CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 4,872	$ 4,156	$ 14,425	$ 12,592
Investment securities:
Net unrealized gain (loss)	7	(18)	57	33
Income tax effect	(1)	4	(12)	(7)
Defined benefit pension and other postretirement plans:
Net unrealized actuarial gain (loss) and prior service credit (cost)	0	1	8	6
Income tax effect	0	0	(2)	(1)
Reclassification adjustments	0	3	6	7
Income tax effect	0	(1)	(2)	(1)
Derivative instruments:
Net unrealized gain (loss)	73	(4)	54	(195)
Income tax effect	(11)	5	(2)	36
Reclassification adjustments	(21)	18	12	17
Income tax effect	1	(10)	(7)	(17)
Foreign currency translation adjustments:
Translation adjustments	(100)	14	131	1,513
Income tax effect	(10)	0	14	0
Other comprehensive income (loss)	(62)	12	257	1,391
Comprehensive income	$ 4,810	$ 4,168	$ 14,682	$ 13,983