Derivative instruments - Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Derivative Asset
Derivatives subject to netting arrangements, Gross assets recognized	$ 16,634	$ 8,302
Total derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	13,047	6,973
Derivatives subject to netting arrangements, Net assets recognized in the balance sheet	3,587	1,329
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	239	275
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Derivative assets subject to netting arrangements, Net amount	3,348	1,054
Total derivatives not subject to netting arrangements	1,420	1,491
Total derivatives, Gross assets recognized	18,054	9,793
Fair value after effect of master netting agreements	5,007	2,820
Total derivatives, Net amount	4,768	2,545
Reverse repurchase agreements, Gross assets recognized	60,063	72,661
Reverse repurchase agreements, Gross amounts offset in the balance sheet	45,006	54,709
Reverse repurchase agreements, Net assets recognized on the balance sheet	15,057	17,952
Reverse repurchase agreements, Gross amounts not offset in the balance sheet, Financial instruments	14,940	17,922
Reverse repurchase agreements, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Reverse repurchase agreements, Net amount	117	30
Securities borrowing, Gross assets recognized	8,426	11,655
Securities borrowing, Net assets recognized on the balance sheet	8,426	11,655
Securities borrowing, Gross amounts not offset in the balance sheet, Financial instruments	8,001	11,036
Securities borrowing, Net amount	425	619
Total, Gross assets recognized	86,543	94,109
Total, Gross amounts offset in the balance sheet	58,053	61,682
Total, Net assets recognized on the balance sheet	28,490	32,427
Total, Gross amounts not offset in the balance sheet, Financial instruments	23,180	29,233
Total, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Total, Net amount	5,310	3,194
Derivative Liability
Derivatives subject to netting arrangements, Gross liabilities recognized	16,479	9,093
Derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	13,652	6,335
Derivatives subject to netting arrangements, Net liabilities recognized in the balance sheet	2,827	2,758
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	457	1,226
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral pledged	0	0
Derivative liabilities subject to netting arrangements, Net amount	2,370	1,532
Total derivatives not subject to netting arrangements	1,139	666
Total derivatives, Gross liabilities recognized	17,618	9,759
Fair value after effect of master netting agreements	3,966	3,424
Total derivatives, Net amount	3,509	2,198
Repurchase agreements, Gross liabilities recognized	54,476	64,734
Repurchase agreements, Gross amounts offset in the balance sheet	45,006	54,709
Repurchase agreements, Net liabilities recognized on the balance sheet	9,470	10,025
Repurchase agreements, Gross amounts not offset in the balance sheet, Financial instruments	9,440	10,025
Repurchase agreements, Gross amounts not offset in the balance sheet, Cash collateral pledged	29	0
Repurchase agreements, Net amount	1	0
Securities lending, Gross liabilities recognized	1,869	1,541
Securities lending, Net liabilities recognized on the balance sheet	1,869	1,541
Securities lending, Gross amounts not offset in the balance sheet, Financial instruments	1,777	1,478
Securities lending, Net amount	92	63
Total, Gross liabilities recognized	73,963	76,034
Total, Gross amounts offset in the balance sheet	58,658	61,044
Total, Net liabilities recognized on the balance sheet	15,305	14,990
Total, Gross amounts not offset in the balance sheet, Financial instruments	11,674	12,729
Total, Gross amounts not offset in the balance sheet, Cash collateral pledged	29	0
Total, Net amount	3,602	2,261
Interest rate contracts
Derivative Asset
Derivatives subject to netting arrangements, Gross assets recognized	1,404	2,132
Total derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	1,054	1,424
Derivatives subject to netting arrangements, Net assets recognized in the balance sheet	350	708
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	57	206
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Derivative assets subject to netting arrangements, Net amount	293	502
Derivative Liability
Derivatives subject to netting arrangements, Gross liabilities recognized	1,560	3,263
Derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	1,026	2,028
Derivatives subject to netting arrangements, Net liabilities recognized in the balance sheet	534	1,235
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	66	1,197
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral pledged	0	0
Derivative liabilities subject to netting arrangements, Net amount	468	38
Foreign exchange contracts
Derivative Asset
Derivatives subject to netting arrangements, Gross assets recognized	14,986	6,122
Total derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	11,914	5,501
Derivatives subject to netting arrangements, Net assets recognized in the balance sheet	3,072	621
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	162	69
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Derivative assets subject to netting arrangements, Net amount	2,910	552
Derivative Liability
Derivatives subject to netting arrangements, Gross liabilities recognized	14,897	5,619
Derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	12,624	4,111
Derivatives subject to netting arrangements, Net liabilities recognized in the balance sheet	2,273	1,508
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	391	29
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral pledged	0	0
Derivative liabilities subject to netting arrangements, Net amount	1,882	1,479
Equity and other contracts
Derivative Asset
Derivatives subject to netting arrangements, Gross assets recognized	244	48
Total derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	79	48
Derivatives subject to netting arrangements, Net assets recognized in the balance sheet	165	0
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	20	0
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral received	0	0
Derivative assets subject to netting arrangements, Net amount	145	0
Derivative Liability
Derivatives subject to netting arrangements, Gross liabilities recognized	22	211
Derivatives subject to netting arrangements, Gross amounts offset in the balance sheet	2	196
Derivatives subject to netting arrangements, Net liabilities recognized in the balance sheet	20	15
Total derivatives, Gross amounts not offset in the balance sheet, Financial instruments	0	0
Total derivatives, Gross amounts not offset in the balance sheet, Cash collateral pledged	0	0
Derivative liabilities subject to netting arrangements, Net amount	$ 20	$ 15