Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 33	$ 26
Net amounts recognized on the Condensed Consolidated Balance Sheet	33	26
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	537	419
Net amounts recognized on the Condensed Consolidated Balance Sheet	537	419
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	18
Gross amounts offset	(1)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	26	8
Gross amounts offset	(15)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	4
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	376	271
Gross amounts offset	(16)	(22)
Net amounts recognized on the Condensed Consolidated Balance Sheet	360	249
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	161	148
Gross amounts offset	(23)	(16)
Net amounts recognized on the Condensed Consolidated Balance Sheet	138	132
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	13
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	81	45
Net amounts recognized on the Condensed Consolidated Balance Sheet	81	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1
Gross amounts offset	(1)
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	12
Gross amounts offset	(12)
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	37	32
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	36	32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	44	13
Gross amounts offset	(12)
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	17	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	298	322
Net amounts recognized on the Condensed Consolidated Balance Sheet	298	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	7
Gross amounts offset	(1)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	4
Gross amounts offset	(3)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	232	225
Gross amounts offset	(15)	(21)
Net amounts recognized on the Condensed Consolidated Balance Sheet	217	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	66	97
Gross amounts offset	(11)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	87	98
Net amounts recognized on the Condensed Consolidated Balance Sheet	87	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	78	77
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	78	76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	21
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	11	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	206	216
Net amounts recognized on the Condensed Consolidated Balance Sheet	206	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Gross amounts offset	(1)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	154	145
Gross amounts offset	(15)	(20)
Net amounts recognized on the Condensed Consolidated Balance Sheet	139	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	52	71
Gross amounts offset	(9)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	43	56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 2	$ 7