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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Bank deposits belonging to an acquired bank that can be counted on as a stable source of lending funds. These deposits have the following attributes: predictable costs and low sensitivity to interest rates. This intangible asset is usually amortized over its estimated useful life.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Intangible Assets - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Mar. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 22, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets		$ 14	$ 2	$ 31	$ 4
Core deposit intangible asset						$ 195
MB Financial, Inc.
Finite-Lived Intangible Assets [Line Items]
Estimated weighted-average life (in years)	7 years 2 months 12 days