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Taxes (Details 4) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Changes in unrecognized tax benefits |  |  |
Beginning balance | $ 84 | $ 34 | $ 34
Current year increases | 2 | 2 | 3
Prior years increases |  | 69 | 7
Prior years decreases |  | (21) | (10)
Decrease for lapse in statute | (6) |  |
Ending balance | 80 | 84 | 34
FES |  |  |
Changes in unrecognized tax benefits |  |  |
Beginning balance | 0 | 8 | 3
Current year increases | 0 | 0 | 0
Prior years increases |  | 0 | 5
Prior years decreases |  | (8) | 0
Decrease for lapse in statute | 0 |  |
Ending balance | $ 0 | $ 0 | $ 8

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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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