ACQUISITIONS - Schedule of Acquisition and Integration Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Provision for credit losses	$ 724	$ 394	$ (360)
Salaries and employee benefits	2,599	2,549	2,132
Outside services	687	700	595
Other operating expense	973	585	411
Income before income tax expense	2,030	$ 2,655	$ 2,977
Investors Acquisition | Acquisition-related Costs
Business Acquisition [Line Items]
Provision for credit losses	145
Salaries and employee benefits	83
Outside services	61
Mark-to-market losses on LHFS portfolio	31
Other operating expense	15
Income before income tax expense	$ 335