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Derivative Instruments (Details Textuals) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 USD ($) agreement | Jun. 30, 2018 USD ($) agreement | Dec. 31, 2017 USD ($) agreement
Cash Flow Hedges |  |  |
Derivative [Line Items] |  |  |
Unamortized losses associated with prior interest rate hedges | $ 18 | $ 18 | $ 22
Gains (losses) to be amortized to interest expenses during next twelve months |  | $ (4) |
Number of outstanding commodity or interest rate derivatives | agreement | 0 | 0 | 0
Fair Value Hedging |  |  |
Derivative [Line Items] |  |  |
Number of fixed-for-floating interest rate swap agreements outstanding | agreement | 0 | 0 | 0
Gains included in long-term debt associated with prior fixed-for-floating interest rate swap agreements | $ 2 | $ 2 | $ 3
NUGs |  |  |
Derivative [Line Items] |  |  |
Liability position | 65 | 65 | $ 79
Settlements | $ 9 | 16 |
Unrealized gain (loss) |  | $ (2) |

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- Definition Settled Contracts. + References No definition available. + Details
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- Definition Derivative instruments not designated as hedging instruments unrealized gain (loss). + References No definition available. + Details
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- Definition Gains (Losses) To Be Amortized To Interest Expenses During Next Twelve Months. + References No definition available. + Details
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- Definition Unamortized gains included in long-term debt associated with prior fixed-for-floating interest rate swap agreements. + References No definition available. + Details
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- Definition Unamortized losses associated with prior interest rate hedges. + References No definition available. + Details
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- Definition Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41678-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226006-175313 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313 + Details
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