Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities: Derivatives and Collateral Posted) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 913	$ 636
Net amounts recognized on the Condensed Consolidated Balance Sheet	428	321
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	570	461
Net amounts recognized on the Condensed Consolidated Balance Sheet	85	145
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	388	214
Gross amounts offset	(362)	(179)
Net amount subject to master netting	26	35
Amounts not subject to master netting
Net amounts recognized on the Condensed Consolidated Balance Sheet	26	35
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	175	233
Gross amounts offset	(127)	(138)
Net amount subject to master netting	48	95
Amounts not subject to master netting	7	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	109
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	583	322
Gross amounts offset	(402)	(192)
Net amounts subject to master netting	181	130
Amounts not subject to master netting	3	4
Net amounts recognized on the Condensed Consolidated Balance Sheet	184	134
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	314	299
Gross amounts offset	(203)	(155)
Net amounts subject to master netting	111	144
Amounts not subject to master netting	13	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	124	155
Progress Energy [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	144	204
Net amounts recognized on the Condensed Consolidated Balance Sheet	142	187
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	20
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	15
Gross amounts offset	(1)	(13)
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	5
Gross amounts offset	(1)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	115	107
Gross amounts offset	(1)	(17)
Net amounts subject to master netting	114	90
Amounts not subject to master netting
Net amounts recognized on the Condensed Consolidated Balance Sheet	114	90
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	29	93
Gross amounts offset	(1)	(10)
Net amounts subject to master netting	28	83
Amounts not subject to master netting		4
Net amounts recognized on the Condensed Consolidated Balance Sheet	28	87
Duke Energy Progress [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	48	71
Net amounts recognized on the Condensed Consolidated Balance Sheet	45	66
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	6
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Gross amounts offset	(2)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	3
Gross amounts offset	(1)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	40	41
Gross amounts offset	(2)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	38	38
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	30
Gross amounts offset	(1)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	27
Duke Energy Florida [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	96	129
Net amounts recognized on the Condensed Consolidated Balance Sheet	97	116
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	14
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	1
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	12
Gross amounts offset	(1)	(10)
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	2
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	75	66
Gross amounts offset	(1)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	74	51
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	21	63
Gross amounts offset	(1)	(7)
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	56
Duke Energy Ohio [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	778	390
Net amounts recognized on the Condensed Consolidated Balance Sheet	221	95
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	564	391
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	96
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	381	186
Gross amounts offset	(377)	(165)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	21
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	183	205
Gross amounts offset	(177)	(132)
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	73
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	485	199
Gross amounts offset	(419)	(173)
Net amounts subject to master netting	66	26
Amounts not subject to master netting		1
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	27
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	293	186
Gross amounts offset	(251)	(143)
Net amounts subject to master netting	42	43
Amounts not subject to master netting		4
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 42	$ 47