| Investment Owned Balance Principal Amount | $99.1B | $105.4B | $109.2B | $112.9B | $117.7B | $131.5B | $143.4B | $147.8B |
| Financial Assets, Fair Value Disclosure | — | — | $98.4B | — | — | — | $132.2B | $134.5B |
| Secured financings and interest rate swaps - collateral held, estimated fair value | $65.8B | $69.3B | $71.8B | $68B | $73.5B | $81.7B | $89B | $90.1B |
| Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss | $69.3B | $71.7B | $72.1B | $71.5B | $74.5B | $85.3B | $91B | $88.9B |
| Estimated Fair Value | $67B | $71.7B | $69.8B | $70.4B | $73.5B | $85.1B | $91.3B | $88.5B |
| Mortgage-backed securities, fair value | — | — | $67.4B | — | — | — | $89.6B | $86.4B |
| Security Sold under Agreement to Repurchase, Subject to Master Netting Arrangement, after Offset | $60.8B | $64.3B | $65.7B | $61.7B | $66.5B | $75.1B | $81.9B | $85.1B |
| Loans retained by Huntington | $17.9B | $21B | $22B | $24.5B | $27B | $29.5B | $32.1B | $34.2B |
| Fair Value Measurement Disclosure | — | — | $23.2B | — | — | — | $33.3B | $33.4B |
| Debt issued by securitization vehicles | $15.8B | $18.7B | $19.5B | $21.8B | $24.1B | $26.6B | $28.9B | $30.7B |
| Securitized Debt Of Consolidated VIE Fair Value Disclosure | — | — | $19.5B | — | — | — | $28.9B | $30.7B |
| Repurchase agreement amount | $2.9B | $3.5B | $3.6B | $3.9B | $4.2B | $4.3B | $4.8B | $5.3B |
| Transfer of residential loans to securitization vehicles, carrying value | $5.6B | $8.8B | $11.2B | $3.2B | $7B | $10.9B | $15.8B | $4.9B |
| Remaining Premium | $2.2B | $2.4B | $2.5B | $2.5B | $2.6B | $2.7B | $2.9B | $2.9B |
| Participations issued | $1.1B | $467M | $1.2B | $1.7B | $1.6B | $1.8B | $1.9B | $2.5B |
| Remaining capacity of repurchase agreement | $1.9B | $2.2B | $2.2B | $2.2B | $2.5B | $2.5B | $2.5B | $1.9B |
| Cash Collateral for Borrowed Securities | $1.3B | $1.2B | $1.2B | $1.5B | $1.8B | $1.8B | $1.7B | $1.5B |
| Payable for unsettled trades | $1.1B | $1.9B | $308.3M | $2.3B | $1.5B | $2.6B | $2.1B | $1.5B |
| Common stock, shares authorized (in shares) | $1.5B | $1.5B | $1.5B | $1.5B | $1.5B | $1.5B | $1.5B | $1.5B |
| Debt Securities, Available-for-sale, Remaining Discount | $1.3B | $1.3B | $1.3B | $1.3B | $1.4B | $1.4B | $1.2B | $1.2B |
| Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax | $2.5B | $1.1B | $2.5B | $1.6B | $1.5B | $1.1B | $877.5M | $1.2B |
| Security Purchased under Agreement to Resell, Subject to Master Netting Arrangement, before Offset | $2B | $2.7B | $2.6B | $2.5B | $3.5B | $4.5B | $2.5B | $1B |
| Receivable for unsettled trades | $320.7M | $766.3M | $2.2B | $2.5M | $1.1B | $185.9M | $1M | $891.3M |
| Principal and interest receivable | $917.1M | $1.1B | $1.1B | $836.9M | $830.5M | $959.4M | $926.7M | $806.5M |
| Common stock, shares issued (in shares) | $501M | $558M | $578.4M | $602.3M | $642.1M | $681.1M | $707M | $730.3M |
| Common Stock, Shares, Outstanding | $501M | $558M | $578.4M | $602.3M | $642.1M | $681.1M | $707M | $730.3M |
| Gross Unrealized Gains | $266.4M | $1.1B | $235.8M | $480.7M | $555.5M | $910.2M | $1.2B | $704.8M |
| Exercise of optional redemption provisions of securitization vehicles, carrying value | — | — | — | — | — | $290.4M | $577.3M | $535.8M |
| Secured financings and interest rate swaps - collateral held, accrued interest | $293.3M | $304.7M | $332.7M | $310.1M | $333.2M | $374.6M | $404.1M | $425.6M |
| Other derivatives | — | — | $204.1M | — | — | — | $108.2M | $387M |
| Gross Assets/Liabilities | $100.8M | $102.6M | $59.6M | $181.1M | $426M | $199.1M | $53.8M | $207.4M |
| Derivative Liability | $100.8M | $102.6M | $59.6M | $181.1M | $426M | $199.1M | $53.8M | $207.4M |
| Other derivatives | — | — | $52.4M | — | — | — | $37.4M | $194.5M |
| Deferred Tax Liabilities, Net | — | — | $131.9M | $149.9M | $159.1M | $159.3M | $151.3M | $149.1M |
| Other investments ($20 and $8 pledged as collateral) | — | — | $754.9M | — | — | — | $213.8M | $110.6M |
| Deferred Tax Assets, Net | — | — | $62.9M | $72.6M | $81.4M | $89.4M | $89.2M | $90M |
| Operating Loss Carryforwards | — | — | $50.3M | $61.5M | $79.7M | $97.9M | $109.1M | $81.6M |
| Preferred Stock, Shares Authorized | $63.5M | $63.5M | $63.5M | $63.5M | $63.5M | $75M | $75M | $75M |
| Preferred Stock, Shares Issued | $63.5M | $63.5M | $63.5M | $63.5M | $63.5M | $74.5M | $74.5M | $74.5M |
| Preferred Stock, Shares Outstanding | $63.5M | $63.5M | $63.5M | $63.5M | $63.5M | $74.5M | $74.5M | $74.5M |
| Deferred Tax Assets Operating Loss Carryforwards Not Subject To Expiration | — | — | $42.4M | $53.6M | $71.8M | $90M | $101.2M | $73.9M |
| Lessee Operating Lease Liability Payments Due | $5.8M | $4.7M | $65.6M | $64.6M | $63.6M | $62.6M | $62.5M | $62.4M |
| Noncontrolling interests in subsidiaries | $81.8M | $96.7M | $87.7M | $89.8M | $93.1M | $85.7M | $69.1M | $51.7M |
| Later years | $0 | $0 | $55.9M | $52M | $52M | $52M | $52M | $48.2M |
| Reverse repurchase agreements | — | — | $0 | — | — | $35M | $34.4M | $33.5M |
| Security Purchased under Agreement to Resell, Subject to Master Netting Arrangement, after Offset | $0 | $0 | $0 | $0 | $0 | $35M | $34.4M | $33.5M |
| Lessee Operating Lease Liability Undiscounted Excess Amount | $187K | $143K | $37M | $36.5M | $34.4M | $30.9M | $29.4M | $28.8M |
| Interests in MSR | — | — | $0 | — | — | $35.8M | $28.6M | $27.2M |
| Interests in MSR | — | — | — | — | — | — | $28.6M | $27.2M |
| Deferred Tax Assets Operating Loss Carryforwards Subject To Expiration | — | — | $7.9M | $7.9M | $7.9M | $7.9M | $7.9M | $7.7M |
| Remainder of Fiscal Year 2024 | $2.1M | $1M | — | $2.1M | $1.1M | $63K | — | $196K |
| Operating Lease Weighted Average Discount Rate Percent | $0 | $0 | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 |
| Weighted Average Interest Rate (as a percent) | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 | $0.1 |
| Repurchase agreements weighted average rate | 5.6% | 5.2% | 4.8% | 4.6% | 4.6% | 4.4% | 4.0% | 3.9% |
| Common stock, par value (in dollars per share) | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Percentage of portfolio | — | — | — | — | — | 1.0% | 1.0% | 1.0% |
| Preferred Stock, Par or Stated Value Per Share | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Repurchase agreements, remaining maturities, percentage | 1.0% | 1.0% | 1.0% | 1.0% | 1.0% | 1.0% | 1.0% | 1.0% |
| Deferred Tax Assets, Valuation Allowance | — | — | $0 | $0 | $0 | $0 | $0 | $0 |
| Loss Contingency Accrual | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
| Carrying value of assets pledged as collateral against repurchase agreements | $2B | $2B | $2.5B | $2.5B | $2.5B | $2.4B | $2.4B | $0 |
| Unrecognized tax benefits | $0 | $0 | $0 | $0 | $0 | $0 | — | $0 |
| Penalties and interest accrued on unrecognized tax benefits | $0 | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
