CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 492	$ 462	$ 887	$ 1,056
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(14)	(44)	(9)	(15)
Net unrealized gains (losses) on securities	248	(130)	570	(392)
Net unrealized gains (losses) on derivatives	0	0	(1)	0
Total other comprehensive income (loss), net of tax	234	(174)	560	(407)
Total comprehensive income	$ 726	$ 288	$ 1,447	$ 649