CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Millions, $ in Millions		Total		Series B Preferred Stock	Series C Preferred Stock	Class A common stock		Class B common stock		Class C common stock		Preferred Stock	Preferred Stock Series B Preferred Stock		Preferred Stock Series C Preferred Stock		Common Stock Class A common stock	Common Stock Class B common stock	Common Stock Class C common stock	Treasury Stock	Right to Recover for Covered Losses	Additional Paid-In Capital	Accumulated Income	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Sep. 30, 2015													0	[1]	0	[1]	1,950	245	20
Beginning Balance at Sep. 30, 2015		$ 29,842										$ 0								$ 0	$ 0	$ 18,073	$ 11,843	$ (74)
Net income		5,991	[2]			$ 4,738	[2]	$ 1,006	[2]	$ 185	[2]												5,991
Other comprehensive loss, net of tax		(384)																						(384)
Comprehensive income		5,607
Issuance of preferred stock (Note 11) (in shares)	[1]												2		3
Issuance of preferred stock (Note 11)		5,717										5,717
VE territory covered losses incurred (Note 2)		(34)																			(34)
Class C common stock held by Visa Europe, a wholly-owned subsidiary of Visa Inc. (Note 11) (in shares)																			1
Class C common stock held by Visa Europe, a wholly-owned subsidiary of Visa Inc. (Note 11)		170																		170
Conversion of class C common stock upon sale into public market (in shares)																	8		(2)
Issuance and vesting of restricted stock and performance-based shares (in shares)																	2
Share-based compensation, net of forfeitures (Note 13) (in shares)	[3]																0
Share-based compensation, net of forfeitures (Note 13)		221																				221
Restricted stock and performance-based shares settled in cash for taxes (in shares)																	(1)
Restricted stock and performance-based shares settled in cash for taxes		(92)																				(92)
Excess tax benefit for share-based compensation		63																				63
Cash proceeds from issuance of common stock under employee equity plans (in shares)																	3
Cash proceeds from issuance of common stock under employee equity plans		95																				95
Cash dividends declared and paid		(1,350)																					(1,350)
Repurchase of class A common stock (Note 13) (in shares)						(91)	[4],[5]										(91)
Repurchase of class A common stock (Note 13)		(6,987)				$ (6,987)	[5]															(965)	(6,022)
Ending Balance (in shares) at Sep. 30, 2016													2	[6]	3	[6]	1,871	245	17
Ending Balance at Sep. 30, 2016		32,912										5,717								(170)	(34)	17,395	10,462	(458)
Net income		6,699				$ 5,170	[2]	1,134	[2]	163	[2]												6,699
Other comprehensive loss, net of tax		1,336																						1,336
Comprehensive income		8,035
VE territory covered losses incurred (Note 2)		(209)																			(209)
Recovery through conversion rate adjustment (Note 2 and Note 11)		0		$ 190	$ 1							(191)									191
Charitable contribution of Visa Inc. shares (Note 11 and Note 16) (in shares)																	2
Charitable contribution of Visa Inc. shares (Note 11 and Note 16)		170																		170
Treasury stock appreciation, net of tax		14																				14
Conversion of class C common stock upon sale into public market (in shares)																	17		(4)
Issuance and vesting of restricted stock and performance-based shares (in shares)																	2
Share-based compensation, net of forfeitures (Note 13) (in shares)	[7]																0
Share-based compensation, net of forfeitures (Note 13)		235																				235
Restricted stock and performance-based shares settled in cash for taxes (in shares)																	(1)
Restricted stock and performance-based shares settled in cash for taxes		(76)																				(76)
Cash proceeds from issuance of common stock under employee equity plans (in shares)																	4
Cash proceeds from issuance of common stock under employee equity plans		149																				149
Cash dividends declared and paid		(1,579)																					(1,579)
Repurchase of class A common stock (Note 13) (in shares)						(77)	[4],[5]										(77)
Repurchase of class A common stock (Note 13)		(6,891)				$ (6,891)	[5]															(817)	(6,074)
Ending Balance (in shares) at Sep. 30, 2017													2	[6]	3	[6]	1,818	245	13
Ending Balance at Sep. 30, 2017		32,760										5,526	$ 2,326		$ 3,200					$ 0	(52)	16,900	9,508	878
Net income		10,301				$ 7,937	[2]	$ 1,787	[2]	$ 218	[2]												10,301
Other comprehensive loss, net of tax		(331)																						(331)
Comprehensive income		9,970
VE territory covered losses incurred (Note 2)		(11)																			(11)
Recovery through conversion rate adjustment (Note 2 and Note 11)		$ 0		$ 35	$ 21							(56)	$ (35)		$ (21)						56
Conversion of class C common stock upon sale into public market (in shares)		2,291	[8]			1,768	[8],[9]	400	[8]	47	[8]						4		(1)
Issuance and vesting of restricted stock and performance-based shares (in shares)																	2
Share-based compensation, net of forfeitures (Note 13) (in shares)	[7]																0
Share-based compensation, net of forfeitures (Note 13)		$ 327																				327
Restricted stock and performance-based shares settled in cash for taxes (in shares)																	(1)
Restricted stock and performance-based shares settled in cash for taxes		(94)																				(94)
Cash proceeds from issuance of common stock under employee equity plans (in shares)																	3
Cash proceeds from issuance of common stock under employee equity plans		164																				164
Cash dividends declared and paid		(1,918)																					(1,918)
Repurchase of class A common stock (Note 13) (in shares)						(58)	[4],[5]										(58)
Repurchase of class A common stock (Note 13)		(7,192)				$ (7,192)	[5]															(619)	(6,573)
Ending Balance (in shares) at Sep. 30, 2018													2	[6]	3	[6]	1,768	245	12
Ending Balance at Sep. 30, 2018		$ 34,006										$ 5,470	$ 2,291		$ 3,179						$ (7)	$ 16,678	$ 11,318	$ 547

[1] Series B and C preferred stock are alternatively referred to as UK&I and Europe preferred stock, respectively.

[2] Net income is allocated based on proportional ownership on an as-converted basis. The weighted-average number of shares of as-converted class B common stock used in the income allocation was 403 million for fiscal 2018, and 405 million for fiscal 2017 and 2016. The weighted-average number of shares of as-converted class C common stock used in the income allocation was 49 million, 58 million and 75 million for fiscal 2018, 2017 and 2016, respectively. The weighted-average number of shares of preferred stock included within participating securities was 32 million and 33 million of as-converted UK&I preferred stock for fiscal 2018 and 2017, respectively, and 44 million of as-converted Europe preferred stock for fiscal 2018 and 2017.

[3] Decrease in Class A common stock related to forfeitures of restricted stock awards is less than one million shares.

[4] All shares repurchased in the open market have been retired and constitute authorized but unissued shares.

[5] Shares repurchased in the open market reflect repurchases settled during fiscal 2018, 2017 and 2016. These amounts include repurchases traded but not yet settled on or before September 30, 2017, September 30, 2016 and September 30, 2015 for fiscal 2018, 2017 and 2016, respectively. Also, these exclude repurchases traded but not yet settled on or before September 30, 2018, September 30, 2017 and September 30, 2016 for fiscal 2018, 2017 and 2016, respectively.

[6] Series B and C preferred stock are alternatively referred to as UK&I and Europe preferred stock, respectively.

[7] Decrease in Class A common stock related to forfeitures of restricted stock awards is less than one million shares.

[8] Figures in the table may not recalculate exactly due to rounding. As-converted class A common stock is calculated based on unrounded numbers.

[9] Class A common stock shares outstanding reflect repurchases settled on or before September 30, 2018.