Variable interest entities and asset securitizations - Summary of Carrying Amount (Details) - Variable Interest Entity Primary Beneficiary - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Affordable Housing Projects | ||
| Variable Interest Entity [Line Items] | ||
| Investment in partnership carrying amount | $ 1,816 | $ 1,867 |
| Unfunded commitments includes carrying amount of its investments | 806 | 889 |
| Contingent commitments to provide additional capital contributions to partnerships | 108 | 109 |
| Renewable Energy | ||
| Variable Interest Entity [Line Items] | ||
| Investment in partnership carrying amount | 96 | 67 |
| Unfunded commitments includes carrying amount of its investments | 35 | 66 |
| Other Projects | ||
| Variable Interest Entity [Line Items] | ||
| Investment in partnership carrying amount | 45 | 33 |
| Unfunded commitments includes carrying amount of its investments | $ 0 | $ 0 |