FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Nonrecurring Fair Value Measurements (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) decimal	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) decimal	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) decimal
Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (25,000,000)	$ (94,000,000)	$ (42,000,000)	$ (173,000,000)
Nonrecurring | Level 3
Valuation techniques and inputs
Loans HFS	244,000,000		244,000,000		$ 676,000,000
Loans					296,000,000
Other real estate owned	7,000,000		7,000,000		3,000,000
Price-based | Level 3
Valuation techniques and inputs
Non-marketable equities	222,000,000		222,000,000
Price-based | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	70,000,000		70,000,000		250,000,000
Price-based | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	$ 211,000,000		$ 211,000,000		$ 674,000,000
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	3,190.93		3,190.93
Price-based | Price | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities					56.78
Non-marketable equities	1,756.38		1,756.38
Price-based | Price | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	95.73		95.73		67.50
Non-marketable equities					1.57
Non-marketable equities	1.23		1.23
Nonrecurring fair value changes included in earnings
Other real estate owned	0		0
Price-based | Price | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans HFS	100.00		100.00		100.00
Non-marketable equities					2,637
Non-marketable equities	519.72		519.72
Nonrecurring fair value changes included in earnings
Other real estate owned	8,427		8,427
Price-based | Price | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans HFS	97.91		97.91		93.39
Non-marketable equities					1,114.06
Non-marketable equities	110.65		110.65
Nonrecurring fair value changes included in earnings
Other real estate owned	123.38		123.38
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Other real estate owned					401,042
Nonrecurring fair value changes included in earnings
Other real estate owned	21,600		21,600
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Other real estate owned					2,061,700
Nonrecurring fair value changes included in earnings
Other real estate owned	342,000		342,000
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Other real estate owned					155,696
Nonrecurring fair value changes included in earnings
Other real estate owned	194,563		194,563
Price-based | Revenue multiple | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities					$ 50,000,000
Price-based | Illiquidity discount | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	0.1840		0.1840
Price-based | Illiquidity discount | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	0.1950		0.1950
Price-based | Illiquidity discount | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	0.1895		0.1895
Recovery analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Loans	$ 149,000,000		$ 149,000,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	12,000		12,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	78,595,495		78,595,495
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	40,009,156		40,009,156
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans					12,000
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans					75,997,078
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans					46,121,923
Appraised value | Nonrecurring | Level 3
Valuation techniques and inputs
Loans	$ 62,000,000		$ 62,000,000
Comparable analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 33,000,000		$ 33,000,000
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	6.10		6.10		2.30
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	9.19		9.19		35.70
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	6.89		6.89		11.69
Comparables analysis | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 228,000,000		$ 228,000,000		$ 366,000,000
Comparables analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities					$ 109,000,000
Comparables analysis | Revenue multiple | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	4.30		4.30		2.80
Comparables analysis | Revenue multiple | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	16.26		16.26		13.40
Comparables analysis | Revenue multiple | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	11.95		11.95		12.28
Comparables analysis | Illiquidity discount | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	0.0740		0.0740		0.0800
Comparables analysis | Illiquidity discount | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	0.3300		0.3300		0.1000
Comparables analysis | Illiquidity discount | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	0.1435		0.1435		0.0882
Loans held-for-sale | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (1,000,000)	0	$ (46,000,000)	6,000,000
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	(16,000,000)	(82,000,000)	(16,000,000)	(110,000,000)
Non-marketable equity securities | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (8,000,000)	$ (12,000,000)	$ 20,000,000	$ (69,000,000)