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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, 2023 | Dec. 31, 2022
--- | --- | ---
Debt Securities, Available-for-sale |  |
Estimated Fair Value | $ 2,824 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 4,244 | $ 3,682
Unrealized Holding Losses | 351 | 395
Estimated Fair Value | 9,691 | 9,051
NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 160 | 215
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 4,218 | 3,658
Gross Unrealized Holding Losses | 44 | 105
Estimated Fair Value | 6,530 | 5,871
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 2,569 | 2,550
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 4,218 | 3,661
Unrealized Holding Losses | 319 | 359
Estimated Fair Value | 9,259 | 8,636
Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 36 | 22
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 26 | 21
Gross Unrealized Holding Losses | 9 | 16
Estimated Fair Value | 141 | 128
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 255 | 265
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 26 | 21
Unrealized Holding Losses | 32 | 36
Estimated Fair Value | 432 | 415
Duke Energy Carolinas |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,329 |
Duke Energy Carolinas | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 59 | 117
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 2,468 | 2,147
Gross Unrealized Holding Losses | 25 | 51
Estimated Fair Value | 3,767 | 3,367
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,329 | 1,298
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 2,468 | 2,149
Unrealized Holding Losses | 185 | 192
Estimated Fair Value | 5,155 | 4,782
Progress Energy |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,263 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 1,750 | 1,512
Unrealized Holding Losses | 134 | 167
Estimated Fair Value | 4,135 | 3,890
Progress Energy | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 101 | 98
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 1,750 | 1,511
Gross Unrealized Holding Losses | 19 | 54
Estimated Fair Value | 2,763 | 2,504
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 1,240 | 1,252
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 1,750 | 1,512
Unrealized Holding Losses | 134 | 167
Estimated Fair Value | 4,104 | 3,854
Progress Energy | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 8 | 11
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 23 | 25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Estimated Fair Value | 31 | 36
Duke Energy Progress |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 971 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 1,661 | 1,432
Unrealized Holding Losses | 113 | 142
Estimated Fair Value | 3,700 | 3,439
Duke Energy Progress | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 62 | 56
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 1,661 | 1,431
Gross Unrealized Holding Losses | 19 | 54
Estimated Fair Value | 2,663 | 2,411
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 971 | 963
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 1,661 | 1,432
Unrealized Holding Losses | 113 | 142
Estimated Fair Value | 3,696 | 3,430
Duke Energy Progress | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 4 | 9
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Estimated Fair Value | 4 | 9
Duke Energy Florida |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 292 |
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 89 | 80
Unrealized Holding Losses | 21 | 25
Estimated Fair Value | 432 | 450
Duke Energy Florida | NDTF |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 39 | 42
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 89 | 80
Estimated Fair Value | 100 | 93
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 269 | 289
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 89 | 80
Unrealized Holding Losses | 21 | 25
Estimated Fair Value | 408 | 424
Duke Energy Florida | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 1 | 1
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 23 | 25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Estimated Fair Value | 24 | 26
Duke Energy Indiana |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 59 |
Duke Energy Indiana | Other Investments |  |
Cash and Cash Equivalents |  |
Estimated Fair Value | 3 | 1
Equity Securities, FV-NI |  |
Gross Unrealized Holding Gains | 3 | 2
Gross Unrealized Holding Losses | 9 | 16
Estimated Fair Value | 88 | 79
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 59 | 60
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract] |  |
Unrealized Holding Gains | 3 | 2
Unrealized Holding Losses | 12 | 20
Estimated Fair Value | 150 | 140
Corporate debt securities | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 1
Gross Unrealized Holding Losses | 80 | 85
Estimated Fair Value | 612 | 641
Corporate debt securities | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 10 | 12
Estimated Fair Value | 83 | 84
Corporate debt securities | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 1
Gross Unrealized Holding Losses | 60 | 62
Estimated Fair Value | 376 | 401
Corporate debt securities | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 20 | 23
Estimated Fair Value | 236 | 240
Corporate debt securities | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 19 | 22
Estimated Fair Value | 224 | 230
Corporate debt securities | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 1 | 1
Estimated Fair Value | 12 | 10
Corporate debt securities | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses |  | 1
Estimated Fair Value | 9 | 8
Municipal bonds | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 41 | 39
Estimated Fair Value | 318 | 330
Municipal bonds | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 3 | 3
Estimated Fair Value | 74 | 78
Municipal bonds | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 9 | 10
Estimated Fair Value | 45 | 64
Municipal bonds | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 32 | 29
Estimated Fair Value | 273 | 266
Municipal bonds | Progress Energy | Other Investments |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 23 | 25
Municipal bonds | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 32 | 29
Estimated Fair Value | 273 | 266
Municipal bonds | Duke Energy Florida | Other Investments |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 23 | 25
Municipal bonds | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 3 | 3
Estimated Fair Value | 44 | 45
U.S. government bonds | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 2
Gross Unrealized Holding Losses | 136 | 112
Estimated Fair Value | 1,470 | 1,423
U.S. government bonds | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 5 | 2
Estimated Fair Value | 46 | 62
U.S. government bonds | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 1
Gross Unrealized Holding Losses | 73 | 51
Estimated Fair Value | 745 | 685
U.S. government bonds | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 1
Gross Unrealized Holding Losses | 63 | 61
Estimated Fair Value | 725 | 738
U.S. government bonds | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Gains |  | 1
Gross Unrealized Holding Losses | 43 | 37
Estimated Fair Value | 469 | 460
U.S. government bonds | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 20 | 24
Estimated Fair Value | 256 | 278
U.S. government bonds | Duke Energy Indiana | Other Investments |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 6 | 7
Other debt securities | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 18 | 18
Estimated Fair Value | 169 | 156
Other debt securities | Other Investments |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 5 | 3
Estimated Fair Value | 52 | 41
Other debt securities | Duke Energy Carolinas | NDTF |  |
Debt Securities, Available-for-sale |  |
Gross Unrealized Holding Losses | 18 | 18
Estimated Fair Value | 163 | 148
Other debt securities | Progress Energy | NDTF |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 6 | 8
Other debt securities | Duke Energy Progress | NDTF |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | 5 | 7
Other debt securities | Duke Energy Florida | NDTF |  |
Debt Securities, Available-for-sale |  |
Estimated Fair Value | $ 1 | $ 1

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