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Collateralized Transactions (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Disclosure Collateralized Transactions [Abstract]
Customers receivables	$ 19,409	$ 17,050
Securities repledged and deposited for customers	$ 11,000	$ 600
Percentage of securities repledged and deposited for customers	99.00%	76.00%

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Margin loans to clients stated net of allowance for doubtful accounts.

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Percentage of securities acquired through agreements to resell that are shown as repledged and have been deposited in a separate bank account for the exclusive benefit of customers in accordance with SEC Rule 15c3-3.

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The carrying value of funds, segregated for regulatory purposes and for the exclusive benefit of customers, outstanding loaned in the form of security resale agreements if the agreement requires the purchaser to resell the identical security purchased or a security that meets the definition of "substantially the same" in the case of a dollar roll. Also includes purchases of participations in pools of securities that are subject to a resale agreement.

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