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Derivatives and Hedging - Schedule of amounts of derivative gains (losses) recognized in the Consolidated Financial Statements (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Derivative [Line Items] |  |  |
Gain (loss) recognized in accumulated other comprehensive income | $ 18 | $ (25) | $ (9)
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months | (9) |  |
Gain (loss) reclassified from accumulated other comprehensive loss into income (effective portion) | (1) | (10) | (17)
Compensation and Benefits |  |  |
Derivative [Line Items] |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months | 12 | 8 | 4
Gain (loss) reclassified from accumulated other comprehensive loss into income (effective portion) | 14 | 2 | 4
Other General Expenses |  |  |
Derivative [Line Items] |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months | 4 | (13) | (3)
Gain (loss) reclassified from accumulated other comprehensive loss into income (effective portion) | (5) | (4) | (1)
Interest Expense |  |  |
Derivative [Line Items] |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months | 0 | 0 | 0
Gain (loss) reclassified from accumulated other comprehensive loss into income (effective portion) | (1) | (1) | (9)
Other Income (Expense) |  |  |
Derivative [Line Items] |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months | 2 | (20) | (10)
Gain (loss) reclassified from accumulated other comprehensive loss into income (effective portion) | $ (9) | $ (7) | $ (11)

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- Definition Represents the estimated net amount of unrealized gains (losses) on hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References No definition available. + Details
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- Definition The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959 + Details
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- Definition The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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