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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
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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

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