Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) - Revolving Credit Facility [Member] $ in Millions	Sep. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Facility size	$ 7,500
Commercial paper	(1,652)
Outstanding letters of credit	(77)
Tax exempt bonds	(116)
Coal ash set-aside	(500)
Available capacity	5,155
Parent Company [Member]
Line of Credit Facility [Line Items]
Facility size	3,400
Commercial paper	(1,027)
Outstanding letters of credit	(70)
Available capacity	2,303
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility size	1,100
Commercial paper	(300)
Outstanding letters of credit	(4)
Tax exempt bonds	(35)
Coal ash set-aside	(250)
Available capacity	511
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility size	1,000
Commercial paper	(150)
Outstanding letters of credit	(2)
Coal ash set-aside	(250)
Available capacity	598
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility size	950
Outstanding letters of credit	(1)
Available capacity	949
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility size	450
Commercial paper	(25)
Available capacity	425
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility size	600
Commercial paper	(150)
Tax exempt bonds	(81)
Available capacity	369
Proceeds Loaned To Subsidiary Registrants [Member] | Parent Company [Member]
Line of Credit Facility [Line Items]
Commercial paper	$ (625)