Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 51	$ 351
Net amounts recognized on the Condensed Consolidated Balance Sheet	51	110
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	369	909
Net amounts recognized on the Condensed Consolidated Balance Sheet	369	668
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	37	210
Gross amounts offset	(5)	(153)
Net amount subject to master netting	32	57
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	57
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	14	136
Gross amounts offset	(4)	(88)
Net amount subject to master netting	10	48
Amounts not subject to master netting		5
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	53
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	247	573
Gross amounts offset	(19)	(213)
Net amounts subject to master netting	228	360
Amounts not subject to master netting		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	228	361
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	117	319
Gross amounts offset	(9)	(173)
Net amounts subject to master netting	108	146
Amounts not subject to master netting	5	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	113	162
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	19
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	19
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1
Gross amounts offset	(1)
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	15	14
Gross amounts offset	(1)
Net amounts subject to master netting	14	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	14
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	4	5
Net amounts subject to master netting	4	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	5
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	296	371
Net amounts recognized on the Condensed Consolidated Balance Sheet	296	373
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	2
Gross amounts offset	(3)	(2)
Net amount subject to master netting	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(4)
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	213	289
Gross amounts offset	(17)	(17)
Net amounts subject to master netting	196	272
Net amounts recognized on the Condensed Consolidated Balance Sheet	196	272
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	78	82
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	69	74
Amounts not subject to master netting	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	74	74
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	96	132
Net amounts recognized on the Condensed Consolidated Balance Sheet	96	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amount subject to master netting	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	74	109
Net amounts subject to master netting	74	109
Net amounts recognized on the Condensed Consolidated Balance Sheet	74	109
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	22	23
Net amounts subject to master netting	22	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	22	23
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	195	239
Net amounts recognized on the Condensed Consolidated Balance Sheet	195	241
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6	2
Gross amounts offset	(3)	(2)
Net amount subject to master netting	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(4)
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	139	180
Gross amounts offset	(17)	(17)
Net amounts subject to master netting	122	163
Net amounts recognized on the Condensed Consolidated Balance Sheet	122	163
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	56	59
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	47	51
Net amounts recognized on the Condensed Consolidated Balance Sheet	47	51
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	341
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	49
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	473
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	181
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	204
Gross amounts offset		(179)
Net amount subject to master netting	5	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	25
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		137
Gross amounts offset		(114)
Net amount subject to master netting		23
Net amounts recognized on the Condensed Consolidated Balance Sheet		23
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	257
Gross amounts offset		(222)
Net amounts subject to master netting	1	35
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	35
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	216
Gross amounts offset		(193)
Net amounts subject to master netting	5	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	23
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	18	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	18	14
Net amount subject to master netting	18	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 18	$ 14