Financial Instruments - Narrative (Details) SFr in Millions, $ in Millions		1 Months Ended	9 Months Ended
	Oct. 31, 2025 USD ($) facility	Jan. 31, 2025 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Jan. 31, 2025 CHF (SFr)	Dec. 31, 2024 USD ($)	Dec. 31, 2024 CHF (SFr)
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized losses expected to be reclassified over the next 12 months			$ 19
Subsequent Event | Secured Debt | October 2025 Debt Financing | Line of Credit
Derivative Instruments, Gain (Loss) [Line Items]
Number of debt facilities entered into | facility	3
Proceeds from issuance of debt	$ 2,106
Weighted Average
Derivative Instruments, Gain (Loss) [Line Items]
Effective interest rate			6.18%
Weighted Average | Subsequent Event
Derivative Instruments, Gain (Loss) [Line Items]
Effective interest rate	5.77%
Cross-currency fixed interest rate swap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount			$ 899			$ 1,016
Cross-currency fixed interest rate swap | Designated as Hedging Instrument | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount | SFr					SFr 1,000		SFr 1,000
Payments for derivative instrument		$ 10
Proceeds from derivative instrument		$ 5
Investment income interest			34	$ 23
Interest rate swaps | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount			2,800			2,800
Derivatives not yet effective			$ 850			$ 850
Interest rate swaps | Designated as Hedging Instrument | Subsequent Event
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives settled	$ 500