Organization and Basis of Presentation Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Inventory	$ 3,351	$ 3,810
Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	2,312	2,389
Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	743	1,114
Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	296	307
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,053	1,276
Duke Energy Carolinas [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	760	785
Duke Energy Carolinas [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	256	451
Duke Energy Carolinas [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	37	40
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,653	1,751
Progress Energy [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	1,139	1,133
Progress Energy [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	277	370
Progress Energy [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	237	248
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	998	1,088
Duke Energy Progress [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	781	776
Duke Energy Progress [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	101	192
Duke Energy Progress [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	116	120
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	656	663
Duke Energy Florida [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	358	357
Duke Energy Florida [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	177	178
Duke Energy Florida [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	121	128
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	110	105
Duke Energy Ohio [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	85	81
Duke Energy Ohio [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	18	16
Duke Energy Ohio [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	7	8
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	424	570
Duke Energy Indiana [Member] | Materials and supplies [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	236	301
Duke Energy Indiana [Member] | Coal held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	186	267
Duke Energy Indiana [Member] | Oil, gas and other fuel held for electric generation [Member]
Organization And Basis Of Presentation [Line Items]
Inventory	$ 2	$ 2