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Regulatory Capital (Details) $ in Millions | Jan. 01, 2020 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | --- | ---
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |  |
Retained Earnings (Accumulated Deficit) |  | $ 1,080.7 | $ 1,072.7
Total risk-based capital: |  |  |
Actual, Amount |  | $ 2,899.0 | $ 2,875.8
Actual, Ratio |  | 0.1263 | 0.1248
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,836.6 | $ 1,843.2
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 2,410.6 | $ 2,419.2
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 2,295.8 | $ 2,304.0
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.1000 | 0.1000
Banking Regulation, Common Equity Tier One Risk-Based Capital, Capital Adequacy, Minimum |  | $ 1,033.1 | $ 1,036.8
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 2,415.4 | $ 2,408.8
Actual, Ratio |  | 0.1052 | 0.1045
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,377.5 | $ 1,382.4
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,951.4 | $ 1,958.4
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,836.6 | $ 1,843.2
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0800 | 0.0800
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Well Capitalized, Minimum |  | 0.0650 | 0.0650
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum |  | 0.0450 | 0.0450
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual |  | 0.1052 | 0.1045
Banking Regulation, Common Equity Tier One Risk-Based Capital, Well Capitalized, Minimum |  | $ 1,492.3 | $ 1,497.6
Banking Regulation, Common Equity Tier One Risk-Based Capital, Actual |  | 2,415.4 | 2,408.8
Common equity tier 1 risk-based capital: |  |  |
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,607.1 | $ 1,612.8
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 2,415.4 | $ 2,408.8
Actual, Ratio |  | 0.0772 | 0.0775
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 1,251.6 | $ 1,242.9
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,564.5 | $ 1,553.6
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0500 | 0.0500
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle | $ 24.1 |  |
FIB |  |  |
Total risk-based capital: |  |  |
Actual, Amount |  | $ 2,740.5 | $ 2,713.5
Actual, Ratio |  | 0.1196 | 0.1180
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,833.0 | $ 1,839.6
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 2,405.8 | $ 2,414.5
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 2,291.2 | $ 2,299.5
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.1000 | 0.1000
Banking Regulation, Common Equity Tier One Risk-Based Capital, Capital Adequacy, Minimum |  | $ 1,031.0 | $ 1,034.8
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 2,514.5 | $ 2,504.1
Actual, Ratio |  | 0.1097 | 0.1089
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,374.7 | $ 1,379.7
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,947.5 | $ 1,954.6
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,833.0 | $ 1,839.6
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0800 | 0.0800
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Well Capitalized, Minimum |  | 0.0650 | 0.0650
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum |  | 0.0450 | 0.0450
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual |  | 0.1097 | 0.1089
Banking Regulation, Common Equity Tier One Risk-Based Capital, Well Capitalized, Minimum |  | $ 1,489.3 | $ 1,494.7
Banking Regulation, Common Equity Tier One Risk-Based Capital, Actual |  | 2,514.5 | 2,504.1
Common equity tier 1 risk-based capital: |  |  |
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,603.8 | $ 1,609.7
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 2,514.5 | $ 2,504.1
Actual, Ratio |  | 0.0805 | 0.0807
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 1,249.8 | $ 1,241.1
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,562.2 | $ 1,551.4
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0500 | 0.0500

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- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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