Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 83	$ 162
Net amounts recognized on the Condensed Consolidated Balance Sheet	83	162
Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	60	111
Gross amounts offset	(7)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	53	100
Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	23	51
Gross amounts offset	(2)	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	21	49
Duke Energy Carolinas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	17	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	17	33
Duke Energy Carolinas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	16	23
Net amounts recognized on the Condensed Consolidated Balance Sheet	16	23
Duke Energy Carolinas [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	10
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet		9
Progress Energy [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	34	85
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	85
Progress Energy [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	32	64
Gross amounts offset	(7)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	53
Progress Energy [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	21
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	20
Duke Energy Progress [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	46
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	46
Duke Energy Progress [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	19	36
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	18	36
Duke Energy Progress [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	10
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet		9
Duke Energy Florida [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	14	39
Net amounts recognized on the Condensed Consolidated Balance Sheet	14	39
Duke Energy Florida [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	13	28
Gross amounts offset	(6)	(11)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	17
Duke Energy Florida [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	11
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	11
Duke Energy Ohio [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	5
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		4
Net amounts recognized on the Condensed Consolidated Balance Sheet		4
Duke Energy Ohio [Member] | Noncurrent Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Indiana [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	16
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	16
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	16
Piedmont Natural Gas [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	3
Piedmont Natural Gas [Member] | Current Assets, Other [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 2	$ 3