Condensed Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Operating Revenues
Regulated electric	$ 5,763		$ 3,016		$ 10,892		$ 8,165
Non-regulated electric, natural gas, and other	882		867		2,708		2,586
Regulated natural gas	77		81		329		410
Total operating revenues	6,722		3,964		13,929		11,161
Operating Expenses
Fuel used in electric generation and purchased power - regulated	2,222		957		3,848		2,603
Fuel used in electric generation and purchased power - non-regulated	484		383		1,328		1,147
Cost of natural gas and coal sold	40		48		184		262
Operation, maintenance and other	1,654		866		3,262		2,705
Depreciation and amortization	666		455		1,620		1,346
Property and other taxes	326		183		681		538
Impairment charges	266		300		668		309
Total operating expenses	5,658		3,192		11,591		8,910
Gains (losses) on sales of other assets and other, net	14		(5)		21		9
Operating Income	1,078		767		2,359		2,260
Other Income and Expenses
Equity in earnings of unconsolidated affiliates	33		43		118		123
Impairments and gains on sales of unconsolidated affiliates	0		(3)		(6)		11
Other income and expenses, net	132		83		291		297
Total other income and expenses	165		123		403		431
Interest Expense	401		213		857		635
Income From Continuing Operations Before Income Taxes	842		677		1,905		2,056
Income Tax Expense from Continuing Operations	248		208		565		633
Income From Continuing Operations	594		469		1,340		1,423
Income From Discontinued Operations, net of tax	4		1		5		1
Net Income	598		470		1,345		1,424
Less: Net Income Attributable to Noncontrolling Interests	4		(2)		12		6
Net Income Attributable to Duke Energy Corporation	594		472		1,333		1,418
Other comprehensive income(loss), net of tax
Pension and OPEB related adjustments to AOCI	(21)	[1]	1	[1]	(15)	[1]	(6)	[1]
Reclassification into earnings from cash flow hedges	2	[2]	(1)	[2]	0	[2]	(3)	[2]
Comprehensive income	574		195		1,227		1,228
Income from continuing operations attributable to Duke Energy Corporation common shareholders
Basic	$ 0.84		$ 1.06		$ 2.50		$ 3.19
Diluted	$ 0.84		$ 1.06		$ 2.50		$ 3.19
Income (loss) from discontinued operations attributable To Duke Energy Corporation common shareholders Abstract
Basic	$ 0.01		$ 0		$ 0.01
Diluted	$ 0.01		$ 0		$ 0.01		$ 0
Net income attributable to Duke Energy Corporation common stockholders
Basic			$ 1.06		$ 2.51		$ 3.19
Diluted	$ 0.85				$ 2.51		$ 3.19
Dividends declared per share	$ 0				$ 2.265		$ 2.22
Weighted-average shares outstanding
Basic	699		444		531		444
Diluted					531		444
Duke Energy Carolinas [Member]
Operating Revenues
Total operating revenues	1,939		1,868		5,056		5,027
Operating Expenses
Fuel used in electric generation and purchased power - regulated	576		577		1,398		1,557
Operation, maintenance and other	562		447		1,369		1,377
Depreciation and amortization	233		210		687		601
Property and other taxes	100		94		279		259
Impairment charges	31		0		31		0
Total operating expenses	1,502		1,328		3,764		3,794
Gains (losses) on sales of other assets and other, net	3		1		9		2
Operating Income	440		541		1,301		1,235
Other Income and Expenses
Total other income and expenses	48		47		130		139
Interest Expense	95		93		285		264
Income From Continuing Operations Before Income Taxes	393		495		1,146		1,110
Income Tax Expense from Continuing Operations	135		184		411		401
Net Income	258		311		735		709
Other comprehensive income(loss), net of tax
Reclassification into earnings from cash flow hedges	0	[3]	2	[3]	2	[3]	3	[3]
Comprehensive income	258		313		737		712
Duke Energy Ohio [Member]
Operating Revenues
Regulated electric	387		442		1,047		1,175
Non-regulated electric, natural gas, and other	292		315		1,008		825
Regulated natural gas	78		81		331		411
Total operating revenues	757		838		2,386		2,411
Operating Expenses
Fuel used in electric generation and purchased power - regulated	141		111		375		299
Fuel used in electric generation and purchased power - non-regulated	234		189		649		500
Cost of natural gas and coal sold	8		12		95		153
Operation, maintenance and other	208		186		579		606
Depreciation and amortization	86		83		249		259
Property and other taxes	38		64		166		200
Impairment charges	0		79		0		88
Total operating expenses	715		724		2,113		2,105
Gains (losses) on sales of other assets and other, net	0		2		2		4
Operating Income	42		116		275		310
Other Income and Expenses
Total other income and expenses	5		8		13		17
Interest Expense	21		27		70		78
Income From Continuing Operations Before Income Taxes	26		97		218		249
Income Tax Expense from Continuing Operations	12		46		85		92
Net Income	14		51		133		157
Other comprehensive income(loss), net of tax
Pension and OPEB related adjustments to AOCI	0	[4]	(1)	[4]	1	[4]	0	[4]
Comprehensive income	14		50		134		157
Duke Energy Indiana [Member]
Operating Revenues
Total operating revenues	718		718		2,091		1,997
Operating Expenses
Fuel used in electric generation and purchased power - regulated	283		270		853		748
Operation, maintenance and other	162		148		473		472
Depreciation and amortization	100		100		292		297
Property and other taxes	23		20		61		61
Impairment charges	180		222		580		222
Total operating expenses	748		760		2,259		1,800
Operating Income	(30)		(42)		(168)		197
Other Income and Expenses
Total other income and expenses	24		26		66		70
Interest Expense	35		34		105		104
Income From Continuing Operations Before Income Taxes	(41)		(50)		(207)		163
Income Tax Expense from Continuing Operations	(22)		(19)		(98)		50
Net Income	(19)		(31)		(109)		113
Other comprehensive income(loss), net of tax
Reclassification into earnings from cash flow hedges	(1)				(1)	[5]	(1)
Comprehensive income	$ (19)		$ (32)		$ (110)		$ 112

[1] Net of $10 million tax benefit and $7 million tax benefit for the three and nine months ended September 30, 2012 and insignificant tax expense and $3 tax benefit for the three and nine months ended September 30, 2011.

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

[3] Net of insignificant tax expense and $2 million tax expense for the three and nine months ended September 30, 2012, and $1 million tax benefit and $1 million tax expense for the three and nine months ended September 30, 2011.

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

[5] Net of insignificant tax benefit for the three and nine months ended September 30, 2012, and $1 million tax benefit for the three and nine months ended September 30, 2011.