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Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, realized loss | $ 36 | $ 12 | $ 47 | $ 25 |
Debt securities, available-for-sale, realized gain | 47 | 5 | 57 | 10 |
Equity securities, FV-NI, realized loss | 63 | 31 | 93 | 44 |
Equity securities, FV-NI, realized gain | 66 | 47 | 101 | 66 |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 3,209 |  | 3,209 |  | $ 2,458
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 40 |  | 40 |  | 131
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 8,030 |  | 8,030 |  | 7,075
Debt securities, available-for-sale | 2,577 |  | 2,577 |  |
Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 3,153 |  | 3,153 |  | 2,421
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 39 |  | 39 |  | 126
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 7,603 |  | 7,603 |  | 6,706
Debt securities, available-for-sale | 2,425 |  | 2,425 |  | 2,231
Equity Securities, FV-NI, Accumulated Unrealized Gain | 3,076 |  | 3,076 |  | 2,402
Equity Securities, FV-NI, Accumulated Unrealized Loss | 36 |  | 36 |  | 95
Cash and cash equivalents | 114 |  | 114 |  | 88
Equity securities, FV-NI | 5,178 |  | 5,178 |  | 4,475
Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 56 |  | 56 |  | 37
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 1 |  | 1 |  | 5
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 427 |  | 427 |  | 369
Debt securities, available-for-sale | 315 |  | 315 |  | 270
Equity Securities, FV-NI, Accumulated Unrealized Gain | 49 |  | 49 |  | 36
Equity Securities, FV-NI, Accumulated Unrealized Loss |  |  |  |  | 1
Cash and cash equivalents | 49 |  | 49 |  | 22
Equity securities, FV-NI | 112 |  | 112 |  | 99
Duke Energy Carolinas [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, realized loss | 11 | 8 | 21 | 18 |
Debt securities, available-for-sale, realized gain | 16 | 4 | 25 | 9 |
Equity securities, FV-NI, realized loss | 48 | 17 | 69 | 22 |
Equity securities, FV-NI, realized gain | 44 | 26 | 67 | 36 |
Debt securities, available-for-sale | 1,120 |  | 1,120 |  |
Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 1,711 |  | 1,711 |  | 1,316
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 12 |  | 12 |  | 74
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 4,044 |  | 4,044 |  | 3,553
Debt securities, available-for-sale | 1,161 |  | 1,161 |  | 1,069
Equity Securities, FV-NI, Accumulated Unrealized Gain | 1,671 |  | 1,671 |  | 1,309
Equity Securities, FV-NI, Accumulated Unrealized Loss | 9 |  | 9 |  | 54
Cash and cash equivalents | 41 |  | 41 |  | 29
Equity securities, FV-NI | 2,883 |  | 2,883 |  | 2,484
Progress Energy [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, realized loss | 25 | 4 | 26 | 7 |
Debt securities, available-for-sale, realized gain | 30 | 1 | 31 | 1 |
Equity securities, FV-NI, realized loss | 15 | 14 | 24 | 22 |
Equity securities, FV-NI, realized gain | 22 | 21 | 34 | 30 |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 1,445 |  | 1,445 |  | 1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 27 |  | 27 |  | 52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 3,656 |  | 3,656 |  | 3,217
Debt securities, available-for-sale | 1,241 |  | 1,241 |  |
Progress Energy [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 1,442 |  | 1,442 |  | 1,105
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 27 |  | 27 |  | 52
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 3,559 |  | 3,559 |  | 3,153
Debt securities, available-for-sale | 1,264 |  | 1,264 |  | 1,162
Equity Securities, FV-NI, Accumulated Unrealized Gain | 1,405 |  | 1,405 |  | 1,093
Equity Securities, FV-NI, Accumulated Unrealized Loss | 27 |  | 27 |  | 41
Cash and cash equivalents | 73 |  | 73 |  | 59
Equity securities, FV-NI | 2,295 |  | 2,295 |  | 1,991
Progress Energy [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 3 |  | 3 |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 97 |  | 97 |  | 64
Debt securities, available-for-sale | 97 |  | 97 |  | 64
Cash and cash equivalents | 47 |  | 47 |  | 17
Duke Energy Progress [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, realized loss | 1 | 3 | 2 | 5 |
Debt securities, available-for-sale, realized gain | 1 | 1 | 2 | 1 |
Equity securities, FV-NI, realized loss | 7 | 12 | 15 | 20 |
Equity securities, FV-NI, realized gain | 7 | 17 | 17 | 25 |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 1,128 |  | 1,128 |  | 842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 24 |  | 24 |  | 39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 2,836 |  | 2,836 |  | 2,500
Debt securities, available-for-sale | 906 |  | 906 |  |
Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 1,128 |  | 1,128 |  | 842
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 24 |  | 24 |  | 39
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 2,834 |  | 2,834 |  | 2,494
Debt securities, available-for-sale | 948 |  | 948 |  | 906
Equity Securities, FV-NI, Accumulated Unrealized Gain | 1,092 |  | 1,092 |  | 833
Equity Securities, FV-NI, Accumulated Unrealized Loss | 24 |  | 24 |  | 30
Cash and cash equivalents | 42 |  | 42 |  | 46
Equity securities, FV-NI | 1,886 |  | 1,886 |  | 1,588
Duke Energy Progress [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 2 |  | 2 |  | 6
Debt securities, available-for-sale | 2 |  | 2 |  | 6
Cash and cash equivalents | 2 |  | 2 |  | 6
Duke Energy Florida [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, realized loss | 24 | 1 | 24 | 2 |
Debt securities, available-for-sale, realized gain | 29 |  | 29 |  |
Equity securities, FV-NI, realized loss | 8 | 2 | 9 | 2 |
Equity securities, FV-NI, realized gain | 15 | $ 4 | 17 | $ 5 |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 317 |  | 317 |  | 263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 3 |  | 3 |  | 13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 777 |  | 777 |  | 707
Debt securities, available-for-sale | 335 |  | 335 |  |
Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 314 |  | 314 |  | 263
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 3 |  | 3 |  | 13
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 725 |  | 725 |  | 659
Debt securities, available-for-sale | 316 |  | 316 |  | 256
Equity Securities, FV-NI, Accumulated Unrealized Gain | 313 |  | 313 |  | 260
Equity Securities, FV-NI, Accumulated Unrealized Loss | 3 |  | 3 |  | 11
Cash and cash equivalents | 31 |  | 31 |  | 13
Equity securities, FV-NI | 409 |  | 409 |  | 403
Duke Energy Florida [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 3 |  | 3 |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 52 |  | 52 |  | 48
Debt securities, available-for-sale | 52 |  | 52 |  | 48
Cash and cash equivalents | 2 |  | 2 |  | 1
Duke Energy Indiana [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Gain | 37 |  | 37 |  | 29
Debt Securities, Available-for-sale, and Equity Securities, FV-NI, Unrealized Loss | 1 |  | 1 |  | 1
Debt Securities, Available-for-sale, and Equity Securities, FV-NI | 116 |  | 116 |  | 108
Debt securities, available-for-sale | 42 |  | 42 |  |
Equity Securities, FV-NI, Accumulated Unrealized Gain | 37 |  | 37 |  | 29
Equity securities, FV-NI | 74 |  | 74 |  | 67
Duke Energy Indiana [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Equity securities, FV-NI | 74 |  | 74 |  | 67
Corporate debt securities [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 30 |  | 30 |  | 4
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 13
Debt securities, available-for-sale | 571 |  | 571 |  | 566
Corporate debt securities [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 2 |  | 2 |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 2
Debt securities, available-for-sale | 60 |  | 60 |  | 60
Corporate debt securities [Member] | Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 18 |  | 18 |  | 2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 9
Debt securities, available-for-sale | 360 |  | 360 |  | 341
Corporate debt securities [Member] | Progress Energy [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 12 |  | 12 |  | 2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 4
Debt securities, available-for-sale | 211 |  | 211 |  | 225
Corporate debt securities [Member] | Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 12 |  | 12 |  | 2
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 3
Debt securities, available-for-sale | 211 |  | 211 |  | 171
Corporate debt securities [Member] | Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 1
Debt securities, available-for-sale |  |  |  |  | 54
Corporate debt securities [Member] | Duke Energy Indiana [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale | 7 |  | 7 |  | 8
Municipal bonds [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 10 |  | 10 |  | 1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 4
Debt securities, available-for-sale | 318 |  | 318 |  | 353
Municipal bonds [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 3 |  | 3 |  | 0
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 1
Debt securities, available-for-sale | 90 |  | 90 |  | 85
Municipal bonds [Member] | Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 2 |  | 2 |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 1
Debt securities, available-for-sale | 63 |  | 63 |  | 81
Municipal bonds [Member] | Progress Energy [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 8 |  | 8 |  | 1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 3
Debt securities, available-for-sale | 255 |  | 255 |  | 272
Municipal bonds [Member] | Progress Energy [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 3 |  | 3 |  |
Debt securities, available-for-sale | 50 |  | 50 |  | 47
Municipal bonds [Member] | Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 8 |  | 8 |  | 1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 3
Debt securities, available-for-sale | 255 |  | 255 |  | 271
Municipal bonds [Member] | Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale |  |  |  |  | 1
Municipal bonds [Member] | Duke Energy Florida [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 3 |  | 3 |  |
Debt securities, available-for-sale | 50 |  | 50 |  | 47
Municipal bonds [Member] | Duke Energy Indiana [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 1
Debt securities, available-for-sale | 34 |  | 34 |  | 33
US treasury and government [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 34 |  | 34 |  | 14
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 12
Debt securities, available-for-sale | 1,270 |  | 1,270 |  | 1,076
US treasury and government [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 2 |  | 2 |  | 1
Debt securities, available-for-sale | 51 |  | 51 |  | 45
US treasury and government [Member] | Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 17 |  | 17 |  | 5
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 8
Debt securities, available-for-sale | 556 |  | 556 |  | 475
US treasury and government [Member] | Progress Energy [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 17 |  | 17 |  | 9
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 4
Debt securities, available-for-sale | 714 |  | 714 |  | 601
US treasury and government [Member] | Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 16 |  | 16 |  | 6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 3
Debt securities, available-for-sale | 429 |  | 429 |  | 415
US treasury and government [Member] | Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 1 |  | 1 |  | 3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 1
Debt securities, available-for-sale | 285 |  | 285 |  | 186
US treasury and government [Member] | Duke Energy Indiana [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale | 1 |  | 1 |  |
Other debt obligations [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 3 |  | 3 |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 2
Debt securities, available-for-sale | 152 |  | 152 |  | 148
Other debt obligations [Member] | Other Classification [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax |  |  |  |  | 1
Debt securities, available-for-sale | 65 |  | 65 |  | 58
Other debt obligations [Member] | Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax | 3 |  | 3 |  |
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax | 1 |  | 1 |  | 2
Debt securities, available-for-sale | 141 |  | 141 |  | 143
Other debt obligations [Member] | Progress Energy [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale | 11 |  | 11 |  | 5
Other debt obligations [Member] | Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale | $ 11 |  | $ 11 |  | 3
Other debt obligations [Member] | Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, available-for-sale |  |  |  |  | $ 2

X
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- Definition Amount of accumulated unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Substantially all of the associated unrealized gains and losses on these investments are deferred as a regulatory asset or liability. + References No definition available. + Details
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- Definition Amount of accumulated unrealized loss on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Substantially all of the associated unrealized gains and losses on these investments are deferred as a regulatory asset or liability. + References No definition available. + Details
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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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