Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Weighted-average rate	3.92%	4.13%
Unsecured Debt	$ 22,477	$ 20,955
Secured Debt	4,537	4,297
First mortgage bonds	27,977	25,628
Finance leases	969
Finance leases		941
Tax exempt bonds	730	941
Notes payable and commercial paper	3,588	4,035
Fair value hedge carrying value adjustment	5	5
Unamortized debt discount and premium, net	1,294	1,434
Unamortized debt issuance costs	(316)	(297)
Total debt	61,261	57,939
Short-term notes payable and commercial paper	(3,135)	(3,410)
Current maturities of long-term debt	(3,141)	(3,406)
Total long-term debt	54,985	51,123
Short term obligations classified as long-term debt	$ 937	$ 937
Unsecured Debt
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2078	Dec. 31, 2078
Weighted-average rate	4.02%	4.26%
Secured Debt
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2020
Maturity date range, end	Dec. 31, 2052	Dec. 31, 2037
Weighted-average rate	3.30%	3.69%
First Mortgage
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2020	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2049	Dec. 31, 2048
Weighted-average rate	4.13%	4.32%
Capital Lease Obligations
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2022	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2051	Dec. 31, 2051
Weighted-average rate	6.60%	5.06%
Tax Exempt Bonds
Debt Instrument [Line Items]
Maturity date range, start	Dec. 31, 2022	Dec. 31, 2019
Maturity date range, end	Dec. 31, 2041	Dec. 31, 2041
Weighted-average rate	2.90%	3.40%
Short term obligations classified as long-term debt	$ 312	$ 312
Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 625	$ 625
Notes Payable And Commercial Paper
Debt Instrument [Line Items]
Weighted-average rate	1.98%	2.73%
Short term obligations classified as long-term debt	$ 625	$ 625
Weighted average days to maturity	14 days	16 days
Parent Company | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 37	$ 41
Duke Energy Carolinas
Debt Instrument [Line Items]
Unsecured Debt	1,150	1,150
Secured Debt	544	450
First mortgage bonds	9,557	8,759
Finance leases	179
Finance leases		109
Tax exempt bonds	243	243
Money pool/intercompany borrowings	329	739
Fair value hedge carrying value adjustment	5	5
Unamortized debt discount and premium, net	(23)	(23)
Unamortized debt issuance costs	(55)	(54)
Total debt	11,929	11,378
Short-term money pool/intercompany borrowings	(29)	(439)
Current maturities of long-term debt	(458)	(6)
Total long-term debt	11,442	10,933
Short term obligations classified as long-term debt	300	300
Duke Energy Carolinas | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300	300
Progress Energy
Debt Instrument [Line Items]
Unsecured Debt	3,650	3,800
Secured Debt	1,722	1,703
First mortgage bonds	13,800	13,100
Finance leases	405
Finance leases		251
Tax exempt bonds	48	48
Money pool/intercompany borrowings	1,970	1,385
Unamortized debt discount and premium, net	(29)	(29)
Unamortized debt issuance costs	(111)	(112)
Total debt	21,455	20,146
Short-term money pool/intercompany borrowings	(1,821)	(1,235)
Current maturities of long-term debt	(1,577)	(1,672)
Total long-term debt	18,057	17,239
Duke Energy Progress
Debt Instrument [Line Items]
Unsecured Debt	700	50
Secured Debt	335	300
First mortgage bonds	7,575	7,574
Finance leases	307
Finance leases		137
Tax exempt bonds	48	48
Money pool/intercompany borrowings	216	444
Unamortized debt discount and premium, net	(17)	(15)
Unamortized debt issuance costs	(40)	(40)
Total debt	9,124	8,498
Short-term money pool/intercompany borrowings	(66)	(294)
Current maturities of long-term debt	(1,006)	(603)
Total long-term debt	8,052	7,601
Short term obligations classified as long-term debt	150	150
Duke Energy Progress | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Duke Energy Progress | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Finance leases	44
Finance leases		63
Duke Energy Florida
Debt Instrument [Line Items]
Unsecured Debt	350	350
Secured Debt	1,387	1,403
First mortgage bonds	6,225	5,526
Finance leases	98
Finance leases		114
Money pool/intercompany borrowings		108
Unamortized debt discount and premium, net	(11)	(11)
Unamortized debt issuance costs	(62)	(61)
Total debt	7,987	7,429
Short-term money pool/intercompany borrowings		(108)
Current maturities of long-term debt	(571)	(270)
Total long-term debt	7,416	7,051
Duke Energy Florida | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Finance leases	419
Finance leases		531
Duke Energy Ohio
Debt Instrument [Line Items]
Unsecured Debt	1,110	1,000
First mortgage bonds	1,449	1,099
Finance leases		2
Tax exempt bonds	77	77
Money pool/intercompany borrowings	337	299
Unamortized debt discount and premium, net	(30)	(31)
Unamortized debt issuance costs	(12)	(7)
Total debt	2,931	2,439
Short-term money pool/intercompany borrowings	(312)	(274)
Current maturities of long-term debt		(551)
Total long-term debt	2,619	1,614
Short term obligations classified as long-term debt	52	52
Duke Energy Ohio | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27	27
Duke Energy Ohio | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25	25
Duke Energy Indiana
Debt Instrument [Line Items]
Unsecured Debt	405	408
First mortgage bonds	3,169	2,670
Finance leases	10
Finance leases		10
Tax exempt bonds	362	572
Money pool/intercompany borrowings	180	317
Unamortized debt discount and premium, net	(19)	(8)
Unamortized debt issuance costs	(20)	(20)
Total debt	4,087	3,949
Short-term money pool/intercompany borrowings	(30)	(167)
Current maturities of long-term debt	(503)	(63)
Total long-term debt	3,554	3,719
Short term obligations classified as long-term debt	435	435
Duke Energy Indiana | Tax Exempt Bonds
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	285	285
Duke Energy Indiana | Commercial Paper
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150	150
Piedmont
Debt Instrument [Line Items]
Unsecured Debt	2,399	2,150
Money pool/intercompany borrowings	476	198
Unamortized debt discount and premium, net	(2)	(1)
Unamortized debt issuance costs	(13)	(11)
Total debt	2,860	2,336
Short-term money pool/intercompany borrowings	(476)	(198)
Current maturities of long-term debt		(350)
Total long-term debt	2,384	1,788
Progress Energy | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	1,275	1,380
Piedmont | Purchase Accounting Adjustments
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	$ 137	$ 156