FAIR VALUE MEASUREMENT - Valuation Techniques and Inputs for Level 3 Nonrecurring Fair Value Measurements (Details)	3 Months Ended
	Mar. 31, 2025 USD ($) decimal	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) decimal
Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (102,000,000)	$ (84,000,000)
Nonrecurring | Level 3
Valuation techniques and inputs
Loans HFS	193,000,000		$ 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	60,000,000		81,000,000
Price-based | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	63,000,000		136,000,000
Price-based | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	$ 193,000,000		$ 271,000,000
Price-based | Price | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	0.37		0.54
Nonrecurring fair value changes included in earnings
Loans and leases	0		73.88
Price-based | Price | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	3,088.78		2,960.96
Nonrecurring fair value changes included in earnings
Loans and leases	100.15		99.25
Price-based | Price | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	599.95		432.84
Nonrecurring fair value changes included in earnings
Loans and leases	83.59		85.09
Price-based | Price | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans HFS	79.11		0
Non-marketable equities	8.73		1.50
Price-based | Price | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans HFS	100.00		101.00
Non-marketable equities	203.98		2,961
Price-based | Price | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans HFS	95.46		96.61
Non-marketable equities	136.46		258.00
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Other real estate owned			503,332
Price-based | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Other real estate owned			7,220,000
Price-based | Appraised value (in millions) | 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	$ 401,000,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans	10,000
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans	94,813,103
Recovery analysis | Measurement Input, Discounted Cash Flow | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans	58,847,126
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Loans			10,000
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Loans			104,049,422
Recovery analysis | Appraised value (in millions) | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Loans			58,636,070
Comparable analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 38,000,000
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	3.28		3.80
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	6.00		9.19
Comparable analysis | Revenue multiple | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	5.34		6.67
Comparable analysis | Equity volatility | Nonrecurring | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	0.4788
Comparable analysis | Equity volatility | Nonrecurring | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	1.0857
Comparable analysis | Equity volatility | Nonrecurring | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	0.7457
Comparables analysis | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 243,000,000		$ 222,000,000
Comparables analysis | Nonrecurring | Level 3
Valuation techniques and inputs
Non-marketable equities			$ 29,000,000
Comparables analysis | Revenue multiple | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities | decimal	3.80		4.50
Comparables analysis | Revenue multiple | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities | decimal	13.13		16.31
Comparables analysis | Revenue multiple | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities | decimal	11.46		11.97
Comparables analysis | Illiquidity discount | Level 3 | Minimum
Valuation techniques and inputs
Non-marketable equities	0.0740		0.0740
Comparables analysis | Illiquidity discount | Level 3 | Maximum
Valuation techniques and inputs
Non-marketable equities	0.3300		0.3300
Comparables analysis | Illiquidity discount | Level 3 | Weighted Average
Valuation techniques and inputs
Non-marketable equities	0.1619		0.1647
Model-based | Level 3
Valuation techniques and inputs
Non-marketable equities	$ 102,000,000		$ 50,000,000
Model-based | Equity volatility | Level 3 | Minimum
Nonrecurring fair value changes included in earnings
Loans and leases	0.4252		0.3542
Model-based | Equity volatility | Level 3 | Maximum
Nonrecurring fair value changes included in earnings
Loans and leases	0.4543		0.4194
Model-based | Equity volatility | Level 3 | Weighted Average
Nonrecurring fair value changes included in earnings
Loans and leases	0.4349		0.3721
Loans held-for-sale | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (21,000,000)	(82,000,000)
Other real estate owned | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	0	0
Loans | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	(37,000,000)	(34,000,000)
Non-marketable equity securities | Nonrecurring
Nonrecurring fair value changes included in earnings
Nonrecurring fair value measurements included in earnings	$ (44,000,000)	$ 32,000,000