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Income Taxes - Narrative (Details) € in Millions, $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2018 USD ($) | Sep. 30, 2018 EUR (€) | Sep. 30, 2017 USD ($) | Sep. 30, 2018 USD ($) | Sep. 30, 2017 | Dec. 31, 2017 USD ($)
Income Tax Disclosure [Abstract] |  |  |  |  |  |
Effective income tax rate reconciliation, percent |  |  |  | 26.50% | 28.50% |
Effective income tax rate reconciliation, including discrete items, percent | 35.30% | 35.30% | 30.80% |  |  |
Discrete income tax expense | $ 26 |  | $ 2 |  |  |
Prior year adjustments | 13 |  |  |  |  |
Reversal of a foreign tax reserve that is effectively settled | 38 |  |  |  |  |
Tax Cuts And Jobs Act of 2017, incomplete accounting, provisional income tax expense (benefit) | (8) |  |  | $ 13 |  | $ 272
Tax Cuts and Jobs Act of 2017, incomplete accounting, transition tax benefit | 2 |  |  |  |  |
Tax Cuts and Jobs Act of 2017, incomplete accounting, change in tax rate benefit | 6 |  |  |  |  |
Increase in estimate of one-time transition tax |  |  |  | 16 |  |
Charges recorded for alternative minimum tax credits |  |  |  | (3) |  |
U.S. tax rate change impacts |  |  |  | $ 6 |  |
Spain |  |  |  |  |  |
Operating Loss Carryforwards [Line Items] |  |  |  |  |  |
Established tax reserve | $ 59 | € 51 |  |  |  |

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- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84176650&loc=d3e32059-109318 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 + Details
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