Summary of Significant Accounting Policies Accounts Payable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accounts Payable	$ 139	$ 141
Accrued Salaries, Current	80	57
Accrued Exchange Fee Rebate, Current	48	37
Taxes Payable, Current	4	3
Operating Lease, Liability, Current	8	6
Other Accrued Liabilities, Current	9	10
Accounts payable and accrued liabilities	287	254
Unpaid capital expenditures	32	15	$ 48
Advertising Expense	$ 37	$ 25	$ 28
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accounts payable and accrued liabilities	Accounts payable and accrued liabilities