Change in Benefit Obligation (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits | U.S. Plans
Change in Benefit Obligation
Benefit obligation—beginning of fiscal year		$ 1,072	$ 1,005
Visa Europe acquisition		0	0
Service cost		0	13	$ 47
Interest cost		36	40	40
Actuarial loss (gain)		58	86
Benefit payments		137	64
Plan amendment		0	(8)
Foreign currency exchange rate changes		0	0
Benefit obligation—end of fiscal year		913	1,072	1,005
Accumulated benefit obligation		913	1,072
Change in Plan Assets:
Fair value of plan assets—beginning of fiscal year		1,077	1,022
Visa Europe acquisition		0	0
Actual return on plan assets		125	118
Company contribution		9	1
Benefit payments		137	64
Foreign currency exchange rate changes		0	0
Fair value of plan assets—end of fiscal year		1,074	1,077	1,022
Funded status at end of fiscal year		161	5
Recognized in Consolidated Balance Sheets:
Non-current asset		(168)	(22)
Current liability		(1)	(9)
Non-current liability		(6)	(8)
Funded status at end of fiscal year		161	5
Pension Benefits | Non-U.S. Plans
Change in Benefit Obligation
Benefit obligation—beginning of fiscal year		474	0
Visa Europe acquisition		0	381
Service cost	[1]	6	1
Interest cost	[1]	11	3
Actuarial loss (gain)		52	(86)
Benefit payments		14	1
Plan amendment		0	0
Foreign currency exchange rate changes		8	4
Benefit obligation—end of fiscal year		433	474	0
Accumulated benefit obligation		433	474
Change in Plan Assets:
Fair value of plan assets—beginning of fiscal year		415	0
Visa Europe acquisition		0	287
Actual return on plan assets		17	25
Company contribution		5	102
Benefit payments		14	1
Foreign currency exchange rate changes		10	2
Fair value of plan assets—end of fiscal year		433	415	0
Funded status at end of fiscal year		0	(59)
Recognized in Consolidated Balance Sheets:
Non-current asset		0	0
Current liability		(5)	(6)
Non-current liability		5	(53)
Funded status at end of fiscal year		0	(59)
Other Postretirement Benefits | U.S. Plans
Change in Benefit Obligation
Benefit obligation—beginning of fiscal year		14	18
Visa Europe acquisition		0	0
Service cost		0	0	0
Interest cost		1	1	1
Actuarial loss (gain)		1	2
Benefit payments		3	3
Plan amendment		0	0
Foreign currency exchange rate changes		0	0
Benefit obligation—end of fiscal year		11	14	18
Change in Plan Assets:
Fair value of plan assets—beginning of fiscal year		0	0
Visa Europe acquisition		0	0
Actual return on plan assets		0	0
Company contribution		3	3
Benefit payments		3	3
Foreign currency exchange rate changes		0	0
Fair value of plan assets—end of fiscal year		0	0	$ 0
Funded status at end of fiscal year		(11)	(14)
Recognized in Consolidated Balance Sheets:
Non-current asset		0	0
Current liability		(2)	(3)
Non-current liability		(9)	(11)
Funded status at end of fiscal year		$ (11)	$ (14)

[1] For fiscal 2016, it represents Visa Europe's UK pension plans' net pension benefit cost recognized from the Closing through September 30, 2016.