CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 642	$ 29	$ 1,049	$ 1,064
Income from discontinued operations, net of income taxes	(4)	0	(4)	0
Adjustments:
Provision for transaction losses	66	63	138	125
Depreciation and amortization			349	331
Stock-based compensation			271	238
(Gain) Loss on investments, net			(260)	(28)
Deferred income taxes			(17)	(122)
Change in fair value of warrant			(106)	0
Changes in assets and liabilities, and other, net of acquisition effects			(553)	(327)
Net cash provided by operating activities			867	1,281
Cash flows from investing activities:
Purchases of property and equipment			(342)	(317)
Purchases of investments			(10,365)	(7,603)
Maturities and sales of investments			12,555	5,815
Acquisitions, net of cash acquired			(302)	(20)
Other			1	1
Net cash provided by (used in) investing activities			1,547	(2,124)
Cash flows from financing activities:
Proceeds from issuance of common stock			67	62
Repurchases of common stock			(2,000)	(917)
Tax withholdings related to net share settlements of restricted stock units and awards			(153)	(130)
Proceeds from issuance of long-term debt, net			0	2,484
Repayment of debt			(750)	0
Other			(31)	15
Net cash provided by (used in) financing activities			(2,867)	1,514
Effect of exchange rate changes on cash, cash equivalents and restricted cash			(51)	151
Net increase (decrease) in cash and cash equivalents			(504)	822
Cash and cash equivalents at beginning of period			2,140	1,835	$ 1,835
Cash, cash equivalents and restricted cash at end of period	$ 1,636	$ 2,657	1,636	2,657	2,140
Supplemental cash flow disclosures:
Cash paid for interest			162	131
Cash paid for income taxes			454	$ 163
Noncash investing activities:
Relinquishment of equity method investment			$ 266		$ 0