Summary of Significant Accounting Policies (Expected Reserve for Credit Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 47,951	$ 51,136	$ 49,184	$ 43,834
Accounting Standards Update [Extensible List]	ASU 2016-13
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 4,108	3,265	2,471	3,113
Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			120
Duke Energy Carolinas | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			16
Progress Energy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	15,593	17,148	16,241	14,257
Progress Energy | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 6,465	$ 8,007	7,109	$ 5,131
Progress Energy | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			2
Duke Energy Progress | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			1
Duke Energy Florida | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			1
Piedmont | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Accounting Standards Update, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings			$ 1