Derivative instruments - Impact of Derivative Instruments on the Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Asset derivatives fair value
Total derivatives fair value	$ 12,973	$ 9,793
Effect of master netting agreements	(9,379)	(6,973)
Fair value after effect of master netting agreements	3,594	2,820
Liability derivatives fair value
Total derivatives fair value	12,284	9,759
Effect of master netting agreements	(9,854)	(6,335)
Fair value after effect of master netting agreements	2,430	3,424
Derivative asset, collateral, obligation to return cash, offset	1,965	1,424
Derivative liability, collateral, right to reclaim cash, offset	2,440	786
Interest rate contracts
Asset derivatives fair value
Effect of master netting agreements	(920)	(1,424)
Liability derivatives fair value
Effect of master netting agreements	(1,255)	(2,028)
Foreign exchange contracts
Asset derivatives fair value
Effect of master netting agreements	(8,387)	(5,501)
Liability derivatives fair value
Effect of master netting agreements	(8,563)	(4,111)
Equity contracts
Asset derivatives fair value
Effect of master netting agreements	(72)	(48)
Liability derivatives fair value
Effect of master netting agreements	(36)	(196)
Designated as hedging
Asset derivatives fair value
Total derivatives fair value	525	206
Liability derivatives fair value
Total derivatives fair value	30	493
Designated as hedging | Interest rate contracts
Notional value
Notional amount of hedge	52,621	46,717
Asset derivatives fair value
Total derivatives fair value	57	0
Liability derivatives fair value
Total derivatives fair value	3	453
Designated as hedging | Foreign exchange contracts
Notional value
Notional amount of hedge	9,074	10,367
Asset derivatives fair value
Total derivatives fair value	468	206
Liability derivatives fair value
Total derivatives fair value	27	40
Not designated as hedging
Asset derivatives fair value
Total derivatives fair value	12,448	9,587
Liability derivatives fair value
Total derivatives fair value	12,254	9,266
Not designated as hedging | Interest rate contracts
Notional value
Notional amount of hedge	233,360	193,747
Asset derivatives fair value
Total derivatives fair value	1,650	3,259
Liability derivatives fair value
Total derivatives fair value	1,773	2,835
Not designated as hedging | Foreign exchange contracts
Notional value
Notional amount of hedge	936,363	915,694
Asset derivatives fair value
Total derivatives fair value	10,555	6,279
Liability derivatives fair value
Total derivatives fair value	10,426	6,215
Not designated as hedging | Equity contracts
Notional value
Notional amount of hedge	5,419	9,659
Asset derivatives fair value
Total derivatives fair value	243	49
Liability derivatives fair value
Total derivatives fair value	52	211
Not designated as hedging | Credit contracts
Notional value
Notional amount of hedge	255	190
Asset derivatives fair value
Total derivatives fair value	0	0
Liability derivatives fair value
Total derivatives fair value	$ 3	$ 5