Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 66	$ 26
Net amounts recognized on the Condensed Consolidated Balance Sheet	66	26
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	246	419
Net amounts recognized on the Condensed Consolidated Balance Sheet	246	419
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	44	18
Gross amounts offset	(10)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	22	8
Gross amounts offset	(7)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	4
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	80	271
Gross amounts offset	(10)	(22)
Net amounts recognized on the Condensed Consolidated Balance Sheet	70	249
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	166	148
Gross amounts offset	(7)	(16)
Net amounts recognized on the Condensed Consolidated Balance Sheet	159	132
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	99	45
Net amounts recognized on the Condensed Consolidated Balance Sheet	99	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Carolinas [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 Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	32
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	94	13
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	92	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	31	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	81	322
Net amounts recognized on the Condensed Consolidated Balance Sheet	81	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Gross amounts offset	(7)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	4
Gross amounts offset	(5)	(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	62	225
Gross amounts offset	(7)	(21)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	97
Gross amounts offset	(5)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	15	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	12	98
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	2
Gross amounts offset	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	77
Gross amounts offset	(4)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	3	21
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	64	216
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	3
Gross amounts offset	(3)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	4
Gross amounts offset	(3)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	53	145
Gross amounts offset	(3)	(20)
Net amounts recognized on the Condensed Consolidated Balance Sheet	50	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	11	71
Gross amounts offset	(3)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	3
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	7
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	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	7	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	6
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	7
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 20	$ 7