Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Segment income	$ 2,796	$ 2,451	$ 2,574
Duke Energy Carolinas [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(95)	(79)	(97)
Progress Energy [Member]
Segment Reporting Information [Line Items]
Segment income		875	656
Progress Energy [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(159)	(190)	(241)
Duke Energy Progress [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(32)	(31)	(46)
Duke Energy Florida [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	(16)	(19)	(24)
Duke Energy Indiana [Member] | Other Segment [Member]
Segment Reporting Information [Line Items]
Segment income	$ (10)	$ (11)	$ (16)