Risk Management, Derivative Instruments and Hedging Activities (Schedule of Offsetting Assets and Liabilities: Derivatives and Collateral Posted) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Derivative Assets Subject to Master Netting
Gross amounts recognized	$ 374		$ 264
Net amounts recognized on the Condensed Consolidated Balance Sheet	127	[1]	103	[1]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	720		917
Net amounts recognized on the Condensed Consolidated Balance Sheet	473	[2]	756	[2]
Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	159		127
Gross amounts offset	(142)		(114)
Net amount subject to master netting	17		13
Amounts not subject to master netting	23		22
Net amounts recognized on the Condensed Consolidated Balance Sheet	40	[3]	35	[3]
Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	175		96
Gross amounts offset	(108)		(54)
Net amount subject to master netting	67		42
Amounts not subject to master netting	17		19
Net amounts recognized on the Condensed Consolidated Balance Sheet	84	[4]	61	[4]
Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	338		402
Gross amounts offset	(168)		(151)
Net amount subject to master netting	170		251
Amounts not subject to master netting	89		166
Net amounts recognized on the Condensed Consolidated Balance Sheet	259	[5]	417	[5]
Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	265		295
Gross amounts offset	(122)		(90)
Net amount subject to master netting	143		205
Amounts not subject to master netting	28		54
Net amounts recognized on the Condensed Consolidated Balance Sheet	171	[6]	259	[6]
Duke Energy Carolinas [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	4		12
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	[7]	12	[7]
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Amounts not subject to master netting	3		6
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	[5]	6	[5]
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Amounts not subject to master netting	1		6
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	[6]	6	[6]
Progress Energy [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	3		11
Net amounts recognized on the Condensed Consolidated Balance Sheet			11	[8]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	285		440
Net amounts recognized on the Condensed Consolidated Balance Sheet	282	[9]	440	[9]
Progress Energy [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		3
Gross amounts offset	(1)
Net amount subject to master netting	0		3
Net amounts recognized on the Condensed Consolidated Balance Sheet	0	[3]	3	[3]
Progress Energy [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	2		8
Gross amounts offset	(1)
Net amount subject to master netting	1		8
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	[4]	8	[4]
Progress Energy [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	159		244
Gross amounts offset	(13)		(22)
Net amount subject to master netting	146		222
Net amounts recognized on the Condensed Consolidated Balance Sheet	146	[5]	222	[5]
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	122		192
Gross amounts offset	(15)		(36)
Net amount subject to master netting	107		156
Amounts not subject to master netting	4		4
Net amounts recognized on the Condensed Consolidated Balance Sheet	111	[6]	160	[6]
Duke Energy Progress [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		2
Net amounts recognized on the Condensed Consolidated Balance Sheet			2	[8]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	108		166
Net amounts recognized on the Condensed Consolidated Balance Sheet	107	[9]	166	[9]
Duke Energy Progress [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized			1
Net amount subject to master netting			1
Net amounts recognized on the Condensed Consolidated Balance Sheet			1	[3]
Duke Energy Progress [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		1
Net amount subject to master netting	1		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	[4]	1	[4]
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	65		97
Gross amounts offset	(3)		(2)
Net amount subject to master netting	62		95
Net amounts recognized on the Condensed Consolidated Balance Sheet	62	[5]	95	[5]
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	43		69
Gross amounts offset	(2)		(7)
Net amount subject to master netting	41		62
Net amounts recognized on the Condensed Consolidated Balance Sheet	41	[6]	62	[6]
Duke Energy Florida [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	2		9
Net amounts recognized on the Condensed Consolidated Balance Sheet			9
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	173		270
Net amounts recognized on the Condensed Consolidated Balance Sheet	171	[10]	270	[10]
Duke Energy Florida [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		2
Gross amounts offset	(1)
Net amount subject to master netting	0		2
Net amounts recognized on the Condensed Consolidated Balance Sheet	0	[11]	2	[11]
Duke Energy Florida [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		7
Gross amounts offset	(1)
Net amount subject to master netting	0		7
Net amounts recognized on the Condensed Consolidated Balance Sheet	0	[12]	7	[12]
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	94		147
Gross amounts offset	(10)		(20)
Net amount subject to master netting	84		127
Net amounts recognized on the Condensed Consolidated Balance Sheet	84	[13]	127	[13]
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	79		123
Gross amounts offset	(13)		(29)
Net amount subject to master netting	66		94
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	[14]	94	[14]
Duke Energy Ohio [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	314		220
Net amounts recognized on the Condensed Consolidated Balance Sheet	70	[15]	59	[15]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	290		199
Net amounts recognized on the Condensed Consolidated Balance Sheet	46	[9]	38	[9]
Duke Energy Ohio [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	155		137
Gross amounts offset	(141)		(110)
Net amount subject to master netting	14		27
Amounts not subject to master netting			2
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	[3]	29	[3]
Duke Energy Ohio [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	159		81
Gross amounts offset	(105)		(51)
Net amount subject to master netting	54		30
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	[4]	30	[4]
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	165		136
Gross amounts offset	(154)		(125)
Net amount subject to master netting	11		11
Amounts not subject to master netting	1		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	[5]	12	[5]
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	120		55
Gross amounts offset	(105)		(51)
Net amount subject to master netting	15		4
Amounts not subject to master netting	4		7
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	[6]	11	[6]
Duke Energy Indiana [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	14		10
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	[16]	10	[16]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized			63
Net amounts recognized on the Condensed Consolidated Balance Sheet			63	[2]
Duke Energy Indiana [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	14
Net amount subject to master netting	14
Amounts not subject to master netting			10
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	[3]	10	[3]
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Amounts not subject to master netting			63
Net amounts recognized on the Condensed Consolidated Balance Sheet			$ 63	[5]

[1] Included in Other within Current Assets and Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.

[2] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.

[3] Included in Other within Current Assets on the Condensed Consolidated Balance Sheet.

[4] Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.

[5] Included in Other within Current Liabilities on the Condensed Consolidated Balance Sheet.

[6] Included in Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.

[7] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.

[8] Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[9] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.

[10] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Balance Sheets

[11] Included in Other within Current Assets on the Condensed Balance Sheet.

[12] Included in Other within Investments and Other Assets on the Condensed Balance Sheet.

[13] Included in Other within Current Liabilities on the Condensed Balance Sheet.

[14] Included in Other within Deferred Credits and Other Liabilities on the Condensed Balance Sheet.

[15] Included in Other within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[16] Included in Other within Current Assets on the Condensed Consolidated Balance Sheets.