Funds Receivable and Customer Accounts and Investments - Schedule of Gross Unrealized Losses and Estimated Fair Value of Available-for-Sale Debt Securities in a Continuous Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value
Less than 12 months	$ 4,581	$ 3,156
12 months or longer	74	969
Total	4,655	4,125
Gross Unrealized Losses
Less than 12 months	0	2
12 months or longer	0	13
Total	0	15
Funds receivable and customer accounts | U.S. government and agency securities
Fair Value
Less than 12 months	2,452	2,419
12 months or longer	0	18
Total	2,452	2,437
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	563	295
12 months or longer	30	49
Total	593	344
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	1
Total	0	1
Funds receivable and customer accounts | Corporate debt securities
Fair Value
Less than 12 months	825	281
12 months or longer	0	7
Total	825	288
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Short-term investments | Foreign government and agency securities
Fair Value
Less than 12 months	115
12 months or longer	0
Total	115
Gross Unrealized Losses
Less than 12 months	0
12 months or longer	0
Total	0
Short-term investments | Corporate debt securities
Fair Value
Less than 12 months	424	57
12 months or longer	0	333
Total	424	390
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	3
Total	0	3
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	10
12 months or longer	0	28
Total	75	38
Gross Unrealized Losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Long-term investments | Corporate debt securities
Fair Value
Less than 12 months	27	94
12 months or longer	44	534
Total	71	628
Gross Unrealized Losses
Less than 12 months	0	2
12 months or longer	0	9
Total	$ 0	$ 11