Funds Receivable and Customer Accounts - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Fair Value, Option, Quantitative Disclosures [Line Items]
Total funds receivable and customer accounts	$ 13,034		$ 13,034		$ 12,261
Funds Receivable and Customer Accounts
Fair Value, Option, Quantitative Disclosures [Line Items]
Aggregate fair value of investments in an unrealized loss position	1,300		1,300
Fair Value Option, Foreign Currency Denominated Investments
Fair Value, Option, Quantitative Disclosures [Line Items]
Total funds receivable and customer accounts	1,100		1,100		$ 1,200
Fair Value Option, Foreign Currency Denominated Investments | Funds Receivable and Customer Accounts
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gain (loss) from fair value changes	$ (18)	$ 40	$ (7)	$ (21)