Derivative instruments - Impact of Derivative Instruments on the Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Asset derivatives fair value
Total derivatives fair value	$ 18,054	$ 9,793
Effect of master netting agreements	(13,047)	(6,973)
Fair value after effect of master netting agreements	5,007	2,820
Liability derivatives fair value
Total derivatives fair value	17,618	9,759
Effect of master netting agreements	(13,652)	(6,335)
Fair value after effect of master netting agreements	3,966	3,424
Derivative asset, collateral, obligation to return cash, offset	2,497	1,424
Derivative liability, collateral, right to reclaim cash, offset	3,102	786
Interest rate contracts
Asset derivatives fair value
Effect of master netting agreements	(1,054)	(1,424)
Liability derivatives fair value
Effect of master netting agreements	(1,026)	(2,028)
Foreign exchange contracts
Asset derivatives fair value
Effect of master netting agreements	(11,914)	(5,501)
Liability derivatives fair value
Effect of master netting agreements	(12,624)	(4,111)
Equity contracts
Asset derivatives fair value
Effect of master netting agreements	(79)	(48)
Liability derivatives fair value
Effect of master netting agreements	(2)	(196)
Designated as hedging
Asset derivatives fair value
Total derivatives fair value	875	206
Liability derivatives fair value
Total derivatives fair value	25	493
Designated as hedging | Interest rate contracts
Notional value
Notional amount of hedge	55,575	46,717
Asset derivatives fair value
Total derivatives fair value	195	0
Liability derivatives fair value
Total derivatives fair value	0	453
Designated as hedging | Foreign exchange contracts
Notional value
Notional amount of hedge	8,610	10,367
Asset derivatives fair value
Total derivatives fair value	680	206
Liability derivatives fair value
Total derivatives fair value	25	40
Not designated as hedging
Asset derivatives fair value
Total derivatives fair value	17,179	9,587
Liability derivatives fair value
Total derivatives fair value	17,593	9,266
Not designated as hedging | Interest rate contracts
Notional value
Notional amount of hedge	219,878	193,747
Asset derivatives fair value
Total derivatives fair value	1,532	3,259
Liability derivatives fair value
Total derivatives fair value	1,804	2,835
Not designated as hedging | Foreign exchange contracts
Notional value
Notional amount of hedge	870,047	915,694
Asset derivatives fair value
Total derivatives fair value	15,389	6,279
Liability derivatives fair value
Total derivatives fair value	15,756	6,215
Not designated as hedging | Equity contracts
Notional value
Notional amount of hedge	4,304	9,659
Asset derivatives fair value
Total derivatives fair value	257	49
Liability derivatives fair value
Total derivatives fair value	30	211
Not designated as hedging | Credit contracts
Notional value
Notional amount of hedge	275	190
Asset derivatives fair value
Total derivatives fair value	1	0
Liability derivatives fair value
Total derivatives fair value	$ 3	$ 5