Noninterest Revenue and Noninterest Expense - Principal Transactions (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Principal transactions revenue
Total trading revenue	$ 3,817	$ 3,697	$ 7,867	$ 7,779
Private equity gains/(losses)	(103)	85	(77)	(45)
Principal transactions	3,714	3,782	7,790	7,734
Interest rate
Principal transactions revenue
Total trading revenue	461	672	1,066	1,446
Credit
Principal transactions revenue
Total trading revenue	488	648	1,047	1,028
Foreign exchange
Principal transactions revenue
Total trading revenue	729	745	1,617	1,769
Equity
Principal transactions revenue
Total trading revenue	1,912	1,386	3,527	3,013
Commodity
Principal transactions revenue
Total trading revenue	$ 227	$ 246	$ 610	$ 523

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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