Accrued Expenses And Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued payroll and related employee costs	$ 239	$ 114
Advances from clients	65	19
Accrued volume incentives	46	35
Accrued commissions	48	32
Restructuring accruals	16	15
Deferred income	46	51
Accrued interest	18	19
Current portion of finance lease liabilities	13	13
Due to former parent	19	18
Other	90	89
Total accrued expenses and other current liabilities	$ 600	$ 405