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Investments in Debt and Equity Securities (Estimated Fair Value of Investments in Debt and Equity Securities) (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
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Debt Securities, Available-for-sale |  |
Estimated Fair Value | $ 4,414 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 6,052 | $ 5,804
Gross Unrealized Holding Losses | 109 | 219
Estimated Fair Value | 13,231 | 11,905
NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 172 | 139
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 5,938 | 5,753
Gross Unrealized Holding Losses | 17 | 61
Estimated Fair Value | 8,435 | 8,233
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 4,170 | 3,060
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 5,998 | 5,765
Gross Unrealized Holding Losses | 99 | 200
Estimated Fair Value | 12,777 | 11,432
Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 76 | 47
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 54 | 39
Gross Unrealized Holding Losses | 0 | 4
Estimated Fair Value | 134 | 160
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 244 | 266
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 54 | 39
Gross Unrealized Holding Losses | 10 | 19
Estimated Fair Value | 454 | 473
Duke Energy Carolinas |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 2,329 |
Duke Energy Carolinas | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 84 | 62
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 3,483 | 3,386
Gross Unrealized Holding Losses | 11 | 33
Estimated Fair Value | 4,856 | 4,751
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 2,329 | 1,651
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 3,514 | 3,389
Gross Unrealized Holding Losses | 65 | 122
Estimated Fair Value | 7,269 | 6,464
Progress Energy |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,865 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 2,484 | 2,376
Gross Unrealized Holding Losses | 35 | 78
Estimated Fair Value | 5,546 | 5,015
Progress Energy | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 88 | 77
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 2,455 | 2,367
Gross Unrealized Holding Losses | 6 | 28
Estimated Fair Value | 3,579 | 3,482
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,841 | 1,409
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 2,484 | 2,376
Gross Unrealized Holding Losses | 34 | 78
Estimated Fair Value | 5,508 | 4,968
Progress Energy | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 14 | 23
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 24 | 24
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 1 | 0
Estimated Fair Value | 38 | 47
Duke Energy Progress |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,685 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 2,358 | 2,265
Gross Unrealized Holding Losses | 30 | 70
Estimated Fair Value | 5,211 | 4,653
Duke Energy Progress | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 72 | 54
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 2,330 | 2,256
Gross Unrealized Holding Losses | 6 | 28
Estimated Fair Value | 3,445 | 3,362
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,685 | 1,221
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 2,358 | 2,265
Gross Unrealized Holding Losses | 30 | 70
Estimated Fair Value | 5,202 | 4,637
Duke Energy Progress | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 9 | 16
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 9 | 16
Duke Energy Florida |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 180 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 126 | 111
Gross Unrealized Holding Losses | 5 | 8
Estimated Fair Value | 331 | 358
Duke Energy Florida | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 16 | 23
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 125 | 111
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 134 | 120
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 156 | 188
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 126 | 111
Gross Unrealized Holding Losses | 4 | 8
Estimated Fair Value | 306 | 331
Duke Energy Florida | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 1 | 3
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 24 | 24
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 1 | 0
Estimated Fair Value | 25 | 27
Duke Energy Indiana |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 28 |
Duke Energy Indiana | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 1 | 1
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 5 |
Gross Unrealized Holding Losses | 0 | 4
Estimated Fair Value | 51 | 89
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 28 | 56
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Gross Unrealized Holding Gains | 5 |
Gross Unrealized Holding Losses | 1 | 5
Estimated Fair Value | 80 | 146
Corporate debt securities | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 21 | 6
Gross Unrealized Holding Losses | 19 | 33
Estimated Fair Value | 1,021 | 673
Corporate debt securities | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 2 | 5
Estimated Fair Value | 70 | 79
Corporate debt securities | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 11 | 2
Gross Unrealized Holding Losses | 16 | 27
Estimated Fair Value | 637 | 401
Corporate debt securities | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 10 | 4
Gross Unrealized Holding Losses | 3 | 6
Estimated Fair Value | 384 | 272
Corporate debt securities | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 10 | 4
Gross Unrealized Holding Losses | 3 | 6
Estimated Fair Value | 367 | 256
Corporate debt securities | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 17 | 16
Corporate debt securities | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 |
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 1 | 6
Municipal bonds | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 4 | 2
Gross Unrealized Holding Losses | 15 | 14
Estimated Fair Value | 374 | 342
Municipal bonds | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 2 | 1
Estimated Fair Value | 69 | 83
Municipal bonds | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 5 | 4
Estimated Fair Value | 50 | 36
Municipal bonds | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 4 | 2
Gross Unrealized Holding Losses | 10 | 10
Estimated Fair Value | 324 | 306
Municipal bonds | Progress Energy | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 1 | 0
Estimated Fair Value | 24 | 24
Municipal bonds | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 4 | 2
Gross Unrealized Holding Losses | 10 | 10
Estimated Fair Value | 324 | 306
Municipal bonds | Duke Energy Florida | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 1 | 0
Estimated Fair Value | 24 | 24
Municipal bonds | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 |
Gross Unrealized Holding Losses | 1 | 1
Estimated Fair Value | 24 | 43
U.S. government bonds | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 32 | 3
Gross Unrealized Holding Losses | 43 | 84
Estimated Fair Value | 2,488 | 1,806
U.S. government bonds | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 4 | 5
Estimated Fair Value | 56 | 59
U.S. government bonds | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 17 | 0
Gross Unrealized Holding Losses | 28 | 50
Estimated Fair Value | 1,397 | 991
U.S. government bonds | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 15 | 3
Gross Unrealized Holding Losses | 15 | 34
Estimated Fair Value | 1,091 | 815
U.S. government bonds | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 14 | 3
Gross Unrealized Holding Losses | 11 | 26
Estimated Fair Value | 953 | 645
U.S. government bonds | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 1 | 0
Gross Unrealized Holding Losses | 4 | 8
Estimated Fair Value | 138 | 170
U.S. government bonds | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 |
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 3 | 7
Other debt securities | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 3 | 1
Gross Unrealized Holding Losses | 5 | 8
Estimated Fair Value | 287 | 239
Other debt securities | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 2 | 4
Estimated Fair Value | 49 | 45
Other debt securities | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 3 | 1
Gross Unrealized Holding Losses | 5 | 8
Estimated Fair Value | 245 | 223
Other debt securities | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 42 | 16
Other debt securities | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | 41 | 14
Other debt securities | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains | 0 | 0
Gross Unrealized Holding Losses | 0 | 0
Estimated Fair Value | $ 1 | $ 2

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