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Commitments, Contingencies, Guarantees and Others - Litigation (Details) $ in Millions		1 Months Ended
	Jul. 30, 2025 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2025 USD ($)	Feb. 25, 2025 claim
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss			$ 300
Litigation settlement, loss		$ 5,500
Cybersecurity Incident
Loss Contingencies [Line Items]
Number of consumer class action cases filed for cybersecurity incident | claim				2
Discover Card Product Misclassification
Loss Contingencies [Line Items]
Gain (loss) from Litigation Settlement	$ (1,200)
Savings Account and Related Attorney General Litigation
Loss Contingencies [Line Items]
Loss contingency accrual			$ 425

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