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Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | $ 3,002 |
Derivative assets | 61 | $ 25
Total assets | 9,748 | 8,610
Derivative liabilities | (324) | (277)
Net assets (liabilities) | 9,424 | 8,310
Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 1 | 3
Total assets | 7,551 | 6,675
Derivative liabilities | 0 | (15)
Net assets (liabilities) | 7,551 | 6,660
Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 53 | 7
Total assets | 2,144 | 1,869
Derivative liabilities | (240) | (145)
Net assets (liabilities) | 1,904 | 1,701
Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 7 | 15
Total assets | 7 | 15
Derivative liabilities | (84) | (117)
Net assets (liabilities) | (77) | (102)
Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 46 | 51
Net assets (liabilities) | 46 | 51
NDTF |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 177 | 101
Equity securities, FV-NI | 6,235 | 5,661
Debt securities, available-for-sale | 2,717 | 2,368
NDTF | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 177 | 101
Debt securities, available-for-sale | 874 | 725
NDTF | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Debt securities, available-for-sale | 1,843 | 1,643
NDTF | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
NDTF | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
NDTF equity securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 6,235 | 5,684
Derivative liabilities |  | (23)
NDTF equity securities | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 6,189 | 5,633
Derivative liabilities |  | 0
NDTF equity securities | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative liabilities |  | (23)
NDTF equity securities | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative liabilities |  | 0
NDTF equity securities | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 46 | 51
Other Investments |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 146 | 122
Debt securities, available-for-sale | 285 | 258
Other Investments | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 146 | 122
Debt securities, available-for-sale | 37 | 39
Other Investments | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 248 | 219
Other cash and cash equivalents |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 127 | 52
Other cash and cash equivalents | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 127 | 52
Other cash and cash equivalents | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Other cash and cash equivalents | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Other cash and cash equivalents | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Duke Energy Carolinas |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI |  | 3,154
Debt securities, available-for-sale | 1,250 |
Total assets | 4,985 | 4,347
Derivative liabilities | (20) | (49)
Net assets (liabilities) | 4,965 | 4,298
Duke Energy Carolinas | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI |  | 3,103
Total assets | 3,861 | 3,330
Net assets (liabilities) | 3,861 | 3,330
Duke Energy Carolinas | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 1,078 | 966
Derivative liabilities | (20) | (49)
Net assets (liabilities) | 1,058 | 917
Duke Energy Carolinas | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI |  | 51
Total assets | 46 | 51
Net assets (liabilities) | 46 | 51
Duke Energy Carolinas | NDTF |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 30 | 21
Equity securities, FV-NI | 3,685 | 3,154
Debt securities, available-for-sale | 1,250 | 1,172
Derivative assets | 20 |
Duke Energy Carolinas | NDTF | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 30 | 21
Debt securities, available-for-sale | 192 | 206
Derivative assets | 0 |
Duke Energy Carolinas | NDTF | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Debt securities, available-for-sale | 1,058 | 966
Derivative assets | 20 |
Duke Energy Carolinas | NDTF | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Derivative assets | 0 |
Duke Energy Carolinas | NDTF equity securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 3,685 |
Duke Energy Carolinas | NDTF equity securities | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 3,639 |
Duke Energy Carolinas | NDTF equity securities | Not Categorized |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 46 |
Progress Energy |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 1,493 |
Derivative assets | 33 | 7
Total assets | 4,329 | 3,913
Derivative liabilities | (29) | (65)
Net assets (liabilities) | 4,300 | 3,825
Progress Energy | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 3,485 | 3,178
Net assets (liabilities) | 3,485 | 3,178
Progress Energy | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 33 | 7
Total assets | 844 | 735
Derivative liabilities | (29) | (65)
Net assets (liabilities) | 815 | 647
Progress Energy | NDTF |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 147 | 80
Equity securities, FV-NI | 2,550 | 2,507
Debt securities, available-for-sale | 1,467 | 1,196
Derivative liabilities |  | (23)
Progress Energy | NDTF | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 147 | 80
Debt securities, available-for-sale | 682 | 519
Progress Energy | NDTF | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Debt securities, available-for-sale | 785 | 677
Derivative liabilities |  | (23)
Progress Energy | NDTF equity securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 2,550 | 2,530
Progress Energy | NDTF equity securities | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 2,550 | 2,530
Progress Energy | Other Investments |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 26 | 51
Progress Energy | Other Investments | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 26 | 51
Progress Energy | Other cash and cash equivalents |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 106 | 49
Progress Energy | Other cash and cash equivalents | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 106 | 49
Progress Energy | Other cash and cash equivalents | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents |  | 0
Duke Energy Progress |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 993 |
Derivative assets | 33 |
Total assets | 3,562 | 3,053
Derivative liabilities | (14) | (49)
Net assets (liabilities) | 3,548 | 3,004
Duke Energy Progress | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 2,773 | 2,376
Net assets (liabilities) | 2,773 | 2,376
Duke Energy Progress | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 33 | 0
Total assets | 789 | 677
Derivative liabilities | (14) | (49)
Net assets (liabilities) | 775 | 628
Duke Energy Progress | NDTF |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 76 | 53
Equity securities, FV-NI | 2,459 | 2,077
Debt securities, available-for-sale | 993 | 921
Duke Energy Progress | NDTF | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 76 | 53
Debt securities, available-for-sale | 237 | 244
Duke Energy Progress | NDTF | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Debt securities, available-for-sale | 756 | 677
Duke Energy Progress | NDTF equity securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 2,459 | 2,077
Duke Energy Progress | NDTF equity securities | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 2,459 | 2,077
Duke Energy Progress | Other cash and cash equivalents |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 2
Duke Energy Progress | Other cash and cash equivalents | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 2
Duke Energy Progress | Other cash and cash equivalents | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Duke Energy Florida |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 500 |
Derivative assets |  | 7
Total assets | 663 | 817
Derivative liabilities |  | (1)
Net assets (liabilities) | 663 | 793
Duke Energy Florida | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 608 | 759
Net assets (liabilities) | 608 | 759
Duke Energy Florida | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets |  | 7
Total assets | 55 | 58
Derivative liabilities |  | (1)
Net assets (liabilities) | 55 | 34
Duke Energy Florida | NDTF |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 71 | 27
Equity securities, FV-NI | 91 | 430
Debt securities, available-for-sale | 474 | 275
Derivative liabilities |  | (23)
Duke Energy Florida | NDTF | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 71 | 27
Debt securities, available-for-sale | 445 | 275
Duke Energy Florida | NDTF | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Debt securities, available-for-sale | 29 |
Derivative liabilities |  | (23)
Duke Energy Florida | NDTF equity securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 91 | 453
Duke Energy Florida | NDTF equity securities | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 91 | 453
Duke Energy Florida | Other Investments |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 26 | 51
Duke Energy Florida | Other Investments | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 26 | 51
Duke Energy Florida | Other cash and cash equivalents |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 4
Duke Energy Florida | Other cash and cash equivalents | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 4
Duke Energy Florida | Other cash and cash equivalents | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Duke Energy Indiana |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 45 |
Derivative assets | 6 | 13
Total assets | 149 | 138
Derivative liabilities | (1) | (1)
Net assets (liabilities) | 148 | 137
Duke Energy Indiana | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets |  | 2
Total assets | 98 | 83
Derivative liabilities | (1) | (1)
Net assets (liabilities) | 97 | 82
Duke Energy Indiana | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total assets | 45 | 44
Net assets (liabilities) | 45 | 44
Duke Energy Indiana | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 6 | 11
Total assets | 6 | 11
Net assets (liabilities) | 6 | 11
Duke Energy Indiana | Other Investments |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 97 | 81
Debt securities, available-for-sale | 45 | 44
Duke Energy Indiana | Other Investments | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Equity securities, FV-NI | 97 | 81
Duke Energy Indiana | Other Investments | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, available-for-sale | 45 | 44
Duke Energy Indiana | Other cash and cash equivalents |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 0
Duke Energy Indiana | Other cash and cash equivalents | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 1 | 0
Duke Energy Indiana | Other cash and cash equivalents | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Duke Energy Indiana | Other cash and cash equivalents | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Cash and cash equivalents | 0 | 0
Piedmont |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 1 | 1
Derivative liabilities | (122) | (117)
Net assets (liabilities) | (121) | (116)
Piedmont | Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative assets | 1 | 1
Net assets (liabilities) | 1 | 1
Piedmont | Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative liabilities | (122) |
Net assets (liabilities) | $ (122) |
Piedmont | Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Derivative liabilities |  | (117)
Net assets (liabilities) |  | $ (117)

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
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