Organization and Basis of Presentation (Schedule of New Accounting Pronouncements) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 47,951	$ 49,545	$ 49,658	$ 49,184	$ 46,611	$ 48,083
Accounting Standards Update [Extensible List]	ASU 2016-13
Progress Energy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 15,593	16,942	16,530	16,241	16,221	15,877
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	4,108	2,687	2,680	2,471	2,707	4,221
Retained Earnings | Progress Energy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	6,465	$ 7,809	$ 7,400	$ 7,109	$ 7,090	$ 6,747
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	120
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment | Duke Energy Carolinas
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	16
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment | Progress Energy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	2
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment | Duke Energy Progress
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	1
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment | Duke Energy Florida
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	1
Cumulative Change in Accounting Principle | Retained Earnings | Revision of Prior Period, Accounting Standards Update, Adjustment | Piedmont
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total pretax impact to Retained Earnings	$ 1