Settlement and Other Risk Management Estimated Settlement Exposure and Portion of Uncollateralized Settlement Exposure for MasterCard-Branded Transactions (Details) - Guarantee Obligations - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items] | ||
| Gross settlement exposure | $ 52,360 | $ 55,800 |
| Collateral applied to settlement exposure | (6,021) | (4,772) |
| Net uncollateralized settlement exposure | $ 46,339 | $ 51,028 |