Summary of Significant Accounting Policies Accounts Payable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accounts Payable	$ 178	$ 180
Accrued Salaries, Current	66	65
Accrued Exchange Fee Rebate, Current	46	31
Taxes Payable, Current	10	12
Operating Lease, Liability, Current	8	7
Loss Contingency, Accrual, Current	1	1
Other Accrued Liabilities, Current	9	9
Accounts payable and accrued liabilities	317	304
Unpaid capital expenditures	48	46	$ 16
Advertising Expense	$ 28	$ 24	$ 20