Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment income	$ 2,571	$ 2,645	$ 2,533
Duke Energy Carolinas [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(104)	(95)	(79)
Progress Energy [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(200)	(159)	(190)
Duke Energy Progress [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(56)	(32)	(31)
Duke Energy Florida [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(23)	(16)	(19)
Duke Energy Indiana [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	$ (13)	$ (10)	$ (11)