Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Public Utilities, Inventory [Line Items]
Inventory	$ 3,366	$ 3,522
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,328	2,374
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	724	774
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	314	374
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,051	1,055
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	766	767
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	248	251
Duke Energy Carolinas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	37	37
Progress Energy [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,652	1,717
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,122	1,167
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	297	314
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	233	236
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,053	1,076
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	780	813
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	162	148
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	111	115
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	599	641
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	341	354
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	135	166
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	123	121
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	118	137
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	85	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	17	19
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	16	34
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	478	504
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	315	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	161	190
Duke Energy Indiana [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	2
Piedmont Natural Gas [Member]
Public Utilities, Inventory [Line Items]
Inventory	29	66
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	1
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 27	$ 65