FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Nonrecurring Fair Value Measurements (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) decimal	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) decimal	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) decimal
Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (98,000,000)	$ (25,000,000)	$ (141,000,000)	$ (42,000,000)
Nonrecurring | Level 3
Valuation techniques and inputs
Loans HFS	236,000,000		236,000,000		$ 271,000,000
Loans					353,000,000
Other real estate owned					19,000,000
Price-based | Level 3
Valuation techniques and inputs
Non-marketable equities	96,000,000		96,000,000		81,000,000
Price-based | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	163,000,000		163,000,000		136,000,000
Price-based | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	$ 235,000,000		$ 235,000,000		$ 271,000,000
Price-based | Price | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	2.90		2.90		0.54
Price-based | Price | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	353.72		353.72		2,960.96
Price-based | Price | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	125.66		125.66		432.84
Price-based | Price | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	80.00		80.00		0
Non-marketable equities	9.94		9.94		1.50
Price-based | Price | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans HFS	100.00		100.00		101.00
Non-marketable equities	205.01		205.01		2,961
Price-based | Price | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans HFS	95.55		95.55		96.61
Non-marketable equities	94.50		94.50		258.00
Price-based | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Other real estate owned					503,332
Price-based | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Other real estate owned					7,220,000
Price-based | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Other real estate owned					4,309,976
Recovery analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Loans	$ 620,000,000		$ 620,000,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	10,000		10,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	184,687,798		184,687,798
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	99,270,639		99,270,639
Recovery analysis | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans					10,000
Recovery analysis | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans					104,049,422
Recovery analysis | Measurement Input, Appraised Value [Member] | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans					58,636,070
Recovery analysis | Recovery rate | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	0.3510		0.3510
Recovery analysis | Recovery rate | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	0.9010		0.9010
Recovery analysis | Recovery rate | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	0.5797		0.5797
Comparable analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 127,000,000		$ 127,000,000
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	3.00		3.00		3.80
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	53.75		53.75		9.19
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	31.84		31.84		6.67
Comparable analysis | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 277,000,000		$ 277,000,000		$ 222,000,000
Comparable analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities					$ 29,000,000
Comparable analysis | Revenue multiple | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	8.61		8.61		4.50
Comparable analysis | Revenue multiple | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	30.71		30.71		16.31
Comparable analysis | Revenue multiple | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	14.10		14.10		11.97
Loans held-for-sale | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (10,000,000)	(1,000,000)	$ (22,000,000)	(46,000,000)
Other real estate owned | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	(1,000,000)	0	(1,000,000)	0
Loans | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	(79,000,000)	(16,000,000)	(67,000,000)	(16,000,000)
Non-marketable equity securities | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (8,000,000)	$ (8,000,000)	$ (51,000,000)	$ 20,000,000