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Fair Value Measurements (Details Textuals) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Fair Value of Financial Instruments [Line Items] |  |
Investment excludes receivables, payables and accrued income | $ (3) | $ 7
Cash balance excluded from available for sale securities | 61 | 157
Investments not required to be disclosed | 266 | 255
FES |  |
Fair Value of Financial Instruments [Line Items] |  |
Investment excludes receivables, payables and accrued income | 2 | 1
Cash balance excluded from available for sale securities | $ 44 | $ 139

X
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- Definition Fair Value of Financial Instruments. + References No definition available. + Details
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Balance Type: | na
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X
- Definition Investments not required to be disclosed. + References No definition available. + Details
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Namespace Prefix: | fe_
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- Details
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Balance Type: |
Period Type: |