Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Public Utilities, Inventory [Line Items]
Inventory	$ 3,189	$ 3,084
Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	2,252	2,238
Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	624	491
Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	313	355
Duke Energy Carolinas [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,025	948
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	749	731
Duke Energy Carolinas [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	235	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	1,480	1,459
Progress Energy [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	1,036	1,049
Progress Energy [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	234	192
Progress Energy [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	210	218
Duke Energy Progress [Member]
Public Utilities, Inventory [Line Items]
Inventory	980	954
Duke Energy Progress [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	709	734
Duke Energy Progress [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	160	106
Duke Energy Progress [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	111	114
Duke Energy Florida [Member]
Public Utilities, Inventory [Line Items]
Inventory	499	504
Duke Energy Florida [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	327	315
Duke Energy Florida [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	74	86
Duke Energy Florida [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	98	103
Duke Energy Ohio [Member]
Public Utilities, Inventory [Line Items]
Inventory	124	126
Duke Energy Ohio [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	76	84
Duke Energy Ohio [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	17	14
Duke Energy Ohio [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	31	28
Duke Energy Indiana [Member]
Public Utilities, Inventory [Line Items]
Inventory	463	422
Duke Energy Indiana [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	323	312
Duke Energy Indiana [Member] | Coal [Member]
Public Utilities, Inventory [Line Items]
Inventory	139	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	33	70
Piedmont Natural Gas [Member] | Materials and supplies [Member]
Public Utilities, Inventory [Line Items]
Inventory	3	2
Piedmont Natural Gas [Member] | Natural gas, oil and other fuel [Member]
Public Utilities, Inventory [Line Items]
Inventory	$ 30	$ 68