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Debt and Credit Facilities (Summary of Debt and Related Terms) (Details) - USD ($) | 12 Months Ended
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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 |

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