OPERATING SEGMENTS (Details) $ in Millions			3 Months Ended
		Mar. 01, 2023 USD ($)	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			5
Segment Reporting Information [Line Items]
Net interest income			$ 13,507	$ 13,348
Non-interest revenue			7,597	8,099
Total revenues, net of interest expense			21,104	21,447
Provisions for credit losses and for benefits and claims	[1]		2,365	1,975
Provision (benefits) for income taxes			1,136	1,531
Income (loss) from continuing operations			3,408	4,652
Identifiable assets			2,432,510		$ 2,411,834
Average loans			679,000	654,000
Average deposits			1,326,000	1,363,000
Sold | India
Segment Reporting Information [Line Items]
Pretax loss on sale of business		$ (1,000)		(1,059)
Loss on sale of business, after-tax		$ (717)		(727)
Held for sale | Mexico and Asia Exit Markets
Segment Reporting Information [Line Items]
Operating expenses, before tax			110
Operating expenses, after tax			77
Operating Segments
Segment Reporting Information [Line Items]
Income (loss) from continuing operations			3,502	4,004
Operating Segments | Services
Segment Reporting Information [Line Items]
Net interest income			3,317	3,126
Non-interest revenue			1,449	1,268
Total revenues, net of interest expense			4,766	4,394
Provisions for credit losses and for benefits and claims			64	(14)
Provision (benefits) for income taxes			517	690
Income (loss) from continuing operations			1,519	1,309
Identifiable assets			577,000		586,000
Average loans			82,000	79,000
Average deposits			808,000	830,000
Operating Segments | Markets
Segment Reporting Information [Line Items]
Net interest income			1,713	1,562
Non-interest revenue			3,665	4,228
Total revenues, net of interest expense			5,378	5,790
Provisions for credit losses and for benefits and claims			200	83
Provision (benefits) for income taxes			388	676
Income (loss) from continuing operations			1,410	1,869
Identifiable assets			1,037,000		1,007,000
Average loans			120,000	111,000
Average deposits			24,000	23,000
Operating Segments | Banking
Segment Reporting Information [Line Items]
Net interest income			574	500
Non-interest revenue			1,140	651
Total revenues, net of interest expense			1,714	1,151
Provisions for credit losses and for benefits and claims			(129)	(123)
Provision (benefits) for income taxes			120	(19)
Income (loss) from continuing operations			539	57
Identifiable assets			152,000		149,000
Average loans			89,000	95,000
Average deposits			1,000	1,000
Operating Segments | USPB
Segment Reporting Information [Line Items]
Net interest income			5,226	4,854
Non-interest revenue			(48)	(143)
Total revenues, net of interest expense			5,178	4,711
Provisions for credit losses and for benefits and claims			2,204	1,649
Provision (benefits) for income taxes			108	131
Income (loss) from continuing operations			347	402
Identifiable assets			237,000		242,000
Average loans			204,000	184,000
Average deposits			100,000	111,000
Operating Segments | Wealth
Segment Reporting Information [Line Items]
Net interest income			979	1,121
Non-interest revenue			716	645
Total revenues, net of interest expense			1,695	1,766
Provisions for credit losses and for benefits and claims			(170)	(58)
Provision (benefits) for income taxes			47	39
Income (loss) from continuing operations			150	159
Identifiable assets			230,000		232,000
Average loans			150,000	150,000
Average deposits			319,000	323,000
All Other
Segment Reporting Information [Line Items]
Net interest income			1,698	2,185
Non-interest revenue			687	432
Total revenues, net of interest expense			2,385	2,617
Provisions for credit losses and for benefits and claims			185	446
Provision (benefits) for income taxes			(5)	(291)
Income (loss) from continuing operations			(463)	208
Identifiable assets			200,000		$ 196,000
Average loans			34,000	35,000
Average deposits			74,000	75,000
Reconciling Items
Segment Reporting Information [Line Items]
Net interest income			0	0
Non-interest revenue			(12)	1,018
Total revenues, net of interest expense			(12)	1,018
Provisions for credit losses and for benefits and claims			11	(8)
Provision (benefits) for income taxes			(39)	305
Income (loss) from continuing operations			$ (94)	$ 648

[1] This total excludes the provision for credit losses on AFS debt securities, which is disclosed separately above.