| Payments to Acquire Debt Securities, Available-for-Sale | $3.8B | $3.6B | $3.4B | $1.6B | $2.3B | $162M | $1.3B | $7.1B |
| Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation | $366M | $39M | — | $2.5B | -$5B | — | — | $5.7B |
| Debt issued (Note 13) | $2.5B | $68M | $2.3B | $2B | $48M | $461M | $38M | $5.4B |
| Cash Provided by (Used in) Financing Activity, Including Discontinued Operation | $2.3B | $3B | $3.9B | $4.1B | — | $2.2B | $1.3B | $5.3B |
| Sale of investments | $0 | $10M | $980M | $0 | $850M | $10M | $831M | $4.5B |
| Goodwill Additions | — | — | — | — | — | — | — | $3.5B |
| Increase (Decrease) in Deposits | $1.1B | $4B | — | $2.9B | — | $1.8B | — | $3.3B |
| Interest and Dividend Income, Operating | $2.5B | $2.6B | $2.5B | $2.5B | $2.6B | $2.6B | $2.7B | $3.1B |
| Payments for (Proceeds from) Other Loans and Leases | $2.3B | $2.3B | — | $2.9B | $3B | $3.7B | — | $2.8B |
| Interest and Fee Income, Loans and Leases | $1.9B | $1.9B | $1.9B | $1.9B | $2B | $2.1B | $2.2B | $2.5B |
| Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale | $3.1B | $3.5B | $2.8B | $1.5B | $1.2B | $2.6B | $1.8B | $2B |
| Interest Income (Expense), Operating | $1.3B | $1.4B | $1.4B | $1.4B | $1.5B | $1.5B | $1.6B | $1.9B |
| Repayments of Long-Term Debt | $925M | $1.2B | $1.3B | $378M | $758M | $623M | $294M | $1.9B |
| Noninterest Expense | $1.1B | $1.1B | $1.2B | $1.2B | $1.2B | $1.2B | $1.4B | $1.8B |
| Interest Income (Expense), after Provision for Loan Loss | $1.2B | $1.2B | $1.3B | $1.3B | $1.4B | $1.4B | $1.5B | $1.7B |
| Cash Acquired From Acquisition | — | — | — | $0 | — | — | — | $1.7B |
| Interest Paid, Excluding Capitalized Interest, Operating Activity | $1.1B | $1.2B | $1.1B | $1.1B | $1B | $1.1B | $1B | $1.2B |
| Proceeds from (Repayments of) Short-Term Debt | -$186M | — | -$461M | -$82M | -$56M | $12M | $911M | -$1.1B |
| Interest Expense, Deposits | $907M | $945M | $863M | $810M | $822M | $830M | $820M | $920M |
| Other noninterest expense, including corporate allocations | $454M | $446M | — | $481M | $475M | $489M | — | $782M |
| Accrued Income and Other Assets | $207M | $44M | $125M | -$52M | $262M | $217M | $398M | $780M |
| Payments for (Proceeds from) Interest Receivables and Other Receivables Activity | -$41M | $13M | $561M | -$476M | -$56M | $60M | $804M | -$676M |
| ACL, period increase (decrease) | — | $13M | — | $32M | $37M | $47M | — | $625M |
| Cash Provided by (Used in) Operating Activity, Including Discontinued Operation | $297M | $0 | $1.1B | $513M | $554M | $487M | $928M | $524M |
| Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities | $372M | $355M | $343M | $571M | $354M | $373M | $344M | $494M |
| Revenue | $360M | $362M | $410M | $351M | $377M | $424M | $410M | $472M |
| Increase (Decrease) in Loan, Held-for-Sale | $188M | $9M | — | -$70M | $296M | — | — | -$468M |
| Principal payments received under direct finance leases | $449M | $448M | $425M | $356M | $384M | $622M | $494M | $428M |
| Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest | $448M | $1.3B | — | $964M | $729M | $808M | — | $376M |
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | $442M | $1.3B | — | $960M | $723M | $804M | — | $372M |
| Allowance for credit losses for acquired credit deteriorated receivables | — | — | — | — | — | — | — | $322M |
| Dividends, Common Stock, Cash | $230M | $229M | — | $230M | $230M | $230M | — | $318M |
| Data processing and equipment | $165M | $167M | $167M | $170M | $182M | $198M | $222M | $311M |
| Long-term debt | $238M | $245M | $235M | $239M | $254M | $251M | $243M | $259M |
| Amortized Cost | $415M | $408M | — | $348M | $294M | $287M | — | $252M |
| Provision for credit losses | $114M | $24M | — | $105M | $134M | $118M | — | $250M |
| Payments of Ordinary Dividends, Common Stock | $225M | $226M | $226M | $226M | $227M | $227M | $228M | $248M |
| Allowance on purchased seasoned loans and leases at acquisition | — | — | — | — | — | — | — | $245M |
| Payments To Acquire Other Securities | $135M | $9M | $0 | $97M | $23M | $39M | $52M | $225M |
| Revenue from contracts outside the scope of ASC Topic 606 | $131M | $161M | — | $143M | $94M | $204M | — | $210M |
| Proceeds from maturities of investments | $18M | $27M | $3M | $40M | $25M | $42M | $2M | $197M |
| Depreciation, Amortization and Accretion, Net | $170M | $132M | $130M | $209M | $188M | $175M | $190M | $191M |
| Gross charge-offs | $145M | $129M | — | $133M | $111M | $137M | — | $173M |
| Financing Receivable, Excluding Accrued Interest, Allowance For Credit Loss, Writeoff, Including Writeoff From Acquisition | — | — | — | — | — | — | — | $173M |
| Payments to Acquire Finance Receivables | $25M | $299M | $333M | $195M | $122M | $310M | $354M | $164M |
| Other Interest And Dividend Income | $165M | $187M | $154M | $143M | $157M | $154M | $139M | $162M |
| Provision for credit losses | $100M | $106M | $107M | $115M | $103M | $122M | $123M | $158M |
| Other comprehensive income (loss) | -$32M | $807M | — | $433M | $187M | $175M | — | -$151M |
| Other comprehensive income/(loss) | -$32M | $807M | — | $433M | $187M | $175M | — | -$151M |
| Payments for Repurchase of Common Stock | — | — | — | $0 | — | — | — | $150M |
| Value of shares repurchased | — | — | — | — | — | — | — | $150M |
| Proceeds From Payments For In Interest Bearing Deposits In Banks | -$9M | -$20M | — | $183M | $2M | $100M | — | $149M |
| Short-term borrowings | — | $380M | — | $503M | — | — | $69M | $144M |
| Loans reclassified to held for sale | $100M | $104M | $122M | $73M | $95M | $215M | $605M | $140M |
| AOCI before reclass, net of taxes | -$87M | $761M | — | $409M | $130M | $167M | — | -$137M |
| Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI | -$13M | $318M | -$419M | $424M | $4M | — | — | $136M |
| Cash Provided by (Used in) Investing Activity, Including Discontinued Operation | -$2.2B | -$2.9B | -$4.8B | -$2.2B | -$2.5B | -$266M | -$1.4B | -$135M |
| Proceeds from Sale, Loan, Held-for-Investment | $93M | $104M | — | $49M | $112M | $215M | — | $133M |
| Payments to Acquire Property, Plant, and Equipment | $42M | $42M | $27M | $54M | $54M | $41M | $118M | $124M |
| Stock Issued During Period, Value, Conversion of Convertible Securities | — | — | — | — | — | — | — | $117M |
| Interest Income, Held-to-maturity | $93M | $93M | $104M | $108M | $107M | $105M | $103M | $99M |
| Direct Financing Lease Interest Income | $81M | $86M | — | $89M | $92M | $93M | — | $98M |
| Equipment | $62M | $65M | $70M | $67M | $68M | $66M | $67M | $93M |
| Deferred taxes | — | -$28M | — | -$25M | -$148M | -$94M | -$136M | -$83M |
| Net unrealized debt securities gains (losses), net of tax | -$70M | $445M | — | $255M | $97M | $153M | — | -$76M |
| Change in net unrealized gain (loss) on derivative instruments | $37M | $360M | — | $177M | $83M | $23M | — | -$76M |
| Prior | $30M | $10M | — | $18M | $14M | $27M | — | $67M |
| Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery | $55M | $36M | — | $47M | $45M | $62M | — | $62M |
| Financing — other | -$30M | -$7M | -$10M | -$29M | -$33M | -$11M | -$17M | -$58M |
| Other share-based compensation activity | -$18M | $3M | — | -$26M | -$9M | $0 | — | -$49M |
| Increase (decrease) in all other liabilities | — | -$832M | — | -$543M | $462M | -$183M | $494M | $47M |
| Share-based compensation expense related to employee stock plans | $33M | $28M | — | $21M | $32M | $31M | — | $45M |
| Stock-based compensation | $33M | $28M | $25M | $21M | $32M | $31M | $29M | $45M |
| Other Noncash Income (Expense) | -$5M | -$13M | — | -$4M | $21M | $58M | $0 | $44M |
| Payments of Ordinary Dividends, Preferred Stock and Preference Stock | $35M | $36M | $36M | $27M | $27M | $27M | $27M | $43M |
| Amortization of capitalized software and acquired intangible assets | $12M | $11M | $12M | $11M | $11M | $11M | $13M | $41M |
| Dividends on preferred shares | $35M | $36M | $27M | $27M | $27M | $27M | $43M | $41M |
| Marketing | $29M | $29M | $29M | $29M | — | — | — | $37M |
| FDIC assessments | $26M | $21M | $42M | $37M | $22M | $31M | — | $35M |
| Currency exchange and other | — | — | — | — | — | — | — | -$33M |
| Add: dilutive effect of potential common shares (in shares) | $23.1M | $24.3M | — | $27.4M | $23.7M | $25.5M | — | $31.3M |
| Term loan by year, year 2 | $17M | $22M | — | $18M | $16M | $19M | — | $30M |
| Income Taxes Paid, Net | $45M | $12M | $19M | $34M | $125M | $61M | $54M | $30M |
| Add - Incremental shares under stock-based compensation plans (in shares) | $15.4M | $17.1M | — | $20.3M | $16.6M | $18.5M | — | $24.1M |
| Term loan by year, year 3 | $49M | $39M | — | $21M | $26M | $39M | — | $19M |
| Revolving Loans | $11M | $12M | — | $10M | $10M | $9M | — | $17M |
| Term loan by year, year 4 | $14M | $22M | — | $44M | $18M | $11M | — | $16M |
| Other securities—taxable | $10M | $11M | $12M | $12M | $12M | $12M | $11M | $16M |
| Increase (decrease) to net interest income due to derivative adjustment | -$70M | -$57M | — | -$18M | -$7M | -$38M | — | -$15M |
| Revolving Loans Converted to Term | $10M | $10M | — | $11M | $12M | $14M | — | $14M |
| Reclassified net gains (losses) from AOCI into earnings | -$55M | -$46M | — | -$24M | -$57M | -$8M | — | $14M |
| Transfers out of Level 3 | $6M | $8M | — | $7M | $10M | $14M | — | $13M |
| Realized and unrealized gains (losses): Included in income (loss) | — | — | — | — | — | — | — | $13M |
| Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months | — | — | — | $30M | — | — | — | -$11M |
| Acquired unfunded lending commitments | — | — | — | — | — | — | — | $11M |
| Term loan by year, year 5 | $3M | $4M | — | $10M | $8M | $8M | — | $8M |
| Payment for (Proceeds from) Other Investing Activity | -$23M | -$19M | -$27M | -$15M | -$16M | -$20M | -$30M | $8M |
| Add - Incremental shares associated with contingently issuable shares (in shares) | 7.6M | 7.2M | — | 7M | 7.1M | 7M | — | 7.2M |
| Less: comprehensive income attributable to noncontrolling interest | $6M | $5M | — | $4M | $6M | $4M | — | $4M |
| Net Income Loss Attributable To Noncontrolling Interest | $6M | $5M | — | $4M | $6M | $4M | — | $4M |
| Stockholders' Equity, Other | $8M | $6M | — | -$2M | $11M | $7M | — | -$4M |
| Depreciation Nonproduction | $4M | $4M | $3M | $4M | $2M | $4M | $3M | $3M |
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements | -$5M | -$4M | — | -$3M | -$3M | -$2M | — | -$2M |
| Term loan by year, year 1 | $11M | $10M | — | $1M | $7M | $10M | — | $2M |
| Change in unrealized gains (losses) for the period included in earnings for assets held at end of the reporting date | -$1M | $2M | — | $3M | $2M | -$1M | — | $1M |
| Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent | -$1M | $0 | — | $0 | -$1M | $0 | — | -$1M |
| Number of primary groups | — | — | — | — | — | — | — | 2.00 |
| Number of reportable segments | — | — | — | 2.00 | — | — | — | 2.00 |
| Dividends declared (in dollars per share) | $0.15 | $0.15 | — | $0.15 | $0.15 | $0.15 | — | $0.15 |
| Percent of total loans | 0.3% | 0.3% | — | 0.3% | 0.2% | 0.2% | — | 0.1% |
| Included in OCI | $0 | $0 | — | $0 | $0 | $0 | — | $0 |
| Fair Value, Net Derivative Asset (Liability) Measured On Recurring Basis, Unobservable Inputs Reconciliation, Repayments | — | — | — | $0 | — | — | — | $0 |
| Transfers into Level 3 | $0 | $0 | — | $0 | $0 | $0 | — | $0 |
| Purchases/originations | $0 | $0 | — | $0 | $0 | $0 | — | $0 |
| Foreign currency translation | $0 | $2M | — | $1M | $6M | -$1M | — | $0 |
| Payments to Acquire Held-to-Maturity Securities | $0 | $995M | $1B | $515M | — | — | — | $0 |
