Condensed Consolidated Statements Of Operations (USD $) In Millions, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating Revenues
Regulated electric	$ 3,016	$ 3,077	$ 8,165	$ 8,233
Non-regulated electric, natural gas, and other	867	791	2,586	2,159
Regulated natural gas	81	78	410	435
Total operating revenues	3,964	3,946	11,161	10,827
Operating Expenses
Fuel used in electric generation and purchased power - regulated	957	990	2,603	2,598
Fuel used in electric generation and purchased power - non-regulated	383	335	1,147	895
Cost of natural gas and coal sold	48	36	262	272
Operation, maintenance and other	866	881	2,705	2,724
Depreciation and amortization	455	447	1,346	1,329
Property and other taxes	183	182	538	538
Goodwill and other impairment charges	300	44	309	700
Total operating expenses	3,192	2,915	8,910	9,056
(Losses) Gains on Sales of Other Assets and Other, net	(5)	2	9	9
Operating Income (Loss)	767	1,033	2,260	1,780
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	43	21	123	86
(Losses) gains on sales of unconsolidated affiliates	(3)	(1)	11	(3)
Other income and expenses, net	83	116	297	297
Total other income and expenses	123	136	431	380
Interest Expense	213	202	635	624
Income (Loss) From Continuing Operations Before Income Taxes	677	967	2,056	1,536
Income Tax Expense (Benefit) from Continuing Operations	208	301	633	643
Income From Continuing Operations	469	666	1,423	893
Income From Discontinued Operations, net of tax	1		1	1
Net Income (Loss)	470	666	1,424	894
Less: Net (Loss) Income Attributable to Noncontrolling Interests	(2)	(4)	6	1
Net Income Attributable to Duke Energy Corporation	472	670	1,418	893
Income from continuing operations attributable to Duke Energy Corporation common shareholders
Basic	$ 0.35	$ 0.51	$ 1.06	$ 0.68
Diluted	$ 0.35	$ 0.51	$ 1.06	$ 0.68
Income from discontinued operations attributable to Duke Energy Corporation common shareholders
Basic
Diluted
Net income attributable to Duke Energy Corporation common shareholders
Basic	$ 0.35	$ 0.51	$ 1.06	$ 0.68
Diluted	$ 0.35	$ 0.51	$ 1.06	$ 0.68
Dividends declared per share			$ 0.74	$ 0.725
Weighted-average shares outstanding
Basic	1,332,000,000.00	1,320,000,000.00	1,331,000,000.00	1,315,000,000.00
Diluted	1,333,000,000.00	1,322,000,000.00	1,332,000,000.00	1,316,000,000.00
Duke Energy Carolinas [Member]
Operating Revenues
Regulated electric	1,868	1,877	5,027	4,935
Operating Expenses
Fuel used in electric generation and purchased power - regulated	577	594	1,557	1,506
Operation, maintenance and other	447	471	1,377	1,401
Depreciation and amortization	210	200	601	585
Property and other taxes	94	93	259	269
Total operating expenses	1,328	1,358	3,794	3,761
(Losses) Gains on Sales of Other Assets and Other, net	1	2	2	7
Operating Income (Loss)	541	521	1,235	1,181
Other Income and Expenses
Other income and expenses, net	47	51	139	163
Interest Expense	93	95	264	271
Income (Loss) From Continuing Operations Before Income Taxes	495	477	1,110	1,073
Income Tax Expense (Benefit) from Continuing Operations	184	162	401	364
Net Income (Loss)	311	315	709	709
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	442	520	1,175	1,449
Non-regulated electric, natural gas, and other	315	325	825	664
Regulated natural gas	81	78	411	436
Total operating revenues	838	923	2,411	2,549
Operating Expenses
Fuel used in electric generation and purchased power - regulated	111	140	299	410
Fuel used in electric generation and purchased power - non-regulated	189	138	500	319
Cost of natural gas and coal sold	12	13	153	191
Operation, maintenance and other	186	191	606	577
Depreciation and amortization	83	97	259	300
Property and other taxes	64	65	200	198
Goodwill and other impairment charges	79		88	837
Total operating expenses	724	644	2,105	2,832
(Losses) Gains on Sales of Other Assets and Other, net	2		4	3
Operating Income (Loss)	116	279	310	(280)
Other Income and Expenses
Other income and expenses, net	8	8	17	22
Interest Expense	27	26	78	84
Income (Loss) From Continuing Operations Before Income Taxes	97	261	249	(342)
Income Tax Expense (Benefit) from Continuing Operations	46	85	92	111
Net Income (Loss)	51	176	157	(453)
Duke Energy Indiana [Member]
Operating Revenues
Regulated electric	718	694	1,997	1,883
Operating Expenses
Fuel used in electric generation and purchased power - regulated	270	256	748	682
Operation, maintenance and other	148	131	472	445
Depreciation and amortization	100	95	297	281
Property and other taxes	20	19	61	52
Goodwill and other impairment charges	222	44	222	44
Total operating expenses	760	545	1,800	1,504
Operating Income (Loss)	(42)	149	197	379
Other Income and Expenses
Other income and expenses, net	26	19	70	51
Interest Expense	34	32	104	99
Income (Loss) From Continuing Operations Before Income Taxes	(50)	136	163	331
Income Tax Expense (Benefit) from Continuing Operations	(19)	44	50	112
Net Income (Loss)	$ (31)	$ 92	$ 113	$ 219