Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unsecured Debt	$ 20,955,000,000	$ 20,409,000,000
Secured Debt	4,297,000,000	4,458,000,000
First mortgage bonds	25,628,000,000	23,529,000,000
Capital leases	941,000,000	1,000,000,000
Tax exempt bonds	941,000,000	941,000,000
Notes payable and commercial paper	4,035,000,000	2,788,000,000
Fair value hedge carrying value adjustment	5,000,000	6,000,000
Unamortized debt discount and premium, net	1,434,000,000	1,582,000,000
Unamortized debt issuance costs	(297,000,000)	(271,000,000)
Total debt	57,939,000,000	54,442,000,000
Short-term notes payable and commercial paper	(3,410,000,000)	(2,163,000,000)
Current maturities of long-term debt	(3,406,000,000)	(3,244,000,000)
Total long-term debt	$ 51,123,000,000	$ 49,035,000,000
Weighted-average rate	4.13%	4.09%
Short term obligations classified as long-term debt	$ 937,000,000	$ 937,000,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument, Maturity Date Range, End	Dec. 31, 2078	Dec. 31, 2073
Weighted-average rate	4.26%	4.17%
Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2020	Dec. 31, 2018
Debt Instrument, Maturity Date Range, End	Dec. 31, 2037	Dec. 31, 2037
Weighted-average rate	3.69%	3.15%
First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument, Maturity Date Range, End	Dec. 31, 2048	Dec. 31, 2047
Weighted-average rate	4.32%	4.51%
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument, Maturity Date Range, End	Dec. 31, 2051	Dec. 31, 2051
Weighted-average rate	5.06%	4.55%
Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, Start	Dec. 31, 2019	Dec. 31, 2019
Debt Instrument, Maturity Date Range, End	Dec. 31, 2041	Dec. 31, 2041
Weighted-average rate	3.40%	3.23%
Short term obligations classified as long-term debt	$ 312,000,000	$ 312,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	$ 625,000,000	$ 625,000,000
Notes Payable And Commercial Paper [Member]
Debt Instrument [Line Items]
Weighted-average rate	2.73%	1.57%
Short term obligations classified as long-term debt	$ 625,000,000	$ 625,000,000
Weighted Average Days to Maturity	16 days	14 days
Parent Company [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 41,000,000	$ 47,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,150,000,000	1,150,000,000
Secured Debt	450,000,000	450,000,000
First mortgage bonds	8,759,000,000	7,959,000,000
Capital leases	109,000,000	61,000,000
Tax exempt bonds	243,000,000	243,000,000
Money pool borrowings	739,000,000	404,000,000
Fair value hedge carrying value adjustment	5,000,000	6,000,000
Unamortized debt discount and premium, net	(23,000,000)	(19,000,000)
Unamortized debt issuance costs	(54,000,000)	(47,000,000)
Total debt	11,378,000,000	10,207,000,000
Short-term money pool borrowings	(439,000,000)	(104,000,000)
Current maturities of long-term debt	(6,000,000)	(1,205,000,000)
Total long-term debt	10,933,000,000	8,898,000,000
Short term obligations classified as long-term debt	300,000,000	300,000,000
Duke Energy Carolinas [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	300,000,000	300,000,000
Progress Energy [Member]
Debt Instrument [Line Items]
Unsecured Debt	3,800,000,000	3,950,000,000
Secured Debt	1,703,000,000	1,757,000,000
First mortgage bonds	13,100,000,000	11,801,000,000
Capital leases	251,000,000	269,000,000
Tax exempt bonds	48,000,000	48,000,000
Money pool borrowings	1,385,000,000	955,000,000
Unamortized debt discount and premium, net	(29,000,000)	(30,000,000)
Unamortized debt issuance costs	(112,000,000)	(108,000,000)
Total debt	20,146,000,000	18,642,000,000
Short-term money pool borrowings	(1,235,000,000)	(805,000,000)
Current maturities of long-term debt	(1,672,000,000)	(771,000,000)
Total long-term debt	17,239,000,000	17,066,000,000
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Unsecured Debt	50,000,000
Secured Debt	300,000,000	300,000,000
First mortgage bonds	7,574,000,000	6,776,000,000
Capital leases	137,000,000	139,000,000
Tax exempt bonds	48,000,000	48,000,000
Money pool borrowings	444,000,000	390,000,000
Unamortized debt discount and premium, net	(15,000,000)	(16,000,000)
Unamortized debt issuance costs	(40,000,000)	(40,000,000)
Total debt	8,498,000,000	7,597,000,000
Short-term money pool borrowings	(294,000,000)	(240,000,000)
Current maturities of long-term debt	(603,000,000)	(3,000,000)
Total long-term debt	7,601,000,000	7,354,000,000
Short term obligations classified as long-term debt	150,000,000	150,000,000
Duke Energy Progress [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150,000,000	150,000,000
Duke Energy Progress [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	63,000,000	81,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Unsecured Debt	350,000,000	550,000,000
Secured Debt	1,403,000,000	1,457,000,000
First mortgage bonds	5,526,000,000	5,025,000,000
Capital leases	114,000,000	129,000,000
Money pool borrowings	108,000,000
Unamortized debt discount and premium, net	(11,000,000)	(10,000,000)
Unamortized debt issuance costs	(61,000,000)	(56,000,000)
Total debt	7,429,000,000	7,095,000,000
Short-term money pool borrowings	(108,000,000)
Current maturities of long-term debt	(270,000,000)	(768,000,000)
Total long-term debt	7,051,000,000	6,327,000,000
Duke Energy Florida [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Capital leases	531,000,000	603,000,000
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Unsecured Debt	1,000,000,000	900,000,000
First mortgage bonds	1,099,000,000	1,100,000,000
Capital leases	2,000,000	5,000,000
Tax exempt bonds	77,000,000	77,000,000
Money pool borrowings	299,000,000	54,000,000
Unamortized debt discount and premium, net	(31,000,000)	(33,000,000)
Unamortized debt issuance costs	(7,000,000)	(7,000,000)
Total debt	2,439,000,000	2,096,000,000
Short-term money pool borrowings	(274,000,000)	(29,000,000)
Current maturities of long-term debt	(551,000,000)	(3,000,000)
Total long-term debt	1,614,000,000	2,064,000,000
Short term obligations classified as long-term debt	52,000,000	52,000,000
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	27,000,000	27,000,000
Duke Energy Ohio [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	25,000,000	25,000,000
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Unsecured Debt	408,000,000	411,000,000
First mortgage bonds	2,670,000,000	2,669,000,000
Capital leases	10,000,000	11,000,000
Tax exempt bonds	572,000,000	572,000,000
Money pool borrowings	317,000,000	311,000,000
Unamortized debt discount and premium, net	(8,000,000)	(9,000,000)
Unamortized debt issuance costs	(20,000,000)	(21,000,000)
Total debt	3,949,000,000	3,944,000,000
Short-term money pool borrowings	(167,000,000)	(161,000,000)
Current maturities of long-term debt	(63,000,000)	(3,000,000)
Total long-term debt	3,719,000,000	3,780,000,000
Short term obligations classified as long-term debt	435,000,000	435,000,000
Duke Energy Indiana [Member] | Tax Exempt Bonds [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	285,000,000	285,000,000
Duke Energy Indiana [Member] | Commercial Paper [Member]
Debt Instrument [Line Items]
Short term obligations classified as long-term debt	150,000,000	150,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Unsecured Debt	2,150,000,000	2,050,000,000
Money pool borrowings	198,000,000	364,000,000
Unamortized debt discount and premium, net	(1,000,000)	(1,000,000)
Unamortized debt issuance costs	(11,000,000)	(12,000,000)
Total debt	2,336,000,000	2,401,000,000
Short-term money pool borrowings	(198,000,000)	(364,000,000)
Current maturities of long-term debt	(350,000,000)	(250,000,000)
Total long-term debt	1,788,000,000	1,787,000,000
Piedmont Natural Gas [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	156,000,000	176,000,000
Progress Energy [Member] | Purchase Accounting Adjustments [Member]
Debt Instrument [Line Items]
Unamortized debt discount and premium, net	$ 1,380,000,000	$ 1,509,000,000
June 2017 Three Year Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	3 years
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Tax exempt bonds	$ 81,000,000
Revolving Credit Facility [Member] | Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Tax exempt bonds	$ 81,000,000
Line of Credit [Member] | Revolving Credit Facility [Member] | Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	2 years