Related Party Transactions Intercompany Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Duke Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	$ 163	$ 107
Intercompany income tax payable	247	229
Duke Energy Carolinas [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	1	122
Progress Energy [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	106	375
Intercompany income tax payable	348	311
Progress Energy [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		120
Intercompany income tax payable	37
Duke Energy Progress [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	5	16
Intercompany income tax payable	227	190
Duke Energy Progress [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		104
Intercompany income tax payable	90
Duke Energy Florida [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	5	84
Intercompany income tax payable	125	116
Duke Energy Florida [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	37
Intercompany income tax payable		96
Duke Energy Ohio [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	129	84
Intercompany income tax payable	63	53
Duke Energy Ohio [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax receivable		54
Intercompany income tax payable	1
Duke Energy Indiana [Member]
Income Tax Disclosure [Line Items]
Intercompany income tax receivable	114	71
Intercompany income tax payable	74	83
Duke Energy Indiana [Member] | Income Taxes
Income Tax Disclosure [Line Items]
Intercompany income tax payable	$ 3	$ 47