Revenue (Unbilled Revenues) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	$ 716	$ 843
Duke Energy Carolinas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	285	298
Progress Energy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	195	217
Duke Energy Progress
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	85	122
Duke Energy Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	110	95
Duke Energy Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	1	1
Duke Energy Indiana
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	16	16
Piedmont Natural Gas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	32	78
CRC | Duke Energy Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	61	82
CRC | Duke Energy Indiana
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables	$ 94	$ 115