Property and Equipment - Schedule of PPE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 212	$ 167
Less: Accumulated depreciation	(96)	(55)
Total property and equipment, net	116	112
Furniture, fixtures, and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 55	50
Furniture, fixtures, and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Furniture, fixtures, and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Capitalized software costs
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 87	54
Capitalized software costs | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Capitalized software costs | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Software in development and other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 29	31
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 33	24
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Long-term finance leases - computer equipment
Property, Plant and Equipment [Line Items]
Long-term finance leases	$ 8	$ 8
Estimated Useful Life	5 years