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Fair Value Measurements (Details Textuals) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2016 | Dec. 31, 2015
Fair Value of Financial Instruments [Line Items] |  |
Investment excludes receivables, payables and accrued income | $ (8) | $ 7
Cash balance excluded from available for sale securities | 50 | 157
Investments not required to be disclosed | $ 276 | 255
NUG contracts |  |
Fair Value of Financial Instruments [Line Items] |  |
Period of future observable data to determine contract price | 3 years |
FES |  |
Fair Value of Financial Instruments [Line Items] |  |
Investment excludes receivables, payables and accrued income | $ 1 | 1
Cash balance excluded from available for sale securities | $ 39 | $ 139

X
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- Details
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- Details
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