CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 2,059	$ 412	[1]	$ 4,559	$ 4,060	[1]
Investment securities, available-for-sale:
Net unrealized gain (loss)	22	(18)		38	42
Income tax effect	(9)	8		(17)	(15)
Reclassification adjustment for net loss (gain) realized in net income	0	0		1	(3)
Income tax effect	0	0		0	1
Defined benefit pension and other postretirement plans:
Net unrealized actuarial (loss) gain and prior service credit	0	0		(5)	61
Income tax effect	0	0		2	(23)
Amortization of actuarial loss (gain) and prior service credit realized in net income	12	0		33	(5)
Income tax effect	(3)	0		(12)	2
Derivative instruments classified as cash flow hedges:
Net unrealized (loss) gain	(20)	(22)		5	(60)
Income tax effect	5	3		9	9
Reclassification adjustment for net loss (gain) realized in net income	11	(22)		31	(107)
Income tax effect	(5)	8		(10)	33
Foreign currency translation adjustments	1,085	(404)		501	(404)
Other comprehensive income (loss), net of tax	1,098	(447)		576	(469)
Comprehensive income (loss)	$ 3,157	$ (35)		$ 5,135	$ 3,591

[1] The Company did not include Visa Europe's financial results in the Company's unaudited consolidated statements of operations from the acquisition date, June 21, 2016, through June 30, 2016 as the impact was immaterial. The dilutive impact of the outstanding shares of series B and C convertible participating preferred stock from June 21, 2016 through June 30, 2016 was also not included in the calculation of basic or diluted earnings per share as the effect was immaterial. See Note 2—Visa Europe and Note 10—Earnings Per Share to these unaudited consolidated financial statements.