Goodwill and Other Intangibles - Schedule of Changes in Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Finite-lived Intangible Assets [Roll Forward]
Intangible asset amortization	$ 6	$ 3
Core Deposits
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets, beginning balance	19
Intangible asset amortization	(6)
Finite-lived intangible assets, ending balance	156
Core Deposits \| CIT Group Inc.
Finite-lived Intangible Assets [Roll Forward]
Core deposit intangibles related to the CIT Merger	$ 143

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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