CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 4,179	$ 3,959
Investment securities:
Net unrealized gain (loss)	15	(10)
Income tax effect	(3)	2
Defined benefit pension and other postretirement plans:
Net unrealized actuarial gain (loss) and prior service credit (cost)	2	1
Income tax effect	(1)	0
Reclassification adjustments	1	1
Derivative instruments:
Net unrealized gain (loss)	(116)	114
Income tax effect	14	(22)
Reclassification adjustments	(7)	(6)
Income tax effect	(4)	0
Foreign currency translation adjustments	1,209	(588)
Other comprehensive income (loss), net of tax	1,110	(508)
Comprehensive income	$ 5,289	$ 3,451