Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Inventory	$ 3,102	$ 3,084
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,231	2,238
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	572	491
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	299	355
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,007	948
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	738	731
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	228	175
Duke Energy Carolinas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	41	42
Progress Energy [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,464	1,459
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,033	1,049
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	218	192
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	213	218
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	959	954
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	720	734
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	127	106
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	112	114
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	505	504
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	313	315
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	91	86
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	101	103
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	111	126
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	79	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	13	14
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	19	28
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	435	422
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	321	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	113	109
Duke Energy Indiana [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	1	1
Piedmont Natural Gas [Member]
Public Utilities, Inventory [Line Items]
Inventory	25	70
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2	2
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 23	$ 68