Revenue (Unbilled Revenues) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 964	$ 969
Duke Energy Carolinas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	316	328
Progress Energy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	266	283
Duke Energy Progress
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	193	167
Duke Energy Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	73	116
Duke Energy Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	4	2
Duke Energy Ohio | CRC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	82	87
Duke Energy Indiana
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	27	16
Duke Energy Indiana | CRC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	121	134
Piedmont
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 106	$ 86