CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities
Net income	$ 5,954	$ 5,127
Adjustments to reconcile net income to net cash provided by operating activities:
Client incentives (Note 2)	2,934	2,615
Share-based compensation (Note 11)	211	153
Depreciation and amortization of property, equipment, technology and intangible assets	319	298
Deferred income taxes	256	(945)
Right to recover for covered losses recorded in equity (Note 4)	(162)	(4)
Other	(106)	(10)
Change in operating assets and liabilities:
Settlement receivable	(23)	(1,039)
Accounts receivable	(203)	(113)
Client incentives	(3,142)	(2,177)
Other assets	(245)	41
Accounts payable	(48)	(26)
Settlement payable	(38)	986
Accrued and other liabilities	170	975
Accrued litigation (Note 13)	(519)	(152)
Net cash provided by operating activities	5,358	5,729
Investing Activities
Purchases of property, equipment and technology	(313)	(354)
Investment securities:
Purchases	1,806	2,342
Proceeds from maturities and sales	2,038	1,771
Acquisitions, net of cash acquired	0	(196)
Purchases of / contributions to other investments	(236)	(16)
Proceeds / distributions from other investments	10	0
Other investing activities	(89)	0
Net cash used in investing activities	(396)	(1,137)
Financing Activities
Repurchase of class A common stock (Note 9)	(4,331)	(3,850)
Repayments of long-term debt	0	(1,750)
Dividends paid (Note 9)	(1,141)	(948)
Cash proceeds from issuance of common stock under employee equity plans	89	103
Restricted stock and performance-based shares settled in cash for taxes	(103)	(88)
Net cash used in financing activities	(5,486)	(6,533)
Effect of exchange rate changes on cash and cash equivalents	(171)	206
Decrease in cash, cash equivalents, restricted cash and restricted cash equivalents	(695)	(1,735)
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period (Note 3)	10,977	12,011
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period (Note 3)	10,282	10,276
Supplemental Disclosure
Income taxes paid, net of refunds	1,381	1,197
Interest payments on debt (Note 6)	269	276
Accruals related to purchases of property, equipment and technology	$ 51	$ 21