Derivative instruments - Revenue from Foreign Exchange and Other Trading (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Foreign exchange revenue	$ 222	$ 207	$ 184	$ 429	$ 415
Other trading revenue (loss)	45	5	(1)	50	(8)
Gain or (loss) recognized in income on derivatives	$ 7	$ 3	$ 2	$ 10	$ 12

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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