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Employee Benefit Plans (Projected Benefit Obligations Reconciliation of Funded Status to Net Amount Recognized) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Pension Plan |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | $ 77
Pension Plan | Duke Energy Carolinas |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 7
Pension Plan | Progress Energy |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 57
Pension Plan | Duke Energy Progress |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 4
Pension Plan | Duke Energy Florida |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 53
Pension Plan | Duke Energy Ohio |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 2
Pension Plan | Duke Energy Indiana |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 2
Pension Plan | Piedmont |  |  |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Employer contributions |  |  | 1
Pension Plan | Qualified Plan |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | $ 8,634 | $ 8,321 |
Service cost | 168 | 157 | 158
Interest cost | 220 | 269 | 317
Actuarial gain | (200) | 433 |
Benefits paid | (615) | (541) |
Benefits paid – settlements |  | (5) |
Obligation at measurement date | 8,207 | 8,634 | 8,321
Accumulated Benefit Obligation at measurement date | 8,144 | 8,577 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 9,337 | 8,910 |
Actual return on plan assets | 513 | 973 |
Benefits paid | (615) | (541) |
Benefits paid – settlements |  | (5) |
Plan assets at measurement date | 9,235 | 9,337 | 8,910
Funded status of plan | 1,028 | 703 |
Pension Plan | Qualified Plan | Duke Energy Carolinas |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 1,988 | 1,923 |
Service cost | 54 | 49 | 49
Interest cost | 51 | 62 | 75
Actuarial gain | (42) | 83 |
Benefits paid | (148) | (137) |
Transfers |  | 8 |
Obligation at measurement date | 1,903 | 1,988 | 1,923
Accumulated Benefit Obligation at measurement date | 1,904 | 1,989 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 2,381 | 2,263 |
Actual return on plan assets | 132 | 247 |
Benefits paid | (148) | (137) |
Transfers |  | 8 |
Plan assets at measurement date | 2,365 | 2,381 | 2,263
Funded status of plan | 462 | 393 |
Pension Plan | Qualified Plan | Progress Energy |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 2,715 | 2,608 |
Service cost | 48 | 46 | 46
Interest cost | 70 | 85 | 100
Actuarial gain | (108) | 144 |
Benefits paid | (161) | (160) |
Transfers | (4) | (8) |
Obligation at measurement date | 2,560 | 2,715 | 2,608
Accumulated Benefit Obligation at measurement date | 2,529 | 2,684 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 3,049 | 2,898 |
Actual return on plan assets | 169 | 319 |
Benefits paid | (161) | (160) |
Transfers | (4) | (8) |
Plan assets at measurement date | 3,053 | 3,049 | 2,898
Funded status of plan | 493 | 334 |
Pension Plan | Qualified Plan | Duke Energy Progress |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 1,193 | 1,170 |
Service cost | 28 | 26 | 26
Interest cost | 30 | 38 | 45
Actuarial gain | (18) | 50 |
Benefits paid | (80) | (83) |
Transfers |  | (8) |
Obligation at measurement date | 1,153 | 1,193 | 1,170
Accumulated Benefit Obligation at measurement date | 1,154 | 1,194 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 1,422 | 1,364 |
Actual return on plan assets | 79 | 149 |
Benefits paid | (80) | (83) |
Transfers |  | (8) |
Plan assets at measurement date | 1,421 | 1,422 | 1,364
Funded status of plan | 268 | 229 |
Pension Plan | Qualified Plan | Duke Energy Florida |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 1,507 | 1,424 |
Service cost | 20 | 20 | 20
Interest cost | 39 | 46 | 54
Actuarial gain | (89) | 93 |
Benefits paid | (81) | (76) |
Transfers | (4) |  |
Obligation at measurement date | 1,392 | 1,507 | 1,424
Accumulated Benefit Obligation at measurement date | 1,361 | 1,476 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 1,605 | 1,515 |
Actual return on plan assets | 90 | 166 |
Benefits paid | (81) | (76) |
Transfers | (4) |  |
Plan assets at measurement date | 1,610 | 1,605 | 1,515
Funded status of plan | 218 | 98 |
Pension Plan | Qualified Plan | Duke Energy Ohio |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 502 | 481 |
Service cost | 5 | 4 | 4
Interest cost | 13 | 15 | 18
Actuarial gain | (10) | 21 |
Benefits paid | (50) | (34) |
Transfers | (10) | 15 |
Obligation at measurement date | 450 | 502 | 481
Accumulated Benefit Obligation at measurement date | 439 | 493 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 472 | 443 |
Actual return on plan assets | 26 | 48 |
Benefits paid | (50) | (34) |
Transfers | (10) | 15 |
Plan assets at measurement date | 438 | 472 | 443
Funded status of plan | (12) | (30) |
Pension Plan | Qualified Plan | Duke Energy Indiana |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 715 | 693 |
Service cost | 9 | 8 | 9
Interest cost | 18 | 22 | 26
Actuarial gain | (10) | 46 |
Benefits paid | (52) | (49) |
Benefits paid – settlements |  | (5) |
Obligation at measurement date | 680 | 715 | 693
Accumulated Benefit Obligation at measurement date | 672 | 709 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 684 | 667 |
Actual return on plan assets | 37 | 71 |
Benefits paid | (52) | (49) |
Benefits paid – settlements |  | (5) |
Plan assets at measurement date | 669 | 684 | 667
Funded status of plan | (11) | (31) |
Pension Plan | Qualified Plan | Piedmont |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 293 | 292 |
Service cost | 6 | 5 | 5
Interest cost | 7 | 9 | 10
Actuarial gain | (5) | 14 |
Benefits paid | (28) | (27) |
Obligation at measurement date | 273 | 293 | 292
Accumulated Benefit Obligation at measurement date | 274 | 294 |
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 343 | 335 |
Actual return on plan assets | 19 | 35 |
Benefits paid | (28) | (27) |
Plan assets at measurement date | 334 | 343 | 335
Funded status of plan | 61 | 50 |
Other Post-Retirement Benefit Plans |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 709 | 723 |
Service cost | 4 | 4 | 4
Interest cost | 18 | 23 | 30
Plan participants' contributions | 14 | 15 |
Actuarial gain | (47) | 19 |
Benefits paid | (73) | (75) |
Obligation at measurement date | 625 | 709 | 723
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 237 | 220 |
Employer contributions | 18 |  |
Actual return on plan assets | 15 | 24 |
Benefits paid | (73) | (75) |
Plan participants' contributions | 14 | 15 |
Employer contributions |  | 53 |
Plan assets at measurement date | 211 | 237 | 220
Funded status of plan | (414) | (472) |
Other Post-Retirement Benefit Plans | Duke Energy Carolinas |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 174 | 175 |
Service cost | 1 | 1 | 1
Interest cost | 4 | 5 | 7
Plan participants' contributions | 3 | 3 |
Actuarial gain | (14) | 8 |
Benefits paid | (19) | (18) |
Obligation at measurement date | 149 | 174 | 175
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 139 | 130 |
Employer contributions | 3 |  |
Actual return on plan assets | 9 | 14 |
Benefits paid | (19) | (18) |
Plan participants' contributions | 3 | 3 |
Employer contributions |  | 10 |
Plan assets at measurement date | 135 | 139 | 130
Funded status of plan | (14) | (35) |
Other Post-Retirement Benefit Plans | Progress Energy |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 299 | 303 |
Service cost | 1 | 1 | 1
Interest cost | 7 | 10 | 12
Plan participants' contributions | 5 | 5 |
Actuarial gain | (20) | 8 |
Benefits paid | (29) | (28) |
Obligation at measurement date | 263 | 299 | 303
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | (1) | (1) |
Employer contributions | 24 |  |
Benefits paid | (29) | (28) |
Plan participants' contributions | 5 | 5 |
Employer contributions |  | 23 |
Plan assets at measurement date | (1) | (1) | (1)
Funded status of plan | (264) | (300) |
Other Post-Retirement Benefit Plans | Duke Energy Progress |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 166 | 168 |
Interest cost | 4 | 5 | 7
Plan participants' contributions | 3 | 3 |
Actuarial gain | (10) | 5 |
Benefits paid | (16) | (15) |
Obligation at measurement date | 147 | 166 | 168
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | (2) | (1) |
Employer contributions | 13 |  |
Benefits paid | (16) | (15) |
Plan participants' contributions | 3 | 3 |
Employer contributions |  | 11 |
Plan assets at measurement date | (2) | (2) | (1)
Funded status of plan | (149) | (168) |
Other Post-Retirement Benefit Plans | Duke Energy Florida |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 130 | 135 |
Service cost |  |  | 1
Interest cost | 3 | 4 | 5
Plan participants' contributions | 2 | 2 |
Actuarial gain | (10) | 2 |
Benefits paid | (13) | (13) |
Obligation at measurement date | 112 | 130 | 135
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | (1) |  |
Employer contributions | 10 |  |
Benefits paid | (13) | (13) |
Plan participants' contributions | 2 | 2 |
Employer contributions |  | 10 |
Plan assets at measurement date | (2) | (1) |
Funded status of plan | (114) | (131) |
Other Post-Retirement Benefit Plans | Duke Energy Ohio |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 27 | 29 |
Interest cost | 1 | 1 | 1
Plan participants' contributions | 1 | 1 |
Actuarial gain | (1) |  |
Benefits paid | (3) | (4) |
Obligation at measurement date | 25 | 27 | 29
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 9 | 9 |
Employer contributions | 1 |  |
Actual return on plan assets | 1 |  |
Benefits paid | (3) | (4) |
Plan participants' contributions | 1 | 1 |
Employer contributions |  | 3 |
Plan assets at measurement date | 9 | 9 | 9
Funded status of plan | (16) | (18) |
Other Post-Retirement Benefit Plans | Duke Energy Indiana |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 61 | 64 |
Service cost | 1 | 1 | 1
Interest cost | 1 | 2 | 3
Plan participants' contributions | 2 | 2 |
Actuarial gain | (2) | 1 |
Benefits paid | (9) | (9) |
Obligation at measurement date | 54 | 61 | 64
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 7 | 5 |
Employer contributions | 6 |  |
Actual return on plan assets |  | 1 |
Benefits paid | (9) | (9) |
Plan participants' contributions | 2 | 2 |
Employer contributions |  | 8 |
Plan assets at measurement date | 6 | 7 | 5
Funded status of plan | (48) | (54) |
Other Post-Retirement Benefit Plans | Piedmont |  |  |
Change in Projected Benefit Obligation [Rollforward] |  |  |
Obligation at prior measurement date | 30 | 30 |
Interest cost | 1 | 1 | 1
Actuarial gain | (2) | 1 |
Benefits paid | (2) | (2) |
Obligation at measurement date | 27 | 30 | 30
Change in Fair Value of Plan Assets [Rollforward] |  |  |
Plan assets at prior measurement date | 37 | 34 |
Employer contributions | 1 |  |
Actual return on plan assets | 3 | 4 |
Benefits paid | (2) | (2) |
Employer contributions |  | 1 |
Plan assets at measurement date | 39 | 37 | $ 34
Funded status of plan | $ 12 | $ 7 |

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- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 + Details
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- Definition Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(5) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964 + Details
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