Shareholders' Equity - Changes in Certain Components of Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2023	Jun. 30, 2022	Jun. 01, 2023	Nov. 30, 2021	Sep. 24, 2013
Beginning balance			$ 25,282				$ 25,282
Net income	$ 407			$ 360			1,376	$ 1,491
Stockholders' Equity Note, Spinoff Transaction				$ 251
Ending balance	$ 25,937						$ 25,937
Dividends per Common Share (USD per share)	$ 0.91	$ 0.91	$ 0.91	$ 0.87	$ 0.87	$ 0.87	$ 2.73	$ 2.61
Number of shares authorized to be repurchased (in shares)											10,000
Number of additional shares authorized to be repurchased (in shares)										10,000
Common Stock  Issued at Par Value
Convertible Preferred Stock, Shares Issued upon Conversion									5,955
Convertible Preferred Stock
Preferred Stock, Shares Outstanding									1,500
Common Stock  Issued at Par Value
Beginning balance	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365
Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments	6
Ending balance	371	365	365	365	365	365	371	365
Capital in Excess of Par Value
Beginning balance	19,639	19,590	19,553	19,495	19,435	19,272	19,553	19,272
Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments	(4)
Issuance of shares under employee and other plans, net	(9)	(7)	(52)	(9)	(21)	(71)
Share-based compensation	56	56	89	50	56	83
Common stock held in trusts, net				(24)	24
Repurchase of common stock						150
Ending balance	19,681	19,639	19,590	19,511	19,495	19,435	19,681	19,511
Retained Earnings
Beginning balance	15,563	15,384	15,157	14,416	14,233	13,826	15,157	13,826
Net income	407	460	509	360	454	677
Common dividends	(264)	(259)	(259)	(248)	(248)	(248)
Preferred dividends	(15)	(23)	(23)	(23)	(23)	(23)
Stockholders' Equity Note, Spinoff Transaction				583
Ending balance	15,691	15,563	15,384	15,088	14,416	14,233	15,691	15,088
Deferred Compensation
Beginning balance	24	24	23	24	24	23	23	23
Issuance of shares under employee and other plans, net	(1)				1
Ending balance	23	24	24	24	24	24	23	24
Treasury Stock, Common
Beginning balance	$ (8,327)	$ (8,333)	$ (8,330)	$ (7,866)	$ (7,855)	$ (7,723)	$ (8,330)	$ (7,723)
Beginning balance (shares)	(80,625)	(80,738)	(81,283)	(79,575)	(79,869)	(80,164)	(81,283)	(80,164)
Issuance of shares under employee and other plans, net	$ 6	$ 5	$ (3)	$ 5	$ 14	$ 19
Common stock issued for share-based compensation and other plans, net (in shares)	131	21	556	122	284	762
Common stock held in trusts, net (in shares)	8	92	(11)	9	9	(5)
Common stock held in trusts, net				$ 24	$ (24)
Repurchase of common stock						$ (150)
Repurchase of common stock (in shares)						(462)
Ending balance	$ (8,321)	$ (8,327)	$ (8,333)	$ (7,836)	$ (7,866)	$ (7,855)	$ (8,321)	$ (7,836)
Ending balance (shares)	(80,486)	(80,625)	(80,738)	(79,445)	(79,575)	(79,869)	(80,486)	(79,445)