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Variable interest entities and asset securitizations - Summary of Carrying Amount (Details) - Variable Interest Entity Primary Beneficiary - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
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Affordable Housing Projects |  |
Variable Interest Entity [Line Items] |  |
Investment in partnership carrying amount | $ 1,384 | $ 1,340
Unfunded commitments includes carrying amount of its investments | 467 | 410
Contingent commitments to provide additional capital contributions to partnerships | 69 | 55
Renewable Energy |  |
Variable Interest Entity [Line Items] |  |
Investment in partnership carrying amount | 135 | 80
Unfunded commitments includes carrying amount of its investments | 46 | 31
Other Projects |  |
Variable Interest Entity [Line Items] |  |
Investment in partnership carrying amount | 37 | 41
Unfunded commitments includes carrying amount of its investments | $ 0 | $ 0

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