Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities: Derivatives and Collateral Posted) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	$ 351	$ 461
Net amounts recognized on the Consolidated Balance Sheet	110us-gaap_DerivativeAssets	145us-gaap_DerivativeAssets
Gross amounts recognized	909	636
Net amounts recognized on the Consolidated Balance Sheet	668us-gaap_DerivativeLiabilities	321us-gaap_DerivativeLiabilities
Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	210	214
Gross amounts offset	(153)	(179)
Net amount subject to master netting	57	35
Net amounts recognized on the Consolidated Balance Sheet	57	35
Other Noncurrent Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	136	233
Gross amounts offset	(88)	(138)
Net amount subject to master netting	48	95
Amounts not subject to master netting	5	14
Net amounts recognized on the Consolidated Balance Sheet	53	109
Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	573	322
Gross amounts offset	(213)	(192)
Net amount subject to master netting	360	130
Amounts not subject to master netting	1	4
Net amounts recognized on the Consolidated Balance Sheet	361	134
Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	319	299
Gross amounts offset	(173)	(155)
Net amount subject to master netting	146	144
Amounts not subject to master netting	16	11
Net amounts recognized on the Consolidated Balance Sheet	162	155
Duke Energy Carolinas [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	19	2
Net amounts recognized on the Consolidated Balance Sheet	19	2
Duke Energy Carolinas [Member] \| Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	14
Net amount subject to master netting	14
Amounts not subject to master netting		1
Net amounts recognized on the Consolidated Balance Sheet	14	1
Duke Energy Carolinas [Member] \| Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	5
Net amount subject to master netting	5
Amounts not subject to master netting		1
Net amounts recognized on the Consolidated Balance Sheet	5	1
Progress Energy [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	2	20
Net amounts recognized on the Consolidated Balance Sheet	4	3
Gross amounts recognized	371	204
Net amounts recognized on the Consolidated Balance Sheet	373	187
Progress Energy [Member] \| Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	2	15
Gross amounts offset	(2)	(13)
Net amounts recognized on the Consolidated Balance Sheet		2
Progress Energy [Member] \| Other Noncurrent Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized		5
Gross amounts offset		(4)
Net amounts recognized on the Consolidated Balance Sheet		1
Progress Energy [Member] \| Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	289	107
Gross amounts offset	(17)	(17)
Net amount subject to master netting	272	90
Net amounts recognized on the Consolidated Balance Sheet	272	90
Progress Energy [Member] \| Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	82	93
Gross amounts offset	(8)	(10)
Net amount subject to master netting	74	83
Amounts not subject to master netting		4
Net amounts recognized on the Consolidated Balance Sheet	74	87
Duke Energy Progress [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized		6
Net amounts recognized on the Consolidated Balance Sheet		1
Gross amounts recognized	132	71
Net amounts recognized on the Consolidated Balance Sheet	132	66
Duke Energy Progress [Member] \| Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized		3
Gross amounts offset		(3)
Duke Energy Progress [Member] \| Other Noncurrent Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized		3
Gross amounts offset		(3)
Duke Energy Progress [Member] \| Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	109	41
Gross amounts offset		(3)
Net amounts recognized on the Consolidated Balance Sheet	109	38
Duke Energy Progress [Member] \| Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	23	30
Gross amounts offset		(3)
Net amounts recognized on the Consolidated Balance Sheet	23	27
Duke Energy Florida [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	2	14
Net amounts recognized on the Consolidated Balance Sheet	4	1
Gross amounts recognized	239	129
Net amounts recognized on the Consolidated Balance Sheet	241	116
Duke Energy Florida [Member] \| Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	2	12
Gross amounts offset	(2)	(10)
Net amounts recognized on the Consolidated Balance Sheet		2
Duke Energy Florida [Member] \| Other Noncurrent Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Florida [Member] \| Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	180	66
Gross amounts offset	(17)	(15)
Net amounts recognized on the Consolidated Balance Sheet	163	51
Duke Energy Florida [Member] \| Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	59	63
Gross amounts offset	(8)	(7)
Net amounts recognized on the Consolidated Balance Sheet	51	56
Duke Energy Ohio [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	341	391
Net amounts recognized on the Consolidated Balance Sheet	49	96
Gross amounts recognized	473	390
Net amounts recognized on the Consolidated Balance Sheet	181	95
Duke Energy Ohio [Member] \| Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	204	186
Gross amounts offset	(179)	(165)
Net amounts recognized on the Consolidated Balance Sheet	25	21
Duke Energy Ohio [Member] \| Other Noncurrent Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	137	205
Gross amounts offset	(114)	(132)
Net amounts recognized on the Consolidated Balance Sheet	23	73
Duke Energy Ohio [Member] \| Other Current Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	257	199
Gross amounts offset	(222)	(173)
Net amount subject to master netting	35	26
Amounts not subject to master netting		1
Net amounts recognized on the Consolidated Balance Sheet	35	27
Duke Energy Ohio [Member] \| Other Noncurrent Liabilities [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	216	186
Gross amounts offset	(193)	(143)
Net amount subject to master netting	23	43
Amounts not subject to master netting		4
Net amounts recognized on the Consolidated Balance Sheet	23	47
Duke Energy Indiana [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	14	12
Net amounts recognized on the Consolidated Balance Sheet	14	12
Duke Energy Indiana [Member] \| Other Current Assets [Member]
Offsetting Assets Liabilities [Line Items]
Gross amounts recognized	14	12
Gross amounts offset		(1)
Net amounts recognized on the Consolidated Balance Sheet	$ 14	$ 11

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