CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions		6 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Operating Activities
Net income		$ 9,696	$ 9,553
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Client incentives		7,531	6,605
Share-based compensation		483	451
Depreciation and amortization		587	496
Deferred income taxes		(86)	(68)
VE territory covered losses		(24)	(60)
(Gains) losses on equity investments, net		98	26
Other		65	58
Change in operating assets and liabilities:
Settlement receivable		132	(1,335)
Accounts receivable		(156)	34
Client incentives		(7,190)	(7,088)
Other assets		(400)	(258)
Accounts payable		(45)	(25)
Settlement payable		(155)	1,143
Accrued and other liabilities		(796)	(1,479)
Accrued litigation		351	99
Net cash provided by (used in) operating activities		10,091	8,152
Investing Activities
Purchases of property, equipment and technology		(672)	(548)
Purchases of investment securities		0	(3,686)
Proceeds from maturities and sales of investment securities		2,268	2,145
Acquisitions, net of cash and restricted cash acquired		(887)	(915)
Purchases of other investments		(24)	(14)
Other investing activities		(25)	(47)
Net cash provided by (used in) investing activities		660	(3,065)
Financing Activities
Repurchases of class A common stock		(8,607)	(6,338)
Dividends paid		(2,334)	(2,120)
Proceeds from stock issued under equity plans		246	183
Taxes paid related to stock issued under equity plans		(242)	(181)
Other financing activities		(198)	203
Net cash provided by (used in) financing activities		(11,135)	(8,253)
Effect of exchange rate changes on cash, cash equivalents, restricted cash and restricted cash equivalents		(243)	124
Increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents		(627)	(3,042)
Cash, cash equivalents, restricted cash and restricted cash equivalents as of beginning of period		19,763	21,990
Cash, cash equivalents, restricted cash and restricted cash equivalents as of end of period		19,136	18,948
Supplemental Disclosure
Cash paid for income taxes, net	[1]	3,055	3,658
Interest payments on debt		261	261
Accruals related to purchases of property, equipment and technology		$ 60	$ 99

[1] For the six months ended March 31, 2025, the amount includes $1.3 billion of cash paid for federal transferable tax credits.