Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 921	$ 374
Other comprehensive income, net of tax
Net unrealized gains on available-for-sale marketable securities [net of tax provision of ($3) and ($5), respectively]	9	23
Reclassification adjustment for net gains on available-for-sale marketable securities included in investment and other income, net [net of tax provision of $0 and $3, respectively]	0	(11)
Other comprehensive income	9	12
Comprehensive income	$ 930	$ 386