FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Nonrecurring Fair Value Measurements (Details) - Nonrecurring	3 Months Ended
	Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($) decimal
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (37,000,000)	$ (102,000,000)
Level 3
Valuation techniques and inputs
Loans HFS	353,000,000		$ 453,000,000
Loans			271,000,000
Price-based \| Level 3
Valuation techniques and inputs
Non-marketable equities	100,000,000		254,000,000
Price-based \| Level 3 \| Minimum
Valuation techniques and inputs
Loans HFS	$ 353,000,000		$ 453,000,000
Price-based \| Price \| Level 3 \| Minimum
Valuation techniques and inputs
Loans HFS	80.50		83.00
Non-marketable equities	1.49		4.57
Price-based \| Price \| Level 3 \| Maximum
Valuation techniques and inputs
Loans HFS	100.00		100.00
Non-marketable equities	159.59		205.01
Price-based \| Price \| Level 3 \| Weighted Average
Valuation techniques and inputs
Loans HFS	97.98		98.66
Non-marketable equities	50.06		70.91
Recovery analysis \| Level 3
Valuation techniques and inputs
Loans	$ 97,000,000
Recovery analysis \| Measurement Input, Discounted Cash Flow \| Level 3 \| Minimum
Valuation techniques and inputs
Loans	10,000
Recovery analysis \| Measurement Input, Discounted Cash Flow \| Level 3 \| Maximum
Valuation techniques and inputs
Loans	23,657,415
Recovery analysis \| Measurement Input, Discounted Cash Flow \| Level 3 \| Weighted Average
Valuation techniques and inputs
Loans	9,267,682
Recovery analysis \| Measurement Input, Appraised Value [Member] \| Level 3 \| Minimum
Valuation techniques and inputs
Loans			10,000
Recovery analysis \| Measurement Input, Appraised Value [Member] \| Level 3 \| Maximum
Valuation techniques and inputs
Loans			75,424,500
Recovery analysis \| Measurement Input, Appraised Value [Member] \| Level 3 \| Weighted Average
Valuation techniques and inputs
Loans			30,328,429
Recovery analysis \| Measurement Input, Recovery Rate [Member] \| Level 3 \| Minimum
Valuation techniques and inputs
Loans	0.3130		0.3510
Recovery analysis \| Measurement Input, Recovery Rate [Member] \| Level 3 \| Maximum
Valuation techniques and inputs
Loans	0.6860		0.8520
Recovery analysis \| Measurement Input, Recovery Rate [Member] \| Level 3 \| Weighted Average
Valuation techniques and inputs
Loans	0.4697		0.6055
Comparable analysis \| Revenue multiple \| Level 3 \| Minimum
Valuation techniques and inputs
Non-marketable equities \| decimal			2.07
Comparable analysis \| Revenue multiple \| Level 3 \| Maximum
Valuation techniques and inputs
Non-marketable equities \| decimal			27.20
Comparable analysis \| Revenue multiple \| Level 3 \| Weighted Average
Valuation techniques and inputs
Non-marketable equities \| decimal			15.51
Comparable analysis \| Level 3
Valuation techniques and inputs
Non-marketable equities			$ 96,000,000
Loans held-for-sale
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (43,000,000)	(21,000,000)
Other real estate owned
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	0	0
Loans
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	(8,000,000)	(37,000,000)
Non-marketable equity securities
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ 14,000,000	$ (44,000,000)