CONDENSED CONSOLIDATED STATEMENT OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net revenues	$ 3,136	$ 2,650	$ 6,111	$ 5,194
Operating expenses:
Transaction expense	1,064	810	2,051	1,562
Transaction and loan losses	308	255	608	510
Customer support and operations	335	318	652	614
Sales and marketing	284	250	522	483
Product development	232	209	446	404
General and administrative	282	261	547	492
Depreciation and amortization	201	176	384	351
Restructuring	0	0	40	0
Total operating expenses	2,706	2,279	5,250	4,416
Operating income	430	371	861	778
Other income (expense), net	17	9	24	24
Income before income taxes	447	380	885	802
Income tax expense	36	57	90	114
Net income	$ 411	$ 323	$ 795	$ 688
Net income per share:
Basic (in usd per share)	$ 0.34	$ 0.27	$ 0.66	$ 0.57
Diluted (in usd per share)	$ 0.34	$ 0.27	$ 0.65	$ 0.56
Weighted average shares:
Basic (in shares)	1,202	1,210	1,203	1,213
Diluted (in shares)	1,215	1,215	1,216	1,220