Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lending Solutions Business
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other (expense) income	$ 13	$ 7	$ 5
Level 3
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value of line of credit	18	26
Level 3 | Cumulative Effect, Period of Adoption, Adjustment
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent liability	8
Fair Value | Level 2
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Value of total debt	22,500	22,600
Carrying value
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Value of total debt	$ 19,900	$ 21,500