Regulatory Capital Requirements - Narrative (Details) $ in Millions	9 Months Ended
Sep. 30, 2020 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Percentage of net retained profits for the current year combined with retained net profits for the preceding two calendar years that can be declared as dividend	100.00%
TCF Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Net profits for the current year combined with retained net profits for preceding two calendar years	$ 73.6

Represents the percentage of net retained profits for the current year combined with retained net profits for the preceding two calendar years that can be declared as dividend.

No definition available.

Name:	tcf_PercentageOfNetRetainedProfitsForCurrentYearCombinedWithRetainedNetProfitsForPrecedingTwoCalendarYearsThatCanBeDeclaredAsDividend
Namespace Prefix:	tcf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration