Summary of Significant Accounting Principles - Principles of Consolidation and Basis of Presentation (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Market making and similar activities	$ 9,034	$ 9,008	$ 7,102
Restatement Adjustment
Disaggregation of Revenue [Line Items]
Market making and similar activities	$ 930	$ 1,100	$ 332

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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