CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities
Net income	$ 6,152	$ 6,356
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Client incentives	3,850	3,453
Share-based compensation	275	215
Depreciation and amortization of property, equipment, technology and intangible assets	398	374
Deferred income taxes	(27)	(37)
VE territory covered losses incurred	(17)	(13)
Other	(220)	(84)
Change in operating assets and liabilities:
Settlement receivable	(127)	1,642
Accounts receivable	(165)	38
Client incentives	(3,262)	(4,323)
Other assets	(116)	(496)
Accounts payable	(41)	14
Settlement payable	210	(2,165)
Accrued and other liabilities	(39)	303
Accrued litigation	(29)	65
Net cash provided by (used in) operating activities	6,842	5,342
Investing Activities
Purchases of property, equipment and technology	(318)	(407)
Investment securities:
Purchases	(2,015)	(499)
Proceeds from maturities and sales	3,871	3,420
Acquisitions, net of cash acquired	(75)	(77)
Purchases of / contributions to other investments	(30)	(30)
Other investing activities	41	34
Net cash provided by (used in) investing activities	1,474	2,441
Financing Activities
Repurchase of class A common stock	(3,509)	(5,503)
Repayments of debt	(3,000)	0
Dividends paid	(1,404)	(1,339)
Proceeds from issuance of commercial paper	0	1,001
Cash proceeds from issuance of class A common stock under employee equity plans	108	109
Restricted stock and performance-based shares settled in cash for taxes	(140)	(155)
Net cash provided by (used in) financing activities	(7,945)	(5,887)
Effect of exchange rate changes on cash, cash equivalents, restricted cash and restricted cash equivalents	16	88
Increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	387	1,984
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	19,171	10,832
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	19,558	12,816
Supplemental Disclosure
Cash paid for income taxes, net	1,505	1,691
Interest payments on debt	340	269
Accruals related to purchases of property, equipment and technology	$ 17	$ 42