Business Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Interest Expense	$ 482	$ 402	$ 1,493	$ 1,208
Segment income	1,054	937	2,255	2,310
Duke Energy Carolinas [Member]
Segment Reporting Information [Line Items]
Interest Expense	102	105	316	313
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(16)	(10)	(50)	(28)
Progress Energy [Member]
Segment Reporting Information [Line Items]
Interest Expense	177	170	497	504
Progress Energy [Member] | Other [Member]
Segment Reporting Information [Line Items]
Interest Expense	55	61	166	180
Segment income	(45)	(3)	(139)	(87)
Duke Energy Progress [Member]
Segment Reporting Information [Line Items]
Interest Expense	61	59	188	175
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(4)	(26)	(12)
Duke Energy Florida [Member]
Segment Reporting Information [Line Items]
Interest Expense	62	50	143	149
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(5)	(3)	(14)	(9)
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Interest Expense	22	20	63	58
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(10)	(12)	(29)	(20)
Duke Energy Indiana [Member]
Segment Reporting Information [Line Items]
Interest Expense	45	44	136	132
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (3)	$ (2)	$ (10)	$ (6)