Business Segments - Total Net Revenues and Pre-Tax Earnings By Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Net revenues	$ 10,781	$ 8,323	$ 32,819	$ 26,591
Pre-tax earnings	$ 4,299	$ 2,416	$ 6,938	$ 8,262
Percentage of total net revenues	100.00%	100.00%	100.00%	100.00%
Percentage of total pre-tax earnings	100.00%	100.00%	100.00%	100.00%
Americas [Member]
Segment Reporting Information [Line Items]
Net revenues	$ 6,873	$ 4,941	$ 20,333	$ 15,838
Pre-tax earnings	$ 2,926	$ 1,164	$ 5,330	$ 4,444
Percentage of total net revenues	64.00%	59.00%	62.00%	60.00%
Percentage of total pre-tax earnings	68.00%	48.00%	77.00%	54.00%
Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net revenues	$ 2,470	$ 2,329	$ 8,031	$ 7,477
Pre-tax earnings	$ 935	$ 948	$ 1,937	$ 2,855
Percentage of total net revenues	23.00%	28.00%	24.00%	28.00%
Percentage of total pre-tax earnings	22.00%	39.00%	28.00%	34.00%
Asia [Member]
Segment Reporting Information [Line Items]
Net revenues	$ 1,438	$ 1,053	$ 4,455	$ 3,276
Pre-tax earnings	$ 438	$ 304	$ (329)	$ 963
Percentage of total net revenues	13.00%	13.00%	14.00%	12.00%
Percentage of total pre-tax earnings	10.00%	13.00%	(5.00%)	12.00%