Collateral (Detail) - USD ($) $ in Millions		Jun. 30, 2017	Sep. 30, 2016
Settlement Guarantee Management [Abstract]
Cash equivalents(1)	[1]	$ 1,443	$ 1,295
Pledged securities at market value		168	170
Letters of credit		1,488	1,311
Guarantees		1,187	1,418
Total		$ 4,286	$ 4,194

[1] Cash collateral held by Visa Europe is not included on the Company's consolidated balance sheets as its clients retain beneficial ownership and the cash is only accessible to the Company in the event of default by the client on its settlement obligations.