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Fair Value Measurements (Details Textuals) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2017 | Dec. 31, 2016
Fair Value of Financial Instruments [Line Items] |  |
Investment excludes receivables, payables and accrued income | $ (14) | $ (3)
Cash balance excluded from available for sale securities | 53 | 61
Investments not required to be disclosed | $ 269 | 266
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 | $ (2) | 2
Cash balance excluded from available for sale securities | $ 43 | $ 44

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- Details
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- Details
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