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Debt - Narrative (Details) - USD ($) shares in Millions, $ in Millions			1 Months Ended		6 Months Ended	12 Months Ended
	Dec. 18, 2024	Oct. 08, 2024	Aug. 31, 2025	Sep. 30, 2024	Aug. 29, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Repurchase price percentage of principal amount	100.00%
2024 Notes \| Convertible Debt
Debt Instrument [Line Items]
Debt instrument, convertible, payments for debt conversion					$ 610
Debt instrument, convertible, payments for debt conversion, outstanding principal							$ 608
Debt instrument, convertible, payments for debt conversion, accrued interest							$ 2
2024 Notes \| Convertible Debt \| Class C capital stock
Debt Instrument [Line Items]
Settlement of convertible senior notes (in shares)							1.9
Capped call transactions, portion unwound, shares received (in shares)				2.1
2025 Notes
Debt Instrument [Line Items]
Debt instrument, repurchased face amount							$ 88	$ 58
Repayments of convertible debt							89	$ 57
2025 Notes \| Convertible Debt
Debt Instrument [Line Items]
Debt instrument, convertible, payments for debt conversion						$ 425
Debt instrument, convertible, payments for debt conversion, outstanding principal						419
Debt instrument, convertible, payments for debt conversion, accrued interest						6
2026 Notes \| Convertible Debt
Debt Instrument [Line Items]
Debt instrument, convertible, payments for debt conversion							$ 498
Debt instrument, notice for redemption of convertible debt, amount	$ 499
Debt conversion, converted instrument, amount		$ 498
Debt instrument, redemption, aggregate principal, amount not surrendered for conversion	$ 1
Capped Call Transactions, Portion Unwound, Cash Received			$ 38
2026 Notes \| Convertible Debt \| Class C capital stock
Debt Instrument [Line Items]
Settlement of convertible senior notes (in shares)							4.5
Capped call transactions, portion unwound, shares received (in shares)			3.1
JPMorgan Chase Bank, N.A, UBS AG, Bank of Montreal, Bank of Nova Scotia \| Mortgages Segment
Debt Instrument [Line Items]
Short-Term Debt						$ 381	$ 151