Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Interest Expense	$ 500	$ 403	$ 1,011	$ 806
Segment income	510	600	1,201	1,373
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Interest Expense	107	106	214	208
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(17)	(10)	(34)	(18)
Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	160	166	320	334
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Interest Expense	55	59	111	119
Segment income	(45)	(42)	(94)	(84)
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Interest Expense	64	56	127	116
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(8)	(4)	(16)	(8)
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Interest Expense	40	50	81	99
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(5)	(3)	(9)	(6)
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Interest Expense	21	18	41	38
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(6)	(19)	(8)
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Interest Expense	47	43	91	88
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (5)	$ (2)	$ (7)	$ (4)