ALLOWANCE FOR CREDIT LOSSES - Credit Card Receivable Aging Analysis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
On-balance sheet	$ 14,390	$ 8,239
Credit Card Receivable
Financing Receivable, Past Due [Line Items]
On-balance sheet	535	189
Off-balance sheet	207	202
Total credit card loans	$ 742	$ 391
% of Total loans	100.00%	100.00%
Credit Card Receivable | Current
Financing Receivable, Past Due [Line Items]
On-balance sheet	$ 517	$ 186
Off-balance sheet	184	177
Total credit card loans	$ 701	$ 363
% of Total loans	94.00%	93.00%
Credit Card Receivable | Total Past due receivables
Financing Receivable, Past Due [Line Items]
On-balance sheet	$ 18	$ 3
Off-balance sheet	23	25
Total credit card loans	$ 41	$ 28
% of Total loans	6.00%	7.00%
Credit Card Receivable | Less than 90 days
Financing Receivable, Past Due [Line Items]
On-balance sheet	$ 14	$ 2
Off-balance sheet	15	15
Total credit card loans	$ 29	$ 17
% of Total loans	4.00%	4.00%
Credit Card Receivable | ≥ 90 days
Financing Receivable, Past Due [Line Items]
On-balance sheet	$ 4	$ 1
Off-balance sheet	8	10
Total credit card loans	$ 12	$ 11
% of Total loans	2.00%	3.00%