FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Nonrecurring Fair Value Measurements (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) year
Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (83,000,000)	$ (58,000,000)	$ (85,000,000)	$ (98,000,000)
Nonrecurring | Level 3
Valuation techniques and inputs
Loans HFS	332,000,000		332,000,000		$ 676,000,000
Price-based | Level 3
Valuation techniques and inputs
Non-marketable equities	90,000,000		90,000,000
Price-based | Nonrecurring | Level 3
Valuation techniques and inputs
Loans HFS	306,000,000		306,000,000		674,000,000
Non-marketable equities	$ 27,000,000		$ 27,000,000		250,000,000
Other real estate owned					$ 3,000,000
Price-based | Price | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities					0.40
Non-marketable equities	0.55		0.55
Price-based | Price | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities					158.92
Non-marketable equities	164.44		164.44
Price-based | Price | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities					56.78
Non-marketable equities	65.60		65.60
Price-based | Price | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	49.00		49.00		67.50
Non-marketable equities	1.27		1.27		1.57
Price-based | Price | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans HFS	100.00		100.00		100.00
Non-marketable equities	1,091.71		1,091.71		2,637
Price-based | Price | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans HFS	90.17		90.17		93.39
Non-marketable equities	115.52		115.52		1,114.06
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Other real estate owned					401,042
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Other real estate owned					2,061,700
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Other real estate owned					155,696
Price-based | Revenue multiple | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities					$ 50,000,000
Recovery analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Loans	$ 98,000,000		$ 98,000,000		$ 296,000,000
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	12,000		12,000		12,000
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	27,279,987		27,279,987		75,997,078
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	13,015,794		13,015,794		46,121,923
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	19,994,171		19,994,171
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	77,680,848		77,680,848
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	58,074,015		58,074,015
Comparable analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 4,000,000		$ 4,000,000		$ 109,000,000
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	750,000		750,000		2.30
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	1,749,000		1,749,000		35.70
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	1,529,043		1,529,043		11.69
Appraised value | Nonrecurring | Level 3
Valuation techniques and inputs
Loans	$ 78,000,000		$ 78,000,000
Loans held-for-sale | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	(82,000,000)	(15,000,000)	(123,000,000)	(26,000,000)
Other real estate owned | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	0	0	0	0
Loans | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	4,000,000	(16,000,000)	10,000,000	(18,000,000)
Non-marketable equity securities | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (5,000,000)	$ (27,000,000)	$ 28,000,000	$ (54,000,000)