Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 216	$ 252
Net amounts recognized on the Condensed Consolidated Balance Sheet	216	252
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	41	52
Gross amounts offset	(7)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	41
Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	175	200
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	173	198
Duke Energy Carolinas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	14	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	16
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	14	16
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	13	15
Progress Energy [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	34	25
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	25
Progress Energy [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	17	12
Gross amounts offset	(7)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	1
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	17	13
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	12
Duke Energy Progress [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	10	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	7
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1
Gross amounts offset	(1)
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	9	7
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	6
Duke Energy Florida [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	19	12
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	12
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	17	12
Gross amounts offset	(6)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	11	1
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Ohio [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	5	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	6
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	4	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	5
Duke Energy Indiana [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Duke Energy Indiana [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		2
Net amounts recognized on the Condensed Consolidated Balance Sheet		2
Piedmont Natural Gas [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	145	187
Net amounts recognized on the Condensed Consolidated Balance Sheet	145	187
Piedmont Natural Gas [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	14	35
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	35
Piedmont Natural Gas [Member] | Other Noncurrent Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	131	152
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 131	$ 152