Fair Value Measurement of Assets and Liabilities - Summary of Investments Under the Fair Value Option (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 10,687		$ 12,013
Fair Value Option, Investments | Funds receivable and customer accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,283		1,690
Net gains (losses) from fair value changes	(20)	$ (29)
Fair Value Option, Investments | Short term investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	365		$ 246
Net gains (losses) from fair value changes	$ (18)	$ 0