Business Combinations - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
3 Months Ended | 27 Months Ended | ||
|---|---|---|---|---|
Apr. 07, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
Dec. 31, 2025 |
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| Business Combination [Line Items] | ||||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 | $ 0.01 | |
| Brex Inc. | Subsequent Event | ||||
| Business Combination [Line Items] | ||||
| Business combination, consideration transferred | $ 4,500 | |||
| Total cash consideration for acquisition | $ 2,600 | |||
| Number of shares of Capital One treasury stock issued in the acquisition (in shares) | 10.6 | |||
| Common stock, par value (in dollars per share) | $ 0.01 | |||
| Business combination, consideration transferred, equity interest, share issued, value | $ 1,900 | |||
| Discover | ||||
| Business Combination [Line Items] | ||||
| Business combination, acquisition related costs | $ 415 | $ 1,800 |
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- Definition Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Number of shares of equity interest issued or issuable by acquirer as part of consideration transferred in business combination. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of expense for acquisition-related cost incurred to effect business combination. Includes, but is not limited to, finder's fee; advisory, legal, accounting, valuation, and other professional and consulting fees; and general administrative cost, including cost of maintaining internal acquisition department. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Face amount or stated value per share of common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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