Fair values of financial instruments carried at fair value - Financial instruments measured at fair value using a valuation technique with significant unobservable inputs - Level 3 (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	$ 2,923,319	$ 2,948,360
Financial liabilities	2,682,252	2,711,852
Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	31,302	28,781
Financial liabilities	12,743	13,975
Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	1	1
Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	9,113	10,331
Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	2,842	2,569
Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	787	1,074
Trading liabilities
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	65,982	73,150
Trading liabilities | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	65,982	73,150
Trading liabilities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	784	478	$ 474
Trading liabilities | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Trading liabilities | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Trading liabilities | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Trading liabilities | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Trading liabilities | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	784	478
Financial liabilities designated at fair value
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	138,727	141,426
Financial liabilities designated at fair value | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	138,727	141,426
Financial liabilities designated at fair value | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	9,117	10,928	10,432
Financial liabilities designated at fair value | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	1	1
Financial liabilities designated at fair value | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Financial liabilities designated at fair value | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	9,113	10,331
Financial liabilities designated at fair value | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Financial liabilities designated at fair value | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	3	596
Derivatives | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	264,448	234,772
Derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	2,842	2,569	2,920
Derivatives | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Derivatives | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Derivatives | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Derivatives | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	2,842	2,569
Derivatives | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	18,258	18,154
Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	380	445
Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	3	3
Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,149	2,069
Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	10,512	8,110
Financial investments
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	339,193	294,437
Financial investments | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	339,193	294,437
Financial investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,734	2,618	2,961
Financial investments | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	552	507
Financial investments | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	182	309
Financial investments | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Financial investments | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Financial investments | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,000	1,802
Trading assets
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	314,842	289,159
Trading assets | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	314,842	289,159
Trading assets | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	6,675	4,306	4,817
Trading assets | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	1	7
Trading assets | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	198	128
Trading assets | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Trading assets | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Trading assets | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	6,476	4,171
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	3,357	2,724
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	115,769	110,643
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	19,744	19,788	17,407
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	17,705	17,640
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	8
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	3	3
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,036	2,137
Derivatives | Recurring fair value measurement
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	268,637	229,714
Derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,149	2,069	$ 1,964
Derivatives | Private equity including strategic investments | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Derivatives | Asset-backed securities | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Derivatives | Structured notes | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Derivatives | Other derivatives | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	2,149	2,069
Derivatives | Other portfolios | Recurring fair value measurement | Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	$ 0	$ 0