Parent Company Financial Statements - Condensed Statements of Income - Parent Company Only - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Dividends from consolidated nonbank subsidiaries	$ 3,000	$ 1,300
MB Financial, Inc.
Dividends from consolidated nonbank subsidiaries			$ 200
Parent Company
Dividends from Bancorp's banking subsidiary to the Bancorp's non-bank subsidiary	3,000	1,300	2,000
Dividends from consolidated nonbank subsidiaries	$ 3,040	$ 1,285	$ 2,155