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Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2019 | Nov. 12, 2019 | Sep. 30, 2019 | Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Decommissioning fund investments | $ 0 |  |  | $ 790
Investment excludes receivables, payables and accrued income | (16) |  |  | 4
Noncurrent liabilities - held for sale (Note 10) | 691 |  |  | 0
Investments - held for sale (Note 10) | 882 |  |  | 0
Investments not required to be disclosed | $ 299 |  |  | $ 253
NUG contracts |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Period of future observable data to determine contract price | 2 years |  |  |
Nuclear Plant Matters |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Decommissioning fund investments | $ 882 |  |  |
Financial Guarantee | Nuclear Plant Matters | JCP&L, ME, PN and GPUN |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Decommissioning fund investments |  |  | $ 900 |
Ownership interest |  | 25.00% |  |
TMI-2 |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Noncurrent liabilities - held for sale (Note 10) | $ 691 |  |  |

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- Definition Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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