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Employee Benefits - Schedule of expense recognized in Compensation and benefit in the Consolidated Statements of Income (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expense recognized for defined contribution savings plans | $ 164 | $ 168 | $ 173
U.S. |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expense recognized for defined contribution savings plans | 98 | 98 | 105
U.K. |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expense recognized for defined contribution savings plans | 41 | 45 | 43
Netherlands and Canada |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Expense recognized for defined contribution savings plans | $ 25 | $ 25 | $ 25

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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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