Regulatory Capital Requirements - Summary of Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Tier 1 leverage ratio
Capital conservation buffer	2.50%	2.50%
TCF
Regulatory Capital:
Common equity Tier 1 capital	$ 4,026,304	$ 4,050,826
Tier 1 capital	4,225,755	4,236,648
Total capital	$ 4,744,899	$ 4,681,630
Common equity Tier 1 capital ratio
Common equity Tier 1 capital - actual, ratio	10.44%	10.99%
Risk-based capital ratios
Tier 1 risk-based capital - actual, ratio	10.96%	11.49%
Total risk-based capital - actual, ratio	12.31%	12.70%
Tier 1 leverage ratio
Tier 1 leverage - actual, ratio	9.27%	9.49%
TCF Bank
Regulatory Capital:
Common equity Tier 1 capital	$ 4,035,278	$ 4,039,191
Tier 1 capital	4,065,427	4,059,417
Total capital	$ 4,565,533	$ 4,524,051
Common equity Tier 1 capital ratio
Common equity Tier 1 capital - actual, ratio	10.48%	10.97%
Common equity Tier 1 capital - well-capitalized capital requirement, ratio	6.50%
Common equity Tier 1 capital - minimum capital requirement, ratio	4.50%
Risk-based capital ratios
Tier 1 risk-based capital - actual, ratio	10.56%	11.03%
Tier 1 risk-based capital - well-capitalized capital requirement, ratio	8.00%
Tier 1 risk-based capital - minimum capital requirement, ratio	6.00%
Total risk-based capital - actual, ratio	11.86%	12.29%
Total risk-based capital - well-capitalized capital requirement, ratio	10.00%
Total risk-based capital - minimum capital requirement, ratio	8.00%
Tier 1 leverage ratio
Tier 1 leverage - actual, ratio	8.93%	9.10%
Tier 1 leverage - well-capitalized capital requirement, ratio	5.00%
Tier 1 leverage - minimum capital requirement, ratio	4.00%

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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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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets 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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