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Income Taxes, Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Income Tax Disclosure [Abstract] |  |  |
Net accrued interest and penalties | $ 15 | $ 17 |
Interest and penalties expense related to unrecognized income tax benefits | (2) | 1 | $ 4
Effect of unrecognized tax benefit on income tax expense | $ 29 | $ 25 | $ 23
State |  |  |
Income Tax Disclosure [Abstract] |  |  |
All audit periods prior to this year are closed | 2012 |  |
Federal |  |  |
Income Tax Disclosure [Abstract] |  |  |
All audit periods prior to this year are closed | 2013 |  |

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- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32718-109319 + Details
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + 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 (b) -URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319 + Details
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