Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Information technology/cybersecurity/data is one of our primary risks, which we define as risks resulting from the failure of, or insufficiency in, information technology (for example, a system outage) or intentional or accidental unauthorized access, sharing, removal, tampering, or disposal of company and customer data or records (for example, a cybersecurity incident), or the lack of data governance, the mismanagement of data, or poor data privacy and protection. We and our service providers rely extensively on digital communications, data management, and other operating systems and infrastructure to conduct our business and operations. Disruptions to these systems or their infrastructure from cyberattacks, or failures in the management of information underlying these systems, may impede our ability to conduct business and operations and may result in business, reputational, financial, regulatory, or other harm. We and other financial institutions continue to be the target of various cyberattacks, including through phishing, the introduction of malware, denial-of-service, or other means. These cyberattacks often are intended to disrupt the operations of financial institutions or obtain confidential, proprietary, or other information or assets of Ally, our customers, employees, or other third parties with whom we transact. Refer to the Risk Factors section for additional information on our information technology/cybersecurity/data risks. Information technology/cybersecurity/data risk management is part of our broader enterprise risk-management framework described earlier in Risk Management, including the multiple layers of defense described there. We seek to minimize the occurrence and impact of unauthorized access, disruption, alteration, poor privacy or protection, mismanagement or compromise of our systems and information through real-time review and monitoring of applicable risk exposures and the implementation of processes and controls to manage those risks. In addition, we make investments in people, processes, and technology to assist us in our efforts to prevent, monitor, and respond to incidents. More specifically, information technology/cybersecurity operational metrics and data are monitored on an ongoing basis and assessed against established risk-appetite limits. An inventory of information technology/cybersecurity/data processes, risks, and controls is maintained, which is derived utilizing regulatory and industry guidance, including the Federal Financial Institutions Examination Council Information Technology Examination Handbook and the National Institute of Standards and Technology Cybersecurity Framework. This inventory is used to assist in the identification and assessment of information technology/cybersecurity/data risks. In addition, information protection and risk management teams managed by our CISO are responsible for the administration, governance, and ongoing assessment of information technology/cybersecurity/data risks that pertain to their areas of responsibility. We have adopted a CSRP, which provides a structured approach for our response to cybersecurity incidents. The CSRP describes internal roles and responsibilities and describes the operational coordination among internal cybersecurity teams, application owners, business partners and other stake holders to detect, track, respond to, and escalate cybersecurity incidents promptly, mitigate the impact of them, and resume normal operations. When cybersecurity events merit escalation beyond the CSRP, they are managed at the enterprise level via Ally’s EIMT. Further escalation to Ally’s ECMT may occur based on severity of the event, as appropriate. The Response Team Operations Plans for both EIMT and ECMT address all hazards and include responsibilities for applicable disclosure. We regularly assess threats and vulnerabilities to our environment utilizing various resources including independent third-party assessments to evaluate the effectiveness of our layered system of controls. This includes routinely engaging third-party experts to perform comprehensive institutional-wide simulations for senior management, which evaluates our preparedness to respond to crisis-level events, including cybersecurity incidents. Third parties are also engaged to conduct cybersecurity penetration testing to assist us in identifying system vulnerabilities. We actively partner with other industry peers in order to share knowledge and information to further our security environment and invest in training and employee awareness regarding cyber-related risks. Our business lines are actively engaged in overseeing our third-party service providers. Our Enterprise TPRM Policy establishes requirements and practices used to oversee and manage the activities of third parties with whom Ally has a relationship, under which we identify, measure, monitor, and manage third-party risk (including information technology/cybersecurity risks) in alignment with our strategic objectives and in compliance with applicable law. Any identified threats, vulnerabilities, or cybersecurity incidents are addressed as appropriate through the CSRP or our business-continuity and crisis-management plans, as described earlier. Cybersecurity and the continued enhancement of our controls, processes, and systems to protect our technology and data infrastructure, customer information, and other proprietary information or assets remain a critical and ongoing priority. We recognize that cyber-related risks continue to evolve, including through the emergence of artificial intelligence, and have become increasingly sophisticated. As a result we continuously evaluate the adequacy of our preventive and detective measures. As a further protective measure, we maintain insurance coverage that, subject to terms and conditions, may cover certain aspects of cybersecurity and information risks. However, such insurance may not be sufficient to cover all losses, and there is no guarantee that such insurance will continue to be available to us on acceptable terms, if at all. We have not identified risks from cybersecurity threats, including as a result of any previous cybersecurity incidents, that have materially affected or are reasonably likely to materially affect, Ally or its business strategy, results of operations, or financial condition. However, we face ongoing cybersecurity threats and there can be no assurances we will not be materially impacted in the future. Refer to the Risk Factors section for additional information.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	Information technology/cybersecurity/data risk management is part of our broader enterprise risk-management framework described earlier in Risk Management, including the multiple layers of defense described there. We seek to minimize the occurrence and impact of unauthorized access, disruption, alteration, poor privacy or protection, mismanagement or compromise of our systems and information through real-time review and monitoring of applicable risk exposures and the implementation of processes and controls to manage those risks. In addition, we make investments in people, processes, and technology to assist us in our efforts to prevent, monitor, and respond to incidents. More specifically, information technology/cybersecurity operational metrics and data are monitored on an ongoing basis and assessed against established risk-appetite limits. An inventory of information technology/cybersecurity/data processes, risks, and controls is maintained, which is derived utilizing regulatory and industry guidance, including the Federal Financial Institutions Examination Council Information Technology Examination Handbook and the National Institute of Standards and Technology Cybersecurity Framework. This inventory is used to assist in the identification and assessment of information technology/cybersecurity/data risks. In addition, information protection and risk management teams managed by our CISO are responsible for the administration, governance, and ongoing assessment of information technology/cybersecurity/data risks that pertain to their areas of responsibility.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our Board is actively involved in the oversight of Ally’s information technology/cybersecurity/data risk-management program, including through the RC and TC. The RC has primary oversight responsibility for our risk-management framework and sets the risk appetite across Ally. The TC assists the Board in overseeing information-technology, information-security (including cybersecurity), and data risks, and our management of the risks commensurate with our structure, risk profile, complexity, activities, and size. To this end, the TC periodically reviews and approves policies addressing information-technology, information-security, and data risks, and reviews reports and trends on these risks—including those involving cybersecurity, data management and protection, and crisis management—and receives reports from management on its actions to assess, monitor, and control them. The RC reviews reports and other information from the TC in approving our information-technology, information-security, and data risk appetite, and in exercising oversight of our independent risk-management program. Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Our Board is actively involved in the oversight of Ally’s information technology/cybersecurity/data risk-management program, including through the RC and TC. The RC has primary oversight responsibility for our risk-management framework and sets the risk appetite across Ally. The TC assists the Board in overseeing information-technology, information-security (including cybersecurity), and data risks, and our management of the risks commensurate with our structure, risk profile, complexity, activities, and size.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The RC has primary oversight responsibility for our risk-management framework and sets the risk appetite across Ally. The TC assists the Board in overseeing information-technology, information-security (including cybersecurity), and data risks, and our management of the risks commensurate with our structure, risk profile, complexity, activities, and size. To this end, the TC periodically reviews and approves policies addressing information-technology, information-security, and data risks, and reviews reports and trends on these risks—including those involving cybersecurity, data management and protection, and crisis management—and receives reports from management on its actions to assess, monitor, and control them. The RC reviews reports and other information from the TC in approving our information-technology, information-security, and data risk appetite, and in exercising oversight of our independent risk-management program. Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.
Cybersecurity Risk Role of Management [Text Block]	Risk-oriented management committees, the executive leadership team, and our associates identify and monitor current and emerging risks and manage those risks within our risk appetite. More specifically, our ERMC is responsible for supporting the Chief Risk Officer’s oversight of senior management’s responsibility to execute on our strategy within our risk appetite set by the RC, and the Chief Risk Officer’s implementation of our independent risk-management. Our Technology and Security Risk Management Committee and Data Risk Management Committee, which report to our ERMC, provide oversight of senior management’s responsibility to manage and measure information technology/cybersecurity/data risks against the established risk appetite and monitors compliance with legal requirements and regulatory commitments. For additional information on the role of management in monitoring the prevention, detection, mitigation, and remediation of cybersecurity incidents, refer to the Risk Management and Strategy section above.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Our CIDDO, who brings to Ally more than 20 years of technology leadership experience in complex businesses, is responsible for overseeing all of Ally’s technical and digital capabilities, including cybersecurity and infrastructure. Our CISO, who reports to the CIDDO, is principally responsible for managing and implementing our cybersecurity program.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our CIDDO, who brings to Ally more than 20 years of technology leadership experience in complex businesses, is responsible for overseeing all of Ally’s technical and digital capabilities, including cybersecurity and infrastructure. Our CISO, who reports to the CIDDO, is principally responsible for managing and implementing our cybersecurity program. Our CIDDO and CISO collectively possess substantial expertise in the areas of information technology, information security, cybersecurity, and data risk management. Our CISO, who has over 27 years of experience within the financial-services industry, is supported by employees involved in the management of information security/cybersecurity/data risks that possess experience across a variety of areas.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Cybersecurity Risk Management and Strategy Disclosure

12 Months Ended

Dec. 31, 2024

Cybersecurity Risk Management, Strategy, and Governance [Line Items]

Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]

Information technology/cybersecurity/data is one of our primary risks, which we define as risks resulting from the failure of, or insufficiency in, information technology (for example, a system outage) or intentional or accidental unauthorized access, sharing, removal, tampering, or disposal of company and customer data or records (for example, a cybersecurity incident), or the lack of data governance, the mismanagement of data, or poor data privacy and protection. We and our service providers rely extensively on digital communications, data management, and other operating systems and infrastructure to conduct our business and operations. Disruptions to these systems or their infrastructure from cyberattacks, or failures in the management of information underlying these systems, may impede our ability to conduct business and operations and may result in business, reputational, financial, regulatory, or other harm. We and other financial institutions continue to be the target of various cyberattacks, including through phishing, the introduction of malware, denial-of-service, or other means. These cyberattacks often are intended to disrupt the operations of financial institutions or obtain confidential, proprietary, or other information or assets of Ally, our customers, employees, or other third parties with whom we transact. Refer to the Risk Factors section for additional information on our information technology/cybersecurity/data risks.

Information technology/cybersecurity/data risk management is part of our broader enterprise risk-management framework described earlier in Risk Management, including the multiple layers of defense described there. We seek to minimize the occurrence and impact of unauthorized access, disruption, alteration, poor privacy or protection, mismanagement or compromise of our systems and information through real-time review and monitoring of applicable risk exposures and the implementation of processes and controls to manage those risks. In addition, we make investments in people, processes, and technology to assist us in our efforts to prevent, monitor, and respond to incidents.

More specifically, information technology/cybersecurity operational metrics and data are monitored on an ongoing basis and assessed against established risk-appetite limits. An inventory of information technology/cybersecurity/data processes, risks, and controls is maintained, which is derived utilizing regulatory and industry guidance, including the Federal Financial Institutions Examination Council Information Technology Examination Handbook and the National Institute of Standards and Technology Cybersecurity Framework. This inventory is used to assist in the identification and assessment of information technology/cybersecurity/data risks. In addition, information protection and risk management teams managed by our CISO are responsible for the administration, governance, and ongoing assessment of information technology/cybersecurity/data risks that pertain to their areas of responsibility.

We have adopted a CSRP, which provides a structured approach for our response to cybersecurity incidents. The CSRP describes internal roles and responsibilities and describes the operational coordination among internal cybersecurity teams, application owners, business partners and other stake holders to detect, track, respond to, and escalate cybersecurity incidents promptly, mitigate the impact of them, and resume normal operations. When cybersecurity events merit escalation beyond the CSRP, they are managed at the enterprise level via Ally’s EIMT. Further escalation to Ally’s ECMT may occur based on severity of the event, as appropriate. The Response Team Operations Plans for both EIMT and ECMT address all hazards and include responsibilities for applicable disclosure.

We regularly assess threats and vulnerabilities to our environment utilizing various resources including independent third-party assessments to evaluate the effectiveness of our layered system of controls. This includes routinely engaging third-party experts to perform comprehensive institutional-wide simulations for senior management, which evaluates our preparedness to respond to crisis-level events, including cybersecurity incidents. Third parties are also engaged to conduct cybersecurity penetration testing to assist us in identifying system vulnerabilities. We actively partner with other industry peers in order to share knowledge and information to further our security environment and invest in training and employee awareness regarding cyber-related risks.

Our business lines are actively engaged in overseeing our third-party service providers. Our Enterprise TPRM Policy establishes requirements and practices used to oversee and manage the activities of third parties with whom Ally has a relationship, under which we identify, measure, monitor, and manage third-party risk (including information technology/cybersecurity risks) in alignment with our strategic objectives and in compliance with applicable law. Any identified threats, vulnerabilities, or cybersecurity incidents are addressed as appropriate through the CSRP or our business-continuity and crisis-management plans, as described earlier.

Cybersecurity and the continued enhancement of our controls, processes, and systems to protect our technology and data infrastructure, customer information, and other proprietary information or assets remain a critical and ongoing priority. We recognize that cyber-related risks continue to evolve, including through the emergence of artificial intelligence, and have become increasingly sophisticated. As a result we continuously evaluate the adequacy of our preventive and detective measures. As a further protective measure, we maintain insurance coverage that, subject to terms and conditions, may cover certain aspects of cybersecurity and information risks. However, such insurance may not be sufficient to cover all losses, and there is no guarantee that such insurance will continue to be available to us on acceptable terms, if at all.

We have not identified risks from cybersecurity threats, including as a result of any previous cybersecurity incidents, that have materially affected or are reasonably likely to materially affect, Ally or its business strategy, results of operations, or financial condition. However, we face ongoing cybersecurity threats and there can be no assurances we will not be materially impacted in the future. Refer to the Risk Factors section for additional information.

Cybersecurity Risk Management Processes Integrated [Flag]

true

Cybersecurity Risk Management Processes Integrated [Text Block]

Cybersecurity Risk Management Third Party Engaged [Flag]

true

Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]

true

Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]

false

Cybersecurity Risk Board of Directors Oversight [Text Block]

Our Board is actively involved in the oversight of Ally’s information technology/cybersecurity/data risk-management program, including through the RC and TC. The RC has primary oversight responsibility for our risk-management framework and sets the risk appetite across Ally. The TC assists the Board in overseeing information-technology, information-security (including cybersecurity), and data risks, and our management of the risks commensurate with our structure, risk profile, complexity, activities, and size. To this end, the TC periodically reviews and approves policies addressing information-technology, information-security, and data risks, and reviews reports and trends on these risks—including those involving cybersecurity, data management and protection, and crisis management—and receives reports from management on its actions to assess, monitor, and control them. The RC reviews reports and other information from the TC in approving our information-technology, information-security, and data risk appetite, and in exercising oversight of our independent risk-management program. Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.

Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]

Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]

The RC has primary oversight responsibility for our risk-management framework and sets the risk appetite across Ally. The TC assists the Board in overseeing information-technology, information-security (including cybersecurity), and data risks, and our management of the risks commensurate with our structure, risk profile, complexity, activities, and size. To this end, the TC periodically reviews and approves policies addressing information-technology, information-security, and data risks, and reviews reports and trends on these risks—including those involving cybersecurity, data management and protection, and crisis management—and receives reports from management on its actions to assess, monitor, and control them. The RC reviews reports and other information from the TC in approving our information-technology, information-security, and data risk appetite, and in exercising oversight of our independent risk-management program. Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.

Cybersecurity Risk Role of Management [Text Block]

Risk-oriented management committees, the executive leadership team, and our associates identify and monitor current and emerging risks and manage those risks within our risk appetite. More specifically, our ERMC is responsible for supporting the Chief Risk Officer’s oversight of senior management’s responsibility to execute on our strategy within our risk appetite set by the RC, and the Chief Risk Officer’s implementation of our independent risk-management. Our Technology and Security Risk Management Committee and Data Risk Management Committee, which report to our ERMC, provide oversight of senior management’s responsibility to manage and measure information technology/cybersecurity/data risks against the established risk appetite and monitors compliance with legal requirements and regulatory commitments. For additional information on the role of management in monitoring the prevention, detection, mitigation, and remediation of cybersecurity incidents, refer to the Risk Management and Strategy section above.

Cybersecurity Risk Management Positions or Committees Responsible [Flag]

true

Cybersecurity Risk Management Positions or Committees Responsible [Text Block]

Cybersecurity Risk Management Expertise of Management Responsible [Text Block]

Our CIDDO, who brings to Ally more than 20 years of technology leadership experience in complex businesses, is responsible for overseeing all of Ally’s technical and digital capabilities, including cybersecurity and infrastructure. Our CISO, who reports to the CIDDO, is principally responsible for managing and implementing our cybersecurity program. Our CIDDO and CISO collectively possess substantial expertise in the areas of information technology, information security, cybersecurity, and data risk management. Our CISO, who has over 27 years of experience within the financial-services industry, is supported by employees involved in the management of information security/cybersecurity/data risks that possess experience across a variety of areas.

Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]

Senior management briefs the RC, the TC, or the Board on information-technology, information-security, and data risk matters at least quarterly and identified cybersecurity incidents are reported to the Board as deemed appropriate pursuant to our business-continuity and crisis-management plans.

Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]

true