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Regulatory Capital (Details) $ in Millions | Jan. 01, 2020 USD ($) | Jun. 30, 2024 USD ($) | Dec. 31, 2023 USD ($)
--- | --- | --- | ---
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |  |
Retained Earnings (Accumulated Deficit) |  | $ 1,156.9 | $ 1,135.1
Total risk-based capital: |  |  |
Actual, Amount |  | $ 2,970.0 | $ 2,941.1
Actual, Ratio |  | 0.1380 | 0.1328
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,721.8 | $ 1,771.6
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 2,259.9 | $ 2,325.2
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 2,152.3 | $ 2,214.5
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 |  | $ 968.5 | $ 996.5
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 2,482.1 | $ 2,454.4
Actual, Ratio |  | 0.1153 | 0.1108
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,291.4 | $ 1,328.7
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,829.4 | $ 1,882.3
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,721.8 | $ 1,771.6
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 |  | 0.1153 | 0.1108
Banking Regulation, Common Equity Tier One Risk-Based Capital, Well Capitalized, Minimum |  | $ 1,399.0 | $ 1,439.4
Banking Regulation, Common Equity Tier One Risk-Based Capital, Actual |  | 2,482.1 | 2,454.4
Common equity tier 1 risk-based capital: |  |  |
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,506.6 | $ 1,550.1
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 2,482.1 | $ 2,454.4
Actual, Ratio |  | 0.0844 | 0.0822
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 1,176.4 | $ 1,193.9
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,470.6 | $ 1,492.3
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 |  | $ 2,689.2 | $ 2,662.0
Actual, Ratio |  | 0.1252 | 0.1204
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,718.2 | $ 1,768.3
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 2,255.1 | $ 2,320.8
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 2,147.7 | $ 2,210.3
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 |  | $ 966.5 | $ 994.6
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 2,458.9 | $ 2,433.0
Actual, Ratio |  | 0.1145 | 0.1101
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 1,288.6 | $ 1,326.2
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,825.6 | $ 1,878.8
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,718.2 | $ 1,768.3
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 |  | 0.1145 | 0.1101
Banking Regulation, Common Equity Tier One Risk-Based Capital, Well Capitalized, Minimum |  | $ 1,396.0 | $ 1,436.7
Banking Regulation, Common Equity Tier One Risk-Based Capital, Actual |  | 2,458.9 | 2,433.0
Common equity tier 1 risk-based capital: |  |  |
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,503.4 | $ 1,547.2
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 2,458.9 | $ 2,433.0
Actual, Ratio |  | 0.0837 | 0.0816
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 1,174.7 | $ 1,192.2
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,468.4 | $ 1,490.2
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0500 | 0.0500

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