Other Assets - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Goodwill [Line Items] | |||||
| Proportional amortization investments | $ 2,054 | $ 2,054 | $ 2,094 | ||
| Unfunded commitments for proportional amortization investments | 735 | $ 735 | 819 | ||
| Unfunded commitments, period to be paid | 5 years | ||||
| Goodwill impairment | $ 0 | $ 0 | $ 0 | $ 305 | 305 |
| Goodwill, transfers | 56 | ||||
| Corporate and Other | |||||
| Goodwill [Line Items] | |||||
| Goodwill impairment | $ 0 | $ 305 | 305 | ||
| Goodwill, transfers | 56 | ||||
| Corporate and Other | Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations | Ally Credit Card | |||||
| Goodwill [Line Items] | |||||
| Goodwill impairment | $ 305 | ||||
| X | ||||||||||
- Definition Investment Program, Proportional Amortization Method, Elected, Commitment, Period To Be Paid No definition available.
|
| X | ||||||||||
- Definition Amount of investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under program not meeting condition for accounting under proportional amortization method. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
|
| X | ||||||||||
- Definition Amount of impairment loss from asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- 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/exampleRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) from transfer into (out of) asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of commitment and contingent commitment, including amount of delayed equity contribution, for investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, commitment and contingent commitment related to investment under tax credit program not meeting condition for accounting under proportional amortization method. Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|