Noninterest Revenue and Noninterest Expense - Principal Transactions (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Principal transactions revenue
Total trading revenue	$ 4,050	$ 4,082
Private equity gains/(losses)	26	(130)
Principal transactions	4,076	3,952
Interest rate
Principal transactions revenue
Total trading revenue	605	774
Credit
Principal transactions revenue
Total trading revenue	559	380
Foreign exchange
Principal transactions revenue
Total trading revenue	888	1,024
Equity
Principal transactions revenue
Total trading revenue	1,615	1,627
Commodity
Principal transactions revenue
Total trading revenue	$ 383	$ 277

Amount of realized and unrealized gain (loss), from the firm's direct investment activity, conducted separately from customer trading activities, and includes, but is not limited to, investments in private equity, alternative investment products, real estate, and exchanges and memberships.

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Amount of gain (loss) resulting from the difference between the acquisition price and the selling price or fair value of trading assets and trading liabilities, conducted separately from customer trading activities. Includes, but is not limited to, changes in fair value of trading assets and trading liabilities.

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