Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
Securities available-for-sale and financial instruments	$ 180	$ 284
Loan valuations and loss reserves	179	152
Employee benefits	121	119
Lease liability	91	82
Depreciation and amortization	19	54
Federal carryforwards	36	29
State carryforwards	4	3
Other	42	45
Gross deferred tax assets	672	768
Deferred tax liabilities:
Leasing	398	363
ROU lease asset	80	73
Other intangible assets	67	71
Other	35	34
Gross deferred tax liabilities	580	541
Net deferred tax assets	$ 92	$ 227

Deferred Tax Assets, Lease Liability

No definition available.

Name:	fhn_DeferredTaxAssetsLeaseLiability
Namespace Prefix:	fhn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from the provision for loan losses, which can only be deducted for tax purposes when actual loan losses are known, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken. Also includes losses associated with the repurchase obligations and other loss reserves.

+ References

No definition available.