GOODWILL AND INTANGIBLE ASSETS - Changes in Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Goodwill
Balance at December 31, 2023	$ 20,098
Foreign currency translation	(56)
Balance at March 31, 2024	20,042	$ 20,098
All Other
Goodwill
Balance at December 31, 2023	1,108
Foreign currency translation	28
Balance at March 31, 2024	1,136	1,108
Services \| Operating Segments
Goodwill
Balance at December 31, 2023	2,214
Foreign currency translation	(27)
Balance at March 31, 2024	2,187	2,214
Markets
Goodwill
Transfers		537
Markets \| Operating Segments
Goodwill
Balance at December 31, 2023	5,870
Foreign currency translation	(82)
Balance at March 31, 2024	5,788	5,870
Banking
Goodwill
Transfers		(537)
Banking \| Operating Segments
Goodwill
Balance at December 31, 2023	1,039
Foreign currency translation	2
Balance at March 31, 2024	1,041	1,039
USPB \| Operating Segments
Goodwill
Balance at December 31, 2023	5,398
Foreign currency translation	23
Balance at March 31, 2024	5,421	5,398
Wealth \| Operating Segments
Goodwill
Balance at December 31, 2023	4,469
Foreign currency translation	0
Balance at March 31, 2024	$ 4,469	$ 4,469

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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