Investments in Unconsolidated Affiliates (Significant Subsidiaries) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments In Unconsolidated Affiliates [Line Items]
Current assets	$ 9,940	$ 8,682
Noncurrent assets	48,239	46,924
Current liabilities	15,931	16,305
Noncurrent liabilities	42,072	41,274
Membership interests	1,840	1,220
Operating loss	5,373	4,553	$ 5,709
Net income (loss)	3,579	1,082	3,571
Net (loss) income attributable to Duke Energy	$ 3,908	1,377	3,748
Atlantic Coast Pipeline (ACP) | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Investments In Unconsolidated Affiliates [Line Items]
Current assets		43
Noncurrent assets		93
Current liabilities		1,965
Noncurrent liabilities		167
Membership interests		(1,996)
Operating loss		(4,612)	(5)
Net income (loss)		(4,512)	246
Net (loss) income attributable to Duke Energy		$ (2,121)	$ 116