Condensed Consolidated Statements Of Operations (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Operating Revenues
Regulated electric	$ 2,628		$ 2,576		$ 5,129		$ 5,149
Non-regulated electric, natural gas, and other	868		864		1,826		1,719
Regulated natural gas	81		94		252		329
Total operating revenues	3,577		3,534		7,207		7,197
Operating Expenses
Fuel used in electric generation and purchased power - regulated	849		834		1,626		1,646
Fuel used in electric generation and purchased power - non-regulated	396		388		844		764
Cost of natural gas and coal sold	42		63		144		214
Operation, maintenance and other	862		959		1,608		1,839
Depreciation and amortization	475		437		954		891
Property and other taxes	171		169		355		355
Impairment charges	0		9		402		9
Total operating expenses	2,795		2,859		5,933		5,718
Gains on Sales of Other Assets and Other, net	4		4		7		14
Operating Income	786		679		1,281		1,493
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	40		48		85		80
Impairments and gains on sales of unconsolidated affiliates	(1)		12		(6)		14
Other income and expenses, net	70		97		159		214
Total other income and expenses	109		157		238		308
Interest Expense	232		203		456		422
Income From Continuing Operations Before Income Taxes	663		633		1,063		1,379
Income Tax Expense from Continuing Operations	214		192		317		425
Income From Continuing Operations	449		441		746		954
Income From Discontinued Operations, net of tax	(1)		0		1		0
Net Income	448		441		747		954
Less: Net Income Attributable to Noncontrolling Interests	4		6		8		8
Net Income Attributable to Duke Energy Corporation	444		435		739		946
Other comprehensive income(loss), net of tax
Pension and OPEB related adjustments to AOCI	2	[1]	2	[1]	6	[1]	(7)	[1]
Reclassification into earnings from cash flow hedges	(3)	[2]	(1)	[2]	(2)	[2]	(2)	[2]
Comprehensive income	298		494		653		1,033
Income from continuing operations attributable to Duke Energy Corporation common shareholders
Basic	$ 0.99		$ 0.98		$ 1.65		$ 2.13
Diluted	$ 0.99		$ 0.98		$ 1.65		$ 2.13
Net income attributable to Duke Energy Corporation common stockholders
Basic	$ 0.99		$ 0.98		$ 1.65		$ 2.13
Diluted	$ 0.99		$ 0.98		$ 1.65		$ 2.13
Dividends declared per share	$ 1.515		$ 1.485		$ 2.265		$ 2.22
Weighted-average shares outstanding
Basic	446,000,000		444,000,000		446,000,000		444,000,000
Diluted	446,000,000		444,000,000		446,000,000		444,000,000
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	1,616		1,607		3,117		3,159
Operating Expenses
Fuel used in electric generation and purchased power - regulated	442		511		822		980
Operation, maintenance and other	476		495		807		930
Depreciation and amortization	226		190		454		391
Property and other taxes	89		81		179		165
Total operating expenses	1,233		1,277		2,262		2,466
Gains on Sales of Other Assets and Other, net	3		1		6		1
Operating Income	386		331		861		694
Other Income and Expenses
Total other income and expenses	43		50		82		92
Interest Expense	93		82		190		171
Income From Continuing Operations Before Income Taxes	336		299		753		615
Income Tax Expense from Continuing Operations	125		106		276		217
Net Income	211		193		477		398
Other comprehensive income(loss), net of tax
Reclassification into earnings from cash flow hedges	2	[3]	1	[3]	2	[3]	1	[3]
Comprehensive income	213		194		479		399
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	336		361		660		733
Non-regulated electric, natural gas, and other	299		239		716		510
Regulated natural gas	82		94		253		330
Total operating revenues	717		694		1,629		1,573
Operating Expenses
Fuel used in electric generation and purchased power - regulated	120		91		234		188
Fuel used in electric generation and purchased power - non-regulated	176		147		415		311
Cost of natural gas and coal sold	12		22		87		141
Operation, maintenance and other	175		215		371		420
Depreciation and amortization	80		88		163		176
Property and other taxes	60		63		128		136
Impairment charges	0		9		0		9
Total operating expenses	623		635		1,398		1,381
Gains on Sales of Other Assets and Other, net	1		0		2		2
Operating Income	95		59		233		194
Other Income and Expenses
Total other income and expenses	4		4		8		9
Interest Expense	25		27		49		51
Income From Continuing Operations Before Income Taxes	74		36		192		152
Income Tax Expense from Continuing Operations	29		3		73		46
Net Income	45		33		119		106
Other comprehensive income(loss), net of tax
Pension and OPEB related adjustments to AOCI	0	[4]	1	[4]	1	[4]	1	[4]
Comprehensive income	45		34		120		107
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	685		620		1,373		1,279
Operating Expenses
Fuel used in electric generation and purchased power - regulated	287		232		570		478
Operation, maintenance and other	151		163		311		324
Depreciation and amortization	96		97		192		197
Property and other taxes	17		19		38		41
Impairment charges	0		0		400		0
Total operating expenses	551		511		1,511		1,040
Operating Income	134		109		(138)		239
Other Income and Expenses
Total other income and expenses	19		21		42		44
Interest Expense	36		34		70		70
Income From Continuing Operations Before Income Taxes	117		96		(166)		213
Income Tax Expense from Continuing Operations	40		28		(76)		69
Net Income	77		68		(90)		144
Other comprehensive income(loss), net of tax
Reclassification into earnings from cash flow hedges					(1)	[5]
Comprehensive income	$ 77		$ 68		$ (91)		$ 144

[1] Net of $1 million tax expense and $3 million tax expense for the three and six months ended June 30, 2012 and insignificant tax expense and $3 tax benefit for the three and six months ended June 30, 2011.

[2] Net of $2 million tax benefit and insignificant tax expense for the three and six months ended June 30, 2012 and $1 million tax expense for the three and six months ended June 30, 2011, respectively.

[3] Net of $2 million tax expense for the three and six months ended June 30, 2012 and 2011.

[4] Net of insignificant tax expense for the three and six months ended June 30, 2012, and insignificant tax expense and $1 million tax expense for the three and six months ended June 30, 2011.

[5] Net of insignificant tax benefit for the three and six months ended June 30, 2012.