Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Servicing Liability, Fair Value, Change in Fair Value, Valuation Input, Statement of Income or Comprehensive Income [Extensible Enumeration]	Servicing income
Period of suspended accrued interest past due	120 days
Allowance for accounts receivable	$ 18.8	$ 14.9
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other Assets	Other Assets
Advertising costs	$ 30.8	$ 19.2	$ 22.6
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accrued expenses and other liabilities
Senior Notes and Residual Trust Certificates
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Liability, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Restricted stock units
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Service period	4 years
Minimum
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Sales period for loans held for sale	1 day
Service period	1 year
Minimum \| Property, Plant and Equipment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Estimated useful life	3 years
Minimum \| Internally developed software
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Estimated useful life	3 years
Maximum
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Sales period for loans held for sale	3 days
Service period	4 years
Maximum \| Property, Plant and Equipment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Estimated useful life	7 years
Maximum \| Internally developed software
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Estimated useful life	5 years

Affirm Holdings, Inc. 10-K