Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 33	$ 351
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	110
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	406	909
Net amounts recognized on the Condensed Consolidated Balance Sheet	406	668
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	26	210
Gross amounts offset	(2)	(153)
Net amount subject to master netting	24	57
Net amounts recognized on the Condensed Consolidated Balance Sheet	24	57
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	136
Gross amounts offset	(2)	(88)
Net amount subject to master netting	5	48
Amounts not subject to master netting		5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	53
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	257	573
Gross amounts offset	(15)	(213)
Net amounts subject to master netting	242	360
Amounts not subject to master netting		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	242	361
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	144	319
Gross amounts offset	(9)	(173)
Net amounts subject to master netting	135	146
Amounts not subject to master netting	5	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	140	162
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	33	19
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	19
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	25	14
Net amounts subject to master netting	25	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	14
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	5
Net amounts subject to master netting	8	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	5
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	13	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	309	371
Net amounts recognized on the Condensed Consolidated Balance Sheet	309	373
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	2
Gross amounts offset	(1)	(2)
Net amount subject to master netting	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	6
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6
Gross amounts offset	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	215	289
Gross amounts offset	(14)	(17)
Net amounts subject to master netting	201	272
Net amounts recognized on the Condensed Consolidated Balance Sheet	201	272
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	89	82
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	80	74
Amounts not subject to master netting	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	85	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	95	132
Net amounts recognized on the Condensed Consolidated Balance Sheet	95	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	77	109
Net amounts subject to master netting	77	109
Net amounts recognized on the Condensed Consolidated Balance Sheet	77	109
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	23
Net amounts subject to master netting	18	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	23
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	4
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	209	239
Net amounts recognized on the Condensed Consolidated Balance Sheet	209	241
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Gross amounts offset	(1)	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	6
Gross amounts offset	(2)
Net amount subject to master netting	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	4
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	138	180
Gross amounts offset	(14)	(17)
Net amounts subject to master netting	124	163
Net amounts recognized on the Condensed Consolidated Balance Sheet	124	163
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	71	59
Gross amounts offset	(9)	(8)
Net amounts subject to master netting	62	51
Net amounts recognized on the Condensed Consolidated Balance Sheet	62	51
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	341
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	49
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	473
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	181
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	204
Gross amounts offset		(179)
Net amount subject to master netting	4	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	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	6	216
Gross amounts offset		(193)
Net amounts subject to master netting	6	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	23
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12	14
Net amount subject to master netting	12	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 12	$ 14