Visa (V) 10-Q 1 Feb 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2017	Jan. 26, 2018
Entity Registrant Name	VISA INC.
Entity Central Index Key	1,403,161
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A common stock
Entity Common Stock, Shares Outstanding		1,802,624,578
Class B common stock
Entity Common Stock, Shares Outstanding		245,513,385
Class C common stock
Entity Common Stock, Shares Outstanding		12,400,261

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions		Dec. 31, 2017	Sep. 30, 2017
Assets
Cash and cash equivalents		$ 8,138	$ 9,874
Restricted cash—U.S. litigation escrow (Note 2)		883	1,031
Investment securities (Note 3):
Trading		106	82
Available-for-sale		3,307	3,482
Settlement receivable		1,618	1,422
Accounts receivable		1,281	1,132
Customer collateral (Note 5)		1,155	1,106
Current portion of client incentives		295	344
Prepaid expenses and other current assets		504	550
Total current assets		17,287	19,023
Investment securities, available-for-sale (Note 3)		2,674	1,926
Client incentives		557	591
Property, equipment and technology, net		2,238	2,253
Other assets		1,127	1,226
Intangible assets, net		28,109	27,848
Goodwill		15,162	15,110
Total assets		67,154	67,977
Liabilities
Accounts payable		108	179
Settlement payable		2,302	2,003
Customer collateral (Note 5)		1,155	1,106
Accrued compensation and benefits		389	757
Client incentives		2,355	2,089
Accrued liabilities		1,224	1,129
Current maturities of long-term debt (Note 4)		0	1,749
Accrued litigation (Note 11)		830	982
Total current liabilities		8,363	9,994
Long-term debt (Note 4)		16,621	16,618
Deferred tax liabilities		5,107	5,980
Deferred purchase consideration		1,330	1,304
Other liabilities		2,332	1,321
Total liabilities		33,753	35,217
Equity
Preferred stock	[1]	5,476	5,526
Right to recover for covered losses (Note 2)	[1]	(5)	(52)
Additional paid-in capital		16,761	16,900
Accumulated income		9,966	9,508
Accumulated other comprehensive income (loss), net:
Investment securities, available-for-sale		61	73
Defined benefit pension and other postretirement plans		(76)	(76)
Derivative instruments classified as cash flow hedges		(33)	(36)
Foreign currency translation adjustments		1,251	917
Total accumulated other comprehensive income, net		1,203	878
Total equity		33,401	32,760
Total liabilities and equity		67,154	67,977
Series A Preferred Stock
Equity
Preferred stock		0	0
U.K.& I preferred stock
Equity
Preferred stock	[1]	2,295	2,326
Europe preferred stock
Equity
Preferred stock	[1]	3,181	3,200
Class A common stock
Equity
Common stock		0	0
Class B common stock
Equity
Common stock		0	0
Class C common stock
Equity
Common stock		$ 0	$ 0
[1]	Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers.

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Millions	Dec. 31, 2017		Sep. 30, 2017
Preferred Stock
Preferred stock, par value	$ 0.0001		$ 0.0001
Preferred stock, shares authorized	25		25
Preferred stock, shares issued	5		5
Preferred stock, shares outstanding	5		5
Series A Preferred Stock
Preferred stock, shares issued	0		0
U.K.& I preferred stock
Preferred stock, shares issued	2		2
Preferred stock, shares outstanding	2		2
Europe preferred stock
Preferred stock, shares issued	3		3
Preferred stock, shares outstanding	3		3
Class A common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	2,001,622		2,001,622
Common stock, shares issued	1,805		1,818
Common stock, shares outstanding	1,805	[1]	1,818
Class B common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	622		622
Common stock, shares issued	245		245
Common stock, shares outstanding	245		245
Class C common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	1,097		1,097
Common stock, shares issued	12		13
Common stock, shares outstanding	12		13
[1]	Class A common stock shares outstanding exclude repurchases traded but not yet settled on or before December 31, 2017.

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Operating Revenues
Service revenues		$ 2,146	$ 1,918
Data processing revenues		2,147	1,892
International transaction revenues		1,666	1,489
Other revenues		229	203
Client incentives		(1,326)	(1,041)
Net operating revenues		4,862	4,461
Operating Expenses
Personnel		679	571
Marketing		223	218
Network and processing		160	145
Professional fees		92	80
Depreciation and amortization		145	146
General and administrative		236	186
Litigation provision (Note 11)		0	15
Total operating expenses		1,535	1,361
Operating income		3,327	3,100
Non-operating Income (Expense)
Interest expense		(154)	(140)
Other		66	19
Total non-operating expense		(88)	(121)
Income before income taxes		3,239	2,979
Income tax provision (Note 10)		717	909
Net income		$ 2,522	$ 2,070
Class A common stock
Earnings Per Share
Basic earnings per share (in dollars per share)	[1]	$ 1.07	$ 0.86
Basic weighted-average shares outstanding (in shares)		1,811	1,860
Diluted earnings per share (in dollars per share)	[1]	$ 1.07	$ 0.86
Diluted weighted-average shares outstanding (in shares)	[2]	2,353	2,421
Class B common stock
Earnings Per Share
Basic earnings per share (in dollars per share)	[1]	$ 1.77	$ 1.41
Basic weighted-average shares outstanding (in shares)		245	245
Diluted earnings per share (in dollars per share)	[1]	$ 1.77	$ 1.41
Diluted weighted-average shares outstanding (in shares)		245	245
Class C common stock
Earnings Per Share
Basic earnings per share (in dollars per share)	[1]	$ 4.30	$ 3.43
Basic weighted-average shares outstanding (in shares)		13	17
Diluted earnings per share (in dollars per share)	[1]	$ 4.29	$ 3.42
Diluted weighted-average shares outstanding (in shares)		13	17
[1]	Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers.
[2]	Weighted-average diluted shares outstanding are calculated on an as-converted basis, and include incremental common stock equivalents, as calculated under the treasury stock method. The computation includes approximately 5 million common stock equivalents for the three months ended December 31, 2017 and 2016, because their effect would be dilutive. The computation excludes 2 million and 3 million of common stock equivalents for the three months ended December 31, 2017 and 2016, respectively, because their effect would have been anti-dilutive.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 2,522	$ 2,070
Investment securities, available-for-sale:
Net unrealized gain (loss)	9	(3)
Income tax effect	(3)	(1)
Reclassification adjustment for net gain realized in net income	(28)	0
Income tax effect	10	0
Defined benefit pension and other postretirement plans:
Amortization of actuarial loss and prior service credit realized in net income	0	6
Income tax effect	0	(2)
Derivative instruments classified as cash flow hedges:
Net unrealized (loss) gain	(1)	74
Income tax effect	(5)	(7)
Reclassification adjustment for net loss realized in net income	11	12
Income tax effect	(2)	(2)
Foreign currency translation adjustments	334	(988)
Other comprehensive income (loss), net of tax	325	(911)
Comprehensive income	$ 2,847	$ 1,159

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 2,522	$ 2,070
Adjustments to reconcile net income to net cash provided by operating activities:
Client incentives	1,326	1,041
Share-based compensation (Note 9)	68	45
Depreciation and amortization of property, equipment, technology and intangible assets	145	146
Deferred income taxes	(919)	77
Right to recover for covered losses recorded in equity (Note 2)	(3)	(94)
Other	(23)	13
Change in operating assets and liabilities:
Settlement receivable	(180)	56
Accounts receivable	(146)	(89)
Client incentives	(986)	(1,129)
Other assets	92	66
Accounts payable	(51)	(102)
Settlement payable	275	79
Accrued and other liabilities	794	316
Accrued litigation (Note 11)	(152)	13
Net cash provided by operating activities	2,762	2,508
Investing Activities
Purchases of property, equipment, technology and intangible assets	(141)	(171)
Investment securities, available-for-sale:
Purchases	(1,636)	(1,032)
Proceeds from maturities and sales	1,076	788
Purchases of / contributions to other investments	(6)	(2)
Net cash used in investing activities	(707)	(417)
Financing Activities
Repayments of long-term debt (Note 4)	(1,750)	0
Dividends paid (Note 7)	(458)	(399)
Proceeds from issuance of commercial paper	0	566
Payments from litigation escrow account—U.S. retrospective responsibility plan (Note 2 and Note 11)	150	0
Cash proceeds from issuance of common stock under employee equity plans	53	56
Restricted stock and performance-based shares settled in cash for taxes	(88)	(60)
Net cash used in financing activities	(3,871)	(1,730)
Effect of exchange rate changes on cash and cash equivalents	80	(156)
(Decrease) increase in cash and cash equivalents	(1,736)	205
Cash and cash equivalents at beginning of period	9,874	5,619
Cash and cash equivalents at end of period	8,138	5,824
Supplemental Disclosure
Income taxes paid, net of refunds	183	96
Interest payments on debt (Note 4)	241	244
Accruals related to purchases of property, equipment, technology and intangible assets	26	69
Class A common stock
Financing Activities
Repurchase of class A common stock (Note 7)	$ (1,778)	$ (1,893)

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 1—Summary of Significant Accounting Policies Organization. Visa Inc. ("Visa" or the "Company") is a global payments technology company that enables fast, secure and reliable electronic payments across more than 200 countries and territories. Visa and its wholly-owned consolidated subsidiaries, including Visa U.S.A. Inc. ("Visa U.S.A."), Visa International Service Association ("Visa International"), Visa Worldwide Pte. Limited, Visa Europe Limited ("Visa Europe"), Visa Canada Corporation, Visa Technology & Operations LLC and CyberSource Corporation, operate one of the world’s largest retail electronic payments networks — VisaNet — which facilitates authorization, clearing and settlement of payment transactions and enables the Company to provide its financial institution and merchant clients a wide range of products, platforms and value-added services. VisaNet also offers fraud protection for account holders and assured payment for merchants. Visa is not a bank and does not issue cards, extend credit or set rates and fees for account holders on Visa products. In most cases, account holder and merchant relationships belong to, and are managed by, Visa's financial institution clients. Consolidation and basis of presentation. The accompanying unaudited consolidated financial statements include the accounts of Visa and its consolidated entities and are presented in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"). The Company consolidates its majority-owned and controlled entities, including variable interest entities ("VIEs") for which the Company is the primary beneficiary. The Company’s investments in VIEs have not been material to its consolidated financial statements as of and for the periods presented. All significant intercompany accounts and transactions are eliminated in consolidation. The accompanying unaudited consolidated financial statements are presented in accordance with the U.S. Securities and Exchange Commission (SEC) requirements for Quarterly Reports on Form 10-Q and, consequently, do not include all of the annual disclosures required by U.S. GAAP. Reference should be made to the Visa Annual Report on Form 10-K for the year ended September 30, 2017 for additional disclosures, including a summary of the Company’s significant accounting policies. In the opinion of management, the accompanying unaudited consolidated financial statements include all normal recurring adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash flows for the interim periods presented. Recently Issued and Adopted Accounting Pronouncements. In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of goods or services to customers. The ASU will replace existing revenue recognition guidance in U.S. GAAP when it becomes effective. Subsequently, the FASB also issued a series of amendments to the new revenue standard. The Company will adopt the standard effective October 1, 2018, and expects to adopt the standard using the modified retrospective transition method. The Company expects that the new standard will primarily impact recognition timing for certain fixed incentives and price discounts provided to clients, and the classification of certain client incentives between contra revenues and operating expenses. The Company is still in the process of quantifying the full effect that ASU 2014-09 and all of its related subsequent updates will have on its consolidated financial statements and related disclosures. The impact of the new standard to future financial results is unknowable as it is not possible to estimate the impact to the recognition of new customer contracts which may be executed in future periods. The Company has completed an assessment of its existing customer contracts through December 31, 2017. Application of the new standard to consolidated financial statements for the first quarter of fiscal 2018 would not have resulted in a material impact. The Company will continue to assess the impact of the new standard as new customer contracts are executed going forward. In March 2016, the FASB issued ASU 2016-05, which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815, Derivatives and Hedging , does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-06, which clarifies the requirements for assessing whether contingent call/put options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. An entity performing the assessment is required to assess the embedded call/put options solely in accordance with a four-step decision sequence. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, which eliminates the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The equity method investor is required to add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements.

U.S. and Europe Retrospective R

U.S. and Europe Retrospective Responsibility Plans	3 Months Ended
	Dec. 31, 2017
Retrospective Responsibility Plan [Abstract]
U.S. and Europe Retrospective Responsibility Plans	Note 2—U.S. and Europe Retrospective Responsibility Plans U.S. Retrospective Responsibility Plan Under the terms of the U.S. retrospective responsibility plan, the Company maintains an escrow account from which settlements of, or judgments in, certain litigation referred to as the "U.S. covered litigation" are paid. The escrow funds are held in money market investments along with interest income earned, less applicable taxes, and are classified as restricted cash on the consolidated balance sheets. The balance of the escrow account was $0.9 billion at December 31, 2017 and $1.0 billion at September 30, 2017 . The Company paid $150 million from the litigation escrow account during the three months ended December 31, 2017 . See Note 11—Legal Matters . The accrual related to the U.S. covered litigation could be either higher or lower than the litigation escrow account balance. The Company did not record an additional accrual for the U.S. covered litigation during the three months ended December 31, 2017 . See Note 11—Legal Matters . Europe Retrospective Responsibility Plan The Company, Visa Europe or their affiliates are parties to certain existing and potential litigation relating to the setting of multilateral interchange fee rates in the Visa Europe territory (the "VE territory covered litigation"). Under the terms of the Europe retrospective responsibility plan, the Company is entitled to recover certain losses resulting from VE territory covered litigation (the "VE territory covered losses") through a periodic adjustment to the class A common stock conversion rates applicable to the UK&I and Europe preferred stock. VE territory covered losses are recorded in "right to recover for covered losses" within equity before the corresponding adjustment to the applicable conversion rate is effected. Adjustments to the conversion rate may be executed once in any six-month period unless a single, individual loss greater than € 20 million is incurred, in which case, the six-month limitation does not apply. When the adjustment to the conversion rate is made, the amount previously recorded in "right to recover for covered losses" as contra-equity is then recorded against the book value of the preferred stock within stockholders' equity. During the three months ended December 31, 2017 , the Company recovered $50 million of VE territory covered losses through adjustments to the class A common stock conversion rates applicable to the UK&I and Europe preferred stock, from 13.077 and 13.948 , respectively, at September 30, 2017 to 12.966 and 13.893 , respectively, at December 31, 2017 . The following table sets forth the activities related to VE territory covered losses in preferred stock and "right to recover for covered losses" within equity during the three months ended December 31, 2017 . VE territory covered losses incurred reflect settlements with merchants and additional legal costs. See Note 11—Legal Matters . Preferred Stock Right to Recover for Covered Losses UK&I Europe (in millions) Balance as of September 30, 2017 $ 2,326 $ 3,200 $ (52 ) VE territory covered losses incurred — — (3 ) Recovery through conversion rate adjustment (31 ) (19 ) 50 Balance as of December 31, 2017 $ 2,295 $ 3,181 $ (5 ) The following table sets forth the as-converted value of the preferred stock available to recover VE territory covered losses compared to the book value of preferred shares recorded in stockholders' equity within the Company's unaudited consolidated balance sheet as of December 31, 2017 and September 30, 2017 . (1) December 31, 2017 September 30, 2017 As-Converted Value of Preferred Stock (2) Book Value of Preferred Stock As-Converted Value of Preferred Stock (3) Book Value of Preferred Stock (in millions) UK&I preferred stock $ 3,667 $ 2,295 $ 3,414 $ 2,326 Europe preferred stock 5,001 3,181 4,634 3,200 Total 8,668 5,476 8,048 5,526 Less: right to recover for covered losses (5 ) (5 ) (52 ) (52 ) Total recovery for covered losses available $ 8,663 $ 5,471 $ 7,996 $ 5,474 (1) Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers. (2) The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of December 31, 2017 ; (b) 12.966 and 13.893 , the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of December 31, 2017 , respectively; and (c) $114.02 , Visa's class A common stock closing stock price as of December 31, 2017 . (3) The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of September 30, 2017 ; (b) 13.077 and 13.948 , the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of September 30, 2017 , respectively; and (c) $105.24 , Visa's class A common stock closing stock price as of September 30, 2017 .

Fair Value Measurements and Inv

Fair Value Measurements and Investments	3 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements and Investments	Note 3—Fair Value Measurements and Investments Fair Value Measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair Value Measurements Using Inputs Considered as Level 1 Level 2 December 31, September 30, December 31, September 30, (in millions) Assets Cash equivalents and restricted cash: Money market funds $ 5,918 $ 5,935 U.S. government-sponsored debt securities $ 567 $ 2,870 Investment securities, trading: Equity securities 106 82 Investment securities, available-for-sale: U.S. government-sponsored debt securities 3,530 3,663 U.S. Treasury securities 2,337 1,621 Equity securities 114 124 Prepaid and other current assets: Foreign exchange derivative instruments 26 18 Total $ 8,475 $ 7,762 $ 4,123 $ 6,551 Liabilities Accrued liabilities: Foreign exchange derivative instruments $ 65 $ 98 Total $ — $ — $ 65 $ 98 There were no transfers between Level 1 and Level 2 assets during the three months ended December 31, 2017 . Level 1 assets measured at fair value on a recurring basis. Money market funds, publicly-traded equity securities and U.S. Treasury securities are classified as Level 1 within the fair value hierarchy, as fair value is based on quoted prices in active markets. Level 2 assets and liabilities measured at fair value on a recurring basis. The fair value of U.S. government-sponsored debt securities, as provided by third-party pricing vendors, is based on quoted prices in active markets for similar, not identical, assets. The pricing data obtained from outside sources is reviewed internally for reasonableness, compared against benchmark quotes from independent pricing sources, then confirmed or revised accordingly. Foreign exchange derivative instruments are valued using inputs that are observable in the market or can be derived principally from or corroborated by observable market data. There were no substantive changes to the valuation techniques and related inputs used to measure fair value during the three months ended December 31, 2017 . Assets Measured at Fair Value on a Non-recurring Basis Non-marketable equity investments and investments accounted for under the equity method . These investments are classified as Level 3 due to the absence of quoted market prices, the inherent lack of liquidity, and the fact that inputs used to measure fair value are unobservable and require management's judgment. When certain events or circumstances indicate that impairment may exist, the Company revalues the investments using various assumptions, including the financial metrics and ratios of comparable public companies. There were no significant impairments during the three months ended December 31, 2017 or 2016 . These investments totaled $99 million and $94 million at December 31, 2017 and September 30, 2017 , respectively, and are classified in other assets on the consolidated balance sheets. Non-financial assets and liabilities. Long-lived assets such as goodwill, indefinite-lived intangible assets, finite-lived intangible assets, and property, equipment and technology are considered non-financial assets. The Company does not have any non-financial liabilities measured at fair value on a non-recurring basis. Finite-lived intangible assets primarily consist of customer relationships, trade names and reseller relationships, all of which were obtained through acquisitions. If the Company were required to perform a quantitative assessment for impairment testing of goodwill and indefinite-lived intangible assets, the fair values would generally be estimated using an income approach. As the assumptions employed to measure these assets on a non-recurring basis are based on management's judgment using internal and external data, these fair value determinations are classified as Level 3 in the fair value hierarchy. The Company completed its annual impairment review of its indefinite-lived intangible assets and goodwill as of February 1, 2017, and concluded that there was no impairment. No recent events or changes in circumstances indicate that impairment existed at December 31, 2017 . Other Fair Value Disclosures Long-term debt. Debt instruments are measured at amortized cost on the Company's unaudited consolidated balance sheet at December 31, 2017 . The fair value of the debt instruments, as provided by third-party pricing vendors, is based on quoted prices in active markets for similar, not identical, assets. The pricing data obtained from outside sources is reviewed internally for reasonableness, compared against benchmark quotes from independent pricing sources, then confirmed or revised accordingly. If measured at fair value in the financial statements, these instruments would be classified as Level 2 in the fair value hierarchy. The following table presents the carrying amount and estimated fair value of the Company’s debt in order of maturity: December 31, 2017 September 30, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value (in millions) 1.20% Senior Notes due December 2017 $ — $ — $ 1,749 $ 1,751 2.20% Senior Notes due December 2020 2,991 2,998 2,990 3,031 2.15% Senior Notes due September 2022 993 986 993 997 2.80% Senior Notes due December 2022 2,240 2,283 2,240 2,301 3.15% Senior Notes due December 2025 3,969 4,089 3,967 4,098 2.75% Senior Notes due September 2027 740 740 740 737 4.15% Senior Notes due December 2035 1,486 1,665 1,485 1,637 4.30% Senior Notes due December 2045 3,462 3,983 3,463 3,873 3.65% Senior Notes due September 2047 740 770 740 746 Total $ 16,621 $ 17,514 $ 18,367 $ 19,171 Other financial instruments not measured at fair value. The following financial instruments are not measured at fair value on the Company's unaudited consolidated balance sheet at December 31, 2017 , but disclosure of their fair values is required: time deposits recorded in prepaid expenses and other current assets, settlement receivable and payable, commercial paper and customer collateral. The estimated fair value of such instruments at December 31, 2017 approximates their carrying value due to their generally short maturities. If measured at fair value in the financial statements, these financial instruments would be classified as Level 2 in the fair value hierarchy. Investments Available-for-sale investment securities. The Company had $110 million in gross unrealized gains and $12 million in gross unrealized losses at December 31, 2017 . There were $120 million gross unrealized gains and $4 million gross unrealized losses at September 30, 2017 . A majority of the Company's available-for-sale investment securities with stated maturities are due within one to two years.

Debt

Debt	3 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	Note 4—Debt The Company had outstanding debt as follows: December 31, 2017 September 30, 2017 Principal Amount Unamortized Discounts and Debt Issuance Costs Carrying Amount Principal Amount Unamortized Discounts and Debt Issuance Costs Carrying Amount Effective Interest Rate (in millions, except percentages) 1.20% Senior Notes due December 2017 (the "2017 Notes") $ — $ — $ — $ 1,750 $ (1 ) $ 1,749 1.37 % Total current maturities of long-term debt — — — 1,750 (1 ) 1,749 2.20% Senior Notes due December 2020 3,000 (9 ) 2,991 3,000 (10 ) 2,990 2.30 % 2.15% Senior Notes due September 2022 1,000 (7 ) 993 1,000 (7 ) 993 2.30 % 2.80% Senior Notes due December 2022 2,250 (10 ) 2,240 2,250 (10 ) 2,240 2.89 % 3.15% Senior Notes due December 2025 4,000 (31 ) 3,969 4,000 (33 ) 3,967 3.26 % 2.75% Senior Notes due September 2027 750 (10 ) 740 750 (10 ) 740 2.91 % 4.15% Senior Notes due December 2035 1,500 (14 ) 1,486 1,500 (15 ) 1,485 4.23 % 4.30% Senior Notes due December 2045 3,500 (38 ) 3,462 3,500 (37 ) 3,463 4.37 % 3.65% Senior Notes due September 2047 750 (10 ) 740 750 (10 ) 740 3.73 % Total long-term debt 16,750 (129 ) 16,621 16,750 (132 ) 16,618 Total debt $ 16,750 $ (129 ) $ 16,621 $ 18,500 $ (133 ) $ 18,367 Senior Notes On October 11, 2017, the Company redeemed all of the $1.75 billion principal amount outstanding of the 2017 Notes. The redemption was funded with net proceeds from new fixed-rate senior notes issued by the Company in September 2017. As a result of this redemption, we recorded a $1 million loss on extinguishment of debt during the three months ended December 31, 2017 . The Company recognized interest expense for the senior notes of $138 million and $125 million for the three months ended December 31, 2017 and 2016 , respectively, as non-operating expense .

Settlement Guarantee Management

Settlement Guarantee Management	3 Months Ended
	Dec. 31, 2017
Settlement Guarantee Management [Abstract]
Settlement Guarantee Management	Note 5—Settlement Guarantee Management The Company indemnifies its clients for settlement losses suffered due to failure of any other clients to fund its settlement obligations in accordance with the Visa rules. This indemnification creates settlement risk for the Company due to the difference in timing between the date of a payment transaction and the date of subsequent settlement. The Company’s settlement exposure is limited to the amount of unsettled Visa payment transactions at any point in time. The Company requires certain clients that do not meet its credit standards to post collateral to offset potential loss from their estimated unsettled transactions. The Company’s estimated maximum settlement exposure was $71.3 billion during the three months ended December 31, 2017 , compared to $67.7 billion during the three months ended September 30, 2017 . Of these amounts, $4.5 billion and $2.8 billion were covered by collateral at December 31, 2017 and September 30, 2017 , respectively. The total available collateral balances presented in the table below were greater than the settlement exposure covered by customer collateral held due to instances in which the available collateral exceeded the total settlement exposure for certain financial institutions at each date presented. The Company maintained collateral as follows: December 31, September 30, (in millions) Cash equivalents (1) $ 1,569 $ 1,490 Pledged securities at market value 169 167 Letters of credit 1,319 1,316 Guarantees 617 941 Total $ 3,674 $ 3,914 (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. The fair value of the settlement risk guarantee is estimated based on a proprietary probability-weighted model and was approximately $ 3 million at December 31, 2017 and September 30, 2017 . These amounts are reflected in accrued liabilities on the Company's consolidated balance sheets.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	3 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	Note 6—Pension and Other Postretirement Benefits The Company sponsors various qualified and non-qualified defined benefit pension and other postretirement benefit plans that provide for retirement and medical benefits for all eligible employees residing in the United States. The Company also sponsors other pension benefit plans that provide benefits for internationally-based employees at certain non-U.S. locations. The components of net periodic benefit cost presented below include the U.S. pension and other postretirement benefit plans and the non-U.S. pension plans, comprising only the Visa Europe plans. Disclosures relating to other non-U.S. pension benefit plans are not included as they are immaterial, individually and in aggregate. U.S. Plans Non-U.S. Plans Pension Benefits Other Postretirement Benefits Pension Benefits Three Months Ended Three Months Ended Three Months Ended 2017 2016 2017 2016 2017 2016 (in millions) Service cost $ — $ — $ — $ — $ 1 $ 2 Interest cost 8 9 — — 3 3 Expected return on plan assets (17 ) (18 ) — — (5 ) (4 ) Amortization of: Prior service credit — — — (1 ) — — Actuarial loss — 4 — — — — Settlement loss — 2 — — — — Total net periodic benefit cost $ (9 ) $ (3 ) $ — $ (1 ) $ (1 ) $ 1

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Note 7—Stockholders' Equity As-Converted Class A Common Stock. The number of shares of each series and class and the number of shares of class A common stock on an as-converted basis at December 31, 2017 , are as follows: (in millions, except conversion rates) Shares Outstanding Conversion Rate Into Class A Common Stock As-converted Class A Common Stock (1) UK&I preferred stock 2 12.9660 32 Europe preferred stock 3 13.8930 44 Class A common stock (2) 1,805 — 1,805 Class B common stock 245 1.6483 (3) 405 Class C common stock 12 4.0000 49 Total 2,335 (1) Figures in the table may not recalculate exactly due to rounding. As-converted class A common stock is calculated based on unrounded numbers. (2) Class A common stock shares outstanding exclude repurchases traded but not yet settled on or before December 31, 2017 . (3) The class B to class A common stock conversion rate is presented on a rounded basis. Conversion calculations for dividend payments are based on a conversion rate rounded to the tenth decimal. Reduction in as-converted shares. During the three months ended December 31, 2017 , total as-converted class A common stock was reduced by 17 million shares at an average price of $110.27 per share. Of the 17 million shares, 16 million were repurchased in the open market using $1.8 billion of operating cash on hand. Additionally, the Company recovered $50 million of VE territory covered losses in accordance with the Europe retrospective responsibility plan. The recovery has the same economic effect on earnings per share as repurchasing the Company's class A common stock, because it reduces the UK&I and Europe preferred stock conversion rates and consequently the as-converted class A common stock share count. See Note 2—U.S. and Europe Retrospective Responsibility Plans . The following table presents share repurchases in the open market. (1) (in millions, except per share data) Three Months Ended Shares repurchased in the open market (2) 16 Average repurchase price per share (3) $ 110.24 Total cost $ 1,778 (1) Shares repurchased in the open market reflect repurchases settled during the three months ended December 31, 2017 . These amounts include repurchases traded but not yet settled on or before September 30, 2017 and exclude repurchases traded but not yet settled on or before December 31, 2017 . (2) All shares repurchased in the open market have been retired and constitute authorized but unissued shares. (3) Figures in the table may not recalculate exactly due to rounding. Average repurchase price per share is calculated based on unrounded numbers. As of December 31, 2017 , the Company's April 2017 share repurchase program had remaining authorized funds of $2.1 billion for share repurchase. All share repurchase programs authorized prior to April 2017 have been completed. In January 2018 , the Company's board of directors authorized an additional $7.5 billion share repurchase program. Under the terms of the Europe retrospective responsibility plan, the Company is entitled to recover VE territory covered losses through periodic adjustments to the class A common stock conversion rates applicable to the UK&I and Europe preferred stock. See Note 2—U.S. and Europe Retrospective Responsibility Plans . The following table presents as-converted UK&I and Europe preferred stock, after the Company recovered VE territory covered losses through conversion rate adjustments, for the three months ended December 31, 2017 . Three Months Ended (in millions, except per share data) UK&I Preferred Stock Europe Preferred Stock Reduction in equivalent number of shares of class A common stock (1) — — Effective price per share (2) $ 111.32 $ 111.32 Recovery through conversion rate adjustment $ 31 $ 19 (1) The reduction in equivalent number of shares of class A common stock was less than one million shares for both series of preferred stock. (2) Effective price per share is calculated using the volume-weighted average price of the Company's class A common stock over a pricing period in accordance with the Company's current certificates of designations for its series B and C convertible participating preferred stock. Dividends. In January 2018 , the Company’s board of directors declared a quarterly cash dividend of $0.21 per share of class A common stock (determined in the case of class B and C common stock and UK&I and Europe preferred stock on an as-converted basis). The cash dividend will be paid on March 6, 2018 , to all holders of record of the Company's common and preferred stock as of February 16, 2018 . The Company declared and paid $458 million in dividends to holders of the Company's common stock during the three months ended December 31, 2017 .

Earnings Per Share

Earnings Per Share	3 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Note 8—Earnings Per Share Basic earnings per share is computed by dividing net income available to each class by the weighted-average number of shares of common stock outstanding and participating securities during the period. Net income is allocated to each class of common stock and participating securities based on its proportional ownership on an as-converted basis. The weighted-average number of shares of each class of common stock outstanding reflects changes in ownership over the periods presented. See Note 7—Stockholders' Equity . Diluted earnings per share is computed by dividing net income available by the weighted-average number of shares of common stock outstanding, participating securities and, if dilutive, potential class A common stock equivalent shares outstanding during the period. Dilutive class A common stock equivalents may consist of: (1) shares of class A common stock issuable upon the conversion of UK&I and Europe preferred stock and class B and C common stock based on the conversion rates in effect through the period, and (2) incremental shares of class A common stock calculated by applying the treasury stock method to the assumed exercise of employee stock options, the assumed purchase of stock under the Employee Stock Purchase Plan and the assumed vesting of unearned performance shares. The following table presents earnings per share for the three months ended December 31, 2017 . (1) Basic Earnings Per Share Diluted Earnings Per Share (in millions, except per share data) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Class A common stock $ 1,945 1,811 $ 1.07 $ 2,522 2,353 (3) $ 1.07 Class B common stock 435 245 $ 1.77 $ 434 245 $ 1.77 Class C common stock 54 13 $ 4.30 $ 54 13 $ 4.29 Participating securities (4) 88 Not presented Not presented $ 87 Not presented Not presented Net income $ 2,522 The following table presents earnings per share for the three months ended December 31, 2016 . (1) Basic Earnings Per Share Diluted Earnings Per Share (in millions, except per share data) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Class A common stock $ 1,594 1,860 $ 0.86 $ 2,070 2,421 (3) $ 0.86 Class B common stock 347 245 $ 1.41 $ 346 245 $ 1.41 Class C common stock 57 17 $ 3.43 $ 57 17 $ 3.42 Participating securities (4) 72 Not presented Not presented $ 72 Not presented Not presented Net income $ 2,070 (1) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (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 405 million for the three months ended December 31, 2017 and 2016 . The weighted-average number of shares of as-converted class C common stock used in the income allocation was 51 million and 67 million for the three months ended December 31, 2017 and 2016 , respectively. The weighted-average number of shares of preferred stock, included within participating securities, was 32 million and 35 million of as-converted UK&I preferred stock for the three months ended December 31, 2017 and 2016 , respectively, and 44 million of as-converted Europe preferred stock for the three months ended December 31, 2017 and 2016 . (3) Weighted-average diluted shares outstanding are calculated on an as-converted basis, and include incremental common stock equivalents, as calculated under the treasury stock method. The computation includes approximately 5 million common stock equivalents for the three months ended December 31, 2017 and 2016 , because their effect would be dilutive. The computation excludes 2 million and 3 million of common stock equivalents for the three months ended December 31, 2017 and 2016 , respectively, because their effect would have been anti-dilutive. (4) Participating securities include preferred stock outstanding and unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents, such as the Company's UK&I and Europe preferred stock, restricted stock awards, restricted stock units and earned performance-based shares. Participating securities' income is allocated based on the weighted-average number of shares of as-converted stock.

Share-based Compensation

Share-based Compensation	3 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Share-based Compensation	Note 9—Share-based Compensation The Company granted the following equity awards to employees and non-employee directors under the 2007 Equity Incentive Compensation Plan during the three months ended December 31, 2017 : Granted Weighted-Average Grant Date Fair Value Weighted-Average Exercise Price Non-qualified stock options 1,622,760 $ 17.88 $ 109.82 Restricted stock units ("RSUs") 2,626,011 $ 109.82 Performance-based shares (1) 641,498 $ 120.11 (1) Represents the maximum number of performance-based shares which could be earned. The Company’s non-qualified stock options and RSUs are equity awards with service-only conditions and are accordingly expensed on a straight-line basis over the vesting period. The Company's performance-based shares are equity awards with service, market and performance conditions that are accounted for using the graded-vesting method. The Company recorded share-based compensation cost of $68 million for the three months ended December 31, 2017 , net of estimated forfeitures, which are adjusted as appropriate.

Income Taxes

Income Taxes	3 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 10—Income Taxes The effective income tax rates were 22% and 31% for the three months ended December 31, 2017 and 2016, respectively. The effective tax rate for the three months ended December 31, 2017 differs from the effective tax rate in the same prior-year period primarily due to U.S. tax reform legislation, commonly referred to as the Tax Cuts and Jobs Act (the "Tax Act”), enacted on December 22, 2017. The Tax Act transitions the U.S. tax system to a new territorial system and lowers the statutory federal corporate income tax rate from 35% to 21% . The reduction of the statutory federal corporate tax rate to 21% became effective on January 1, 2018. In fiscal 2018, the Company’s statutory federal corporate rate is a blended rate of 24.5% , which will be reduced to 21% in fiscal 2019 and thereafter. As a result of the reduction in the federal corporate tax rate, the Company remeasured its net deferred tax liabilities as of the enactment date of the Tax Act. The deferred tax remeasurement resulted in a one-time, non-cash tax benefit estimated to be approximately $1.1 billion , recorded in the three months ended December 31, 2017. In transitioning to the new territorial tax system, the Tax Act requires the Company to include certain untaxed foreign earnings of non-U.S. subsidiaries in its fiscal 2018 taxable income. Such foreign earnings are subject to a one-time tax at 15.5% on the amount held in cash or cash equivalents, and at 8% on the remaining non-cash amount. The 15.5% and 8% tax, collectively referred to as the “transition tax”, was estimated to be $1.1 billion , and was recorded in the three months ended December 31, 2017. The Company intends to elect to pay the transition tax over a period of eight years as permitted by the Tax Act. The above-mentioned accounting impacts of the deferred tax remeasurement and transition tax are provisional, based on currently available information and technical guidance on the interpretations of the new law. The Company continues to obtain and analyze additional information and guidance as they become available to complete the accounting for the tax impacts of the Tax Act. Additional information currently unavailable that is needed to complete the analysis includes, but is not limited to, foreign tax returns and foreign tax documentation for the computation of foreign tax credits, the final determination of the untaxed foreign earnings subject to the transition tax, and the final determination of the net deferred tax liabilities subject to remeasurement. The provisional accounting impacts may change in future reporting periods until the accounting analysis is finalized, which will occur no later than the first quarter of fiscal 2019, as permitted by Staff Accounting Bulletin 118. The Tax Act also introduces several tax provisions, including: • Tax on global intangible low-tax income, which, in general, is determined annually based on the Company’s aggregate foreign subsidiaries’ income in excess of certain qualified business asset investment return. This provision is effective for the Company on October 1, 2018. The Company needs additional information to complete its analysis on whether to adopt an accounting policy to account for the tax effects of global intangible low-tax income in the period that it is subject to such tax, or to provide deferred taxes for book and tax basis differences that, upon reversal, may be subject to such tax. Hence, the Company has not recorded any tax on global intangible low-tax income in the three months ended December 31, 2017. The Company will make an accounting policy election no later than the first quarter of fiscal 2019. • Base erosion and anti-abuse tax, which, in general, functions like a minimum tax that partially disallows deductions for certain related party transactions. This new minimum tax is determined on a year-by-year basis, and this provision is effective for the Company on October 1, 2018. Hence, no base erosion anti-abuse tax was recorded in the three months ended December 31, 2017. • Deduction for foreign-derived intangible income, which, in general, allows a deduction of certain intangible income derived from serving foreign markets. This provision is effective for the Company on October 1, 2018. Hence, the Company has not recorded the impact of this provision in the three months ended December 31, 2017. • Other new tax provisions, which disallow certain deductions related to entertainment expenses, fringe benefits provided to employees, executive compensation, and fines or penalties or similar payments to governments. The Company has recorded provisional amounts for the tax effects of these new provisions in the three months ended December 31, 2017, based on information currently available. The provisional amounts may change in future reporting periods when additional information is obtained and analyzed, which will occur no later than the first quarter of fiscal 2019. During the three months ended December 31, 2017 , the Company's gross unrecognized tax benefits increased by $44 million . The Company's net unrecognized tax benefits that, if recognized, would favorably impact the effective tax rate increased by $38 million . The increase in unrecognized tax benefits is primarily related to various tax positions across several jurisdictions. During the three months ended December 31, 2017 and 2016, there were no significant changes in interest and penalties related to uncertain tax positions. The Company’s tax filings are subject to examination by the U.S. federal, state and foreign taxing authorities. The timing and outcome of the final resolutions of the various ongoing income tax examinations are highly uncertain. It is not reasonably possible to estimate the increase or decrease in unrecognized tax benefits within the next twelve months.

Legal Matters

Legal Matters	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Legal Matters [Abstract]
Legal Matters	Note 11—Legal Matters The Company is party to various legal and regulatory proceedings. Some of these proceedings involve complex claims that are subject to substantial uncertainties and unascertainable damages. Accordingly, except as disclosed, the Company has not established reserves or ranges of possible loss related to these proceedings, as at this time in the proceedings, the matters do not relate to a probable loss and/or the amount or range of losses are not reasonably estimable. Although the Company believes that it has strong defenses for the litigation and regulatory proceedings described below, it could, in the future, incur judgments or fines or enter into settlements of claims that could have a material adverse effect on the Company's financial position, results of operations or cash flows. From time to time, the Company may engage in settlement discussions or mediations with respect to one or more of its outstanding litigation matters, either on its own behalf or collectively with other parties. The litigation accrual is an estimate and is based on management’s understanding of its litigation profile, the specifics of each case, advice of counsel to the extent appropriate and management’s best estimate of incurred loss as of the balance sheet date. The following table summarizes the activity related to accrued litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 982 $ 981 Provision for uncovered legal matters — 15 Accrual of VE territory covered litigation — 86 Payments on legal matters (152 ) (88 ) Balance at end of period $ 830 $ 994 Accrual Summary—U.S. Covered Litigation Visa Inc., Visa U.S.A. and Visa International are parties to certain legal proceedings that are covered by the U.S. retrospective responsibility plan, which the Company refers to as the U.S. covered litigation. See Note 2—U.S. and Europe Retrospective Responsibility Plans . An accrual for the U.S. covered litigation and a charge to the litigation provision are recorded when a loss is deemed to be probable and reasonably estimable. In making this determination, the Company evaluates available information, including but not limited to actions taken by the litigation committee. The total accrual related to the U.S. covered litigation could be either higher or lower than the escrow account balance. The following table summarizes the activity related to U.S. covered litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 978 $ 978 Payments on U.S. covered litigation (150 ) — Balance at end of period $ 828 $ 978 Accrual Summary—VE Territory Covered Litigation Visa Inc., Visa International and Visa Europe are parties to certain legal proceedings that are covered by the Europe retrospective responsibility plan. Unlike the U.S. retrospective responsibility plan, the Europe retrospective responsibility plan does not have an escrow account that is used to fund settlements or judgments. The Company is entitled to recover VE territory covered losses through periodic adjustments to the conversion rates applicable to the UK&I preferred stock and Europe preferred stock. An accrual for the VE territory covered losses and a reduction to stockholders' equity will be recorded when the loss is deemed to be probable and reasonably estimable. See further discussion below under VE Territory Covered Litigation and Note 2—U.S. and Europe Retrospective Responsibility Plans . The following table summarizes the activity related to VE territory covered litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 1 $ 2 Accrual for VE territory covered litigation — 86 Payments on VE territory covered litigation (1 ) (88 ) Balance at end of period $ — $ —	Interchange Multidistrict Litigation (MDL) – Individual Merchant Actions A number of individual merchant actions previously filed have been settled, and remain settled. In addition, following the automatic termination of the settlement agreement with Wal-Mart Stores Inc., Visa and Wal-Mart Stores Inc. entered into a new, unconditional settlement agreement on October 31, 2017. Consequently, as of the filing date, Visa has reached settlement agreements with individual merchants representing approximately 51% of the Visa-branded payment card sales volume of merchants who opted out of the 2012 Settlement Agreement. VE Territory Covered Litigation UK Merchant Litigation Since July 2013, in excess of 300 Merchants (the capitalized term "Merchant," when used in this section, means a merchant together with subsidiary/affiliate companies that are party to the same claim) have commenced proceedings against Visa Europe, Visa Inc. and Visa International relating to interchange rates in Europe. They seek damages for alleged anti-competitive conduct in relation to one or more of the following types of interchange fees for credit and debit card transactions: UK domestic, Irish domestic, other European domestic, intra-European Economic Area and/or other inter-regional. As of the filing date, Visa Europe, Visa Inc. and Visa International have settled the claims asserted by over 75 Merchants, leaving more than 200 Merchants with outstanding claims. In November 2016, a trial commenced relating to claims filed by a number of Merchants. All of these Merchants except one settled before the trial concluded in March 2017. On November 30, 2017, the court found entirely in Visa’s favor and entered judgment dismissing the remaining claim . An appeal has been lodged, and the Court of Appeal listed the matter for hearing in April 2018. A further judgment on exemption issues is expected to be released in early 2018, which will not change the overall finding on liability set out in the November 30, 2017 judgment . In addition, over 30 additional Merchants have threatened to commence similar proceedings. Standstill agreements have been entered into with respect to some of those Merchants' claims. While the amount of interchange being challenged could be substantial, these claims have not yet been filed and their full scope is not yet known. The Company has learned that several additional European entities have indicated that they may also bring similar claims and the Company anticipates additional claims in the future . Other Litigation Canadian Competition Proceedings Merchant Litigation. The court in Quebec held a class certification hearing in November 2017 and reserved decision. Black Card On December 28, 2017, Black Card LLC ("Black Card") filed a lawsuit against Visa Inc., Visa U.S.A. Inc., and certain Visa member financial institutions in the U.S. District Court for the Western District of Wisconsin. The complaint alleges that defendants conspired to impede Black Card's business in violation of Section 1 of the Sherman Act and fraudulently concealed their conduct. Black Card seeks treble damages, post-judgment interest, and attorneys' fees. This action follows a lawsuit filed by Black Card in the U.S. District Court for the District of Wyoming in February 2015 relating to a contractual dispute. The District Court in Wyoming granted Visa's motions for summary judgment and the matter was dismissed. Black Card appealed this decision to the U.S. Court of Appeals for the Tenth Circuit on May 10, 2017.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Consolidation and basis of presentation	Consolidation and basis of presentation. The accompanying unaudited consolidated financial statements include the accounts of Visa and its consolidated entities and are presented in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP"). The Company consolidates its majority-owned and controlled entities, including variable interest entities ("VIEs") for which the Company is the primary beneficiary. The Company’s investments in VIEs have not been material to its consolidated financial statements as of and for the periods presented. All significant intercompany accounts and transactions are eliminated in consolidation. The accompanying unaudited consolidated financial statements are presented in accordance with the U.S. Securities and Exchange Commission (SEC) requirements for Quarterly Reports on Form 10-Q and, consequently, do not include all of the annual disclosures required by U.S. GAAP. Reference should be made to the Visa Annual Report on Form 10-K for the year ended September 30, 2017 for additional disclosures, including a summary of the Company’s significant accounting policies. In the opinion of management, the accompanying unaudited consolidated financial statements include all normal recurring adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash flows for the interim periods presented.
Recently issued and adopted accounting pronouncements	Recently Issued and Adopted Accounting Pronouncements. In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of goods or services to customers. The ASU will replace existing revenue recognition guidance in U.S. GAAP when it becomes effective. Subsequently, the FASB also issued a series of amendments to the new revenue standard. The Company will adopt the standard effective October 1, 2018, and expects to adopt the standard using the modified retrospective transition method. The Company expects that the new standard will primarily impact recognition timing for certain fixed incentives and price discounts provided to clients, and the classification of certain client incentives between contra revenues and operating expenses. The Company is still in the process of quantifying the full effect that ASU 2014-09 and all of its related subsequent updates will have on its consolidated financial statements and related disclosures. The impact of the new standard to future financial results is unknowable as it is not possible to estimate the impact to the recognition of new customer contracts which may be executed in future periods. The Company has completed an assessment of its existing customer contracts through December 31, 2017. Application of the new standard to consolidated financial statements for the first quarter of fiscal 2018 would not have resulted in a material impact. The Company will continue to assess the impact of the new standard as new customer contracts are executed going forward. In March 2016, the FASB issued ASU 2016-05, which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815, Derivatives and Hedging , does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-06, which clarifies the requirements for assessing whether contingent call/put options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. An entity performing the assessment is required to assess the embedded call/put options solely in accordance with a four-step decision sequence. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, which eliminates the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The equity method investor is required to add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. The Company adopted the standard effective October 1, 2017. The adoption did not have a material impact on the consolidated financial statements.

U.S. and Europe Retrospective19

U.S. and Europe Retrospective Responsibility Plans (Tables)	3 Months Ended
	Dec. 31, 2017
Retrospective Responsibility Plan [Abstract]
Schedule of Activities Related to Territory Covered Losses and Right to Recover for Covered Losses	The following table sets forth the activities related to VE territory covered losses in preferred stock and "right to recover for covered losses" within equity during the three months ended December 31, 2017 . VE territory covered losses incurred reflect settlements with merchants and additional legal costs. See Note 11—Legal Matters . Preferred Stock Right to Recover for Covered Losses UK&I Europe (in millions) Balance as of September 30, 2017 $ 2,326 $ 3,200 $ (52 ) VE territory covered losses incurred — — (3 ) Recovery through conversion rate adjustment (31 ) (19 ) 50 Balance as of December 31, 2017 $ 2,295 $ 3,181 $ (5 )
Schedule of As-converted and Book Value of Preferred Stock Available to Recover Europe Covered Losses	The following table sets forth the as-converted value of the preferred stock available to recover VE territory covered losses compared to the book value of preferred shares recorded in stockholders' equity within the Company's unaudited consolidated balance sheet as of December 31, 2017 and September 30, 2017 . (1) December 31, 2017 September 30, 2017 As-Converted Value of Preferred Stock (2) Book Value of Preferred Stock As-Converted Value of Preferred Stock (3) Book Value of Preferred Stock (in millions) UK&I preferred stock $ 3,667 $ 2,295 $ 3,414 $ 2,326 Europe preferred stock 5,001 3,181 4,634 3,200 Total 8,668 5,476 8,048 5,526 Less: right to recover for covered losses (5 ) (5 ) (52 ) (52 ) Total recovery for covered losses available $ 8,663 $ 5,471 $ 7,996 $ 5,474 (1) Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers. (2) The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of December 31, 2017 ; (b) 12.966 and 13.893 , the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of December 31, 2017 , respectively; and (c) $114.02 , Visa's class A common stock closing stock price as of December 31, 2017 . (3) The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of September 30, 2017 ; (b) 13.077 and 13.948 , the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of September 30, 2017 , respectively; and (c) $105.24 , Visa's class A common stock closing stock price as of September 30, 2017 .

Fair Value Measurements and I20

Fair Value Measurements and Investments (Tables)	3 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair Value Measurements Using Inputs Considered as Level 1 Level 2 December 31, September 30, December 31, September 30, (in millions) Assets Cash equivalents and restricted cash: Money market funds $ 5,918 $ 5,935 U.S. government-sponsored debt securities $ 567 $ 2,870 Investment securities, trading: Equity securities 106 82 Investment securities, available-for-sale: U.S. government-sponsored debt securities 3,530 3,663 U.S. Treasury securities 2,337 1,621 Equity securities 114 124 Prepaid and other current assets: Foreign exchange derivative instruments 26 18 Total $ 8,475 $ 7,762 $ 4,123 $ 6,551 Liabilities Accrued liabilities: Foreign exchange derivative instruments $ 65 $ 98 Total $ — $ — $ 65 $ 98
Schedule of Long-term Debt Instruments	The following table presents the carrying amount and estimated fair value of the Company’s debt in order of maturity: December 31, 2017 September 30, 2017 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value (in millions) 1.20% Senior Notes due December 2017 $ — $ — $ 1,749 $ 1,751 2.20% Senior Notes due December 2020 2,991 2,998 2,990 3,031 2.15% Senior Notes due September 2022 993 986 993 997 2.80% Senior Notes due December 2022 2,240 2,283 2,240 2,301 3.15% Senior Notes due December 2025 3,969 4,089 3,967 4,098 2.75% Senior Notes due September 2027 740 740 740 737 4.15% Senior Notes due December 2035 1,486 1,665 1,485 1,637 4.30% Senior Notes due December 2045 3,462 3,983 3,463 3,873 3.65% Senior Notes due September 2047 740 770 740 746 Total $ 16,621 $ 17,514 $ 18,367 $ 19,171

Debt (Tables)

Debt (Tables)	3 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Debt	The Company had outstanding debt as follows: December 31, 2017 September 30, 2017 Principal Amount Unamortized Discounts and Debt Issuance Costs Carrying Amount Principal Amount Unamortized Discounts and Debt Issuance Costs Carrying Amount Effective Interest Rate (in millions, except percentages) 1.20% Senior Notes due December 2017 (the "2017 Notes") $ — $ — $ — $ 1,750 $ (1 ) $ 1,749 1.37 % Total current maturities of long-term debt — — — 1,750 (1 ) 1,749 2.20% Senior Notes due December 2020 3,000 (9 ) 2,991 3,000 (10 ) 2,990 2.30 % 2.15% Senior Notes due September 2022 1,000 (7 ) 993 1,000 (7 ) 993 2.30 % 2.80% Senior Notes due December 2022 2,250 (10 ) 2,240 2,250 (10 ) 2,240 2.89 % 3.15% Senior Notes due December 2025 4,000 (31 ) 3,969 4,000 (33 ) 3,967 3.26 % 2.75% Senior Notes due September 2027 750 (10 ) 740 750 (10 ) 740 2.91 % 4.15% Senior Notes due December 2035 1,500 (14 ) 1,486 1,500 (15 ) 1,485 4.23 % 4.30% Senior Notes due December 2045 3,500 (38 ) 3,462 3,500 (37 ) 3,463 4.37 % 3.65% Senior Notes due September 2047 750 (10 ) 740 750 (10 ) 740 3.73 % Total long-term debt 16,750 (129 ) 16,621 16,750 (132 ) 16,618 Total debt $ 16,750 $ (129 ) $ 16,621 $ 18,500 $ (133 ) $ 18,367

Settlement Guarantee Manageme22

Settlement Guarantee Management (Tables)	3 Months Ended
	Dec. 31, 2017
Settlement Guarantee Management [Abstract]
Schedule of Customer Collateral	The Company maintained collateral as follows: December 31, September 30, (in millions) Cash equivalents (1) $ 1,569 $ 1,490 Pledged securities at market value 169 167 Letters of credit 1,319 1,316 Guarantees 617 941 Total $ 3,674 $ 3,914 (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.

Pension and Other Postretirem23

Pension and Other Postretirement Benefits (Tables)	3 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures	U.S. Plans Non-U.S. Plans Pension Benefits Other Postretirement Benefits Pension Benefits Three Months Ended Three Months Ended Three Months Ended 2017 2016 2017 2016 2017 2016 (in millions) Service cost $ — $ — $ — $ — $ 1 $ 2 Interest cost 8 9 — — 3 3 Expected return on plan assets (17 ) (18 ) — — (5 ) (4 ) Amortization of: Prior service credit — — — (1 ) — — Actuarial loss — 4 — — — — Settlement loss — 2 — — — — Total net periodic benefit cost $ (9 ) $ (3 ) $ — $ (1 ) $ (1 ) $ 1

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of Stock by Class	The number of shares of each series and class and the number of shares of class A common stock on an as-converted basis at December 31, 2017 , are as follows: (in millions, except conversion rates) Shares Outstanding Conversion Rate Into Class A Common Stock As-converted Class A Common Stock (1) UK&I preferred stock 2 12.9660 32 Europe preferred stock 3 13.8930 44 Class A common stock (2) 1,805 — 1,805 Class B common stock 245 1.6483 (3) 405 Class C common stock 12 4.0000 49 Total 2,335 (1) Figures in the table may not recalculate exactly due to rounding. As-converted class A common stock is calculated based on unrounded numbers. (2) Class A common stock shares outstanding exclude repurchases traded but not yet settled on or before December 31, 2017 . (3) The class B to class A common stock conversion rate is presented on a rounded basis. Conversion calculations for dividend payments are based on a conversion rate rounded to the tenth decimal.
Share Repurchase Program Disclosure	The following table presents share repurchases in the open market. (1) (in millions, except per share data) Three Months Ended Shares repurchased in the open market (2) 16 Average repurchase price per share (3) $ 110.24 Total cost $ 1,778 (1) Shares repurchased in the open market reflect repurchases settled during the three months ended December 31, 2017 . These amounts include repurchases traded but not yet settled on or before September 30, 2017 and exclude repurchases traded but not yet settled on or before December 31, 2017 . (2) All shares repurchased in the open market have been retired and constitute authorized but unissued shares. (3) Figures in the table may not recalculate exactly due to rounding. Average repurchase price per share is calculated based on unrounded numbers.
Effect of VE Territory Covered Losses Recovery on the Company Repurchasing its Common Stock	The following table presents as-converted UK&I and Europe preferred stock, after the Company recovered VE territory covered losses through conversion rate adjustments, for the three months ended December 31, 2017 . Three Months Ended (in millions, except per share data) UK&I Preferred Stock Europe Preferred Stock Reduction in equivalent number of shares of class A common stock (1) — — Effective price per share (2) $ 111.32 $ 111.32 Recovery through conversion rate adjustment $ 31 $ 19 (1) The reduction in equivalent number of shares of class A common stock was less than one million shares for both series of preferred stock. (2) Effective price per share is calculated using the volume-weighted average price of the Company's class A common stock over a pricing period in accordance with the Company's current certificates of designations for its series B and C convertible participating preferred stock.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents earnings per share for the three months ended December 31, 2017 . (1) Basic Earnings Per Share Diluted Earnings Per Share (in millions, except per share data) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Class A common stock $ 1,945 1,811 $ 1.07 $ 2,522 2,353 (3) $ 1.07 Class B common stock 435 245 $ 1.77 $ 434 245 $ 1.77 Class C common stock 54 13 $ 4.30 $ 54 13 $ 4.29 Participating securities (4) 88 Not presented Not presented $ 87 Not presented Not presented Net income $ 2,522 The following table presents earnings per share for the three months ended December 31, 2016 . (1) Basic Earnings Per Share Diluted Earnings Per Share (in millions, except per share data) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Income Allocation (A) (2) Weighted- Average Shares Outstanding (B) Earnings per Share = (A)/(B) Class A common stock $ 1,594 1,860 $ 0.86 $ 2,070 2,421 (3) $ 0.86 Class B common stock 347 245 $ 1.41 $ 346 245 $ 1.41 Class C common stock 57 17 $ 3.43 $ 57 17 $ 3.42 Participating securities (4) 72 Not presented Not presented $ 72 Not presented Not presented Net income $ 2,070 (1) Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers. (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 405 million for the three months ended December 31, 2017 and 2016 . The weighted-average number of shares of as-converted class C common stock used in the income allocation was 51 million and 67 million for the three months ended December 31, 2017 and 2016 , respectively. The weighted-average number of shares of preferred stock, included within participating securities, was 32 million and 35 million of as-converted UK&I preferred stock for the three months ended December 31, 2017 and 2016 , respectively, and 44 million of as-converted Europe preferred stock for the three months ended December 31, 2017 and 2016 . (3) Weighted-average diluted shares outstanding are calculated on an as-converted basis, and include incremental common stock equivalents, as calculated under the treasury stock method. The computation includes approximately 5 million common stock equivalents for the three months ended December 31, 2017 and 2016 , because their effect would be dilutive. The computation excludes 2 million and 3 million of common stock equivalents for the three months ended December 31, 2017 and 2016 , respectively, because their effect would have been anti-dilutive. (4) Participating securities include preferred stock outstanding and unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents, such as the Company's UK&I and Europe preferred stock, restricted stock awards, restricted stock units and earned performance-based shares. Participating securities' income is allocated based on the weighted-average number of shares of as-converted stock.

Share-based Compensation (Table

Share-based Compensation (Tables)	3 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	The Company granted the following equity awards to employees and non-employee directors under the 2007 Equity Incentive Compensation Plan during the three months ended December 31, 2017 : Granted Weighted-Average Grant Date Fair Value Weighted-Average Exercise Price Non-qualified stock options 1,622,760 $ 17.88 $ 109.82 Restricted stock units ("RSUs") 2,626,011 $ 109.82 Performance-based shares (1) 641,498 $ 120.11 (1) Represents the maximum number of performance-based shares which could be earned.

Legal Matters (Tables)

Legal Matters (Tables)	3 Months Ended
	Dec. 31, 2017
Loss Contingencies [Line Items]
Schedule of Loss Contingencies by Contingency	The following table summarizes the activity related to accrued litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 982 $ 981 Provision for uncovered legal matters — 15 Accrual of VE territory covered litigation — 86 Payments on legal matters (152 ) (88 ) Balance at end of period $ 830 $ 994
U.S. Covered Litigation
Loss Contingencies [Line Items]
Schedule of Loss Contingencies by Contingency	The following table summarizes the activity related to U.S. covered litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 978 $ 978 Payments on U.S. covered litigation (150 ) — Balance at end of period $ 828 $ 978
VE Territory Covered Litigation
Loss Contingencies [Line Items]
Schedule of Loss Contingencies by Contingency	The following table summarizes the activity related to VE territory covered litigation: Three Months Ended December 31, 2017 December 31, 2016 (in millions) Balance at beginning of period $ 1 $ 2 Accrual for VE territory covered litigation — 86 Payments on VE territory covered litigation (1 ) (88 ) Balance at end of period $ — $ —

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Details)	Jun. 30, 2017country
Accounting Policies [Abstract]
Number of countries in which entity operates (more than)	200

U.S. and Europe Retrospective29

U.S. and Europe Retrospective Responsibility Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Retrospective Responsibility Plan [Abstract]
Escrow account	$ 883		$ 1,031
Payments for Legal Settlements	$ (150)	$ 0

U.S. and Europe Retrospective30

U.S. and Europe Retrospective Responsibility Plans - Preferred Stock Rollforward (Details) € in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2017EUR (€)	Dec. 31, 2017USD ($)	Sep. 30, 2017
Class of Stock [Line Items]
VE territory covered loss, maximum amount of loss to allow adjustment of conversion rate during six-month period | €		€ 20
Recovery through conversion rate adjustment			$ 50
Preferred Stock and Right to Recover for Covered Losses [Roll Forward]
Preferred stock, beginning	[1]		5,526
Recovery through conversion rate adjustment			50
Preferred stock, ending	[1]		5,476
Right to recover for covered losses, beginning	[1]		52
VE territory covered losses incurred			(3)
Right to recover for covered losses, ending	[1]		5
U.K.& I preferred stock
Class of Stock [Line Items]
Recovery through conversion rate adjustment			$ (31)
Preferred stock, conversion ratio		12.9660	12.9660	13.077
Preferred Stock and Right to Recover for Covered Losses [Roll Forward]
Preferred stock, beginning	[1]		$ 2,326
Recovery through conversion rate adjustment			(31)
Preferred stock, ending	[1]		2,295
Europe preferred stock
Class of Stock [Line Items]
Recovery through conversion rate adjustment			$ (19)
Preferred stock, conversion ratio		13.8930	13.8930	13.948
Preferred Stock and Right to Recover for Covered Losses [Roll Forward]
Preferred stock, beginning	[1]		$ 3,200
Recovery through conversion rate adjustment			(19)
Preferred stock, ending	[1]		$ 3,181
[1]	Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers.

U.S. and Europe Retrospective31

U.S. and Europe Retrospective Responsibility Plans - Preferred Stock (Details) $ / shares in Units, shares in Millions, $ in Millions		Dec. 31, 2017USD ($)$ / sharesshares		Sep. 30, 2017USD ($)$ / sharesshares
Class of Stock [Line Items]
As-converted value of preferred stock	[1]	$ 8,668	[2]	$ 8,048	[3]
Book Value of Preferred stock	[1]	5,476		5,526
Right to recover for covered losses	[1]	(5)		(52)
Total recovery for covered losses available, as converted	[1]	8,663		7,996
Total recovery for covered losses available, book value	[1]	$ 5,471		5,474
Closing stock price | $ / shares		$ 114.02
U.K.& I preferred stock
Class of Stock [Line Items]
As-converted value of preferred stock	[1]	$ 3,667	[2]	3,414	[3]
Book Value of Preferred stock	[1]	$ 2,295		$ 2,326
Preferred stock, shares outstanding | shares		2		2
Preferred stock, conversion ratio		12.9660		13.077
Europe preferred stock
Class of Stock [Line Items]
As-converted value of preferred stock	[1]	$ 5,001	[2]	$ 4,634	[3]
Book Value of Preferred stock	[1]	$ 3,181		$ 3,200
Preferred stock, shares outstanding | shares		3		3
Preferred stock, conversion ratio		13.8930		13.948
Class A common stock
Class of Stock [Line Items]
Closing stock price | $ / shares				$ 105.24
[1]	Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers.
[2]	The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of December 31, 2017; (b)12.966 and 13.893, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of December 31, 2017, respectively; and (c) $114.02, Visa's class A common stock closing stock price as of December 31, 2017.
[3]	The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of December 31, 2017; (b)12.966 and 13.893, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of December 31, 2017, respectively; and (c) $114.02, Visa's class A common stock closing stock price as of December 31, 2017.(3) The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of September 30, 2017; (b)13.077 and 13.948, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of September 30, 2017, respectively; and (c) $105.24, Visa's class A common stock closing stock price as of September 30, 2017.

Assets and Liabilities Measured

Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
Assets
Investment securities, trading:	$ 106	$ 82
Liabilities
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0
Fair Value, Measurements, Recurring | Level 1
Assets
Total	8,475	7,762
Liabilities
Total	0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Total	4,123	6,551
Liabilities
Total	65	98
Fair Value, Measurements, Recurring | Level 2 | U.S. government-sponsored debt securities
Assets
Investment securities, available-for-sale:	3,530	3,663
Cash equivalents and restricted cash: | Fair Value, Measurements, Recurring | Level 1 | Money market funds
Assets
Cash equivalents and restricted cash:	5,918	5,935
Cash equivalents and restricted cash: | Fair Value, Measurements, Recurring | Level 2 | U.S. government-sponsored debt securities
Assets
Cash equivalents and restricted cash:	567	2,870
Investment securities, trading: | Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets
Investment securities, trading:	106	82
Investment securities, available-for-sale: | Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets
Investment securities, available-for-sale:	114	124
Investment securities, available-for-sale: | Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities
Assets
Investment securities, available-for-sale:	2,337	1,621
Prepaid and other current assets: | Fair Value, Measurements, Recurring | Level 2 | Foreign exchange derivative instruments
Assets
Prepaid and other current assets:	26	18
Foreign exchange derivative instruments | Accrued liabilities: | Fair Value, Measurements, Recurring | Level 2
Liabilities
Accrued liabilities:	$ 65	$ 98

Fair Value Measurements and I33

Fair Value Measurements and Investments - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable equity investments	$ 99,000,000	$ 94,000,000
Available-for-sale securities, gross unrealized gains	110,000,000	120,000,000
Available-for-sale securities, gross unrealized losses	$ 12,000,000	$ 4,000,000
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, stated maturities	1 year
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, stated maturities	2 years

Fair Value Measurements and I34

Fair Value Measurements and Investments Fair Value Measurements and Investments - Fair Value of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
2017 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.20%
2020 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.20%
September 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.15%
2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.80%
2025 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.15%
2027 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
2035 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.15%
2045 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.30%
2047 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.65%
Senior Notes | 2017 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.20%
Senior Notes | 2020 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.20%
Senior Notes | September 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.15%
Senior Notes | 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.80%
Senior Notes | 2025 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.15%
Senior Notes | 2027 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Senior Notes | 2035 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.15%
Senior Notes | 2045 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.30%
Senior Notes | 2047 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.65%
Senior Notes | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 16,621	$ 18,367
Senior Notes | Carrying Amount | 2017 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0	1,749
Senior Notes | Carrying Amount | 2020 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,991	2,990
Senior Notes | Carrying Amount | September 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	993	993
Senior Notes | Carrying Amount | 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,240	2,240
Senior Notes | Carrying Amount | 2025 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	3,969	3,967
Senior Notes | Carrying Amount | 2027 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	740	740
Senior Notes | Carrying Amount | 2035 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	1,486	1,485
Senior Notes | Carrying Amount | 2045 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	3,462	3,463
Senior Notes | Carrying Amount | 2047 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	740	740
Senior Notes | Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	17,514	19,171
Senior Notes | Estimated Fair Value | 2017 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0	1,751
Senior Notes | Estimated Fair Value | 2020 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,998	3,031
Senior Notes | Estimated Fair Value | September 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	986	997
Senior Notes | Estimated Fair Value | 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,283	2,301
Senior Notes | Estimated Fair Value | 2025 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	4,089	4,098
Senior Notes | Estimated Fair Value | 2027 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	740	737
Senior Notes | Estimated Fair Value | 2035 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	1,665	1,637
Senior Notes | Estimated Fair Value | 2045 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	3,983	3,873
Senior Notes | Estimated Fair Value | 2047 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 770	$ 746

Debt - Debt (Details)

Debt - Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	$ 0	$ 1,749
Carrying Amount, noncurrent	$ 16,621	$ 16,618
2017 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.20%
2020 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.20%
September 2022 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.15%
2022 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.80%
2025 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.15%
2027 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
2035 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.15%
2045 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.30%
2047 Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.65%
Senior Notes
Debt Instrument [Line Items]
Principal Amount, current maturities	$ 0	$ 1,750
Unamortized Discounts and Debt Issuance Costs, current maturities	0	(1)
Long-term Debt, Current Maturities	0	1,749
Principal Amount, noncurrent	16,750	16,750
Unamortized Discounts and Debt Issuance Costs, noncurrent	(129)	(132)
Carrying Amount, noncurrent	16,621	16,618
Total debt, principal	16,750	18,500
Unamortized Discounts and Debt Issuance Costs	(129)	(133)
Carrying Amount	16,621	18,367
Senior Notes | 2017 Notes
Debt Instrument [Line Items]
Principal Amount, current maturities	0	1,750
Unamortized Discounts and Debt Issuance Costs, current maturities	0	(1)
Long-term Debt, Current Maturities	$ 0	$ 1,749
Effective Interest Rate (percent)	1.37%
Debt Instrument, Interest Rate, Stated Percentage		1.20%
Senior Notes | 2020 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 3,000	$ 3,000
Unamortized Discounts and Debt Issuance Costs, noncurrent	(9)	(10)
Carrying Amount, noncurrent	$ 2,991	2,990
Effective Interest Rate (percent)	2.30%
Debt Instrument, Interest Rate, Stated Percentage	2.20%
Senior Notes | September 2022 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 1,000	1,000
Unamortized Discounts and Debt Issuance Costs, noncurrent	(7)	(7)
Carrying Amount, noncurrent	$ 993	993
Effective Interest Rate (percent)	2.30%
Debt Instrument, Interest Rate, Stated Percentage	2.15%
Senior Notes | 2022 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 2,250	2,250
Unamortized Discounts and Debt Issuance Costs, noncurrent	(10)	(10)
Carrying Amount, noncurrent	$ 2,240	2,240
Effective Interest Rate (percent)	2.89%
Debt Instrument, Interest Rate, Stated Percentage	2.80%
Senior Notes | 2025 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 4,000	4,000
Unamortized Discounts and Debt Issuance Costs, noncurrent	(31)	(33)
Carrying Amount, noncurrent	$ 3,969	3,967
Effective Interest Rate (percent)	3.26%
Debt Instrument, Interest Rate, Stated Percentage	3.15%
Senior Notes | 2027 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 750	750
Unamortized Discounts and Debt Issuance Costs, noncurrent	(10)	(10)
Carrying Amount, noncurrent	$ 740	740
Effective Interest Rate (percent)	2.91%
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Senior Notes | 2035 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 1,500	1,500
Unamortized Discounts and Debt Issuance Costs, noncurrent	(14)	(15)
Carrying Amount, noncurrent	$ 1,486	1,485
Effective Interest Rate (percent)	4.23%
Debt Instrument, Interest Rate, Stated Percentage	4.15%
Senior Notes | 2045 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 3,500	3,500
Unamortized Discounts and Debt Issuance Costs, noncurrent	(38)	(37)
Carrying Amount, noncurrent	$ 3,462	3,463
Effective Interest Rate (percent)	4.37%
Debt Instrument, Interest Rate, Stated Percentage	4.30%
Senior Notes | 2047 Notes
Debt Instrument [Line Items]
Principal Amount, noncurrent	$ 750	750
Unamortized Discounts and Debt Issuance Costs, noncurrent	(10)	(10)
Carrying Amount, noncurrent	$ 740	$ 740
Effective Interest Rate (percent)	3.73%
Debt Instrument, Interest Rate, Stated Percentage	3.65%

Debt - Narrative (Details)

Debt - Narrative (Details) - Senior Notes - USD ($) $ in Millions	Oct. 11, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Debt Instrument [Line Items]
Principal Amount, current maturities		$ 0		$ 1,750
Interest expense		138	$ 125
2017 Notes
Debt Instrument [Line Items]
Principal Amount, current maturities		0		$ 1,750
Repayments of Debt	$ 1,750
Gain (Loss) on Extinguishment of Debt		$ (1)

Settlement Guarantee Manageme37

Settlement Guarantee Management - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017
Settlement Guarantee Management [Abstract]
Estimated Maximum Settlement Exposure	$ 71,300	$ 67,700
Covered settlement exposure	4,500	2,800
Estimated probability-weighted value of the guarantee	$ 3	$ 3

Collateral (Detail)

Collateral (Detail) - USD ($) $ in Millions		Dec. 31, 2017	Sep. 30, 2017
Settlement Guarantee Management [Abstract]
Cash equivalents	[1]	$ 1,569	$ 1,490
Pledged securities at market value		169	167
Letters of credit		1,319	1,316
Guarantees		617	941
Total		$ 3,674	$ 3,914
[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.

Components of Net Periodic Bene

Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0
Interest cost	8	9
Expected return on assets	(17)	(18)
Prior service credit	0	0
Actuarial loss (gain)	0	4
Settlement loss	0	2
Total net periodic benefit cost	(9)	(3)
Pension Benefits | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2
Interest cost	3	3
Expected return on assets	(5)	(4)
Prior service credit	0	0
Actuarial loss (gain)	0	0
Settlement loss	0	0
Total net periodic benefit cost	(1)	1
Other Postretirement Benefits | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	0	0
Expected return on assets	0	0
Prior service credit	0	(1)
Actuarial loss (gain)	0	0
Settlement loss	0	0
Total net periodic benefit cost	$ 0	$ (1)

Stockholders' Equity - Number o

Stockholders' Equity - Number of Shares of Class A Common Shares Outstanding on an As-Converted Basis (Detail) shares in Millions		Dec. 31, 2017shares		Sep. 30, 2017shares
Schedule of Common Stock as Converted [Line Items]
As-converted Class A Common Stock		2,335
U.K.& I preferred stock
Schedule of Common Stock as Converted [Line Items]
Preferred stock, shares outstanding		2		2
Preferred stock, conversion rate into Class A Common Stock		12.9660		13.077
As-converted Class A Common Stock	[1]	32
Europe preferred stock
Schedule of Common Stock as Converted [Line Items]
Preferred stock, shares outstanding		3		3
Preferred stock, conversion rate into Class A Common Stock		13.8930		13.948
As-converted Class A Common Stock	[1]	44
Class A common stock
Schedule of Common Stock as Converted [Line Items]
Common stock, shares outstanding		1,805	[2]	1,818
As-converted Class A Common Stock	[1],[2]	1,805
Class B common stock
Schedule of Common Stock as Converted [Line Items]
Common stock, shares outstanding		245		245
Common stock, conversion rate into Class A Common Stock	[3]	1.6483
As-converted Class A Common Stock	[1]	405
Class C common stock
Schedule of Common Stock as Converted [Line Items]
Common stock, shares outstanding		12		13
Common stock, conversion rate into Class A Common Stock		4
As-converted Class A Common Stock	[1]	49
[1]	Figures in the table may not recalculate exactly due to rounding. As-converted class A common stock is calculated based on unrounded numbers.
[2]	Class A common stock shares outstanding exclude repurchases traded but not yet settled on or before December 31, 2017.
[3]	The class B to class A common stock conversion rate is presented on a rounded basis. Conversion calculations for dividend payments are based on a conversion rate rounded to the tenth decimal.

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2017	Jan. 30, 2018
Stockholders Equity Note [Line Items]
Stock Repurchased and Retired During Period, Shares	[1],[2]	16
Stock Repurchased and Retired During Period, Value	[2]	$ 1,778
Recovery through conversion rate adjustment		50
Stock Repurchase Remaining Authorized Amount		2,100
Dividends, Cash		$ 458
Class A common stock
Stockholders Equity Note [Line Items]
Reduction In As-Converted Stock, Shares		17
Reduction in As-Converted Stock, Average Price Per Share		$ 110.27
Subsequent Event
Stockholders Equity Note [Line Items]
Stock Repurchase Program, Authorized Amount			$ 7,500
Subsequent Event | Class A common stock
Stockholders Equity Note [Line Items]
Dividends Payable, Amount Per Share			$ 0.210
[1]	All shares repurchased in the open market have been retired and constitute authorized but unissued shares.
[2]	Shares repurchased in the open market reflect repurchases settled during the three months ended December 31, 2017. These amounts include repurchases traded but not yet settled on or before September 30, 2017 and exclude repurchases traded but not yet settled on or before December 31, 2017.

Stockholders' Equity - Share Re

Stockholders' Equity - Share Repurchases in the Open Market (Detail) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares	[2]
Stockholders' Equity Note [Abstract]
Shares repurchased in the open market | shares	16	[1]
Average repurchase price per share | $ / shares	$ 110.24	[3]
Total cost | $	$ 1,778
[1]	All shares repurchased in the open market have been retired and constitute authorized but unissued shares.
[2]	Shares repurchased in the open market reflect repurchases settled during the three months ended December 31, 2017. These amounts include repurchases traded but not yet settled on or before September 30, 2017 and exclude repurchases traded but not yet settled on or before December 31, 2017.
[3]	Figures in the table may not recalculate exactly due to rounding. Average repurchase price per share is calculated based on unrounded numbers.

Stockholders' Equity Effect of

Stockholders' Equity Effect of VE Territory Covered Losses Recovery on the Company Repurchasing its Common Stock (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Conversion of Stock [Line Items]
Recovery through conversion rate adjustment	$ (50)
U.K.& I preferred stock
Conversion of Stock [Line Items]
Reduction in equivalent number of shares of class A common stock(1) | shares	0	[1]
Effective price per share (in USD per share) | $ / shares	$ 111.32	[2]
Recovery through conversion rate adjustment	$ 31
Europe preferred stock
Conversion of Stock [Line Items]
Reduction in equivalent number of shares of class A common stock(1) | shares	0	[1]
Effective price per share (in USD per share) | $ / shares	$ 111.32	[2]
Recovery through conversion rate adjustment	$ 19
[1]	The reduction in equivalent number of shares of class A common stock was less than one million shares for both series of preferred stock.
[2]	Effective price per share is calculated using the volume-weighted average price of the Company's class A common stock over a pricing period in accordance with the Company's current certificates of designations for its series B and C convertible participating preferred stock.

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income	[1]	$ 2,522	$ 2,070
Class A common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income Allocation - Basic	[1]	$ 1,945	$ 1,594
Weighted- Average Shares Outstanding - Basic		1,811	1,860
Earnings per Share - Basic	[2]	$ 1.07	$ 0.86
Income Allocation - Diluted	[1]	$ 2,522	$ 2,070
Weighted- Average Shares Outstanding - Diluted	[3]	2,353	2,421
Earnings per Share - Diluted	[2]	$ 1.07	$ 0.86
Class B common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income Allocation - Basic	[1]	$ 435	$ 347
Weighted- Average Shares Outstanding - Basic		245	245
Earnings per Share - Basic	[2]	$ 1.77	$ 1.41
Income Allocation - Diluted	[1]	$ 434	$ 346
Weighted- Average Shares Outstanding - Diluted		245	245
Earnings per Share - Diluted	[2]	$ 1.77	$ 1.41
Class C common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income Allocation - Basic	[1]	$ 54	$ 57
Weighted- Average Shares Outstanding - Basic		13	17
Earnings per Share - Basic	[2]	$ 4.30	$ 3.43
Income Allocation - Diluted	[1]	$ 54	$ 57
Weighted- Average Shares Outstanding - Diluted		13	17
Earnings per Share - Diluted	[2]	$ 4.29	$ 3.42
Participating securities
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income Allocation - Basic	[1],[4]	$ 88	$ 72
Income Allocation - Diluted	[1],[4]	$ 87	$ 72
[1]	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 405 million for the three months ended December 31, 2017 and 2016. The weighted-average number of shares of as-converted class C common stock used in the income allocation was 51 million and 67 million for the three months ended December 31, 2017 and 2016, respectively. The weighted-average number of shares of preferred stock, included within participating securities, was 32 million and 35 million of as-converted UK&I preferred stock for the three months ended December 31, 2017 and 2016, respectively, and 44 million of as-converted Europe preferred stock for the three months ended December 31, 2017 and 2016.
[2]	Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers.
[3]	Weighted-average diluted shares outstanding are calculated on an as-converted basis, and include incremental common stock equivalents, as calculated under the treasury stock method. The computation includes approximately 5 million common stock equivalents for the three months ended December 31, 2017 and 2016, because their effect would be dilutive. The computation excludes 2 million and 3 million of common stock equivalents for the three months ended December 31, 2017 and 2016, respectively, because their effect would have been anti-dilutive.
[4]	Participating securities include preferred stock outstanding and unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents, such as the Company's UK&I and Europe preferred stock, restricted stock awards, restricted stock units and earned performance-based shares. Participating securities' income is allocated based on the weighted-average number of shares of as-converted stock.

Basic and Diluted Earnings Pe45

Basic and Diluted Earnings Per Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Common stock equivalents included in the computation of diluted shares outstanding	5	5
Common stock equivalents excluded from computation of average dilutive shares outstanding (less than 1 Million for the 3 months ended June 30, 2017)	2	3
Class B common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation	405	405
Class C common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation	51	67
U.K.& I preferred stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation	32	35
Europe preferred stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation	44	44

Share-based Compensation - Awar

Share-based Compensation - Awards Granted to Company Employees and Non-employee Directors Under the 2007 Equity Incentive Compensation Plan (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation		$ 68	$ 45
Non-qualified stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted		1,622,760
Weighted-Average Grant Date Fair Value		$ 17.88
Weighted-Average Exercise Price		$ 109.82
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted		2,626,011
Weighted-Average Grant Date Fair Value		$ 109.82
Performance-bases shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	[1]	641,498
Weighted-Average Grant Date Fair Value	[1]	$ 120.11
[1]	Represents the maximum number of performance-based shares which could be earned.

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Effective income tax rate reconciliation, percent	22.00%	31.00%
Tax cuts and jobs act of 2017, incomplete accounting, deferred tax liability, provisional income tax (expense) benefit	$ 1,100
Tax cuts and jobs act of 2017, incomplete accounting, transition tax accumulated foreign earnings, provisional income tax expense (benefit)	1,100
Increase in unrecognized tax benefits	44
Effective income tax rate reconciliation Unrecognized Tax Benefits that would Favorably Impact Effective Tax Rate	$ 38
Forecast
Business Acquisition [Line Items]
Federal statutory income tax rate, percent			21.00%	24.50%

Accrued Litigation for Both Cov

Accrued Litigation for Both Covered and Non-Covered Litigation (Detail) $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2017merchant	Dec. 31, 2017USD ($)merchant	Dec. 31, 2016USD ($)	Apr. 20, 2017
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period		$ 982	$ 981
Balance at end of period		$ 830	994
U.K. Merchant Litigation
Loss Contingency Accrual [Roll Forward]
Number of plaintiffs | merchant		300
Number of claims settled | merchant		75
Merchants with outstanding claims | merchant		200
Number of merchant claims not settled before trial | merchant	1
Threatened Litigation | U.K. Merchant Litigation
Loss Contingency Accrual [Roll Forward]
Number of plaintiffs | merchant		30
Unsettled
Loss Contingency Accrual [Roll Forward]
Provision for legal matters		$ 0	15
Settled Litigation
Loss Contingency Accrual [Roll Forward]
Payments on litigation matters		(152)	(88)
U.S. Covered Litigation
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period		978	978
Balance at end of period		828	978
U.S. Covered Litigation | Settled Litigation
Loss Contingency Accrual [Roll Forward]
Payments on litigation matters		(150)	0
VE Territory Covered Litigation
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period		1	2
Provision for legal matters		0	86
Balance at end of period		0	0
VE Territory Covered Litigation | Settled Litigation
Loss Contingency Accrual [Roll Forward]
Payments on litigation matters		$ (1)	$ (88)
Interchange Multidistrict Litigation
Loss Contingency Accrual [Roll Forward]
Merchants with settlement agreements (percent)				51.00%