Risk Management, Derivative Instruments and Hedging Activities (Schedule of Offsetting Assets and Liabilities: Derivatives and Collateral Posted) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Derivative Assets Subject to Master Netting
Gross amounts recognized	$ 369		$ 264
Net amounts recognized on the Condensed Consolidated Balance Sheet	102	[1]	103	[1]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	816		917
Net amounts recognized on the Condensed Consolidated Balance Sheet	549	[2]	756	[2]
Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	183		127
Gross amounts offset	(157)		(114)
Net amount subject to master netting	26		13
Amounts not subject to master netting	22		22
Net amounts recognized on the Condensed Consolidated Balance Sheet	48	[3]	35	[3]
Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	143		96
Gross amounts offset	(99)		(54)
Net amount subject to master netting	44		42
Amounts not subject to master netting	21		19
Net amounts recognized on the Condensed Consolidated Balance Sheet	65	[4]	61	[4]
Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	369		402
Gross amounts offset	(177)		(151)
Net amount subject to master netting	192		251
Amounts not subject to master netting	123		166
Net amounts recognized on the Condensed Consolidated Balance Sheet	315	[5]	417	[5]
Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	287		295
Gross amounts offset	(118)		(90)
Net amount subject to master netting	169		205
Amounts not subject to master netting	37		54
Net amounts recognized on the Condensed Consolidated Balance Sheet	206	[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	6		11
Net amounts recognized on the Condensed Consolidated Balance Sheet	0	[8]	11	[8]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	331		440
Net amounts recognized on the Condensed Consolidated Balance Sheet	325	[9]	440	[9]
Progress Energy [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	4		3
Gross amounts offset	(4)
Net amount subject to master netting			3
Net amounts recognized on the Condensed Consolidated Balance Sheet			3	[3]
Progress Energy [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	2		8
Gross amounts offset	(2)
Net amount subject to master netting			8
Net amounts recognized on the Condensed Consolidated Balance Sheet			8	[4]
Progress Energy [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	176		244
Gross amounts offset	(17)		(22)
Net amount subject to master netting	159		222
Net amounts recognized on the Condensed Consolidated Balance Sheet	159	[5]	222	[5]
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	151		192
Gross amounts offset	(21)		(36)
Net amount subject to master netting	130		156
Amounts not subject to master netting	4		4
Net amounts recognized on the Condensed Consolidated Balance Sheet	134	[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	0	[8]	2	[8]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	125		166
Net amounts recognized on the Condensed Consolidated Balance Sheet	124	[9]	166	[9]
Duke Energy Progress [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	1		1
Gross amounts offset	(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
Net amount subject to master netting			1
Net amounts recognized on the Condensed Consolidated Balance Sheet			1	[4]
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	68		97
Gross amounts offset	(2)		(2)
Net amount subject to master netting	66		95
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	[5]	95	[5]
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	57		69
Gross amounts offset	(3)		(7)
Net amount subject to master netting	54		62
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	[6]	62	[6]
Duke Energy Florida [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	5		9
Net amounts recognized on the Condensed Consolidated Balance Sheet	0	[10]	9	[10]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	202		270
Net amounts recognized on the Condensed Consolidated Balance Sheet	197	[11]	270	[11]
Duke Energy Florida [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	3		2
Gross amounts offset	(3)
Net amount subject to master netting			2
Net amounts recognized on the Condensed Consolidated Balance Sheet			2	[12]
Duke Energy Florida [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	2		7
Gross amounts offset	(2)
Net amount subject to master netting			7
Net amounts recognized on the Condensed Consolidated Balance Sheet			7	[13]
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	108		147
Gross amounts offset	(15)		(20)
Net amount subject to master netting	93		127
Net amounts recognized on the Condensed Consolidated Balance Sheet	93	[14]	127	[14]
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	94		123
Gross amounts offset	(18)		(29)
Net amount subject to master netting	76		94
Net amounts recognized on the Condensed Consolidated Balance Sheet	76	[15]	94	[15]
Duke Energy Ohio [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	309		220
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	[16]	59	[16]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	300		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	178		137
Gross amounts offset	(161)		(110)
Net amount subject to master netting	17		27
Amounts not subject to master netting			2
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	[3]	29	[3]
Duke Energy Ohio [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	131		81
Gross amounts offset	(94)		(51)
Net amount subject to master netting	37		30
Net amounts recognized on the Condensed Consolidated Balance Sheet	37	[4]	30	[4]
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	180		136
Gross amounts offset	(166)		(125)
Net amount subject to master netting	14		11
Amounts not subject to master netting	1		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	[5]	12	[5]
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	114		55
Gross amounts offset	(94)		(51)
Net amount subject to master netting	20		4
Amounts not subject to master netting	5		7
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	[6]	11	[6]
Duke Energy Indiana [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	18		10
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	[17]	10	[17]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	37		63
Net amounts recognized on the Condensed Consolidated Balance Sheet	37	[2]	63	[2]
Duke Energy Indiana [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Gross amounts recognized	18
Net amount subject to master netting	18
Amounts not subject to master netting			10
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	[3]	10	[3]
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Gross amounts recognized	2
Gross amounts offset	(2)
Amounts not subject to master netting	35		63
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 35	[5]	$ 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 Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Balance Sheets.

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

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

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

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

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

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

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