Derivatives and Hedging (Schedule of Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 108	$ 26
Net amounts recognized on the Condensed Consolidated Balance Sheet	108	26
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	428	419
Net amounts recognized on the Condensed Consolidated Balance Sheet	428	419
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	67	18
Gross amounts offset	(15)	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	52	15
Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	41	8
Gross amounts offset	(5)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	36	4
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	263	271
Gross amounts offset	(15)	(22)
Net amounts recognized on the Condensed Consolidated Balance Sheet	248	249
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	165	148
Gross amounts offset	(5)	(16)
Net amounts recognized on the Condensed Consolidated Balance Sheet	160	132
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	18
Net amounts recognized on the Condensed Consolidated Balance Sheet	18
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	89	45
Net amounts recognized on the Condensed Consolidated Balance Sheet	89	45
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Carolinas [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10
Net amounts recognized on the Condensed Consolidated Balance Sheet	10
Duke Energy Carolinas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	32
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	32
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	82	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	82	13
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	54	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	11
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	100	322
Net amounts recognized on the Condensed Consolidated Balance Sheet	100	322
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	23	7
Gross amounts offset	(13)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	5
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	31	4
Gross amounts offset	(5)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	26
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	77	225
Gross amounts offset	(13)	(21)
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	204
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	23	97
Gross amounts offset	(5)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	82
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	25	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	2
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	98
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	98
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	2
Gross amounts offset	(6)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	2
Duke Energy Progress [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	16
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	18	77
Gross amounts offset	(6)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	12	76
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		21
Net amounts recognized on the Condensed Consolidated Balance Sheet		21
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	29	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	29	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	76	216
Net amounts recognized on the Condensed Consolidated Balance Sheet	76	216
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	14	3
Gross amounts offset	(7)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	1
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	15	4
Gross amounts offset	(4)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	11
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	59	145
Gross amounts offset	(7)	(20)
Net amounts recognized on the Condensed Consolidated Balance Sheet	52	125
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	17	71
Gross amounts offset	(4)	(15)
Net amounts recognized on the Condensed Consolidated Balance Sheet	13	56
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	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	5	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	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	31	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	7
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	(1)
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	31	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	$ 7
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 1