Loans - Summary of Credit Concentration by Region (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Product Information [Line Items]
Loans	$ 181,515	$ 162,135
Concentration risk percentage	100.00%	100.00%
Americas
Product Information [Line Items]
Concentration risk percentage	80.00%	76.00%
EMEA
Product Information [Line Items]
Concentration risk percentage	16.00%	19.00%
Asia
Product Information [Line Items]
Concentration risk percentage	4.00%	5.00%
Corporate
Product Information [Line Items]
Loans	$ 63,181	$ 55,927
Concentration risk percentage	100.00%	100.00%
Corporate | Americas
Product Information [Line Items]
Concentration risk percentage	64.00%	54.00%
Corporate | EMEA
Product Information [Line Items]
Concentration risk percentage	29.00%	38.00%
Corporate | Asia
Product Information [Line Items]
Concentration risk percentage	7.00%	8.00%
Wealth management
Product Information [Line Items]
Loans	$ 50,101	$ 43,998
Concentration risk percentage	100.00%	100.00%
Wealth management | Americas
Product Information [Line Items]
Concentration risk percentage	89.00%	87.00%
Wealth management | EMEA
Product Information [Line Items]
Concentration risk percentage	10.00%	10.00%
Wealth management | Asia
Product Information [Line Items]
Concentration risk percentage	1.00%	3.00%
Commercial real estate
Product Information [Line Items]
Loans	$ 26,082	$ 25,883
Concentration risk percentage	100.00%	100.00%
Commercial real estate | Americas
Product Information [Line Items]
Concentration risk percentage	79.00%	80.00%
Commercial real estate | EMEA
Product Information [Line Items]
Concentration risk percentage	16.00%	15.00%
Commercial real estate | Asia
Product Information [Line Items]
Concentration risk percentage	5.00%	5.00%
Residential real estate
Product Information [Line Items]
Loans	$ 14,342	$ 15,913
Concentration risk percentage	100.00%	100.00%
Residential real estate | Americas
Product Information [Line Items]
Concentration risk percentage	95.00%	95.00%
Residential real estate | EMEA
Product Information [Line Items]
Concentration risk percentage	3.00%	2.00%
Residential real estate | Asia
Product Information [Line Items]
Concentration risk percentage	2.00%	3.00%
Installment
Product Information [Line Items]
Loans	$ 5,157	$ 3,672
Concentration risk percentage	100.00%	100.00%
Installment | Americas
Product Information [Line Items]
Concentration risk percentage	100.00%	100.00%
Installment | EMEA
Product Information [Line Items]
Concentration risk percentage	0.00%	0.00%
Installment | Asia
Product Information [Line Items]
Concentration risk percentage	0.00%	0.00%
Credit cards
Product Information [Line Items]
Loans	$ 13,691	$ 8,212
Concentration risk percentage	100.00%	100.00%
Credit cards | Americas
Product Information [Line Items]
Concentration risk percentage	100.00%	100.00%
Credit cards | EMEA
Product Information [Line Items]
Concentration risk percentage	0.00%	0.00%
Credit cards | Asia
Product Information [Line Items]
Concentration risk percentage	0.00%	0.00%
Other
Product Information [Line Items]
Loans	$ 8,961	$ 8,530
Concentration risk percentage	100.00%	100.00%
Other | Americas
Product Information [Line Items]
Concentration risk percentage	89.00%	84.00%
Other | EMEA
Product Information [Line Items]
Concentration risk percentage	10.00%	15.00%
Other | Asia
Product Information [Line Items]
Concentration risk percentage	1.00%	1.00%
Funds
Product Information [Line Items]
Concentration risk percentage	23.00%	21.00%
Technology Media Telecommunications
Product Information [Line Items]
Concentration risk percentage	17.00%	18.00%
Diversified Industrials
Product Information [Line Items]
Concentration risk percentage	12.00%	13.00%
Natural Resources & Utilities
Product Information [Line Items]
Concentration risk percentage		9.00%
Financial Institutions
Product Information [Line Items]
Concentration risk percentage	8.00%	8.00%
Real estate
Product Information [Line Items]
Concentration risk percentage	8.00%