Funds Receivable and Customer Accounts and Investments - Available-for-sale Debt Securities in Continuous Loss Position (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value
Less than 12 months	$ 2,802	$ 4,581
12 months or longer	3	74
Total	2,805	4,655
Gross Unrealized Losses
Less than 12 months	(18)	0
12 months or longer	0	0
Total	(18)	0
Funds receivable and customer accounts | U.S. government and agency securities
Fair Value
Less than 12 months	500	2,452
12 months or longer	0	0
Total	500	2,452
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Funds receivable and customer accounts | Foreign government and agency securities
Fair Value
Less than 12 months	422	563
12 months or longer	0	30
Total	422	593
Gross Unrealized Losses
Less than 12 months	(1)	0
12 months or longer	0	0
Total	(1)	0
Funds receivable and customer accounts | Corporate debt securities
Fair Value
Less than 12 months	769	825
12 months or longer	0	0
Total	769	825
Gross Unrealized Losses
Less than 12 months	(4)	0
12 months or longer	0	0
Total	(4)	0
Short term investments | Foreign government and agency securities
Fair Value
Less than 12 months	55	115
12 months or longer	0	0
Total	55	115
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Short term investments | Corporate debt securities
Fair Value
Less than 12 months	759	424
12 months or longer	0	0
Total	759	424
Gross Unrealized Losses
Less than 12 months	(5)	0
12 months or longer	0	0
Total	(5)	0
Long-term investments | U.S. government and agency securities
Fair Value
Less than 12 months		100
12 months or longer		0
Total		100
Gross Unrealized Losses
Less than 12 months		0
12 months or longer		0
Total		0
Long-term investments | Foreign government and agency securities
Fair Value
Less than 12 months		75
12 months or longer		0
Total		75
Gross Unrealized Losses
Less than 12 months		0
12 months or longer		0
Total		0
Long-term investments | Corporate debt securities
Fair Value
Less than 12 months	297	27
12 months or longer	3	44
Total	300	71
Gross Unrealized Losses
Less than 12 months	(8)	0
12 months or longer	0	0
Total	$ (8)	$ 0