Regulatory Capital Requirements - Summary of Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
TCF
Regulatory Capital:
Common equity Tier 1 capital	$ 4,009,214	$ 2,224,183
Tier 1 capital	4,197,706	2,408,393
Total capital	$ 4,652,708	$ 2,750,581
Common equity Tier 1 capital ratio
Common equity Tier 1 capital - actual, ratio	10.88%	10.82%
Risk-based capital ratios
Tier 1 risk-based capital - actual, ratio	11.40%	11.72%
Total risk-based capital - actual, ratio	12.63%	13.38%
Tier 1 leverage ratio
Tier 1 leverage - actual, ratio	11.16%	10.44%
TCF Bank
Regulatory Capital:
Common equity Tier 1 capital	$ 3,991,895	$ 2,282,013
Tier 1 capital	4,015,208	2,300,472
Total capital	$ 4,487,968	$ 2,675,347
Common equity Tier 1 capital ratio
Common equity Tier 1 capital - actual, ratio	10.85%	11.10%
Common equity Tier 1 capital - well-capitalized capital requirement, ratio	6.50%
Common equity Tier 1 capital - minimum capital requirement, ratio	7.00%
Risk-based capital ratios
Tier 1 risk-based capital - actual, ratio	10.91%	11.19%
Tier 1 risk-based capital - well-capitalized capital requirement, ratio	8.00%
Tier 1 risk-based capital - minimum capital requirement, ratio	8.50%
Total risk-based capital - actual, ratio	12.20%	13.01%
Total risk-based capital - well-capitalized capital requirement, ratio	10.00%
Total risk-based capital - minimum capital requirement, ratio	10.50%
Tier 1 leverage ratio
Tier 1 leverage - actual, ratio	10.68%	9.97%
Tier 1 leverage - well-capitalized capital requirement, ratio	5.00%
Tier 1 leverage - minimum capital requirement, ratio	4.00%

Tier One Common Capital Required for Capital Adequacy to Risk Weighted Assets

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The amount of total capital as defined in the regulations.

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Amount of Common Equity Tier One Risk-based Capital, as defined by regulatory framework.

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