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Variable interest entities and asset securitizations - Summary of Carrying Amount (Details) - Variable Interest Entity Primary Beneficiary - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Affordable Housing Projects
Variable Interest Entity [Line Items]
Investment in partnership carrying amount	$ 1,598	$ 1,384
Unfunded commitments includes carrying amount of its investments	658	467
Contingent commitments to provide additional capital contributions to partnerships	88	69
Renewable Energy
Variable Interest Entity [Line Items]
Investment in partnership carrying amount	115	135
Unfunded commitments includes carrying amount of its investments	65	46
Other Projects
Variable Interest Entity [Line Items]
Investment in partnership carrying amount	34	37
Unfunded commitments includes carrying amount of its investments	$ 0	$ 0

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- Definition

Contingent Commitments to Provide Additional Capital Contributions to Partnerships

+ References

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- Definition

The carrying amount of investments in variable interest entity.

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- Definition

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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