Acquisitions - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 13, 2020	Sep. 30, 2019
Plaid, Inc.
Business Acquisition [Line Items]
Total purchase consideration	$ 5,300
Cash portion of purchase consideration	4,900
Retention equity and deferred equity consideration	$ 400
2019 Business Acquisitions
Business Acquisition [Line Items]
Total purchase consideration		$ 942
Cash portion of purchase consideration		888
Deferred cash portion of purchase consideration		54
Expected deductible portion of goodwill		$ 360