)
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, 2015
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	1,194			$	1,194			$	—			$	—
Nuclear decommissioning trust fund debt securities	545				140				405				—
Other trading and available-for-sale debt securities	1				1				—				—
Derivative assets	2				—				2				—
Total assets	1,742				1,335				407				—
Derivative liabilities	(131		)		—				(131		)		—
Net assets	$	1,611			$	1,335			$	276			$	—
	December 31, 2014
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	1,171			$	1,171			$	—			$	—
Nuclear decommissioning trust fund debt securities	540				151				389				—
Total assets	1,711				1,322				389				—
Derivative liabilities	(132		)		—				(132		)		—
Net assets	$	1,579			$	1,322			$	257			$	—
The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
	Derivatives (net)
	Three Months Ended March 31,
(in millions)	2015				2014
Balance at beginning of period	$	—			$	—
Total pretax realized or unrealized gains included in earnings	—				(3		)
Balance at end of period	$	—			$	(3	)
Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			$	(3	)
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, 2015
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	322			$	322			$	—			$	—
Nuclear decommissioning trust fund debt securities and other	397				271				126				—
Other trading and available-for-sale debt securities and other	44				—				44				—
Derivative assets	4				—				4				—
Total assets	767				593				174				—
Derivative liabilities	(264		)		—				(264		)		—
Net assets (liabilities)	$	503			$	593			$	(90	)		$	—
	31-Dec-14
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Nuclear decommissioning trust fund equity securities	$	317			$	317			$	—			$	—
Nuclear decommissioning trust fund debt securities and other	489				359				130				—
Other trading and available-for-sale debt securities and other	44				—				44				—
Derivative assets	4				—				4				—
Total assets	854				676				178				—
Derivative liabilities	(241		)		—				(241		)		—
Net assets (liabilities)	$	613			$	676			$	(63	)		$	—
DUKE ENERGY OHIO
The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9.
	March 31, 2015
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Derivative assets	$	44			$	20			$	8			$	16
Derivative liabilities	(134		)		(108		)		(17		)		(9		)
Net liabilities	$	(90	)		$	(88	)		$	(9	)		$	7
	December 31, 2014
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Derivative assets	$	49			$	20			$	9			$	20
Derivative liabilities	(181		)		(117		)		(26		)		(38		)
Net liabilities	$	(132	)		$	(97	)		$	(17	)		$	(18	)
The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
	Derivatives (net)
	Three Months Ended March 31,
(in millions)	2015				2014
Balance at beginning of period	$	(18	)		$	(4	)
Total pretax realized or unrealized gains (losses) included in earnings	25				(6		)
Purchases, sales, issuances and settlements:
Settlements	—				(4		)
Transfers out of Level 3 due to observability of inputs	—				(5		)
Balance at end of period	$	7			$	(19	)
Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			(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.
	31-Mar-15
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Available-for-sale equity securities	$	73			$	73			$	—			$	—
Available-for-sale debt securities	30				—				30				—
Derivative assets	3				—				—				3
Net assets	$	106			$	73			$	30			$	3
	31-Dec-14
(in millions)	Total Fair Value				Level 1				Level 2				Level 3
Available-for-sale equity securities	$	71			$	71			$	—			$	—
Available-for-sale debt securities	30				—				30				—
Derivative assets	14				—				—				14
Net assets	$	115			$	71			$	30			$	14
The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
	Derivatives (net)
	Three Months Ended March 31,
(in millions)	2015				2014
Balance at beginning of period	$	14			$	12
Total pretax realized or unrealized gains (losses) included in earnings	(3		)		27
Purchases, sales, issuances and settlements:
Settlements	(9		)		(31		)
Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				(1		)
Balance at end of period	$	3			$	7
QUANTITATIVE DISCLOSURES ABOUT UNOBSERVABLE INPUTS
The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3.
	31-Mar-15
Investment Type	Fair Value			Valuation Technique	Unobservable Input	Range
	(in millions)
Duke Energy
Natural gas contracts	$	11		Discounted cash flow	Forward natural gas curves – price per MMBtu	$	1.96		-	$	3.78
Financial transmission rights (FTRs)	3			RTO auction pricing	FTR price – per MWh	(0.83		)	-	8.47
Electricity contracts	8			Discounted cash flow	Forward electricity curves – price per MWh	24.96			-	51.33
Commodity capacity option contracts	1			Discounted cash flow	Forward capacity option curves – price per MW day	19			-	109.5
Commodity contract reserves	(9		)		Bid-ask spreads, implied volatility, probability of default
Total Level 3 derivatives	$	14
Duke Energy Ohio
Electricity contracts	$	2		Discounted cash flow	Forward electricity curves – price per MWh	25.05			-	51.33
Natural gas contracts	11			Discounted cash flow	Forward natural gas curves – price per MMBtu	1.96			-	3.78
Commodity contract reserves	(6		)		Bid-ask spreads, implied volatility, probability of default
Total Level 3 derivatives	$	7
Duke Energy Indiana
FTRs	$	3		RTO auction pricing	FTR price – per MWh	(0.83		)	-	8.47
	31-Dec-14
Investment Type	Fair Value			Valuation Technique	Unobservable Input	Range
	(in millions)
Duke Energy
Natural gas contracts	$	(5	)	Discounted cash flow	Forward natural gas curves – price per MMBtu	$	2.12		-	$	4.35
Financial transmission rights (FTRs)	14			RTO auction pricing	FTR price – per MWh	(1.92		)	-	9.86
Electricity contracts	(1		)	Discounted cash flow	Forward electricity curves – price per MWh	25.16			-	51.75
Commodity capacity option contracts	2			Discounted cash flow	Forward capacity option curves – price per MW day	21			-	109
Commodity contract reserves	(11		)		Bid-ask spreads, implied volatility, probability of default
Total Level 3 derivatives	$	(1	)
Duke Energy Ohio
Electricity contracts	$	(6	)	Discounted cash flow	Forward electricity curves – price per MWh	25.25			-	51.75
Natural gas contracts	(5		)	Discounted cash flow	Forward natural gas curves – price per MMBtu	2.12			-	4.35
Commodity contract reserves	(7		)		Bid-ask spreads, implied volatility, probability of default
Total Level 3 derivatives	$	(18	)
Duke Energy Indiana
FTRs	$	14		RTO auction pricing	FTR price – per MWh	(1.92		)	-	9.86
OTHER FAIR VALUE DISCLOSURES
The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements.
	March 31, 2015							December 31, 2014
(in millions)	Book Value			Fair Value				Book Value			Fair Value
Duke Energy	$	39,973		$	45,113			$	40,020		$	44,566
Duke Energy Carolinas	8,885			10,301				8,391			9,626
Progress Energy	14,510			16,956				14,754			16,951
Duke Energy Progress	5,957			6,549				6,201			6,696
Duke Energy Florida	4,858			5,867				4,860			5,767
Duke Energy Ohio	1,606			1,810				1,766			1,970
Duke Energy Indiana	3,791			4,529				3,791			4,456
At both March 31, 2015 and December 31, 2014, the fair value of cash and cash equivalents, accounts and notes receivable, accounts payable, notes payable and commercial paper, and non-recourse notes payable of variable interest entities are not materially different from their carrying amounts because of the short-term nature of these instruments and/or because the stated rates approximate market rates.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2015
Variable Interest Entities [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES
	A VIE is an entity that is evaluated for consolidation using more than a simple analysis of voting control. The analysis to determine whether an entity is a VIE considers contracts with an entity, credit support for an entity, the adequacy of the equity investment of an entity and the relationship of voting power to the amount of equity invested in an entity. This analysis is performed either upon the creation of a legal entity or upon the occurrence of an event requiring reevaluation, such as a significant change in an entity’s assets or activities. A qualitative analysis of control determines the party that consolidates a VIE. This assessment is based on (i) what party has the power to direct the activities of the VIE that most significantly impact its economic performance and (ii) what party has rights to receive benefits or is obligated to absorb losses that could potentially be significant to the VIE. The analysis of the party that consolidates a VIE is a continual reassessment.
	No financial support was provided to any of the consolidated VIEs during the three months ended March 31, 2015 and the year ended December 31, 2014, or is expected to be provided in the future, that was not previously contractually required.
	CONSOLIDATED VIEs
	The following tables summarize the impact of VIEs consolidated by Duke Energy and the Subsidiary Registrants on the Condensed Consolidated Balance Sheets.
		March 31, 2015
		Duke Energy
		Duke Energy Carolinas			Duke Energy Progress				Duke Energy Florida
	(in millions)	DERF			DEPR(c)				DEFR(c)			CRC		Renewables			Other			Total
	ASSETS
	Current Assets
	Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	$	658		$	478			$	300		$	540	$	18		$	22		$	2,016
	Other	—			—				—			—		102			7			109
	Investments and Other Assets
	Other	—			—				—			—		22			15			37
	Property, Plant and Equipment
	Property, plant and equipment, cost(a)	—			—				—			—		1,854			19			1,873
	Accumulated depreciation and amortization	—			—				—			—		(267		)	(6		)	(273		)
	Regulatory Assets and Deferred Debits
	Other	—			1				1			—		36			—			38
	Total assets	$	658		$	479			$	301		$	540	$	1,765		$	57		$	3,800
	LIABILITIES AND EQUITY
	Current Liabilities
	Accounts payable	$	—		$	—			$	—		$	—	$	2		$	—		$	2
	Taxes accrued	2			2				1			—		4			—			9
	Current maturities of long-term debt	—			—				—			—		68			17			85
	Other	—			—				—			—		23			8			31
	Long-Term Debt(b)	400			300				225			325		967			12			2,229
	Deferred Credits and Other Liabilities
	Deferred income taxes	—			—				—			—		270			—			270
	Asset retirement obligations	—			—				—			—		30			—			30
	Other	—			—				—			—		40			—			40
	Total liabilities	$	402		$	302			$	226		$	325	$	1,404		$	37		$	2,696
	Net assets of consolidated variable interest entities	$	256		$	177			$	75		$	215	$	361		$	20		$	1,104
	(a)    Restricted as collateral for non-recourse debt of VIEs.
	(b)    Non-recourse to the general assets of the applicable registrant.
	(c)	The amount for Progress Energy is equal to the sum of the amounts for Duke Energy Progress Receivables Company, LLC (DEPR) and Duke Energy Florida Receivables Company, LLC (DEFR).
		December 31, 2014
		Duke Energy
		Duke Energy Carolinas			Duke Energy Progress				Duke Energy Florida
	(in millions)	DERF			DEPR(c)				DEFR(c)			CRC		Renewables			Other			Total
	ASSETS
	Current Assets
	Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	$	647		$	436			$	305		$	547	$	20		$	18		$	1,973
	Other	—			—				—			—		68			6			74
	Investments and Other Assets
	Other	—			—				—			—		25			25			50
	Property, Plant and Equipment
	Property, plant and equipment, cost(a)	—			—				—			—		1,855			18			1,873
	Accumulated depreciation and amortization	—			—				—			—		(250		)	(5		)	(255		)
	Regulatory Assets and Deferred Debits
	Other	—			—				—			—		34			2			36
	Total assets	$	647		$	436			$	305		$	547	$	1,752		$	64		$	3,751
	LIABILITIES AND EQUITY
	Current Liabilities
	Accounts payable	$	—		$	—			$	—		$	—	$	3		$	—		$	3
	Taxes accrued	—			—				—			—		6			—			6
	Current maturities of long-term debt	—			—				—			—		68			16			84
	Other	—			—				—			—		16			5			21
	Long-Term Debt(b)	400			300				225			325		967			17			2,234
	Deferred Credits and Other Liabilities
	Deferred income taxes	—			—				—			—		283			—			283
	Asset retirement obligations	—			—				—			—		29			—			29
	Other	—			—				—			—		34			4			38
Total liabilities	$	400		$	300			$	225		$	325	$	1,406		$	42		$	2,698
Net assets of consolidated variable interest entities	$	247		$	136			$	80		$	222	$	346		$	22		$	1,053
(a)    Restricted as collateral for non-recourse debt of VIEs.
(b)    Non-recourse to the general assets of the applicable registrant.
(c)	The amount for Progress Energy is equal to the sum of the amounts for DEPR and DEFR.
The obligations of these VIEs are non-recourse to Duke Energy, Duke Energy Carolinas, Progress Energy, Duke Energy Progress and Duke Energy Florida. These entities have no requirement to provide liquidity to, purchase assets of or guarantee performance of these VIEs unless noted in the following paragraphs.
DERF / DEPR / DEFR
Duke Energy Receivables Finance Company, LLC (DERF), DEPR and DEFR are bankruptcy remote, special purpose subsidiaries of Duke Energy Carolinas, Duke Energy Progress and Duke Energy Florida, respectively. On a daily basis, DERF, DEPR and DEFR buy certain accounts receivable arising from the sale of electricity and/or related services from their parent companies. DERF, DEPR and DEFR are wholly owned limited liability companies with separate legal existence from their parents, and their assets are not generally available to creditors of their parent companies. DERF, DEPR and DEFR borrow amounts under credit facilities to buy the receivables. Borrowing availability is limited to the amount of qualified receivables sold, which is generally expected to be in excess of the credit facilities. The credit facilities are reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt. The secured credit facilities were not structured to meet the criteria for sale accounting treatment under the accounting guidance for transfers and servicing of financial assets.
The following table summarizes the amounts and expiration dates of the credit facilities reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt.
	DERF		DEPR			DEFR
Credit facility amount (in millions)	$	400	$	300		$	225
Expiration date	Oct-16		Dec-16			Mar-17
The activity that most significantly 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 are the related parties most closely associated with the VIE.
CRC
On a revolving basis, CRC buys certain accounts receivable arising from the sale of electricity and/or related services from Duke Energy Ohio and Duke Energy Indiana. Receivables sold are securitized by CRC through a credit facility managed by two unrelated third parties. The proceeds Duke Energy Ohio and Duke Energy Indiana receive from the sale of receivables to CRC are typically 75 percent cash and 25 percent in the form of a subordinated note from CRC. The subordinated note is a retained interest in the receivables sold. Cash collections from the receivables are the sole source of funds to satisfy the related debt obligation. Depending on experience with collections, additional equity infusions to CRC may be required by Duke Energy to maintain a minimum equity balance of $3 million. Borrowing availability is limited to the amount of qualified receivables sold, which is generally expected to be in excess of the credit facility. The credit facility expires in November 2016 and is reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt.
CRC is considered a VIE because (i) equity capitalization is insufficient to support its operations, (ii) power to direct the activities that most significantly impact the economic performance of the entity are not performed by the equity holder, Cinergy, and (iii) deficiencies in net worth of CRC are not funded by Cinergy, but by Duke Energy. The most significant activities of CRC are decisions made related to the management of delinquent receivables. Duke Energy consolidates CRC as it makes these decisions. Neither Duke Energy Ohio nor Duke Energy Indiana consolidate CRC.
Renewables
Certain of Duke Energy’s renewable energy facilities are VIEs due to long-term fixed-price power purchase agreements. These fixed-price agreements effectively transfer commodity price risk to the buyer of the power. Certain other of Duke Energy’s renewable energy facilities are VIEs due to Duke Energy issuing guarantees for debt service and operations and maintenance reserves in support of debt financings. For certain VIEs, assets are restricted and cannot be pledged as collateral or sold to third parties without prior approval of debt holders. The activities that most significantly impact the economic performance of these renewable energy facilities were decisions associated with siting, negotiating purchase power agreements, engineering, procurement and construction, and decisions associated with ongoing operations and maintenance-related activities. Duke Energy consolidates the entities as it makes all of these decisions.
NON-CONSOLIDATED VIEs
The following tables include VIEs not consolidated and how these entities impact the Condensed Consolidated Balance Sheets.
	31-Mar-15
	Duke Energy										Duke Energy		Duke Energy
(in millions)	Renewables			Other				Total			Ohio		Indiana
Receivables	$	—		$	—			$	—		$	90	$	105
Investments in equity method unconsolidated affiliates	147			66				213			—		$	—
Investments and other assets	—			3				3			—		—
Total assets	$	147		$	69			$	216		$	90	$	105
Other current liabilities	$	—		$	2			$	2		$	—	$	—
Deferred credits and other liabilities	—			14				14			—		—
Total liabilities	$	—		$	16			$	16		$	—	$	—
Net assets (liabilities)	$	147		$	53			$	200		$	90	$	105
	31-Dec-14
	Duke Energy										Duke Energy Ohio		Duke Energy Indiana
(in millions)	Renewables			Other				Total
Receivables	$	—		$	—			$	—		$	91	$	113
Investments in equity method unconsolidated affiliates	150			38				188			—		—
Investments and other assets	—			4				4			—		—
Total assets	$	150		$	42			$	192		$	91	$	113
Other current liabilities	—			3				3			—		—
Deferred credits and other liabilities	—			14				14			—		—
Total liabilities	$	—		$	17			$	17		$	—	$	—
Net assets	$	150		$	25			$	175		$	91	$	113
The Duke Energy Registrants are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying values shown above except for the power purchase agreement with OVEC, which is discussed below, and various guarantees, reflected in the table above as Deferred credits and other liabilities. For more information on various guarantees, refer to Note 5, "Commitments and Contingencies".
Renewables
Duke Energy has investments in various renewable energy project entities. Some of these entities are VIEs due to long-term fixed-price power purchase agreements. These fixed-price agreements effectively transfer commodity price risk to the buyer of the power. Duke Energy does not consolidate these VIEs because power to direct and control key activities is shared jointly by Duke Energy and other owners.
Other
Duke Energy holds a 50 percent equity interest in Duke-American Transmission Company, LLC (DATC). DATC is considered a VIE due to insufficient equity at risk to permit DATC to finance its own activities without additional subordinated financial support. The activities that most significantly impact DATC’s economic performance are the decisions related to investing in existing and development of new transmission facilities. The power to direct these activities is jointly and equally shared by Duke Energy and the other joint venture partner and, therefore, Duke Energy does not consolidate.
Duke Energy has a 40 percent equity interest in ACP, which is considered a VIE as the equity is not sufficient to permit the entity to finance its activities without additional subordinated financial support. The activity that most significantly impacts the economic performance of ACP is construction. Duke Energy does not control these activities and therefore does not consolidate ACP.
OVEC
Duke Energy Ohio’s 9 percent ownership interest in OVEC is considered a non-consolidated VIE. Through its ownership interest in OVEC, Duke Energy Ohio has a contractual arrangement to buy power from OVEC’s power plants through June 2040. Proceeds from the sale of power by OVEC to its power purchase agreement counterparties are designed to be sufficient to meet its operating expenses, fixed costs, debt amortization and interest expense, as well as earn a return on equity. Accordingly, the value of this contract is subject to variability due to fluctuations in power prices and changes in OVEC’s costs of business, including costs associated with its 2,256 MW of coal-fired generation capacity. Proposed environmental rule-making could increase the costs of OVEC, which would be passed through to Duke Energy Ohio. In 2014, Duke Energy recorded a $94 million impairment related to OVEC.
CRC
See discussion under Consolidated VIEs for additional information related to CRC.
Amounts included in Receivables in the above table for Duke Energy Ohio and Duke Energy Indiana reflect their retained interest in receivables sold to CRC. These subordinated notes held by Duke Energy Ohio and Duke Energy Indiana are stated at fair value. Carrying values of retained interests are determined by allocating carrying value of the receivables between assets sold and interests retained based on relative fair value. The allocated bases of the subordinated notes are not materially different than their face value because (i) the receivables generally turnover in less than two months, (ii) credit losses are reasonably predictable due to the broad customer base and lack of significant concentration, and (iii) the equity in CRC is subordinate to all retained interests and thus would absorb losses first. The hypothetical effect on fair value of the retained interests assuming both a 10 percent and a 20 percent unfavorable variation in credit losses or discount rates is not material due to the short turnover of receivables and historically low credit loss history. Interest accrues to Duke Energy Ohio and Duke Energy Indiana on the retained interests using the acceptable yield method. This method generally approximates the stated rate on the notes since the allocated basis and the face value are nearly equivalent. An impairment charge is recorded against the carrying value of both retained interests and purchased beneficial interest whenever it is determined that an other-than-temporary impairment has occurred.
Key assumptions used in estimating fair value are detailed in the following table.
	Duke Energy Ohio					Duke Energy Indiana
	2015		2014			2015			2014
Anticipated credit loss ratio	0.6	%	0.6	%		0.3	%		0.3	%
Discount rate	1.2	%	1.2	%		1.2	%		1.2	%
Receivable turnover rate	12.8	%	12.8	%		10.5	%		10.4	%
The following table shows the gross and net receivables sold.
	Duke Energy Ohio							Duke Energy Indiana
(in millions)	March 31, 2015			December 31, 2014				March 31, 2015			December 31, 2014
Receivables sold	$	284		$	273			$	296		$	310
Less: Retained interests	90			91				105			113
Net receivables sold	$	194		$	182			$	191		$	197
The following table shows sales and cash flows related to receivables sold.
	Duke Energy Ohio							Duke Energy Indiana
	Three Months Ended March 31,							Three Months Ended March 31,
(in millions)	2015			2014				2015			2014
Sales
Receivables sold	$	644		$	741			$	716		$	755
Loss recognized on sale	3			4				3			3
Cash flows
Cash proceeds from receivables sold	640			723				722			761
Return received on retained interests	1			2				2			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, 2015
Earnings Per Share [Abstract]
Common Stock	COMMON STOCK
	Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common shareholders, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted-average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common shareholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted-average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options, phantom shares and stock-based performance unit awards, were exercised or settled. Duke Energy’s participating securities are restricted stock units that are entitled to dividends declared on Duke Energy common shares during the restricted stock unit’s vesting periods.
	The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding.
		Three Months Ended March 31,
	(in millions, except per share amounts)	2015		2014
	Income from continuing operations attributable to Duke Energy common shareholders	$	772	$	744
	Weighted-average shares outstanding – basic	708		706
	Weighted-average shares outstanding – diluted	708		706
	Earnings per share from continuing operations attributable to Duke Energy common shareholders
	Basic	$	1.09	$	1.05
	Diluted	$	1.09	$	1.05
	Potentially dilutive items excluded from the calculation(a)	2		2
	Dividends declared per common share	$	0.795	$	0.78
	(a)	Certain stock options and performance stock awards were not included in the dilutive securities calculation because either the option exercise prices were greater than the average market price of the common shares during the presented periods, or performance measures related to the awards had not yet been met.
	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, which is approximately 85 percent of the total number of shares of Duke Energy common stock expected to be repurchased under the ASR. The total fair market value of the delivered shares, based on the closing Duke Energy stock price of $76.97 per share at the commencement of the ASR, was $1.275 billion. The final number of shares to be repurchased is dependent 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 and subject to adjustments pursuant to the terms and conditions of the ASR agreements. The delivery of additional shares of common stock to Duke Energy or delivery of shares of common stock or cash payment, at Duke Energy’s election, to the Dealers from Duke Energy may be required under certain circumstances. Final settlement of the ASR transaction is expected to occur by the end of the third quarter of 2015.
	The $225 million unsettled portion of the ASR meets the criteria to be accounted for as a forward contract indexed to Duke Energy's stock and qualifies as an equity instrument. The company recorded the $1.5 billion payment as a reduction to common stock, which included the $1.275 billion of initial shares repurchased and the unsettled forward contract of $225 million, as of April 6, 2015. The initial delivery of shares will result in a reduction to Duke Energy's common stock outstanding used to calculate earnings per share beginning in the second quarter of 2015.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION
	For employee awards, equity classified stock-based compensation cost is measured at the service inception date or the grant date, based on the estimated achievement of certain performance metrics or the fair value of the award, and is recognized as expense or capitalized as a component of property, plant and equipment over the requisite service period.
	Duke Energy recorded pretax stock-based compensation expense as follows.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Restricted stock unit awards	$	9	$	11
	Performance awards	5		5
	Total	$	14	$	16
	Tax benefit associated with stock-based compensation expense	$	5	$	6
	Stock-based compensation costs capitalized	1		1

Employee_Benefit_Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS
	DEFINED BENEFIT RETIREMENT PLANS
	Duke Energy maintains, and the Subsidiary Registrants participate in, qualified, non-contributory defined benefit retirement plans. The plans cover most U.S. employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits equal to a percentage of current eligible earnings based on age and/or years of service, and interest credits. Certain employees are covered under plans that use a final average earnings formula. Under these average earnings formulas, a plan participant accumulates a retirement benefit equal to the sum of percentages of their (i) highest three-year or four-year average earnings, (ii) highest three-year or four-year average earnings in excess of covered compensation per year of participation (maximum of 35 years) and/or (iii) highest three-year or four-year average earnings times years of participation in excess of 35 years. Duke Energy also maintains, and the Subsidiary Registrants participate in, non-qualified, non-contributory defined benefit retirement plans which cover certain executives. As of January 1, 2014, the qualified and non-qualified non-contributory defined benefit plans are closed to new and rehired non-union and certain unionized employees.
	Duke Energy uses a December 31 measurement date for its defined benefit retirement plan assets and obligations. Duke Energy’s policy is to fund amounts on an actuarial basis to provide assets sufficient to meet benefit payments to be paid to plan participants. The following table includes information related to the Duke Energy Registrants’ contributions to its U.S. qualified defined benefit pension plans.
		Three Months Ended March 31, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Contributions	$	132		$	42		$	42		$	21		$	21		$	1		$	9
	Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the three months ended March 31, 2014.
	Net periodic benefit costs disclosed in the tables below represent the cost of the respective benefit plan for the periods presented. However, portions of the net periodic benefit costs disclosed in the tables below have been capitalized as a component of property, plant and equipment. Amounts presented in the tables below for the Subsidiary Registrants represent the amounts of pension and other post-retirement benefit costs allocated by Duke Energy for employees of the Subsidiary Registrants. Additionally, the Subsidiary Registrants are allocated their proportionate share of pension and post-retirement benefit costs for employees of Duke Energy’s shared services affiliate that provide support to the Subsidiary Registrants. These allocated amounts are included in the governance and shared service costs discussed in Note 8.
	QUALIFIED PENSION PLANS
	The following tables include the components of net periodic pension costs for qualified pension plans.
		Three Months Ended March 31, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy 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
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Service cost	$	34		$	10		$	10		$	5		$	5		$	1		$	2
	Interest cost on projected benefit obligation	86			21			28			13			14			5			7
	Expected return on plan assets	(128		)	(33		)	(43		)	(21		)	(21		)	(7		)	(9		)
	Amortization of actuarial loss	37			9			17			8			8			1			3
	Amortization of prior service credit	(4		)	(2		)	(1		)	—			—			—			—
	Other	2			1			1			—			—			—			—
	Net periodic pension costs	$	27		$	6		$	12		$	5		$	6		$	—		$	3
	NON-QUALIFIED PENSION PLANS
	The net periodic pension costs for non-qualified pension plans were not material for the three months ended March 31, 2015 and 2014.
	OTHER POST-RETIREMENT BENEFIT PLANS
	Duke Energy provides, and the Subsidiary Registrants participate in, some health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. The health care benefits include medical, dental and prescription drug coverage and are subject to certain limitations, such as deductibles and co-payments.
	Duke Energy did not make any pre-funding contributions to its other post-retirement benefit plans during the three months ended March 31, 2015 and 2014.
	The following tables include the components of net periodic other post-retirement benefit costs.
		Three Months Ended March 31, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy 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	)	$	—		$	—
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Service cost	$	2		$	—		$	1		$	—		$	1		$	—		$	—
	Interest cost on accumulated post-retirement benefit obligation	12			3			6			3			3			—			1
	Expected return on plan assets	(3		)	(2		)	—			—			—			—			—
	Amortization of actuarial loss	10			1			10			7			2			—			—
	Amortization of prior service credit	(31		)	(3		)	(24		)	(18		)	(5		)	—			—
	Net periodic other post-retirement benefit costs	$	(10	)	$	(1	)	$	(7	)	$	(8	)	$	1		$	—		$	1
	EMPLOYEE SAVINGS PLANS
	Duke Energy sponsors, and the Subsidiary Registrants participate in, employee savings plans that cover substantially all U.S. employees. Effective January 1, 2015, all employee savings plans were merged into a single plan. Most employees participate in a matching contribution formula where Duke Energy provides a matching contribution generally equal to 100 percent of employee before-tax and Roth 401(k) contributions of up to 6 percent of eligible pay per pay period. Prior to 2015, Duke Energy also provided a match on after-tax contributions for certain plans. Dividends on Duke Energy shares held by the savings plans are charged to retained earnings when declared and shares held in the plans are considered outstanding in the calculation of basic and diluted earnings per share.
	As of January 1, 2014, for new and rehired non-union and certain unionized employees who are not eligible to participate in Duke Energy’s defined benefit plans, an additional employer contribution of 4 percent of eligible pay per pay period, subject to three-year vesting, is provided to the employee’s savings plan account.
	The following table includes pretax employer matching contributions, as well as the additional contribution of 4 percent of eligible pay per pay period for employees not eligible to participate in a defined benefit plan, made by Duke Energy and expensed by the Subsidiary Registrants.
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Three Months Ended March 31,
	2015	$	49		$	16		$	14		$	11		$	4		$	1		$	2
	2014	43			14			12			9			4			1			2

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table.
		Three Months Ended March 31,
		2015		2014
	Duke Energy	31.9	%	31.2	%
	Duke Energy Carolinas	35.8	%	37.4	%
	Progress Energy	35.4	%	36.9	%
	Duke Energy Progress	33.8	%	36.6	%
	Duke Energy Florida	38.6	%	38.5	%
	Duke Energy Ohio	36.7	%	36.4	%
	Duke Energy Indiana	36.6	%	36.8	%
	The decrease in the effective tax rate for Duke Energy Carolinas for the three months ended March 31, 2015 is primarily due to the reduction of state rates in certain jurisdictions and the tax benefit related to the manufacturing deduction in 2015 as the prior-year deduction was limited by taxable income.
	The decrease in the effective tax rate for Progress Energy for the three months ended March 31, 2015 is primarily due to an increase in AFUDC-equity.
	The decrease in the effective tax rate for Duke Energy Progress for the three months ended March 31, 2015 is primarily due to an increase in AFUDC-equity.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS
	For information on subsequent events related to acquisitions and dispositions, regulatory matters, commitments and contingencies, debt and credit facilities and common stock see Notes 2, 4, 5, 6 and 13, respectively.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Policy)	3 Months Ended
	Mar. 31, 2015
Policy Text Block [Line Items]
Nature of Operations and Basis of Consolidation	NATURE OF OPERATIONS AND BASIS OF CONSOLIDATION
	Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina, subject to regulation by the Federal Energy Regulatory Commission (FERC). Duke Energy operates in the United States (U.S.) and Latin America primarily through its direct and indirect subsidiaries. Duke Energy’s subsidiaries include its subsidiary registrants, Duke Energy Carolinas, LLC (Duke Energy Carolinas); Progress Energy, Inc. (Progress Energy); Duke Energy Progress, Inc. (Duke Energy Progress); Duke Energy Florida, Inc. (Duke Energy Florida); Duke Energy Ohio, Inc. (Duke Energy Ohio) and Duke Energy Indiana, Inc. (Duke Energy Indiana). When discussing Duke Energy’s consolidated financial information, it necessarily includes the results of its six separate subsidiary registrants (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants (Duke Energy Registrants).
	These Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and subsidiaries where the respective Duke Energy Registrants have control. These Condensed Consolidated Financial Statements also reflect the Duke Energy Registrants’ proportionate share of certain jointly owned generation and transmission facilities.
	Duke Energy Carolinas is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), Public Service Commission of South Carolina (PSCSC), U.S. Nuclear Regulatory Commission (NRC) and FERC. Substantially all of Duke Energy Carolinas’ operations qualify for regulatory accounting.
	Progress Energy is a public utility holding company headquartered in Raleigh, North Carolina, subject to regulation by the FERC. Progress Energy conducts operations through its wholly owned subsidiaries, Duke Energy Progress and Duke Energy Florida. Substantially all of Progress Energy’s operations qualify for regulatory accounting.
	Duke Energy Progress is a regulated public utility primarily engaged in the generation, transmission, distribution and sale of electricity in portions of North Carolina and South Carolina. Duke Energy Progress is subject to the regulatory provisions of the NCUC, PSCSC, NRC and FERC. Substantially all of Duke Energy Progress’ operations qualify for regulatory accounting.
	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, in the generation and sale of electricity in portions of Kentucky, and the transportation and sale of natural gas in portions of Ohio and Kentucky. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers. Operations in Kentucky are conducted through its wholly owned subsidiary, Duke Energy Kentucky, Inc. (Duke Energy Kentucky). References herein to Duke Energy Ohio collectively include Duke Energy Ohio and its subsidiaries, unless otherwise noted. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), Kentucky Public Service Commission (KPSC) and FERC. Duke Energy Ohio applied regulatory accounting to a portion of its operations. 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.
Basis of Accounting	BASIS OF PRESENTATION
	Duke Energy completed the sale of Duke Energy Ohio's nonregulated Midwest generation business and Duke Energy Retail Sales LLC to Dynegy on April 2, 2015. The results of operations of these businesses have been classified as Discontinued Operations on the Condensed Consolidated Statements of Operations for all periods presented. Duke Energy has elected to present cash flows of discontinued operations combined with cash flows of continuing operations. Unless otherwise noted, the notes to these Condensed Consolidated Financial Statements exclude amounts related to discontinued operations for all periods presented, assets held for sale and liabilities associated with assets held for sale as of March 31, 2015. 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, 2014.
	The information in these combined notes relate to each of the Duke Energy Registrants as noted in the Index to the Combined Notes to Condensed Consolidated Financial Statements. However, none of the registrants makes any representations as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself.
	These Condensed Consolidated Financial Statements reflect all normal recurring adjustments in the opinion of the respective companies’ management, necessary to fairly present the financial position and results of operations of each of the Duke Energy Registrants. Amounts reported in Duke Energy’s interim Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants’ interim Condensed Consolidated Statements of Operations and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to effects of seasonal temperature variations on energy consumption, regulatory rulings, timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors.
Use of Estimates	In preparing financial statements that conform to GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities, the reported amounts of revenues and expenses, and the disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Unbilled Revenue	UNBILLED REVENUE
	Revenues on sales of electricity and natural gas are recognized when service is provided or the product is delivered. Unbilled revenues are recognized by applying customer billing rates to the estimated volumes of energy delivered but not yet billed. Unbilled revenues can vary significantly from period to period as a result of seasonality, weather, customer usage patterns, customer mix, average price in effect for customer classes and meter reading schedules.
	Unbilled revenues are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets as shown in the following table.
Duke Energy Ohio [Member]
Policy Text Block [Line Items]
Unbilled Revenue	Additionally, Duke Energy Ohio and Duke Energy Indiana sell, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 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, on a revolving basis, nearly all of their retail accounts receivable, including receivables for unbilled revenues, to an affiliate, Cinergy Receivables Company, LLC (CRC), and account for the transfers of receivables as sales. Accordingly, the receivables sold are not reflected on the Condensed Consolidated Balance Sheets of Duke Energy Ohio and Duke Energy Indiana. See Note 12 for further information. These receivables for unbilled revenues are shown in the table below.

Organization_and_Basis_of_Pres2

Organization and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2015
Organization And Basis Of Presentation [Line Items]
Schedule of Excise Taxes	Excise taxes recognized on a gross basis are recorded as Operating Revenues and Property and other taxes on the Condensed Consolidated Statements of Operations. The following table provides the amount of excise taxes accounted for on a gross basis.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy	$	100	$	167
	Duke Energy Carolinas	9		46
	Progress Energy	49		77
	Duke Energy Progress	4		32
	Duke Energy Florida	45		45
	Duke Energy Ohio	32		34
	Duke Energy Indiana	10		10
Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	Unbilled revenues are included within Receivables and Restricted receivables of variable interest entities on the Condensed Consolidated Balance Sheets as shown in the following table.
	(in millions)	March 31, 2015		December 31, 2014
	Duke Energy	$	710	$	827
	Duke Energy Carolinas	257		295
	Progress Energy	188		217
	Duke Energy Progress	114		135
	Duke Energy Florida	74		82
	Duke Energy Ohio	1		—
	Duke Energy Indiana	28		27
Duke Energy Ohio [Member] | Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below.
	(in millions)	March 31, 2015		December 31, 2014
	Duke Energy Ohio	$	62	$	79
	Duke Energy Indiana	91		112
Duke Energy Indiana [Member] | Unbilled Revenues [Member]
Organization And Basis Of Presentation [Line Items]
Schedule Of Unbilled Revenues With Restricted Receivables	These receivables for unbilled revenues are shown in the table below.
	(in millions)	March 31, 2015		December 31, 2014
	Duke Energy Ohio	$	62	$	79
	Duke Energy Indiana	91		112

Acquisitions_and_Dispositions_

Acquisitions and Dispositions (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Generation Facilities of Disposal Group	The following table presents information related to the Duke Energy Ohio generation plants included in the Disposal Group.
	Facility	Plant Type		Primary Fuel		Location		Total MW Capacity(d)		Owned MW Capacity(d)	Ownership Interest
	Stuart(a)(c)	Fossil Steam		Coal		OH		2,308		900	39	%
	Zimmer(a)	Fossil Steam		Coal		OH		1,300		605	46.5	%
	Hanging Rock	Combined Cycle		Natural Gas		OH		1,226		1,226	100	%
	Miami Fort (Units 7 and 8) (b)	Fossil Steam		Coal		OH		1,020		652	64	%
	Conesville(a)(c)	Fossil Steam		Coal		OH		780		312	40	%
	Washington	Combined Cycle		Natural Gas		OH		617		617	100	%
	Fayette	Combined Cycle		Natural Gas		PA		614		614	100	%
	Killen(b)(c)	Fossil Steam		Coal		OH		600		198	33	%
	Lee	Combustion Turbine		Natural Gas		IL		568		568	100	%
	Dick's Creek	Combustion Turbine		Natural Gas		OH		136		136	100	%
	Miami Fort	Combustion Turbine		Oil		OH		56		56	100	%
	Total Midwest Generation							9,225		5,884
	(a)	Jointly owned with America Electric Power Generation Resources and The Dayton Power & Light Company.
	(b)	Jointly owned with The Dayton Power & Light Company.
	(c)	Facility is not operated by Duke Energy Ohio.
	(d)	Total MW capacity is based on summer capacity.
Income Statement Disclosures	The results of operations of the Disposal Group are classified as discontinued operations in the accompanying Condensed Consolidated Statements of Operations and Comprehensive Income. Certain immaterial costs that may be eliminated as a result of the sale have remained in continuing operations. The following table presents the results of discontinued operations.
	Duke Energy
			Three Months Ended March 31,
	(in millions)		2015				2014
	Operating Revenues		$	543			$	368
	Estimated loss on disposition		(43		)		(1,287		)
	Income (loss) before income taxes		$	147			$	(1,303	)
	Income tax expense (benefit)		51				(466		)
	Income (loss) from discontinued operations of the Disposal Group		96				(837		)
	Other, net of tax(a)		(5		)		(6		)
	Income (Loss) from Discontinued Operations, net of tax		$	91			$	(843	)
	(a)	Other discontinued operations relates to prior sales of businesses and includes indemnifications provided for certain legal, tax and environmental matters, and foreign currency translation adjustments.
	Duke Energy Ohio
		Three Months Ended March 31,
	(in millions)	2015				2014
	Operating Revenues	$	412			$	195
	Estimated loss on disposition	(44		)		(1,323		)
	Income (loss) before income taxes	$	140			$	(1,354	)
	Income tax expense (benefit)	50				(479		)
	Income (Loss) from Discontinued Operations, net of tax	$	90			$	(875	)
Held for sale	The following table presents the Disposal Group's carrying values in the Condensed Consolidated Balance Sheets' major classes of Assets held for sale and Liabilities associated with assets held for sale.
		March 31, 2015
	(in millions)	Duke				Duke
		Energy				Energy
						Ohio
	Current assets	$	354			$	295
	Investments and other assets	50				45
	Property, plant and equipment	2,553				2,520
	Total Assets held for sale	$	2,957			$	2,860
	Current liabilities	$	146			$	129
	Deferred credits and other liabilities	26				25
	Total Liabilities associated with assets held for sale	$	172			$	154

Business_Segments_Tables

Business Segments (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting Information [Line Items]
Business Segment Data	The following table summarizes the net loss for Other at each of these registrants.
		Three Months Ended March 31,
	(in millions)	2015			2014
	Duke Energy Carolinas	$	(8	)	$	(21	)
	Progress Energy(a)	(42		)	(52		)
	Duke Energy Progress	(4		)	(10		)
	Duke Energy Florida	(3		)	(4		)
	Duke Energy Indiana	(2		)	(3		)
	(a)	Other for Progress Energy also includes interest expense on corporate debt instruments of $60 million and $63 million for the three months ended March 31, 2015 and 2014, respectively.
		Three Months Ended March 31, 2015
	(in millions)	Regulated Utilities			International			Commercial			Total			Other			Eliminations			Consolidated
					Energy			Power			Reportable
											Segments
	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		$	1		$	811		$	(37	)	$	(1	)	$	773
	Add back noncontrolling interests component																			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 Progress Energy merger of $13 million.
		Three Months Ended March 31, 2014
	(in millions)	Regulated Utilities			International			Commercial			Total			Other			Eliminations			Consolidated
					Energy			Power			Reportable
											Segments
	Unaffiliated revenues	$	5,795		$	382		$	81		$	6,258		$	5		$	—		$	6,263
	Intersegment revenues	10			—			—			10			20			(30		)	—
	Total revenues	$	5,805		$	382		$	81		$	6,268		$	25		$	(30	)	$	6,263
	Segment income (loss)(a)(b)	$	737		$	130		$	(32	)	$	835		$	(87	)	$	(2	)	$	746
	Add back noncontrolling interest																			4
	Loss from discontinued operations, net of tax																			(843		)
	Net loss																			$	(93	)
	(a)	Commercial Power recorded a pretax impairment charge of $94 million related to Ohio Valley Electric Corporation (OVEC). See Note 12 for additional information.
	(b)    Other includes after-tax costs to achieve the Progress Energy merger of $34 million.
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Business Segment Data
		Three Months Ended March 31, 2015
	(in millions)	Regulated Utilities			Commercial Power			Total Reportable Segments			Other			Eliminations			Consolidated
	Unaffiliated revenues	$	572		$	14		$	586		$	—		$	—		$	586
	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
		Three Months Ended March 31, 2014
	(in millions)	Regulated Utilities			Commercial Power			Total Reportable Segments			Other			Eliminations			Consolidated
	Unaffiliated revenues	$	562		$	13		$	575		$	—		$	—		$	575
	Total revenues	$	562		$	13		$	575		$	—		$	—		$	575
	Segment income (loss)(a)	$	61		$	(74	)	$	(13	)	$	(2	)	$	—		$	(15	)
	Loss from discontinued operations, net of tax																(875		)
	Net loss																$	(890	)
	(a)    Commercial Power recorded a pretax impairment charge of $94 million related to OVEC. See Note 12 for additional information.

Regulatory_Matters_Tables

Regulatory Matters (Tables)	3 Months Ended
	Mar. 31, 2015
Public Utilities, General Disclosures [Line Items]
Schedule of Potential Plant Retirements	The table below contains the net carrying value of generating facilities planned for retirement or being evaluated for potential retirement included in recent IRPs. Dollar amounts in the table below are included in Net property, plant and equipment on the Condensed Consolidated Balance Sheets.
		31-Mar-15
		Duke Energy		Progress Energy(b)		Duke Energy Florida(b)			Duke Energy Ohio(c)		Duke Energy Indiana(d)
	Capacity (in MW)	1,704		873		873			163		668
	Remaining net book value (in millions)(a)	$	243	$	120	$	120		$	9	$	114
	(a)	Included in Property, plant and equipment, net as of March 31, 2015, on the Condensed Consolidated Balance Sheets.
	(b)	Includes Crystal River Units 1 and 2.
	(c)	Includes Miami Fort Unit 6, which is expected to be retired by June 1, 2015.
	(d)	Includes Wabash River Units 2 through 6. Wabash River Unit 6 is being evaluated for potential conversion to natural gas. Duke Energy Indiana committed to retire or convert the Wabash River Units 2 through 5 by June 2018 in conjunction with a settlement agreement associated with the Edwardsport air permit.
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Schedule of MISO Exit Fee Obligations	The following table provides a reconciliation of the beginning and ending balances of Duke Energy Ohio’s recorded obligations related to its withdrawal from MISO. As of March 31, 2015, $73 million is recorded as a Regulatory asset on Duke Energy Ohio's Condensed Consolidated Balance Sheets.
	(in millions)	31-Dec-14		Provision /		Cash			31-Mar-15
				Adjustments		Reductions
	Duke Energy Ohio	$	94	$	—	$	(1	)	$	93

Commitments_and_Contingencies_

Commitments and Contingencies (Table)	3 Months Ended
	Mar. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Additional Possible Losses in Excess of Recorded Environmental Reserves	Additional losses in excess of recorded reserves that could be incurred for the stages of investigation, remediation and monitoring for environmental sites that have been evaluated at this time are presented in the table below.
	(in millions)
	Duke Energy	$	89
	Duke Energy Carolinas	25
	Progress Energy	15
	Duke Energy Progress	1
	Duke Energy Florida	14
	Duke Energy Ohio	42
	Duke Energy Indiana	7
Schedule of Loss Contingencies	The table below presents recorded reserves based on management’s best estimate of probable loss for legal matters discussed above, excluding asbestos-related reserves. Reserves are classified on the Condensed Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Accounts payable and Other within Current Liabilities. The reasonably possible range of loss for all non-asbestos-related matters in excess of recorded reserves is not material.
	(in millions)	March 31, 2015			December 31, 2014
	Reserves for Legal Matters
	Duke Energy	$	331		$	323
	Duke Energy Carolinas	72			72
	Progress Energy	93			93
	Duke Energy Progress	37			37
	Duke Energy Florida	34			36
	Duke Energy Ohio	10			—
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, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas		Progress Energy			Duke Energy Progress		Duke Energy Florida			Duke Energy Ohio			Duke Energy 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
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas		Progress Energy			Duke Energy Progress		Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Balance at beginning of period	$	79		$	11	$	27		$	8	$	19		$	27		$	7
	Provisions/adjustments	3			—		3			2		1			—			—
	Cash reductions	(1		)	—		(1		)	—		(1		)	—			—
	Balance at end of period	$	81		$	11	$	29		$	10	$	19		$	27		$	7

Debt_and_Credit_Facilities_Tab

Debt and Credit Facilities (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule Of Debt	The following table shows the significant components of Current maturities of long-term debt on the Condensed Consolidated Balance Sheets. The Duke Energy Registrants currently anticipate satisfying these obligations with cash on hand and proceeds from additional borrowings.
	(in millions)	Maturity Date		Interest Rate			March 31, 2015
	Unsecured Debt
	Duke Energy (Parent)	Apr-15		3.35	%		$	450
	Progress Energy (Parent)	Jan-16		5.625	%		300
	First Mortgage Bonds
	Duke Energy Progress	Apr-15		5.15	%		300
	Duke Energy Carolinas	Oct-15		5.3	%		500
	Duke Energy Florida	Nov-15		0.65	%		250
	Duke Energy Florida	Dec-15		5.1	%		300
	Duke Energy Progress	Dec-15		5.25	%		400
	Other						300
	Current maturities of long-term debt						$	2,800
Schedule Of Line Of Credit Facilities	Duke Energy has a Master Credit Facility with a capacity of $7.5 billion through January 2020. The Duke Energy Registrants, excluding Progress Energy (Parent), have borrowing capacity under the Master Credit Facility up to a specified sublimit for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower. The amount available under the Master Credit Facility has been reduced to backstop issuances of commercial paper, certain letters of credit and variable-rate demand tax-exempt bonds that may be put to the Duke Energy Registrants at the option of the holder. The table below includes the current borrowing sublimits and available capacity under the Master Credit Facility.
		March 31, 2015
	(in millions)	Duke Energy				Duke Energy (Parent)			Duke Energy Carolinas			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Facility size(a)	$	7,500			$	3,200		$	1,200		$	1,000		$	900		$	600		$	600
	Reduction to backstop issuances
	Commercial paper(b)	(3,256		)		(2,764		)	(300		)	—			(17		)	(25		)	(150		)
	Outstanding letters of credit	(66		)		(60		)	(4		)	(1		)	(1		)	—			—
	Tax-exempt bonds	(116		)		—			(35		)	—			—			—			(81		)
	Available capacity	$	4,062			$	376		$	861		$	999		$	882		$	575		$	369
	(a)	Represents the sublimit of each borrower.
	(b)	Duke Energy issued $475 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana. The balances are classified as Long-Term Debt Payable to Affiliated Companies in the Condensed Consolidated Balance Sheets.
Schedule of Long-term Debt Instruments [Table Text Block]	The following table summarizes significant debt issuances (in millions).
						Three Months Ended March 31, 2015
	Issuance Date	Maturity Date		Interest Rate			Duke			Duke
							Energy			Energy
										Carolinas
	First Mortgage Bonds
	March 2015(a)	Jun-45		3.75	%		$	500		$	500
	Total issuances						$	500		$	500
	(a)	Proceeds will be used to redeem $500 million of first mortgage bonds due October 2015.

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2015
Goodwill [Line Items]
Goodwill By Reportable Operating Segment	The following tables present goodwill by reportable operating segment for Duke Energy and Duke Energy Ohio.
	Duke Energy
	(in millions)	Regulated Utilities			International Energy			Commercial Power			Total
	Balance at December 31, 2014
	Goodwill	$	15,950		$	307		$	935		$	17,192
	Accumulated impairment charges	—			—			(871		)	(871		)
	Balance at December 31, 2014, as adjusted for accumulated impairment charges	15,950			307			64			16,321
	Foreign exchange and other changes	—			(16		)	—			(16		)
	Acquisitions	—			—			24			24
	Balance at March 31, 2015
	Goodwill	15,950			291			959			17,200
	Accumulated impairment charges	—			—			(871		)	(871		)
	Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	15,950		$	291		$	88		$	16,329
Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill By Reportable Operating Segment	Duke Energy Ohio
	(in millions)	Regulated Utilities			Commercial Power			Total
	Balance at December 31, 2014
	Goodwill	$	1,136		$	1,188		$	2,324
	Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
	Balance at December 31, 2014, as adjusted for accumulated impairment charges	920			—			920
	Balance at March 31, 2015
	Goodwill	1,136			1,188			2,324
	Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
	Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	920		$	—		$	920

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2015
Duke Energy Carolinas [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Progress Energy [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Duke Energy Progress [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Duke Energy Florida [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Duke Energy Ohio [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.
Duke Energy Indiana [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions, Other Revenue and Expense	Material amounts related to transactions with related parties included in the Condensed Consolidated Statements of Operations and Comprehensive Income are presented in the following table.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Duke Energy Carolinas
	Corporate governance and shared service expenses(a)	$	219	$	222
	Indemnification coverages(b)	6		5
	Joint Dispatch Agreement (JDA) revenue(c)	26		97
	Joint Dispatch Agreement (JDA) expense(c)	57		51
	Progress Energy
	Corporate governance and shared services provided by Duke Energy(a)	$	167	$	178
	Indemnification coverages(b)	10		8
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Progress
	Corporate governance and shared service expenses(a)	$	101	$	96
	Indemnification coverages(b)	4		4
	JDA revenue(c)	57		51
	JDA expense(c)	26		97
	Duke Energy Florida
	Corporate governance and shared service expenses(a)	$	66	$	81
	Indemnification coverages(b)	6		4
	Duke Energy Ohio
	Corporate governance and shared service expenses(a)	$	85	$	77
	Indemnification coverages(b)	3		3
	Duke Energy Indiana
	Corporate governance and shared service expenses(a)	$	89	$	105
	Indemnification coverages(b)	2		3
	(a)	The Subsidiary Registrants are charged their proportionate share of corporate governance and other shared services costs, primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(b)	The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.
	(c)	Duke Energy Carolinas and Duke Energy Progress participate in a JDA which allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.

Derivatives_and_Hedging_Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amounts of Outstanding Derivative Positions	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. Amounts disclosed represent the absolute value of notional amounts. 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, 2015
		Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Electricity (gigawatt-hours)(a)	22,810			—			—			—			—			17,734			571
	Natural gas (millions of decatherms)	666			57			333			111			222			276			—
		December 31, 2014
		Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Electricity (gigawatt-hours)(a)	25,370			—			—			—			—			19,141			—
	Natural gas (millions of decatherms)	676			35			328			116			212			313			—
	(a)	Amounts at Duke Energy Ohio include intercompany positions that eliminate at Duke Energy.
	The following table shows notional amounts for derivatives related to interest rate risk.
		March 31, 2015																December 31, 2014
	(in millions)	Duke				Duke Energy Progress				Duke				Duke Energy Ohio				Duke				Duke				Duke Energy Ohio
		Energy								Energy								Energy				Energy
										Florida												Florida
	Cash flow hedges(a)	$	750			$	—			$	—			$	—			$	750			$	—			$	—
	Undesignated contracts	527				250				250				27				277				250				27
	Total notional amount	$	1,277			$	250			$	250			$	27			$	1,027			$	250			$	27
	(a)	Duke Energy includes amounts related to consolidated Variable Interest Entities (VIEs) of $541 million at March 31, 2015 and December 31, 2014, respectively.
Location And Fair Value Of Derivatives Recognized in the Condensed Consolidated Balance Sheets	The following tables show the fair value of derivatives and the line items in the Condensed Consolidated Balance Sheets where they are reported. Although derivatives subject to master netting arrangements are netted on the Condensed Consolidated Balance Sheets, the fair values presented below show gross and cash collateral on the derivatives has not been netted against the fair values shown.
	Derivative Assets		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Commodity Contracts
	Not Designated as Hedging Instruments
	Current Assets: Other		$	4			$	—			$	—			$	—			$	—			$	—			$	3
	Current Assets: Assets held for sale		45				—				—				—				—				78				—
	Investments and Other Assets: Assets held for sale		21				—				—				—				—				48				—
	Current Liabilities: Other		1				—				1				—				1				—				—
	Current Liabilities: Assets held for sale		206				—				—				—				—				206				—
	Deferred Credits and Other Liabilities: Other		2				—				2				—				2				—				—
	Deferred Credits and Other Liabilities: Assets held for sale		123				—				—				—				—				123				—
	Total Derivative Assets - Commodity Contracts		$	402			$	—			$	3			$	—			$	3			$	455			$	3
	Interest Rate Contracts
	Designated as Hedging Instruments
	Investments and Other Assets: Other		$	3			$	—			$	—			$	—			$	—			$	—			$	—
	Not Designated as Hedging Instruments
	Current Assets: Other		5				—				5				2				3				—				—
	Investments and Other Assets: Other		1				—				1				—				1				—				—
	Total Derivative Assets - Interest Rate Contracts		9				—				6				2				4				—				—
	Total Derivative Assets		$	411			$	—			$	9			$	2			$	7			$	455			$	3
	Derivative Liabilities		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Commodity Contracts
	Not Designated as Hedging Instruments
	Current Assets: Assets held for sale		$	21			$	—			$	—			$	—			$	—			$	59			$	—
	Investments and Other Assets: Assets held for sale		7				—				—				—				—				23				—
	Current Liabilities: Other		308				19				289				100				189				—				—
	Current Liabilities: Assets held for sale		263				—				—				—				—				249				—
	Deferred Credits and Other Liabilities: Other		112				8				104				26				78				—				—
	Deferred Credits and Other Liabilities: Assets held for sale		209				—				—				—				—				207				—
	Total Derivative Liabilities - Commodity Contracts		$	920			$	27			$	393			$	126			$	267			$	538			$	—
	Interest Rate Contracts
	Designated as Hedging Instruments
	Current Liabilities: Other		$	14			$	—			$	—			$	—			$	—			$	1			$	—
	Deferred Credits and Other Liabilities: Other		38				—				—				—				—				6				—
	Not Designated as Hedging Instruments
	Current Liabilities: Other		1				—				—				—				—				—				—
	Deferred Credits and Other Liabilities: Other		11				—				5				5				—				—				—
	Total Derivative Liabilities - Interest Rate Contracts		64				—				5				5				—				7				—
	Total Derivative Liabilities		$	984			$	27			$	398			$	131			$	267			$	545			$	—
	Derivative Assets		December 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Commodity Contracts
	Not Designated as Hedging Instruments
	Current Assets: Other		$	18			$	—			$	—			$	—			$	—			$	1			$	—
	Current Assets: Assets Held for sale		15				—				—				—				—				28				—
	Investments and Other Assets: Other		3				—				—				—				—				—				—
	Investments and Other Assets: Assets held for sale		15				—				—				—				—				26				—
	Current Liabilities: Other		1				—				—				—				—				—				—
	Current Liabilities: Assets held for sale		174				—				—				—				—				175				—
	Deferred Credits and Other Liabilities: Other		2				—				—				—				—				—				—
	Deferred Credits and Other Liabilities: Assets held for sale		111				—				—				—				—				111				—
	Total Derivative Assets - Commodity Contracts		$	339			$	—			$	—			$	—			$	—			$	341			$	—
	Interest Rate Contracts
	Designated as Hedging Instruments
	Current Assets: Other		$	—			$	—			$	—			$	—			$	—			$	—			$	14
	Investments and Other Assets: Other		10				—				—				—				—				—				—
	Not Designated as Hedging Instruments
	Current Assets: Other		2				—				2				—				2				—				—
	Total Derivative Assets - Interest Rate Contracts		12				—				2				—				2				—				14
	Total Derivative Assets		$	351			$	—			$	2			$	—			$	2			$	341			$	14
	Derivative Liabilities		December 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
Commodity Contracts
Designated as Hedging Instruments
Current Liabilities: Other		$	—			$	—			$	1			$	1			$	—			$	—			$	—
Not Designated as Hedging Instruments
Current Assets: Assets held for sale		—				—				—				—				—				4				—
Investments and Other Assets: Assets held for sale		—				—				—				—				—				4				—
Current Liabilities: Other		307				14				288				108				180				—				—
Current Liabilities: Assets held for sale		253				—				—				—				—				252				—
Deferred Credits and Other Liabilities: Other		91				5				80				23				57				—				—
Deferred Credits and Other Liabilities: Assets held for sale		208				—				—				—				—				207				—
Total Derivative Liabilities - Commodity Contracts		$	859			$	19			$	369			$	132			$	237			$	467			$	—
Interest Rate Contracts
Designated as Hedging Instruments
Current Liabilities: Other		$	13			$	—			$	—			$	—			$	—			$	1			$	—
Deferred Credits and Other Liabilities: Other		29				—				—				—				—				5				—
Not Designated as Hedging Instruments
Current Liabilities: Other		1				—				—				—				—				—				—
Deferred Credits and Other Liabilities: Other		7				—				2				—				2				—				—
Total Derivative Liabilities - Interest Rate Contracts		50				—				2				—				2				6				—
Total Derivative Liabilities		$	909			$	19			$	371			$	132			$	239			$	473			$	—
Offsetting Assets	The following tables show the balance sheet location of derivative contracts subject to enforceable master netting agreements and include collateral posted to offset the net position. This disclosure is intended to enable users to evaluate the effect of netting arrangements on financial position. The amounts shown were calculated by counterparty. Accounts receivable or accounts payable may also be available to offset exposures in the event of bankruptcy. These amounts are not included in the tables below.
	Derivative Assets		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Current(a)
	Gross amounts recognized		$	261			$	—			$	6			$	2			$	4			$	284			$	3
	Gross amounts offset		(227		)		—				(1		)		—				(1		)		(265		)		—
	Net amounts subject to master netting		34				—				5				2				3				19				3
	Amounts not subject to master netting		—				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	34			$	—			$	5			$	2			$	3			$	19			$	3
	Non-Current(b)
	Gross amounts recognized		$	150			$	—			$	3			$	—			$	3			$	171			$	—
	Gross amounts offset		(131		)		—				(2		)		—				(2		)		(145		)		—
	Net amounts subject to master netting		19				—				1				—				1				26				—
	Amounts not subject to master netting		—				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	19			$	—			$	1			$	—			$	1			$	26			$	—
	(a)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Current Assets on the Condensed Consolidated Balance Sheets.
	(b)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	Derivative Assets		December 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Current(a)
	Gross amounts recognized		$	210			$	—			$	2			$	—			$	2			$	204			$	14
	Gross amounts offset		(153		)		—				(2		)		—				(2		)		(179		)		—
	Net amounts subject to master netting		57				—				—				—				—				25				14
	Amounts not subject to master netting		—				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	57			$	—			$	—			$	—			$	—			$	25			$	14
	Non-Current(b)
	Gross amounts recognized		$	136			$	—			$	—			$	—			$	—			$	137			$	—
	Gross amounts offset		(88		)		—				—				—				—				(114		)		—
	Net amounts subject to master netting		48				—				—				—				—				23				—
	Amounts not subject to master netting		5				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	53			$	—			$	—			$	—			$	—			$	23			$	—
	(a)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Current Assets on the Condensed Consolidated Balance Sheets.
	(b)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Assets held for sale within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
Offsetting Liabilities
	Derivative Liabilities		December 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Current(c)
	Gross amounts recognized		$	573			$	14			$	289			$	109			$	180			$	257			$	—
	Gross amounts offset		(213		)		—				(17		)		—				(17		)		(222		)		—
	Net amounts subject to master netting		360				14				272				109				163				35				—
	Amounts not subject to master netting		1				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	361			$	14			$	272			$	109			$	163			$	35			$	—
	Non-Current(d)
	Gross amounts recognized		$	319			$	5			$	82			$	23			$	59			$	216			$	—
	Gross amounts offset		(173		)		—				(8		)		—				(8		)		(193		)		—
	Net amounts subject to master netting		146				5				74				23				51				23				—
	Amounts not subject to master netting		16				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	162			$	5			$	74			$	23			$	51			$	23			$	—
	(c)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Current Liabilities on the Condensed Consolidated Balance Sheets.
	(d)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
	Derivative Liabilities		March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Current(c)
	Gross amounts recognized		$	607			$	19			$	289			$	100			$	189			$	309			$	—
	Gross amounts offset		(293		)		—				(32		)		(1		)		(31		)		(300		)		—
	Net amounts subject to master netting		314				19				257				99				158				9				—
	Amounts not subject to master netting		—				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	314			$	19			$	257			$	99			$	158			$	9			$	—
	Non-Current(d)
	Gross amounts recognized		$	377			$	8			$	109			$	31			$	78			$	236			$	—
	Gross amounts offset		(216		)		—				(14		)		—				(14		)		(218		)		—
	Net amounts subject to master netting		161				8				95				31				64				18				—
	Amounts not subject to master netting		—				—				—				—				—				—				—
	Net amounts recognized on the Condensed Consolidated Balance Sheet		$	161			$	8			$	95			$	31			$	64			$	18			$	—
	(c)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Current Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Current Liabilities on the Condensed Consolidated Balance Sheets.
	(d)	Amounts for Duke Energy Registrants, except Duke Energy and Duke Energy Ohio, are included in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets. Amounts for Duke Energy and Duke Energy Ohio are included in Other and Liabilities associated with assets held for sale within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
Gains and Losses Recognized on Cash Flow Hedges	The following tables show the gains and losses recognized on cash flow hedges and the line items on the Condensed Consolidated Statements of Operations or Condensed Consolidated Balance Sheets where such gains and losses are included when reclassified from AOCI. Amounts for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt.
	There was no hedge ineffectiveness during the three months ended March 31, 2015 and 2014, and no gains or losses were excluded from the assessment of hedge effectiveness during the same periods.
			Three Months Ended March 31, 2015
	(in millions)		Duke Energy(a)				Duke Energy Carolinas				Duke Energy Indiana
	Pretax Gains (Losses) Recorded in AOCI
	Interest rate contracts		$	(11	)		$	—			$	—
	Total Pretax Gains (Losses) Recorded in AOCI		(11		)		—				—
	Location of Pretax Gains (Losses) Reclassified from AOCI into Earnings
	Interest rate contracts
	Interest expense		(1		)		(1		)		1
	Total Pretax Gains (Losses) Reclassified from AOCI into Earnings		$	(1	)		$	(1	)		$	1
	(a)    A $5 million pretax gain is expected to be recognized in earnings during the next 12 months as interest expense.
			Three Months Ended March 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Duke Energy Indiana
	Pretax Gains (Losses) Recorded in AOCI
	Interest rate contracts		$	2			$	—			$	—
	Total Pretax Gains (Losses) Recorded in AOCI		2				—				—
	Location of Pretax Gains (Losses) Reclassified from AOCI into Earnings
	Interest rate contracts
	Interest expense		(1		)		—				—
	Total Pretax Gains (Losses) Reclassified from AOCI into Earnings		$	(1	)		$	—			$	—
Gains and Losses Recognized on Undesignated Contracts	The following tables show the gains and losses during the year recognized on undesignated derivatives and the line items on the Condensed Consolidated Statements of Operations or the Condensed Consolidated Balance Sheets where the pretax gains and losses were reported. Amounts included in Regulatory Assets or Liabilities for commodity contracts are reclassified to earnings to match recovery through the fuel clause. Amounts included in Regulatory Assets or Liabilities for interest rate contracts are reclassified to earnings as interest expense over the term of the related debt. These amounts reclassified to earnings from Regulated Assets or Liabilities for commodity and interest rate contracts are excluded from the following tables.
			Three Months Ended March 31, 2015
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Location of Pretax Gains (Losses) Recognized in Earnings
	Commodity contracts
	Revenue: Regulated electric		$	1			$	—			$	—			$	—			$	—			$	—			$	1
	Revenue: Nonregulated electric and other		17				—				—				—				—				13				—
	Fuel used in electric generation and purchased power - nonregulated		37				—				—				—				—				37				—
	Interest rate contracts
	Interest expense		(1		)		—				(1		)		—				(1		)		—				—
	Total Pretax Gains (Losses) Recognized in Earnings		$	54			$	—			$	(1	)		$	—			$	(1	)		$	50			$	1
	Location of Pretax (Losses) Gains Recognized as Regulatory Assets or Liabilities
	Commodity contracts
	Regulatory assets		$	(340	)		$	(28	)		$	(314	)		$	(127	)		$	(187	)		$	—			$	2
	Regulatory liabilities		(2		)		—				—				—				—				2				(4		)
	Interest rate contracts
	Regulatory assets		(5		)		—				(4		)		(5		)		1				(1		)		—
	Regulatory liabilities		3				—				3				2				1				—				—
	Total Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities		$	(344	)		$	(28	)		$	(315	)		$	(130	)		$	(185	)		$	1			$	(2	)
			Three Months Ended March 31, 2014
	(in millions)		Duke Energy				Duke Energy Carolinas				Progress Energy				Duke Energy Progress				Duke Energy Florida				Duke Energy Ohio				Duke Energy Indiana
	Location of Pretax Gains (Losses) Recognized in Earnings
	Commodity contracts
	Revenue: Regulated electric		$	(4	)		$	—			$	(3	)		$	(3	)		$	—			$	—			$	—
	Revenue: Nonregulated electric and other		(397		)		—				—				—				—				(449		)		—
	Fuel used in electric generation and purchased power - regulated		7				—				7				7				—				—				—
	Fuel used in electric generation and purchased power - nonregulated		138				—				—				—				—				138				—
	Interest rate contracts
	Interest expense		(4		)		—				(4		)		(3		)		(1		)		—				—
	Total Pretax Gains (Losses) Recognized in Earnings		$	(260	)		$	—			$	—			$	1			$	(1	)		$	(311	)		$	—
	Location of Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities
	Commodity contracts
	Regulatory assets		$	(2	)		$	—			$	(2	)		$	17			$	(19	)		$	—			$	—
	Regulatory liabilities		27				—				—				—				—				2				—
	Interest rate contracts
	Regulatory assets		4				—				4				3				1				—				—
	Total Pretax Gains (Losses) Recognized as Regulatory Assets or Liabilities		$	29			$	—			$	2			$	20			$	(18	)		$	2			$	—
Derivative Contracts with Contingent Credit Features	The Duke Energy Registrants have elected to offset cash collateral and fair values of derivatives. For amounts to be netted, the derivative must be executed with the same counterparty under the same master netting agreement. Amounts disclosed below represent the receivables related to the right to reclaim cash collateral and payables related to the obligation to return cash collateral under master netting arrangements. Amounts for Duke Energy Carolinas and Duke Energy Indiana were not material.
		March 31, 2015				December 31, 2014
	(in millions)	Receivables				Receivables
	Duke Energy
	Amounts offset against net derivative positions	$	151			$	145
	Amounts not offset against net derivative positions	68				64
	Progress Energy
	Amounts offset against net derivative positions	43				23
	Duke Energy Progress
	Amounts offset against net derivative positions	1				—
	Duke Energy Florida
	Amounts offset against net derivative positions	42				23
	Duke Energy Ohio
	Amounts offset against net derivative positions	108				122
	Amounts not offset against net derivative positions	68				64
	The following tables show information with respect to derivative contracts that are in a net liability position and contain objective credit-risk-related payment provisions. Amounts for Duke Energy Indiana were not material.
		March 31, 2015
	(in millions)	Duke				Duke Energy Carolinas				Progress Energy				Duke				Duke				Duke
		Energy												Energy				Energy				Energy
														Progress				Florida				Ohio
	Aggregate fair value amounts of derivative instruments in a net liability position	$	834			$	11			$	344			$	110			$	234			$	479
	Fair value of collateral already posted	219				—				43				1				42				176
	Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	326				11				301				109				192				14
		December 31, 2014
	(in millions)	Duke				Duke Energy Carolinas				Progress Energy				Duke				Duke				Duke
		Energy												Energy				Energy				Energy
														Progress				Florida				Ohio
	Aggregate fair value amounts of derivative instruments in a net liability position	$	845			$	19			$	370			$	131			$	239			$	456
	Fair value of collateral already posted	209				—				23				—				23				186
	Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	407				19				347				131				216				41

Investments_in_Debt_and_Equity1

Investments in Debt and Equity Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	The following table presents the estimated fair value of investments in available-for-sale securities.
		March 31, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value(c)		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	106	$	—	$	—	$	136
	Equity securities	1,916		28		3,643		1,926		29		3,650
	Corporate debt securities	19		1		482		14		2		454
	Municipal bonds	7		2		227		5		—		184
	U.S. government bonds	24		1		864		19		2		978
	Other debt securities	2		2		148		1		2		147
	Total NDTF(d)	$	1,968	$	34	$	5,470	$	1,965	$	35	$	5,549
	Other Investments
	Cash and cash equivalents	$	—	$	—	$	29	$	—	$	—	$	15
	Equity securities	36		—		98		34		—		96
	Corporate debt securities	3		—		81		1		1		58
	Municipal bonds	3		1		75		3		1		76
	U.S. government bonds	—		—		45		—		—		27
	Other debt securities	1		2		83		1		1		80
	Total Other Investments(a)	$	43	$	3	$	411	$	39	$	3	$	352
	Total Investments	$	2,011	$	37	$	5,881	$	2,004	$	38	$	5,901
	(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
	(c)	These amounts exclude net pending trade receivables of $107 million as of March 31, 2015.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	110
	Due after one through five years	603
	Due after five through 10 years	488
	Due after 10 years	804
	Total	$	2,005
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)	2015		2014
	Realized gains	$	102	$	31
	Realized losses	14		4
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, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value(c)		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	42	$	—	$	—	$	51
	Equity securities	1,076		16		2,127		1,102		17		2,162
	Corporate debt securities	11		1		329		8		2		316
	Municipal bonds	2		1		90		1		—		62
	U.S. government bonds	8		1		296		7		1		308
	Other debt securities	2		2		128		1		2		133
	Total NDTF	$	1,099	$	21	$	3,012	$	1,119	$	22	$	3,032
	Other Investments
	Other debt securities	$	—	$	1	$	3	$	—	$	1	$	3
	Total Other Investments(a)	$	—	$	1	$	3	$	—	$	1	$	3
	Total Investments	$	1,099	$	22	$	3,015	$	1,119	$	23	$	3,035
	(a)	These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)	Substantially all these amounts represent other-than-temporary impairments on investments within Investment Trusts that have been recognized immediately as a regulatory asset.
	(c)	These amounts exclude net pending trade receivables of $107 million as of March 31, 2015.
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	5
	Due after one through five years	177
	Due after five through 10 years	257
	Due after 10 years	407
	Total	$	846
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)	2015		2014
	Realized gains	$	90	$	23
	Realized losses	12		1
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, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	64	$	—	$	—	$	85
	Equity securities	840		12		1,516		824		12		1,488
	Corporate debt securities	8		—		153		6		—		138
	Municipal bonds	5		1		137		4		—		122
	U.S. government bonds	16		—		568		12		1		670
	Other debt securities	—		—		20		—		—		14
	Total NDTF(c)	$	869	$	13	$	2,458	$	846	$	13	$	2,517
	Other Investments
	Cash and cash equivalents	$	—	$	—	$	18	$	—	$	—	$	15
	Municipal bonds	3		—		42		3		—		43
	Total Other Investments(a)	$	3	$	—	$	60	$	3	$	—	$	58
	Total Investments	$	872	$	13	$	2,518	$	849	$	13	$	2,575
	(a)    These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	84
	Due after one through five years	350
	Due after five through 10 years	160
	Due after 10 years	326
	Total	$	920
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)	2015		2014
	Realized gains	$	12	$	7
	Realized losses	1		2
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, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	40	$	—	$	—	$	50
	Equity securities	626		10		1,194		612		10		1,171
	Corporate debt securities	6		—		107		5		—		97
	Municipal bonds	5		1		135		4		—		120
	U.S. government bonds	10		—		251		9		1		265
	Other debt securities	—		—		12		—		—		8
	Total NDTF	$	647	$	11	$	1,739	$	630	$	11	$	1,711
	Other Investments
	Cash and cash equivalents	$	—	$	—	$	1	$	—	$	—	$	—
	Total Other Investments(a)	$	—	$	—	$	1	$	—	$	—	$	—
	Total Investments	$	647	$	11	$	1,740	$	630	$	11	$	1,711
	(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	12
	Due after one through five years	147
	Due after five through 10 years	113
	Due after 10 years	233
	Total	$	505
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)	2015		2014
	Realized gains	$	9	$	6
	Realized losses	1		2
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, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	NDTF
	Cash and cash equivalents	$	—	$	—	$	24	$	—	$	—	$	35
	Equity securities	214		2		322		212		2		317
	Corporate debt securities	2		—		46		1		—		41
	Municipal bonds	—		—		2		—		—		2
	U.S. government bonds	6		—		317		3		—		405
	Other debt securities	—		—		8		—		—		6
	Total NDTF	$	222	$	2	$	719	$	216	$	2	$	806
	Other Investments
	Cash and cash equivalents	$	—	$	—	$	2	$	—	$	—	$	1
	Municipal bonds	3		—		42		3		—		43
	Total Other Investments(a)	$	3	$	—	$	44	$	3	$	—	$	44
	Total Investments	$	225	$	2	$	763	$	219	$	2	$	850
	(a)    These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	72
	Due after one through five years	203
	Due after five through 10 years	47
	Due after 10 years	93
	Total	$	415
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)	2015		2014
	Realized gains	$	3	$	1
	Realized losses	—		1
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, 2015						December 31, 2014
	(in millions)	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses(b)		Estimated Fair Value
	Other Investments
	Equity securities	$	30	$	—	$	73	$	28	$	—	$	71
	Municipal bonds	—		1		30		—		1		30
	Total Other Investments(a)	$	30	$	1	$	103	$	28	$	1	$	101
	Total Investments	$	30	$	1	$	103	$	28	$	1	$	101
	(a)    These amounts are recorded in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
	(b)
Investments Classified by Contractual Maturity Date	The table below summarizes the maturity date for debt securities.
	(in millions)	March 31, 2015
	Due in one year or less	$	2
	Due after one through five years	17
	Due after five through 10 years	8
	Due after 10 years	3
	Total	$	30

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9. See Note 10 for additional information related to investments by major security type.
		March 31, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	3,643			$	3,476			$	3			$	164
	Nuclear decommissioning trust fund debt securities	1,827				542				1,285				—
	Other trading and available-for-sale equity securities	98				98				—				—
	Other trading and available-for-sale debt securities	323				73				245				5
	Derivative assets	52				7				22				23
	Total assets	5,943				4,196				1,555				192
	Derivative liabilities	(625		)		(119		)		(497		)		(9		)
	Net assets	$	5,318			$	4,077			$	1,058			$	183
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	3,650			$	3,493			$	6			$	151
	Nuclear decommissioning trust fund debt securities	1,899				648				1,251				—
	Other trading and available-for-sale equity securities	96				96				—				—
	Other trading and available-for-sale debt securities	263				41				217				5
	Derivative assets	110				49				24				37
	Total assets	6,018				4,327				1,498				193
	Derivative liabilities	(668		)		(162		)		(468		)		(38		)
	Net assets	$	5,350			$	4,165			$	1,030			$	155
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements. Amounts included in earnings for derivatives are primarily included in Operating Revenues.
		Three Months Ended March 31, 2015
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	156			$	(1	)		$	155
	Total pretax realized or unrealized gains (losses) included in earnings	—				24				24
	Purchases, sales, issuances and settlements:
	Purchases	9				—				9
	Sales	(1		)		—				(1		)
	Settlements	—				(10		)		(10		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5				1				6
	Balance at end of period	$	169			$	14			$	183
		Three Months Ended March 31, 2014
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	98			$	13			$	111
	Total pretax realized or unrealized gains (losses) included in earnings	—				18				18
	Purchases, sales, issuances and settlements:
	Purchases	1				—				1
	Sales	(1		)		—				(1		)
	Settlements	—				(39		)		(39		)
	Transfers out of Level 3 due to observability of inputs	—				(5		)		(5		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				(1		)		—
	Balance at end of period	$	99			$	(14	)		$	85
	Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding	$	—			$	7			$	7
Quantitative Information Table - Level 3	The following table includes quantitative information about the Duke Energy Registrants' derivatives classified as Level 3.
		31-Mar-15
	Investment Type	Fair Value			Valuation Technique	Unobservable Input	Range
		(in millions)
	Duke Energy
	Natural gas contracts	$	11		Discounted cash flow	Forward natural gas curves – price per MMBtu	$	1.96		-	$	3.78
	Financial transmission rights (FTRs)	3			RTO auction pricing	FTR price – per MWh	(0.83		)	-	8.47
	Electricity contracts	8			Discounted cash flow	Forward electricity curves – price per MWh	24.96			-	51.33
	Commodity capacity option contracts	1			Discounted cash flow	Forward capacity option curves – price per MW day	19			-	109.5
	Commodity contract reserves	(9		)		Bid-ask spreads, implied volatility, probability of default
	Total Level 3 derivatives	$	14
	Duke Energy Ohio
	Electricity contracts	$	2		Discounted cash flow	Forward electricity curves – price per MWh	25.05			-	51.33
	Natural gas contracts	11			Discounted cash flow	Forward natural gas curves – price per MMBtu	1.96			-	3.78
	Commodity contract reserves	(6		)		Bid-ask spreads, implied volatility, probability of default
	Total Level 3 derivatives	$	7
	Duke Energy Indiana
	FTRs	$	3		RTO auction pricing	FTR price – per MWh	(0.83		)	-	8.47
		31-Dec-14
	Investment Type	Fair Value			Valuation Technique	Unobservable Input	Range
		(in millions)
	Duke Energy
	Natural gas contracts	$	(5	)	Discounted cash flow	Forward natural gas curves – price per MMBtu	$	2.12		-	$	4.35
	Financial transmission rights (FTRs)	14			RTO auction pricing	FTR price – per MWh	(1.92		)	-	9.86
	Electricity contracts	(1		)	Discounted cash flow	Forward electricity curves – price per MWh	25.16			-	51.75
	Commodity capacity option contracts	2			Discounted cash flow	Forward capacity option curves – price per MW day	21			-	109
	Commodity contract reserves	(11		)		Bid-ask spreads, implied volatility, probability of default
	Total Level 3 derivatives	$	(1	)
	Duke Energy Ohio
	Electricity contracts	$	(6	)	Discounted cash flow	Forward electricity curves – price per MWh	25.25			-	51.75
	Natural gas contracts	(5		)	Discounted cash flow	Forward natural gas curves – price per MMBtu	2.12			-	4.35
	Commodity contract reserves	(7		)		Bid-ask spreads, implied volatility, probability of default
	Total Level 3 derivatives	$	(18	)
	Duke Energy Indiana
	FTRs	$	14		RTO auction pricing	FTR price – per MWh	(1.92		)	-	9.86
Schedule of Long-term debt, including current	The fair value and book value of long-term debt, including current maturities, is summarized in the following table. Estimates determined are not necessarily indicative of amounts that could have been settled in current markets. Fair value of long-term debt uses Level 2 measurements.
		March 31, 2015							December 31, 2014
	(in millions)	Book Value			Fair Value				Book Value			Fair Value
	Duke Energy	$	39,973		$	45,113			$	40,020		$	44,566
	Duke Energy Carolinas	8,885			10,301				8,391			9,626
	Progress Energy	14,510			16,956				14,754			16,951
	Duke Energy Progress	5,957			6,549				6,201			6,696
	Duke Energy Florida	4,858			5,867				4,860			5,767
	Duke Energy Ohio	1,606			1,810				1,766			1,970
	Duke Energy Indiana	3,791			4,529				3,791			4,456
Duke Energy Carolinas [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9. See Note 10 for additional information related to investments by major security type.
		March 31, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	2,127			$	1,960			$	3			$	164
	Nuclear decommissioning trust fund debt securities	885				131				754				—
	Other trading and available-for-sale debt securities	3				—				—				3
	Total assets	3,015				2,091				757				167
	Derivative liabilities	(27		)		—				(27		)		—
	Net assets	$	2,988			$	2,091			$	730			$	167
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	2,162			$	2,005			$	6			$	151
	Nuclear decommissioning trust fund debt securities	870				138				732				—
	Other trading and available-for-sale debt securities	3				—				—				3
	Total assets	3,035				2,143				738				154
	Derivative liabilities	(19		)		—				(19		)		—
	Net assets	$	3,016			$	2,143			$	719			$	154
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
		Three Months Ended March 31, 2015
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	154			$	—			$	154
	Purchases, sales, issuances and settlements:
	Purchases	9				—				9
	Issuances	(1		)		—				(1		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5				—				5
	Balance at end of period	$	167			$	—			$	167
		Three Months Ended March 31, 2014
	(in millions)	Investments				Derivatives (net)				Total
	Balance at beginning of period	$	81			$	(2	)		$	79
	Purchases, sales, issuances and settlements:
	Purchases	1				—				1
	Sales	(1		)		—				(1		)
	Settlements	—				(2		)		(2		)
	Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				—				1
	Balance at end of period	$	82			$	(4	)		$	78
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, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	1,516			$	1,516			$	—			$	—
	Nuclear decommissioning trust fund debt securities	942				411				531				—
	Other trading and available-for-sale debt securities	60				16				44				—
	Derivative assets	6				—				6				—
	Total assets	2,524				1,943				581				—
	Derivative liabilities	(395		)		—				(395		)		—
	Net assets	$	2,129			$	1,943			$	186			$	—
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	1,488			$	1,488			$	—			$	—
	Nuclear decommissioning trust fund debt securities	1,029				510				519				—
	Other trading and available-for-sale debt securities	58				15				43				—
	Derivative assets	4				—				4				—
	Total assets	2,579				2,013				566				—
	Derivative liabilities	(373		)		—				(373		)		—
	Net assets	$	2,206			$	2,013			$	193			$	—
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
		Derivatives (net)
		Three Months Ended March 31,
	(in millions)	2015				2014
	Balance at beginning of period	$	—			$	—
	Total pretax realized or unrealized gains included in earnings	—				(3		)
	Balance at end of period	$	—			$	(3	)
	Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			$	(3	)
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, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	1,194			$	1,194			$	—			$	—
	Nuclear decommissioning trust fund debt securities	545				140				405				—
	Other trading and available-for-sale debt securities	1				1				—				—
	Derivative assets	2				—				2				—
	Total assets	1,742				1,335				407				—
	Derivative liabilities	(131		)		—				(131		)		—
	Net assets	$	1,611			$	1,335			$	276			$	—
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	1,171			$	1,171			$	—			$	—
	Nuclear decommissioning trust fund debt securities	540				151				389				—
	Total assets	1,711				1,322				389				—
	Derivative liabilities	(132		)		—				(132		)		—
	Net assets	$	1,579			$	1,322			$	257			$	—
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
		Derivatives (net)
		Three Months Ended March 31,
	(in millions)	2015				2014
	Balance at beginning of period	$	—			$	—
	Total pretax realized or unrealized gains included in earnings	—				(3		)
	Balance at end of period	$	—			$	(3	)
	Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			$	(3	)
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, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	322			$	322			$	—			$	—
	Nuclear decommissioning trust fund debt securities and other	397				271				126				—
	Other trading and available-for-sale debt securities and other	44				—				44				—
	Derivative assets	4				—				4				—
	Total assets	767				593				174				—
	Derivative liabilities	(264		)		—				(264		)		—
	Net assets (liabilities)	$	503			$	593			$	(90	)		$	—
		31-Dec-14
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Nuclear decommissioning trust fund equity securities	$	317			$	317			$	—			$	—
	Nuclear decommissioning trust fund debt securities and other	489				359				130				—
	Other trading and available-for-sale debt securities and other	44				—				44				—
	Derivative assets	4				—				4				—
	Total assets	854				676				178				—
	Derivative liabilities	(241		)		—				(241		)		—
	Net assets (liabilities)	$	613			$	676			$	(63	)		$	—
Duke Energy Ohio [Member]
Fair Value Disclosures [Line Items]
Fair Value Measurement Amounts For Assets And Liabilities	The following tables provide recorded balances for assets and liabilities measured at fair value on a recurring basis on the Condensed Consolidated Balance Sheets. Derivative amounts in the table below exclude cash collateral, which is disclosed in Note 9.
		March 31, 2015
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Derivative assets	$	44			$	20			$	8			$	16
	Derivative liabilities	(134		)		(108		)		(17		)		(9		)
	Net liabilities	$	(90	)		$	(88	)		$	(9	)		$	7
		December 31, 2014
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Derivative assets	$	49			$	20			$	9			$	20
	Derivative liabilities	(181		)		(117		)		(26		)		(38		)
	Net liabilities	$	(132	)		$	(97	)		$	(17	)		$	(18	)
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
		Derivatives (net)
		Three Months Ended March 31,
	(in millions)	2015				2014
	Balance at beginning of period	$	(18	)		$	(4	)
	Total pretax realized or unrealized gains (losses) included in earnings	25				(6		)
	Purchases, sales, issuances and settlements:
	Settlements	—				(4		)
	Transfers out of Level 3 due to observability of inputs	—				(5		)
	Balance at end of period	$	7			$	(19	)
	Pretax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2014	$	—			(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.
		31-Mar-15
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Available-for-sale equity securities	$	73			$	73			$	—			$	—
	Available-for-sale debt securities	30				—				30				—
	Derivative assets	3				—				—				3
	Net assets	$	106			$	73			$	30			$	3
		31-Dec-14
	(in millions)	Total Fair Value				Level 1				Level 2				Level 3
	Available-for-sale equity securities	$	71			$	71			$	—			$	—
	Available-for-sale debt securities	30				—				30				—
	Derivative assets	14				—				—				14
	Net assets	$	115			$	71			$	30			$	14
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs	The following tables provide reconciliations of beginning and ending balances of assets and liabilities measured at fair value using Level 3 measurements.
		Derivatives (net)
		Three Months Ended March 31,
	(in millions)	2015				2014
	Balance at beginning of period	$	14			$	12
	Total pretax realized or unrealized gains (losses) included in earnings	(3		)		27
	Purchases, sales, issuances and settlements:
	Settlements	(9		)		(31		)
	Total gains included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1				(1		)
	Balance at end of period	$	3			$	7

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015
		Duke Energy
		Duke Energy Carolinas			Duke Energy Progress				Duke Energy Florida
	(in millions)	DERF			DEPR(c)				DEFR(c)			CRC		Renewables			Other			Total
	ASSETS
	Current Assets
	Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	$	658		$	478			$	300		$	540	$	18		$	22		$	2,016
	Other	—			—				—			—		102			7			109
	Investments and Other Assets
	Other	—			—				—			—		22			15			37
	Property, Plant and Equipment
	Property, plant and equipment, cost(a)	—			—				—			—		1,854			19			1,873
	Accumulated depreciation and amortization	—			—				—			—		(267		)	(6		)	(273		)
	Regulatory Assets and Deferred Debits
	Other	—			1				1			—		36			—			38
	Total assets	$	658		$	479			$	301		$	540	$	1,765		$	57		$	3,800
	LIABILITIES AND EQUITY
	Current Liabilities
	Accounts payable	$	—		$	—			$	—		$	—	$	2		$	—		$	2
	Taxes accrued	2			2				1			—		4			—			9
	Current maturities of long-term debt	—			—				—			—		68			17			85
	Other	—			—				—			—		23			8			31
	Long-Term Debt(b)	400			300				225			325		967			12			2,229
	Deferred Credits and Other Liabilities
	Deferred income taxes	—			—				—			—		270			—			270
	Asset retirement obligations	—			—				—			—		30			—			30
	Other	—			—				—			—		40			—			40
	Total liabilities	$	402		$	302			$	226		$	325	$	1,404		$	37		$	2,696
	Net assets of consolidated variable interest entities	$	256		$	177			$	75		$	215	$	361		$	20		$	1,104
	(a)    Restricted as collateral for non-recourse debt of VIEs.
	(b)    Non-recourse to the general assets of the applicable registrant.
	(c)	The amount for Progress Energy is equal to the sum of the amounts for Duke Energy Progress Receivables Company, LLC (DEPR) and Duke Energy Florida Receivables Company, LLC (DEFR).
		December 31, 2014
		Duke Energy
		Duke Energy Carolinas			Duke Energy Progress				Duke Energy Florida
	(in millions)	DERF			DEPR(c)				DEFR(c)			CRC		Renewables			Other			Total
	ASSETS
	Current Assets
	Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	$	647		$	436			$	305		$	547	$	20		$	18		$	1,973
	Other	—			—				—			—		68			6			74
	Investments and Other Assets
	Other	—			—				—			—		25			25			50
	Property, Plant and Equipment
	Property, plant and equipment, cost(a)	—			—				—			—		1,855			18			1,873
	Accumulated depreciation and amortization	—			—				—			—		(250		)	(5		)	(255		)
	Regulatory Assets and Deferred Debits
	Other	—			—				—			—		34			2			36
	Total assets	$	647		$	436			$	305		$	547	$	1,752		$	64		$	3,751
	LIABILITIES AND EQUITY
	Current Liabilities
	Accounts payable	$	—		$	—			$	—		$	—	$	3		$	—		$	3
	Taxes accrued	—			—				—			—		6			—			6
	Current maturities of long-term debt	—			—				—			—		68			16			84
	Other	—			—				—			—		16			5			21
	Long-Term Debt(b)	400			300				225			325		967			17			2,234
	Deferred Credits and Other Liabilities
	Deferred income taxes	—			—				—			—		283			—			283
	Asset retirement obligations	—			—				—			—		29			—			29
	Other	—			—				—			—		34			4			38
	Total liabilities	$	400		$	300			$	225		$	325	$	1,406		$	42		$	2,698
	Net assets of consolidated variable interest entities	$	247		$	136			$	80		$	222	$	346		$	22		$	1,053
	(a)    Restricted as collateral for non-recourse debt of VIEs.
	(b)    Non-recourse to the general assets of the applicable registrant.
(c)	The amount for Progress Energy is equal to the sum of the amounts for DEPR and DEFR.
The following table summarizes the amounts and expiration dates of the credit facilities reflected on the Condensed Consolidated Balance Sheets as Long-Term Debt.
	DERF		DEPR			DEFR
Credit facility amount (in millions)	$	400	$	300		$	225
Expiration date	Oct-16		Dec-16			Mar-17
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.
		31-Mar-15
		Duke Energy										Duke Energy		Duke Energy
	(in millions)	Renewables			Other				Total			Ohio		Indiana
	Receivables	$	—		$	—			$	—		$	90	$	105
	Investments in equity method unconsolidated affiliates	147			66				213			—		$	—
	Investments and other assets	—			3				3			—		—
	Total assets	$	147		$	69			$	216		$	90	$	105
	Other current liabilities	$	—		$	2			$	2		$	—	$	—
	Deferred credits and other liabilities	—			14				14			—		—
	Total liabilities	$	—		$	16			$	16		$	—	$	—
	Net assets (liabilities)	$	147		$	53			$	200		$	90	$	105
		31-Dec-14
		Duke Energy										Duke Energy Ohio		Duke Energy Indiana
	(in millions)	Renewables			Other				Total
	Receivables	$	—		$	—			$	—		$	91	$	113
	Investments in equity method unconsolidated affiliates	150			38				188			—		—
	Investments and other assets	—			4				4			—		—
	Total assets	$	150		$	42			$	192		$	91	$	113
	Other current liabilities	—			3				3			—		—
	Deferred credits and other liabilities	—			14				14			—		—
	Total liabilities	$	—		$	17			$	17		$	—	$	—
	Net assets	$	150		$	25			$	175		$	91	$	113
Cinergy Receivables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Schedule Of Variable Interest Entities	Key assumptions used in estimating fair value are detailed in the following table.
		Duke Energy Ohio					Duke Energy Indiana
		2015		2014			2015			2014
	Anticipated credit loss ratio	0.6	%	0.6	%		0.3	%		0.3	%
	Discount rate	1.2	%	1.2	%		1.2	%		1.2	%
	Receivable turnover rate	12.8	%	12.8	%		10.5	%		10.4	%
	The following table shows the gross and net receivables sold.
		Duke Energy Ohio							Duke Energy Indiana
	(in millions)	March 31, 2015			December 31, 2014				March 31, 2015			December 31, 2014
	Receivables sold	$	284		$	273			$	296		$	310
	Less: Retained interests	90			91				105			113
	Net receivables sold	$	194		$	182			$	191		$	197
	The following table shows sales and cash flows related to receivables sold.
		Duke Energy Ohio							Duke Energy Indiana
		Three Months Ended March 31,							Three Months Ended March 31,
	(in millions)	2015			2014				2015			2014
	Sales
	Receivables sold	$	644		$	741			$	716		$	755
	Loss recognized on sale	3			4				3			3
	Cash flows
	Cash proceeds from receivables sold	640			723				722			761
	Return received on retained interests	1			2				2			2

Common_Stock_Tables

Common Stock (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share	The following table presents Duke Energy’s basic and diluted EPS calculations and reconciles the weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding.
		Three Months Ended March 31,
	(in millions, except per share amounts)	2015		2014
	Income from continuing operations attributable to Duke Energy common shareholders	$	772	$	744
	Weighted-average shares outstanding – basic	708		706
	Weighted-average shares outstanding – diluted	708		706
	Earnings per share from continuing operations attributable to Duke Energy common shareholders
	Basic	$	1.09	$	1.05
	Diluted	$	1.09	$	1.05
	Potentially dilutive items excluded from the calculation(a)	2		2
	Dividends declared per common share	$	0.795	$	0.78
	(a)	Certain stock options and performance stock awards were not included in the dilutive securities calculation because either the option exercise prices were greater than the average market price of the common shares during the presented periods, or performance measures related to the awards had not yet been met.

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule Of Stock-Based Compensation Expense	Duke Energy recorded pretax stock-based compensation expense as follows.
		Three Months Ended March 31,
	(in millions)	2015		2014
	Restricted stock unit awards	$	9	$	11
	Performance awards	5		5
	Total	$	14	$	16
	Tax benefit associated with stock-based compensation expense	$	5	$	6
	Stock-based compensation costs capitalized	1		1

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Employee Savings Plan Matching Contributions	The following table includes pretax employer matching contributions, as well as the additional contribution of 4 percent of eligible pay per pay period for employees not eligible to participate in a defined benefit plan, made by Duke Energy and expensed by the Subsidiary Registrants.
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Three Months Ended March 31,
	2015	$	49		$	16		$	14		$	11		$	4		$	1		$	2
	2014	43			14			12			9			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.
		Three Months Ended March 31, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Contributions	$	132		$	42		$	42		$	21		$	21		$	1		$	9
	Duke Energy did not make any contributions to its U.S. qualified defined benefit pension plans during the three months ended March 31, 2014.
Components of Net Periodic Pension Costs	The following tables include the components of net periodic pension costs for qualified pension plans.
		Three Months Ended March 31, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy 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
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Service cost	$	34		$	10		$	10		$	5		$	5		$	1		$	2
	Interest cost on projected benefit obligation	86			21			28			13			14			5			7
	Expected return on plan assets	(128		)	(33		)	(43		)	(21		)	(21		)	(7		)	(9		)
	Amortization of actuarial loss	37			9			17			8			8			1			3
	Amortization of prior service credit	(4		)	(2		)	(1		)	—			—			—			—
	Other	2			1			1			—			—			—			—
	Net periodic pension costs	$	27		$	6		$	12		$	5		$	6		$	—		$	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, 2015
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy 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	)	$	—		$	—
		Three Months Ended March 31, 2014
	(in millions)	Duke Energy			Duke Energy Carolinas			Progress Energy			Duke Energy Progress			Duke Energy Florida			Duke Energy Ohio			Duke Energy Indiana
	Service cost	$	2		$	—		$	1		$	—		$	1		$	—		$	—
	Interest cost on accumulated post-retirement benefit obligation	12			3			6			3			3			—			1
	Expected return on plan assets	(3		)	(2		)	—			—			—			—			—
	Amortization of actuarial loss	10			1			10			7			2			—			—
	Amortization of prior service credit	(31		)	(3		)	(24		)	(18		)	(5		)	—			—
	Net periodic other post-retirement benefit costs	$	(10	)	$	(1	)	$	(7	)	$	(8	)	$	1		$	—		$	1

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Summary of Effective Tax Rates	The effective tax rates from continuing operations for each of the Duke Energy Registrants are included in the following table.
		Three Months Ended March 31,
		2015		2014
	Duke Energy	31.9	%	31.2	%
	Duke Energy Carolinas	35.8	%	37.4	%
	Progress Energy	35.4	%	36.9	%
	Duke Energy Progress	33.8	%	36.6	%
	Duke Energy Florida	38.6	%	38.5	%
	Duke Energy Ohio	36.7	%	36.4	%
	Duke Energy Indiana	36.6	%	36.8	%

Organization_and_Basis_of_Pres3

Organization and Basis of Presentation Organization and Basis of Presentation (Narrative)(Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$137

Organization_and_Basis_of_Pres4

Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$710	$827
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	257	295
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	188	217
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	114	135
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	74	82
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	1
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	62	79
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	28	27
Duke Energy Indiana [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$91	$112

Organization_and_Basis_of_Pres5

Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$100	$167
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	9	46
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	49	77
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4	32
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	45	45
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	32	34
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$10	$10

Acquisitions_and_Dispositions_1

Acquisitions and Dispositions (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Apr. 02, 2015
Significant Acquisitions and Disposals [Line Items]
Payments to acquire businesses	$29,000,000
Duke Energy Ohio [Member] | Midwest Generation Business [Member] | Subsequent Event [Member]
Significant Acquisitions and Disposals [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			2,800,000,000
Scenario, Forecast [Member] | Duke Energy Progress [Member] | NCEMPA Generating Assets [Member]
Significant Acquisitions and Disposals [Line Items]
Payments to acquire businesses		$1,200,000,000

Acquisitions_and_Dispositions_2

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

Acquisitions_and_Dispositions_3

Acquisitions and Dispositions (Assets Held For Sale) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income (Loss) From Discontinued Operations, net of tax	$91	($843)
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Current assets	354		364
Current liabilities	146		262
Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income (Loss) From Discontinued Operations, net of tax	90	-875
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Current assets	295		316
Current liabilities	129		246
Midwest Generation Business [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues	543	368
Estimated loss on disposition	-43	-1,287
Income (loss) before income taxes	147	-1,303
Income tax expense (benefit)	51	-466
Income (Loss) From Discontinued Operations, net of tax	96	-837
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Current assets	354
Investments and other assets	50
Property, plant and equipment	2,553
Total Assets held for sale	2,957
Current liabilities	146
Deferred credits and other liabilities	26
Total Liabilities associated with assets held for sale	172
Midwest Generation Business [Member] | Duke Energy Ohio [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating Revenues	412	195
Estimated loss on disposition	-44	-1,323
Income (loss) before income taxes	140	-1,354
Income tax expense (benefit)	50	-479
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Current assets	295
Investments and other assets	45
Property, plant and equipment	2,520
Total Assets held for sale	2,860
Current liabilities	129
Deferred credits and other liabilities	25
Total Liabilities associated with assets held for sale	154
Other Disposal Groups [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income (Loss) From Discontinued Operations, net of tax	($5)	($6)

Business_Segments_Narrative_De

Business Segments (Narrative) (Details) (National Methanol Company [Member], International Energy [Member])	Mar. 31, 2015
National Methanol Company [Member] | International Energy [Member]
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	25.00%

Business_Segments_Business_Seg

Business Segments (Business Segment Data) (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$6,065	$6,263
Segment income	773	746
Add back noncontrolling interests component	3	4
Income (Loss) From Discontinued Operations, net of tax	91	-843
Net income (loss) attributable to parent	864	-97
Net income (loss)	867	-93
Segment assets	122,142		120,709
Impairment charges	0	96
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,713	5,795
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	273	382
Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	73	81
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6	5
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,059	6,258
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,723	5,805
Segment income	774	737
Segment assets	106,642
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	273	382
Segment income	36	130
Segment assets	4,892
Operating Segments [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	73	81
Segment income	1	-32
Segment assets	6,202
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,069	6,268
Segment income	811	835
Segment assets	117,736
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	-31	-30
Segment income	-1	-2
Segment assets	176
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	-10	-10
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	-21	-20
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	-10	-10
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	27	25
Segment income	-37	-87
Segment assets	4,230
Costs to achieve Progress Energy merger	13	34
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	586	575
Segment income	59	-15
Income (Loss) From Discontinued Operations, net of tax	90	-875
Net income (loss) attributable to parent	149	-890
Segment assets	9,796		9,999
Impairment charges		94
Duke Energy Ohio [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	572	562
Duke Energy Ohio [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	14	13
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	586	575
Duke Energy Ohio [Member] | Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	572	562
Segment income	70	61
Segment assets	6,782
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	14	13
Segment income	-9	-74
Segment assets	2,984
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	586	575
Segment income	61	-13
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	-2
Segment assets	43
Duke Energy Ohio [Member] | Other VIEs [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges		94	94
Duke Energy Ohio [Member] | Other VIEs [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges		$94

Business_Segments_Net_Loss_Det

Business Segments (Net Loss) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Segment income	$773	$746
Interest expense	403	404
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Interest expense	102	101
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	-8	-21
Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest expense	168	169
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	-42	-52
Interest expense	60	63
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Interest expense	60	57
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	-4	-10
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Interest expense	49	49
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	-3	-4
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Segment income	59	-15
Interest expense	20	20
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Interest expense	45	43
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	($2)	($3)

Regulatory_Matters_Narrative_D

Regulatory Matters (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2017	Dec. 31, 2014
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	$11,279,000,000		$11,042,000,000
Payments to Acquire Businesses, Gross	29,000,000
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%
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	2,460,000,000		2,465,000,000
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC	600,000,000
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%
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	2,857,000,000		2,675,000,000
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	2,830,000,000		2,733,000,000
Duke Energy Florida [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	10.80%
Duke Energy Florida [Member] | FERC Complaint 3 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	8.69%
Duke Energy Florida [Member] | Citrus County Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC	1,500,000,000
Duke Energy Florida [Member] | Suwannee Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC	197,000,000
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	512,000,000		512,000,000
Duke Energy Ohio [Member] | FERC Complaint 1 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	11.38%
Duke Energy Ohio [Member] | MGP Remediation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	56,000,000
Duke Energy Ohio [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	12.38%
Percentage Recovered Through Future Rate Case	30.00%
Duke Energy Ohio [Member] | Natural Gas Rate Case [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	9.84%
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
MISO estimate of Duke Energy Ohio's MVP obligation	2,700,000,000
Duke Energy Ohio [Member] | Regional Transmission Organization [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	73,000,000
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	686,000,000		685,000,000
Duke Energy Indiana [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	12.38%
Percentage Recovered Through Future Rate Case	0.50%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	8.67%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Percentage Recovered Through Rider	80.00%
Percentage Recovered Through Future Rate Case	20.00%
Estimated capital cost	1,900,000,000
Scenario, Forecast [Member] | Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Payments to Acquire Businesses, Gross		$166,000,000

Regulatory_Matters_Schedule_of

Regulatory Matters (Schedule of MISO Exit fees)(Details) (Duke Energy Ohio [Member], RTO Realignment [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Duke Energy Ohio [Member] | RTO Realignment [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$94
Cash Reductions	-1
Balance, end of period	$93

Regulatory_Matters_Schedule_of1

Regulatory Matters (Schedule of Net Carrying Value Of Facilities As Well As the Remaining Non-current Regulatory Assets) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
	MW
Public Utilities, General Disclosures [Line Items]
Capacity (in MW)	1,704
Remaining net book value (in millions)	$70,301	$70,046
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	243
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	24,747	24,672
Duke Energy Carolinas [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	110
Progress Energy [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW)	873
Remaining net book value (in millions)	25,353	25,144
Progress Energy [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	120
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	15,282	15,186
Duke Energy Progress [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	150
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW)	873
Remaining net book value (in millions)	10,068	9,955
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	120
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW)	163
Remaining net book value (in millions)	4,953	4,937
Duke Energy Ohio [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	9
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW)	668
Remaining net book value (in millions)	8,866	8,815
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Remaining net book value (in millions)	$114

Commitments_and_Contingencies_1

Commitments and Contingencies (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Feb. 02, 2014	Mar. 31, 2014
			T
			gal
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	331,000,000	$323,000,000
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent	15.00%
Ash Basins Fines and Restitution [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	68,000,000
Ash Basins Community Service and Mitigation [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense	34,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	72,000,000	72,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required	250,000,000
Loss Contingency Accrual	72,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Environmental remediation expense		24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Minimum [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Coal ash released, in tons			30,000
Basin water released, in gallons			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			39,000
Basin water released, in gallons			27,000,000
Duke Energy Carolinas [Member] | New Source Review Provisions Of Clean Air Act [Member]
Valuation and Qualifying Accounts [Abstract]
Maximum civil penalties per day for each violation	37,500
Projects with Alleged NSR Violations	29
Number of Coal Plants with Alleged NSR Violations	25
Loss contingency, pending claims, number	13
Remaining Number of Coal Plants with Alleged NSR Violations	13
Number of Retired Plants	11
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves	570,000,000	575,000,000
Reinsurance retention policy, amount retained	476,000,000
Reinsurance retention policy, excess retention, amount reinsured	864,000,000
Probable insurance recoveries	617,000,000	616,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number	121
Asbestos-related injuries and damages reserves	26,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number	32
Asbestos-related injuries and damages reserves	10,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	93,000,000	93,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	37,000,000	37,000,000
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	30,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed	25,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	34,000,000	36,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount	54,000,000
Loss contingency, damages sought, value				510,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual	10,000,000
Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency, Range of Possible Loss, Maximum	500,000,000

Commitments_and_Contingencies_2

Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$89
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	97	79
Provisions/Adjustments	2	3
Cash reductions	-3	-1
Ending balance	96	81
Duke Energy Carolinas [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	25
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10		11
Ending balance	10	11	11
Progress Energy [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	15
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	27
Provisions/Adjustments		3
Cash reductions		-1
Ending balance	17	29
Duke Energy Progress [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	1
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5	8
Provisions/Adjustments		2
Ending balance	5	10
Duke Energy Florida [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	14
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	12	19
Provisions/Adjustments		1
Cash reductions		-1
Ending balance	12	19
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		27
Provisions/Adjustments	1
Cash reductions	-1
Ending balance	54	27	27
Duke Energy Indiana [Member]
Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	7
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10		7
Provisions/Adjustments	2
Cash reductions	-1
Ending balance	$11	$7	$7

Commitments_and_Contingencies_3

Commitments and Contingencies (Schedule of Reserves) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Loss Contingencies [Line Items]
Reserves for legal matters	$331	$323
Duke Energy Carolinas [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	72	72
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	93	93
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	37	37
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	34	36
Duke Energy Ohio [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$10

Debt_and_Credit_Facilities_Nar

Debt and Credit Facilities (Narrative) (Details) (USD $)	1 Months Ended
	Apr. 30, 2015	Mar. 31, 2015
Subsequent Event [Member]
Line of Credit Facility [Line Items]
Repayments of Commercial Paper	$1,300,000,000
North Carolina Ash Basins [Member] | USDOJ [Member] | Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required		$250,000,000

Debt_and_Credit_Facilities_Sum

Debt and Credit Facilities (Summary of Debt Issuances) (Details) (USD $)	1 Months Ended
	Apr. 30, 2015	Oct. 31, 2015	Mar. 31, 2015
Debt Instrument [Line Items]
Debt issuances			$500,000,000
Subsequent Event [Member]
Debt Instrument [Line Items]
Repayments of Commercial Paper	1,300,000,000
March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
Debt issuances			500,000,000
March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt		500,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances			500,000,000
Duke Energy Carolinas [Member] | March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
Debt issuances			500,000,000
Duke Energy Carolinas [Member] | March 2015 3.750% First Mortgage Bond maturing June 2045 [Member] | First Mortgage Bonds [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Repayments of debt		$500,000,000

Debt_and_Credit_Facilities_Sch

Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (Revolving Credit Facility [Member], USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Line of Credit Facility [Line Items]
Facility size	$7,500
Commercial paper	-3,256
Outstanding letters of credit	-66
Tax exempt bonds	-116
Available capacity	4,062
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	3,200
Commercial paper	-2,764
Outstanding letters of credit	-60
Available capacity	376
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member]
Line of Credit Facility [Line Items]
Commercial paper	-475
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,200
Commercial paper	-300
Outstanding letters of credit	-4
Tax exempt bonds	-35
Available capacity	861
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,000
Outstanding letters of credit	-1
Available capacity	999
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	900
Commercial paper	-17
Outstanding letters of credit	-1
Available capacity	882
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	600
Commercial paper	-25
Available capacity	575
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600
Commercial paper	-150
Tax exempt bonds	-81
Available capacity	$369

Debt_and_Credit_Facilities_Sum1

Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Current maturities of long-term debt	$2,800	$2,807
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	300
Parent Company [Member] | Unsecured Debt [Member] | 3.350% Unsecured Debt Maturing April 2015 [Member]
Debt Instrument [Line Items]
Interest rate	3.35%
Current maturities of long-term debt	450
Progress Energy Parent [Member] | Unsecured Debt [Member] | 5.625% Unsecured Debt Maturing January 2016 [Member]
Debt Instrument [Line Items]
Interest rate	5.63%
Current maturities of long-term debt	300
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	702	945
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 5.150% First Mortgage Bonds Maturing April 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.15%
Current maturities of long-term debt	300
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 5.250% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.25%
Current maturities of long-term debt	400
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	506	507
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 5.300% First Mortgage Bonds Maturing October 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.30%
Current maturities of long-term debt	500
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	562	562
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 0.650% First Mortgage Bonds Maturing November 2015 [Member]
Debt Instrument [Line Items]
Interest rate	0.65%
Current maturities of long-term debt	250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 5.100% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.10%
Current maturities of long-term debt	300
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$56	$157

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill	$17,200		$17,192
Accumulated impairment charges	-871		-871
Foreign exchange and other changes	-16
Goodwill, Acquired During Period	24
Goodwill as adjusted for accumulated impairment charges	16,329		16,321
Asset impairment charges	0	96
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill	15,950		15,950
Goodwill as adjusted for accumulated impairment charges	15,950		15,950
International [Member]
Goodwill [Roll Forward]
Goodwill	291		307
Foreign exchange and other changes	-16
Goodwill as adjusted for accumulated impairment charges	291		307
Commercial Power [Member]
Goodwill [Roll Forward]
Goodwill	959		935
Accumulated impairment charges	-871		-871
Goodwill, Acquired During Period	24
Goodwill as adjusted for accumulated impairment charges	88		64
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	2,324		2,324
Accumulated impairment charges	-1,404		-1,404
Goodwill as adjusted for accumulated impairment charges	920		920
Asset impairment charges		94
Duke Energy Ohio [Member] | Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges		94	94
Duke Energy Ohio [Member] | Regulated Utility [Member]
Goodwill [Roll Forward]
Goodwill	1,136		1,136
Accumulated impairment charges	-216		-216
Goodwill as adjusted for accumulated impairment charges	920		920
Duke Energy Ohio [Member] | Commercial Power [Member]
Goodwill [Roll Forward]
Goodwill	1,188		1,188
Accumulated impairment charges	-1,188		-1,188
Goodwill as adjusted for accumulated impairment charges	0		0
Duke Energy Ohio [Member] | Commercial Power [Member] | Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges		$94

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$219	$222
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	5
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	26	97
Related party transaction, expenses from transactions with related party	57	51
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	167	178
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	10	8
Progress Energy [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	57	51
Related party transaction, expenses from transactions with related party	26	97
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	101	96
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	57	51
Related party transaction, expenses from transactions with related party	26	97
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	66	81
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	4
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	77
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	3	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	89	105
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$2	$3

Related_Party_Transactions_Nar

Related Party Transactions (Narrative) (Details) (Duke Energy Ohio [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Intercompany loan payable	$298		$491
DECAM [Member]
Related Party Transaction [Line Items]
Intercompany loan payable	294		459
MarkTo Market Of Commodity Contracts And Sales Of Power [Member] | DECAM [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$3	$54

Derivatives_and_Hedging_Notion

Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
	GWh	GWh
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	22,810	25,370
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	666,000,000	676,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,277	1,027
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	57,000,000	35,000,000
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	333,000,000	328,000,000
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	111,000,000	116,000,000
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	222,000,000	212,000,000
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	250
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	17,734	19,141
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	276,000,000	313,000,000
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	571
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	750	750
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	527	277
Not Designated as Hedging Instrument [Member] | Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Floating interest rate	1.75%
Notional amount	250
Not Designated as Hedging Instrument [Member] | Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	250
Not Designated as Hedging Instrument [Member] | Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27
Variable Interest Entity, Primary Beneficiary [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	541	541

Derivatives_and_Hedging_Locati

Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$411	$351
Location and fair value amounts of derivatives (Liability)	984	909
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	261	210
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	150	136
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	607	573
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	377	319
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	402	339
Location and fair value amounts of derivatives (Liability)	920	859
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9	12
Location and fair value amounts of derivatives (Liability)	64	50
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	10
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	14	13
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	38	29
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	18
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	45	15
Location and fair value amounts of derivatives (Liability)	21
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	21	15
Location and fair value amounts of derivatives (Liability)	7
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	1
Location and fair value amounts of derivatives (Liability)	308	307
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	206	174
Location and fair value amounts of derivatives (Liability)	263	253
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	2
Location and fair value amounts of derivatives (Liability)	112	91
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	123	111
Location and fair value amounts of derivatives (Liability)	209	208
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	11	7
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	27	19
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	14
Duke Energy Carolinas [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	5
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	27	19
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	14
Duke Energy Carolinas [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	9	2
Location and fair value amounts of derivatives (Liability)	398	371
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	289	289
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	109	82
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	393	369
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Location and fair value amounts of derivatives (Liability)	5	2
Progress Energy [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	289	288
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	104	80
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Progress Energy [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	2
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	131	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	100	109
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	31	23
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	126	132
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	5
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	100	108
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	23
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Duke Energy Progress [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Location and fair value amounts of derivatives (Liability)	267	239
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	2
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	189	180
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	78	59
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	267	237
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	2
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	189	180
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	78	57
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	455	341
Location and fair value amounts of derivatives (Liability)	545	473
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	284	204
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	171	137
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	309	257
Duke Energy Ohio [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	236	216
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	455	341
Location and fair value amounts of derivatives (Liability)	538	467
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	6
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	78	28
Location and fair value amounts of derivatives (Liability)	59	4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	48	26
Location and fair value amounts of derivatives (Liability)	23	4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	206	175
Location and fair value amounts of derivatives (Liability)	249	252
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	123	111
Location and fair value amounts of derivatives (Liability)	207	207
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	14
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Duke Energy Indiana [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		14
Duke Energy Indiana [Member] | Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		14
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$3

Derivatives_and_Hedging_Schedu

Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$411	$351
Net amounts recognized on the Condensed Consolidated Balance Sheet	52	110
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	984	909
Net amounts recognized on the Condensed Consolidated Balance Sheet	625	668
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	261	210
Gross amounts offset	-227	-153
Net amount subject to master netting	34	57
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	57
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	150	136
Gross amounts offset	-131	-88
Net amount subject to master netting	19	48
Amounts not subject to master netting		5
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	53
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	607	573
Gross amounts offset	-293	-213
Net amounts subject to master netting	314	360
Amounts not subject to master netting		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	314	361
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	377	319
Gross amounts offset	-216	-173
Net amounts subject to master netting	161	146
Amounts not subject to master netting		16
Net amounts recognized on the Condensed Consolidated Balance Sheet	161	162
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	27	19
Net amounts recognized on the Condensed Consolidated Balance Sheet	27	19
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	14
Net amounts subject to master netting	19	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	14
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	5
Net amounts subject to master netting	8	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	5
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	398	371
Net amounts recognized on the Condensed Consolidated Balance Sheet	395	373
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6	2
Gross amounts offset	-1	-2
Net amount subject to master netting	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3
Gross amounts offset	-2
Net amount subject to master netting	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	289	289
Gross amounts offset	-32	-17
Net amounts subject to master netting	257	272
Net amounts recognized on the Condensed Consolidated Balance Sheet	257	272
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	109	82
Gross amounts offset	-14	-8
Net amounts subject to master netting	95	74
Net amounts recognized on the Condensed Consolidated Balance Sheet	95	74
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	131	132
Net amounts recognized on the Condensed Consolidated Balance Sheet	131	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amount subject to master netting	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	100	109
Gross amounts offset	-1
Net amounts subject to master netting	99	109
Net amounts recognized on the Condensed Consolidated Balance Sheet	99	109
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	31	23
Net amounts subject to master netting	31	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	23
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	267	239
Net amounts recognized on the Condensed Consolidated Balance Sheet	264	241
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	2
Gross amounts offset	-1	-2
Net amount subject to master netting	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3
Gross amounts offset	-2
Net amount subject to master netting	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	189	180
Gross amounts offset	-31	-17
Net amounts subject to master netting	158	163
Net amounts recognized on the Condensed Consolidated Balance Sheet	158	163
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	78	59
Gross amounts offset	-14	-8
Net amounts subject to master netting	64	51
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	51
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	455	341
Net amounts recognized on the Condensed Consolidated Balance Sheet	44	49
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	545	473
Net amounts recognized on the Condensed Consolidated Balance Sheet	134	181
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	284	204
Gross amounts offset	-265	-179
Net amount subject to master netting	19	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	25
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	171	137
Gross amounts offset	-145	-114
Net amount subject to master netting	26	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	26	23
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	309	257
Gross amounts offset	-300	-222
Net amounts subject to master netting	9	35
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	35
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	236	216
Gross amounts offset	-218	-193
Net amounts subject to master netting	18	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	23
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	14
Net amount subject to master netting	3	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	$3	$14

Derivatives_and_Hedging_Gains_

Derivatives and Hedging (Gains and Losses Recognized on Cash Flow Hedges) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Pretax Gains (Losses) Recorded in AOCI, interest rate contracts	($11)	$2
Total Pretax Gains (Losses) Recorded in AOCI	-11	2
Total Pretax Gains (Losses) Reclassified from AOCI into Earnings	-1	-1
Pretax Gains (Losses) expected to be recognized in earnings during the next 12 months, interest rate contracts	5
Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax Gains (Losses) Reclassified from AOCI into Earnings, interest rate contracts	-1	-1
Duke Energy Carolinas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Pretax Gains (Losses) Reclassified from AOCI into Earnings	-1
Duke Energy Carolinas [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax Gains (Losses) Reclassified from AOCI into Earnings, interest rate contracts	-1
Duke Energy Indiana [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Pretax Gains (Losses) Reclassified from AOCI into Earnings	1
Duke Energy Indiana [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax Gains (Losses) Reclassified from AOCI into Earnings, interest rate contracts	$1

Derivatives_and_Hedging_Gains_1

Derivatives and Hedging (Gains and Losses Recognized on Undesignated Contracts) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings	$54	($260)
Pretax gains (losses) recognized as regulatory assets or liabilities	-344	29
Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-340	-2
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	-5	4
Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-2	27
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	3
Revenue: Regulated electric [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	1	-4
Revenue: Nonregulated electric, natural gas and other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	17	-397
Fuel used in electric generation and purchased power - regulated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts		7
Fuel used in electric generation and purchased power - nonregulated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	37	138
Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - interest rate contracts	-1	-4
Duke Energy Carolinas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities	-28
Duke Energy Carolinas [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-28
Progress Energy [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings	-1
Pretax gains (losses) recognized as regulatory assets or liabilities	-315	2
Progress Energy [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-314	-2
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	-4	4
Progress Energy [Member] | Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	3
Progress Energy [Member] | Revenue: Regulated electric [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts		-3
Progress Energy [Member] | Fuel used in electric generation and purchased power - regulated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts		7
Progress Energy [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - interest rate contracts	-1	-4
Duke Energy Progress [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings		1
Pretax gains (losses) recognized as regulatory assets or liabilities	-130	20
Duke Energy Progress [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-127	17
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	-5	3
Duke Energy Progress [Member] | Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	2
Duke Energy Progress [Member] | Revenue: Regulated electric [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts		-3
Duke Energy Progress [Member] | Fuel used in electric generation and purchased power - regulated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts		7
Duke Energy Progress [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - interest rate contracts		-3
Duke Energy Florida [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings	-1	-1
Pretax gains (losses) recognized as regulatory assets or liabilities	-185	-18
Duke Energy Florida [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-187	-19
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	1	1
Duke Energy Florida [Member] | Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	1
Duke Energy Florida [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - interest rate contracts	-1	-1
Duke Energy Ohio [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings	50	-311
Pretax gains (losses) recognized as regulatory assets or liabilities	1	2
Duke Energy Ohio [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - interest rate contracts	-1
Duke Energy Ohio [Member] | Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	2	2
Duke Energy Ohio [Member] | Revenue: Nonregulated electric, natural gas and other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	13	-449
Duke Energy Ohio [Member] | Fuel used in electric generation and purchased power - nonregulated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	37	138
Duke Energy Indiana [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings	1
Pretax gains (losses) recognized as regulatory assets or liabilities	-2
Duke Energy Indiana [Member] | Regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	2
Duke Energy Indiana [Member] | Regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized as regulatory assets or liabilities - commodity contracts	-4
Duke Energy Indiana [Member] | Revenue: Regulated electric [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses) recognized in earnings - commodity contracts	$1

Derivatives_and_Hedging_Deriva

Derivatives and Hedging (Derivative Instruments with Credit-Risk Related Contingent Features and Cash Collateral) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
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	$834	$845
Fair value of collateral already posted	219	209
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	326	407
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	151	145
Amounts not offset against net derivative positions	68	64
Duke Energy Carolinas [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	11	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	11	19
Progress Energy [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	344	370
Fair value of collateral already posted	43	23
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	301	347
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	43	23
Duke Energy Progress [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	110	131
Fair value of collateral already posted	1
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	109	131
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	1
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	234	239
Fair value of collateral already posted	42	23
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	192	216
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	42	23
Duke Energy Ohio [Member]
Schedule of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	479	456
Fair value of collateral already posted	176	186
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	14	41
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against net derivative positions on the Condensed Consolidated Balance Sheets, payables	108	122
Amounts not offset against net derivative positions	$68	$64

Investments_in_Debt_and_Equity2

Investments in Debt and Equity Securities (Narrative) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]
Trading Securities	$10	$7

Investments_in_Debt_and_Equity3

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	$2,011	$2,004
Gross Unrealized Holding Losses	37	38
Estimated Fair Value	5,881	5,901
Net pending trade receivables	107
Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,968	1,965
Gross Unrealized Holding Losses	34	35
Estimated Fair Value	5,470	5,549
Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	106	136
Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,916	1,926
Gross Unrealized Holding Losses	28	29
Estimated Fair Value	3,643	3,650
Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	19	14
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	482	454
Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	7	5
Gross Unrealized Holding Losses	2
Estimated Fair Value	227	184
Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	24	19
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	864	978
Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	148	147
Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	43	39
Gross Unrealized Holding Losses	3	3
Estimated Fair Value	411	352
Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	29	15
Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	36	34
Estimated Fair Value	98	96
Other Classification [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	1
Gross Unrealized Holding Losses		1
Estimated Fair Value	81	58
Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	75	76
Other Classification [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	45	27
Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	2	1
Estimated Fair Value	83	80
Duke Energy Carolinas [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,099	1,119
Gross Unrealized Holding Losses	22	23
Estimated Fair Value	3,015	3,035
Net pending trade receivables	107
Duke Energy Carolinas [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,099	1,119
Gross Unrealized Holding Losses	21	22
Estimated Fair Value	3,012	3,032
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	42	51
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	1,076	1,102
Gross Unrealized Holding Losses	16	17
Estimated Fair Value	2,127	2,162
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	11	8
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	329	316
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	1
Estimated Fair Value	90	62
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8	7
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	296	308
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	128	133
Duke Energy Carolinas [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	3	3
Progress Energy [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	872	849
Gross Unrealized Holding Losses	13	13
Estimated Fair Value	2,518	2,575
Progress Energy [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	869	846
Gross Unrealized Holding Losses	13	13
Estimated Fair Value	2,458	2,517
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	64	85
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	840	824
Gross Unrealized Holding Losses	12	12
Estimated Fair Value	1,516	1,488
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	8	6
Estimated Fair Value	153	138
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	4
Gross Unrealized Holding Losses	1
Estimated Fair Value	137	122
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	16	12
Gross Unrealized Holding Losses		1
Estimated Fair Value	568	670
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	20	14
Progress Energy [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	60	58
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	18	15
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	42	43
Duke Energy Progress [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	647	630
Gross Unrealized Holding Losses	11	11
Estimated Fair Value	1,740	1,711
Duke Energy Progress [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	647	630
Gross Unrealized Holding Losses	11	11
Estimated Fair Value	1,739	1,711
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	40	50
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	626	612
Gross Unrealized Holding Losses	10	10
Estimated Fair Value	1,194	1,171
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6	5
Estimated Fair Value	107	97
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	5	4
Gross Unrealized Holding Losses	1
Estimated Fair Value	135	120
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	10	9
Gross Unrealized Holding Losses		1
Estimated Fair Value	251	265
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	12	8
Duke Energy Progress [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1	0
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	1
Duke Energy Florida [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	225	219
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	763	850
Duke Energy Florida [Member] | Ndtf [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	222	216
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	719	806
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	24	35
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	214	212
Gross Unrealized Holding Losses	2	2
Estimated Fair Value	322	317
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	2	1
Estimated Fair Value	46	41
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	2
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	6	3
Estimated Fair Value	317	405
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	8	6
Duke Energy Florida [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	44	44
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	2	1
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	3	3
Estimated Fair Value	42	43
Duke Energy Indiana [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	30	28
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	103	101
Duke Energy Indiana [Member] | Other Classification [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	30	28
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	103	101
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Holding Gains	30	28
Estimated Fair Value	73	71
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	$30	$30

Investments_in_Debt_and_Equity4

Investments in Debt and Equity Securities (Maturities) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Due in one year or less	$110
Due after one through five years	603
Due after five through 10 years	488
Due after 10 years	804
Total	2,005
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Due in one year or less	5
Due after one through five years	177
Due after five through 10 years	257
Due after 10 years	407
Total	846
Progress Energy [Member]
Debt Instrument [Line Items]
Due in one year or less	84
Due after one through five years	350
Due after five through 10 years	160
Due after 10 years	326
Total	920
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Due in one year or less	12
Due after one through five years	147
Due after five through 10 years	113
Due after 10 years	233
Total	505
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Due in one year or less	72
Due after one through five years	203
Due after five through 10 years	47
Due after 10 years	93
Total	415
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Due in one year or less	2
Due after one through five years	17
Due after five through 10 years	8
Due after 10 years	3
Total	$30

Investments_in_Debt_and_Equity5

Investments in Debt and Equity Securities (Realized Gains and Losses)(Details) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	$102	$31
Realized losses	14	4
Duke Energy Carolinas [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	90	23
Realized losses	12	1
Progress Energy [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	12	7
Realized losses	1	2
Duke Energy Progress [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	9	6
Realized losses	1	2
Duke Energy Florida [Member]
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Realized gains	3	1
Realized losses		$1

Fair_Value_Measurements_Fair_V

Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$52	$110
Assets, fair value disclosure	5,943	6,018
Derivative liabilities	-625	-668
Net assets, fair value	5,318	5,350
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7	49
Assets, fair value disclosure	4,196	4,327
Derivative liabilities	-119	-162
Net assets, fair value	4,077	4,165
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	22	24
Assets, fair value disclosure	1,555	1,498
Derivative liabilities	-497	-468
Net assets, fair value	1,058	1,030
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	23	37
Assets, fair value disclosure	192	193
Derivative liabilities	-9	-38
Net assets, fair value	183	155
Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,643	3,650
Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3,476	3,493
Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	6
Equity Securities [Member] | Ndtf [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	164	151
Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	98	96
Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	98	96
Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,827	1,899
Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	542	648
Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,285	1,251
Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	323	263
Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	73	41
Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	245	217
Debt Securities [Member] | Other Classification [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	5	5
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	3,015	3,035
Derivative liabilities	-27	-19
Net assets, fair value	2,988	3,016
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	2,091	2,143
Net assets, fair value	2,091	2,143
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	757	738
Derivative liabilities	-27	-19
Net assets, fair value	730	719
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	167	154
Net assets, fair value	167	154
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	2,127	2,162
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,960	2,005
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	3	6
Duke Energy Carolinas [Member] | Equity Securities [Member] | Ndtf [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	164	151
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	885	870
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	131	138
Duke Energy Carolinas [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	754	732
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	6	4
Assets, fair value disclosure	2,524	2,579
Derivative liabilities	-395	-373
Net assets, fair value	2,129	2,206
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	1,943	2,013
Net assets, fair value	1,943	2,013
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	6	4
Assets, fair value disclosure	581	566
Derivative liabilities	-395	-373
Net assets, fair value	186	193
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,516	1,488
Progress Energy [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,516	1,488
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	942	1,029
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	411	510
Progress Energy [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	531	519
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	60	58
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	16	15
Progress Energy [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	44	43
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Assets, fair value disclosure	1,742	1,711
Derivative liabilities	-131	-132
Net assets, fair value	1,611	1,579
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	1,335	1,322
Net assets, fair value	1,335	1,322
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Assets, fair value disclosure	407	389
Derivative liabilities	-131	-132
Net assets, fair value	276	257
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,194	1,171
Duke Energy Progress [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1,194	1,171
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	545	540
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	140	151
Duke Energy Progress [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	405	389
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1
Duke Energy Progress [Member] | Debt Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	1
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	4
Assets, fair value disclosure	767	854
Derivative liabilities	-264	-241
Net assets, fair value	503	613
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	593	676
Net assets, fair value	593	676
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	4
Assets, fair value disclosure	174	178
Derivative liabilities	-264	-241
Net assets, fair value	-90	-63
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	322	317
Duke Energy Florida [Member] | Equity Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	322	317
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	397	489
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	271	359
Duke Energy Florida [Member] | Debt Securities [Member] | Ndtf [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	126	130
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	44	44
Duke Energy Florida [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	44	44
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	44	49
Derivative liabilities	-134	-181
Net assets, fair value	-90	-132
Duke Energy Ohio [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	20	20
Derivative liabilities	-108	-117
Net assets, fair value	-88	-97
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	9
Derivative liabilities	-17	-26
Net assets, fair value	-9	-17
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	16	20
Derivative liabilities	-9	-38
Net assets, fair value	7	-18
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	14
Net assets, fair value	106	115
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets, fair value	73	71
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net assets, fair value	30	30
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	14
Net assets, fair value	3	14
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale equity securities	73	71
Duke Energy Indiana [Member] | Equity Securities [Member] | Other Classification [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale equity securities	73	71
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale debt securities	30	30
Duke Energy Indiana [Member] | Debt Securities [Member] | Other Classification [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale debt securities	$30	$30

Fair_Value_Measurements_Reconc

Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments
Beginning balance	$155	$111
Total pretax gains (losses) included in earnings	24	18
Purchases	9	1
Sales	-1	-1
Settlements	-10	-39
Transfers in and/or out of level 3		-5
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	6
Ending balance	183	85
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	-1	13
Total pretax gains (losses) included in earnings	24	18
Settlements	-10	-39
Transfers out of level 3		-5
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1	-1
Ending balance	14	-14
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		7
Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		7
Investments [Member]
Investments
Beginning balance	156	98
Purchases	9	1
Sales	-1	-1
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5	1
Ending balance	169	99
Duke Energy Carolinas [Member]
Investments
Beginning balance	154	79
Purchases	9	1
Sales		-1
Issuances	-1
Settlements		-2
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5	1
Ending balance	167	78
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance		-2
Settlements		-2
Ending balance		-4
Duke Energy Carolinas [Member] | Investments [Member]
Investments
Beginning balance	154	81
Purchases	9	1
Sales		-1
Issuances	-1
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	5	1
Ending balance	167	82
Progress Energy [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Total pretax gains (losses) included in earnings		-3
Ending balance		-3
Progress Energy [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		-3
Duke Energy Progress [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Total pretax gains (losses) included in earnings		-3
Ending balance		-3
Duke Energy Progress [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		-3
Duke Energy Ohio [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	-18	-4
Total pretax gains (losses) included in earnings	25	-6
Settlements		-4
Transfers out of level 3		-5
Ending balance	7	-19
Duke Energy Ohio [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding		-7
Duke Energy Indiana [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	14	12
Total pretax gains (losses) included in earnings	-3	27
Settlements	-9	-31
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory assets or liabilities	1	-1
Ending balance	$3	$7

Fair_Value_Measurements_Quanti

Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$14	($1)	($14)	$13
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	11	-5
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	1.96	2.12
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	3.78	4.35
Financial Transmission Rights [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	3	14
Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	-0.83	-1.92
Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	8.47	9.86
Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	8	-1
Commodity Power Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	24.96	25.16
Commodity Power Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	51.33	51.75
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	1	2
Commodity Capacity Option Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MW day	19	21
Commodity Capacity Option Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MW day	109.5	109
Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	-9	-11
Duke Energy Carolinas [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)			-4	-2
Progress Energy [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)			-3
Duke Energy Progress [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)			-3
Duke Energy Ohio [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	7	-18	-19	-4
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	11	-5
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	1.96	2.12
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	3.78	4.35
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	2	-6
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	25.05	25.25
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	51.33	51.75
Duke Energy Ohio [Member] | Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	-6	-7
Duke Energy Indiana [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	3	14	7	12
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)	$3	$14
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Minimum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	-0.83	-1.92
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | Maximum [Member] | RTO Auction Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	8.47	9.86

Fair_Value_Measurements_Additi

Fair Value Measurements (Additional Fair Value Disclosure) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$39,973	$40,020
Long-term debt, fair value	45,113	44,566
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,885	8,391
Long-term debt, fair value	10,301	9,626
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	14,510	14,754
Long-term debt, fair value	16,956	16,951
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	5,957	6,201
Long-term debt, fair value	6,549	6,696
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,858	4,860
Long-term debt, fair value	5,867	5,767
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,606	1,766
Long-term debt, fair value	1,810	1,970
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,791	3,791
Long-term debt, fair value	$4,529	$4,456

Variable_Interest_Entities_Nar

Variable Interest Entities (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Variable Interest Entities [Line Items]
Asset impairment charges	$0	$96
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%
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]
Variable Interest Entities [Line Items]
Asset impairment charges		94
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Duke Energy Ohio [Member] | Other VIEs [Member]
Variable Interest Entities [Line Items]
Asset impairment charges		$94	$94
Duke Energy Indiana [Member] | 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 $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	$2,016	$1,973
Other current assets	2,008	1,837
Investments and other assets	3,207	3,008
Property, plant and equipment, cost	105,692	104,861
Accumulated depreciation and amortization	-35,400	-34,824
Other deferred debits	182	171
Accounts payable	1,920	2,271
Current maturities of long-term debt	2,800	2,807
Other current liabilities	2,014	2,188
Long-Term Debt	37,173	37,213
Deferred income taxes	13,914	13,423
Asset retirement obligation	8,541	8,466
Other liabilities	1,667	1,675
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	2,016	1,973
Other current assets	109	74
Investments and other assets	37	50
Property, plant and equipment, cost	1,873	1,873
Accumulated depreciation and amortization	-273	-255
Other deferred debits	38	36
Total assets	3,800	3,751
Accounts payable	2	3
Taxes accrued	9	6
Current maturities of long-term debt	85	84
Other current liabilities	31	21
Long-Term Debt	2,229	2,234
Deferred income taxes	270	283
Asset retirement obligation	30	29
Other liabilities	40	38
Total liabilities	2,696	2,698
Net assets of consolidated VIEs	1,104	1,053
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	658	647
Other current assets	41	77
Investments and other assets	996	959
Property, plant and equipment, cost	37,682	37,372
Accumulated depreciation and amortization	-12,935	-12,700
Other deferred debits	45	42
Accounts payable	504	709
Current maturities of long-term debt	506	507
Other current liabilities	398	434
Long-Term Debt	8,079	7,584
Deferred income taxes	5,901	5,812
Asset retirement obligation	3,460	3,428
Other liabilities	640	642
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	479	436
Other current assets	99	384
Investments and other assets	450	412
Property, plant and equipment, cost	24,444	24,207
Accumulated depreciation and amortization	-9,162	-9,021
Other deferred debits	34	34
Accounts payable	363	481
Current maturities of long-term debt	702	945
Other current liabilities	359	409
Long-Term Debt	5,255	5,256
Deferred income taxes	2,978	2,908
Asset retirement obligation	3,936	3,905
Other liabilities	175	168
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	301	305
Other current assets	333	521
Investments and other assets	270	204
Property, plant and equipment, cost	14,613	14,433
Accumulated depreciation and amortization	-4,545	-4,478
Other deferred debits	39	39
Accounts payable	302	365
Current maturities of long-term debt	562	562
Other current liabilities	577	586
Long-Term Debt	4,296	4,298
Deferred income taxes	2,465	2,452
Asset retirement obligation	803	806
Other liabilities	157	158
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	658	647
Total assets	658	647
Taxes accrued	2
Long-Term Debt	400	400
Total liabilities	402	400
Net assets of consolidated VIEs	256	247
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	478	436
Other deferred debits	1
Total assets	479	436
Taxes accrued	2
Long-Term Debt	300	300
Total liabilities	302	300
Net assets of consolidated VIEs	177	136
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	300	305
Other deferred debits	1
Total assets	301	305
Taxes accrued	1
Long-Term Debt	225	225
Total liabilities	226	225
Net assets of consolidated VIEs	75	80
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	540	547
Total assets	540	547
Long-Term Debt	325	325
Total liabilities	325	325
Net assets of consolidated VIEs	215	222
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	18	20
Other current assets	102	68
Investments and other assets	22	25
Property, plant and equipment, cost	1,854	1,855
Accumulated depreciation and amortization	-267	-250
Other deferred debits	36	34
Total assets	1,765	1,752
Accounts payable	2	3
Taxes accrued	4	6
Current maturities of long-term debt	68	68
Other current liabilities	23	16
Long-Term Debt	967	967
Deferred income taxes	270	283
Asset retirement obligation	30	29
Other liabilities	40	34
Total liabilities	1,404	1,406
Net assets of consolidated VIEs	361	346
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	22	18
Other current assets	7	6
Investments and other assets	15	25
Property, plant and equipment, cost	19	18
Accumulated depreciation and amortization	-6	-5
Other deferred debits		2
Total assets	57	64
Current maturities of long-term debt	17	16
Other current liabilities	8	5
Long-Term Debt	12	17
Other liabilities		4
Total liabilities	37	42
Net assets of consolidated VIEs	$20	$22

Variable_Interest_Entities_Sch1

Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) (USD $)	Mar. 31, 2015
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$500,000,000
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	500,000,000
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	400,000,000
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	300,000,000
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Instrument, Face Amount	$225,000,000

Variable_Interest_Entities_Sch2

Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$343	$358
Investments and other assets	3,207	3,008
Other current liabilities	2,014	2,188
Deferred credits and other liabilities	31,979	31,364
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	213	188
Investments and other assets	3	4
Total assets	216	192
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets (liabilities)	200	175
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	147	150
Total assets	147	150
Net assets (liabilities)	147	150
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	66	38
Investments and other assets	3	4
Total assets	69	42
Other current liabilities	2	3
Deferred credits and other liabilities	14	14
Total liabilities	16	17
Net assets (liabilities)	53	25
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Investments and other assets	35	23
Other current liabilities	64	66
Deferred credits and other liabilities	2,298	2,281
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)	90	91
Total assets	90	91
Net assets (liabilities)	90	91
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Investments and other assets	257	251
Other current liabilities	88	98
Deferred credits and other liabilities	2,777	2,730
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Receivables (net of allowance for doubtful accounts)	105	113
Total assets	105	113
Net assets (liabilities)	$105	$113

Variable_Interest_Entities_Fai

Variable Interest Entities (Fair Value Assumptions)(Details) (Cinergy Receivables [Member])	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.60%	0.60%
Discount rate	1.20%	1.20%
Receivable turnover rate	12.80%	12.80%
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.20%	1.20%
Receivable turnover rate	10.50%	10.40%

Variable_Interest_Entities_Rec

Variable Interest Entities (Receivables Sold)(Details) (Cinergy Receivables [Member], USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$284	$273
Less: Retained interests	90	91
Net receivables sold	194	182
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	296	310
Less: Retained interests	105	113
Net receivables sold	$191	$197

Variable_Interest_Entities_Sal

Variable Interest Entities (Sales and Cash Flows)(Details) (Cinergy Receivables [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Receivables sold	$644	$741
Loss recognized on sale	3	4
Cash proceeds from receivables sold	640	723
Return received on retained interests	1	2
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Receivables sold	716	755
Loss recognized on sale	3	3
Cash proceeds from receivables sold	722	761
Return received on retained interests	$2	$2

Common_Stock_Earnings_Per_Shar

Common Stock (Earnings Per Share Data)(Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$773	$746
Average shares, basic	708	706
Average shares, diluted	708	706
EPS, basic (usd per share)	$1.09	$1.05
EPS, diluted (usd per share)	$1.09	$1.05
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$772	$744
Average shares, basic	708	706
Average shares, diluted	708	706
EPS, basic (usd per share)	$1.09	$1.05
EPS, diluted (usd per share)	$1.09	$1.05
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)	$0.80	$0.78

Common_Stock_Common_Stock_Acce

Common Stock Common Stock (Accelerated Share Repurchase) (Details) (Subsequent Event [Member], USD $)	1 Months Ended
In Millions, except Per Share data, unless otherwise specified	Apr. 30, 2015	Apr. 06, 2015
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock	$1,500
Delivered Shares from Dealers	16.6
Percentage of ASR common stock received		85.00%
Closing Stock Price	$76.97
Fair Market Value of Delivered Shares	1,275
Unsettled Portion of ASR		225
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

StockBased_Compensation_Schedu

Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation expense	$14	$16
Tax benefit associated with stock-based compensation expense	5	6
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	9	11
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) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Maximum years of participation	35 years
Matching contribution percentage	100.00%
Eligible pay percentage	6.00%
Additional savings plan account contribution percentage for employees not participating in defined pension plans	4.00%
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	132
Duke Energy Carolinas [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	42
Progress Energy [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	42
Duke Energy Progress [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	21
Duke Energy Florida [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	21
Duke Energy Ohio [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	1
Duke Energy Indiana [Member] | Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	9

Employee_Benefit_Plans_Compone

Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$40	$34
Interest cost on projected benefit obligation	82	86
Expected return on plan assets	-129	-128
Amortization of actuarial loss (gain)	43	37
Amortization of prior service cost (credit)	-4	-4
Other	2	2
Net periodic costs	34	27
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	13	10
Interest cost on projected benefit obligation	21	21
Expected return on plan assets	-36	-33
Amortization of actuarial loss (gain)	10	9
Amortization of prior service cost (credit)	-2	-2
Other	1	1
Net periodic costs	7	6
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11	10
Interest cost on projected benefit obligation	26	28
Expected return on plan assets	-43	-43
Amortization of actuarial loss (gain)	17	17
Amortization of prior service cost (credit)	-1	-1
Other	1	1
Net periodic costs	11	12
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	6	5
Interest cost on projected benefit obligation	12	13
Expected return on plan assets	-20	-21
Amortization of actuarial loss (gain)	8	8
Net periodic costs	6	5
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	-22	-21
Amortization of actuarial loss (gain)	8	8
Net periodic costs	5	6
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	-6	-7
Amortization of actuarial loss (gain)	2	1
Net periodic costs	2	0
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3	2
Interest cost on projected benefit obligation	7	7
Expected return on plan assets	-10	-9
Amortization of actuarial loss (gain)	3	3
Net periodic costs	3	3
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	2
Interest cost on projected benefit obligation	9	12
Expected return on plan assets	-3	-3
Amortization of actuarial loss (gain)	6	10
Amortization of prior service cost (credit)	-35	-31
Net periodic costs	-21	-10
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	3
Expected return on plan assets	-2	-2
Amortization of actuarial loss (gain)		1
Amortization of prior service cost (credit)	-4	-3
Net periodic costs	-4	-1
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1
Interest cost on projected benefit obligation	4	6
Amortization of actuarial loss (gain)	7	10
Amortization of prior service cost (credit)	-26	-24
Net periodic costs	-15	-7
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	3
Amortization of actuarial loss (gain)	5	7
Amortization of prior service cost (credit)	-17	-18
Net periodic costs	-10	-8
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1
Interest cost on projected benefit obligation	2	3
Amortization of actuarial loss (gain)	3	2
Amortization of prior service cost (credit)	-9	-5
Net periodic costs	-4	1
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic costs	0	0
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
Net periodic costs	$0	$1

Employee_Benefit_Plans_Employe

Employee Benefit Plans (Employee Savings Plans) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Employee Savings Plans [Abstract]
Pretax employer matching contributions	$49	$43
Duke Energy Carolinas [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	16	14
Progress Energy [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	14	12
Duke Energy Progress [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	11	9
Duke Energy Florida [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	4	4
Duke Energy Ohio [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	1	1
Duke Energy Indiana [Member]
Employee Savings Plans [Abstract]
Pretax employer matching contributions	$2	$2

Income_Taxes_Effective_Tax_Rat

Income Taxes (Effective Tax Rates) (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	31.90%	31.20%
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	35.80%	37.40%
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	35.40%	36.90%
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	33.80%	36.60%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	38.60%	38.50%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	36.70%	36.40%
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	36.60%	36.80%