Fair Value Measurements - Summary of Level 3 Financial Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	$ 694,838	$ 738,615	$ 715,812
Investment at fair value	77,580		83,427
Loans at fair value	8,250		10,769
Derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	157,828		130,001
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	29,275	28,884	24,083
Loans at fair value	2,058		2,354
Level 3 | Trading cash instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading cash instrument at fair value	1,828	2,080	1,889
Level 3 | Derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	8,435	8,348	5,938
Level 3 | Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment at fair value	16,954	16,109	13,902
Level 3 | Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans at fair value	$ 2,058	$ 2,347	$ 2,354