ACQUISITIONS, Identifiable Intangible Assets Acquired (Details) - USD ($) $ in Millions	Jun. 01, 2022	Jan. 21, 2022
TriState Capital
Acquired Finite-Lived Intangible Assets [Line Items]
Total identifiable intangibles assets acquired	$ 197
TriState Capital | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, indefinite lived intangible assets	5
TriState Capital | Core deposit intangible
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets	$ 89
Weighted average estimated useful life	10 years
TriState Capital | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets	$ 54
Weighted average estimated useful life	17 years
TriState Capital | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets	$ 33
Weighted average estimated useful life	20 years
TriState Capital | Other
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets	$ 16
Weighted average estimated useful life	10 years
Charles Stanley
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets		$ 85
Total identifiable intangibles assets acquired		85
Charles Stanley | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets		$ 65
Weighted average estimated useful life		13 years
Charles Stanley | Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets		$ 15
Weighted average estimated useful life		10 years
Charles Stanley | Other
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value, definite lived intangible assets		$ 5
Weighted average estimated useful life		6 years