Segment Information - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) segment	Jun. 30, 2025 USD ($)
Segment Reporting [Line Items]
Number of reportable segment \| segment			2
Total revenue	$ 4,246	$ 4,155	$ 9,280	$ 8,884
Eliminations
Segment Reporting [Line Items]
Total revenue	(4)	(2)	(11)	(9)
Eliminations \| Risk Capital
Segment Reporting [Line Items]
Total revenue	1	1	5	5
Eliminations \| Human Capital
Segment Reporting [Line Items]
Total revenue	$ 3	$ 2	$ 6	$ 4

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details

- 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.

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+ Details