Regulatory Matters (Other Regulatory Matters) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Equity in losses (earnings) of unconsolidated affiliates	$ 80,000,000	$ (50,000,000)	$ 2,004,000,000	$ (137,000,000)
Income tax benefit	105,000,000	188,000,000	(74,000,000)	424,000,000
Current Liabilities: Other	2,829,000,000		2,829,000,000		$ 2,367,000,000
Asset retirement obligations	742,000,000		742,000,000		881,000,000
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Income tax benefit	76,000,000	118,000,000	178,000,000	255,000,000
Current Liabilities: Other	487,000,000		487,000,000		611,000,000
Asset retirement obligations	267,000,000		267,000,000		206,000,000
Duke Energy Progress
Public Utilities, General Disclosures [Line Items]
Income tax benefit	11,000,000	$ 48,000,000	79,000,000	$ 125,000,000
Current Liabilities: Other	389,000,000		389,000,000		478,000,000
Asset retirement obligations	297,000,000		297,000,000		485,000,000
ACP
Public Utilities, General Disclosures [Line Items]
Current Liabilities: Other	935,000,000		935,000,000		$ 0
ACP | ACP
Public Utilities, General Disclosures [Line Items]
Equity in losses (earnings) of unconsolidated affiliates			2,100,000,000
Income tax benefit			389,000,000
Expected costs (less than)	50,000,000		50,000,000
Current Liabilities: Other	927,000,000		927,000,000
Other Noncurrent Liabilities	19,000,000		19,000,000
ACP | ACP | Current liabilities
Public Utilities, General Disclosures [Line Items]
Guarantees of outstanding debt	860,000,000		860,000,000
Asset retirement obligations	$ 86,000,000		$ 86,000,000
ACP
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage	47.00%		47.00%