Shareholders' Equity - Changes in Certain Components of Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Nov. 04, 2021
Beginning balance	$ 23,677
Net income	677	$ 1,003
Ending balance	$ 24,160
Dividends per Common Share (USD per share)	$ 0.87	$ 0.83
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	10,000
Stock Repurchase Program, Number of Additional Shares Authorized to be Repurchased			10,000
Common Stock  Issued at Par Value
Beginning balance	$ 365	$ 365
Ending balance	365	365
Capital in Excess of Par Value
Beginning balance	19,272	19,270
Common stock issued for share-based compensation and other plans, net	(71)	(53)
Share-based compensation	83	83
Treasury Stock, Value, Acquired, Cost Method	(150)
Ending balance	19,435	19,301
Retained Earnings
Beginning balance	13,826	12,791
Net income	677	1,003
Common dividends	(248)	(242)
Preferred dividends	(23)	(23)
Ending balance	14,233	13,522
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity, Other		(9)
Deferred Compensation
Beginning balance	23	23
Ending balance	24	23
Treasury Stock
Beginning balance	$ (7,723)	$ (6,138)
Beginning balance (shares)	(80,164)	(74,623)
Common stock issued for share-based compensation and other plans, net	$ 19	$ 2
Common stock issued for share-based compensation and other plans, net (in shares)	762	549
Common stock held in trusts, net (in shares)	(5)	(7)
Treasury Stock, Value, Acquired, Cost Method	$ 150
Treasury Stock, Shares, Acquired	462
Ending balance	$ (7,855)	$ (6,136)
Ending balance (shares)	(79,869)	(74,080)