Legal Matters - Additional Information (Details) $ in Millions					1 Months Ended	2 Months Ended	12 Months Ended				52 Months Ended	136 Months Ended	137 Months Ended
	May 29, 2020 state	Dec. 13, 2019 USD ($)	Sep. 17, 2018 USD ($)	Jun. 30, 2016 case	Oct. 31, 2011 financial_institution claim non-bankATMOperator	Jun. 16, 2021 complaint state	Sep. 30, 2025 USD ($) plaintiff	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2024 USD ($) complaint	Nov. 13, 2024 merchant	Sep. 30, 2024 USD ($) case_filed	Jun. 01, 2022 class_action_case
Loss Contingencies [Line Items]
Deposits into the U.S. litigation escrow account							$ 875	$ 1,500	$ 1,000
Loss contingency accrual							$ 3,033	1,727	1,751		$ 1,727		$ 1,727
Number of complaints filed | complaint						2					3
Number of states | state	24					25
Number of plaintiffs appealed | plaintiff							3
Number of class action lawsuits | class_action_case														2
Visa, MasterCard, and Certain U.S. Financial Institutions
Loss Contingencies [Line Items]
Loss contingency accrual			$ 5,300
Possible return to defendants		$ 700
U.S. Covered Litigation
Loss Contingencies [Line Items]
Provision for unsettled legal matters							$ 2,210	140
Period of accrual			5 years
Company's share of an additional settlement payment							1,049	224
Loss contingency accrual							2,698	$ 1,537	$ 1,621		$ 1,537		$ 1,537
Possible return to defendants		$ 467
U.S. Covered Litigation
Loss Contingencies [Line Items]
Provision for unsettled legal matters							$ 2,200
Settled Litigation | U.S. Covered Litigation
Loss Contingencies [Line Items]
Company's share of an additional settlement payment			$ 600
Class Plaintiffs
Loss Contingencies [Line Items]
Payments for legal settlements										$ 4,000
Settlement, further distribution of default interchange										$ 500
Loss contingency, further distributions, default period										8 months
Loss contingency, number of cases appointed counsel | case				2
Interchange Multidistrict Litigation
Loss Contingencies [Line Items]
Settlement percentage							82.00%
Interchange Multidistrict Litigation | U.S. Covered Litigation | Visa, MasterCard, and Certain U.S. Financial Institutions
Loss Contingencies [Line Items]
Provision for unsettled legal matters			$ 900
Interchange Multidistrict Litigation | U.S. Covered Litigation
Loss Contingencies [Line Items]
Provision for unsettled legal matters										$ 1,100
Interchange Opt Out Litigation
Loss Contingencies [Line Items]
Number of cases | case_filed													50
Europe Merchant Litigation
Loss Contingencies [Line Items]
Number of plaintiffs | merchant												1,150
Number of claims settled | merchant												950
Number of claims pending | merchant												100
National ATM Council Class Action
Loss Contingencies [Line Items]
Number of non-bank ATM operators | non-bankATMOperator					13
Consumer Class Actions
Loss Contingencies [Line Items]
Number of claims pending | claim					2
Mackim v. Visa Inc.
Loss Contingencies [Line Items]
Number of financial institutions | financial_institution					3