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, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Nov. 30, 2021	Sep. 24, 2013
Beginning balance			$ 23,677				$ 23,677
Net income	$ 360			$ 525			1,491	$ 1,827
Stockholders' Equity Note, Spinoff Transaction	251
Ending balance	$ 25,493						$ 25,493
Dividends per Common Share (USD per share)	$ 0.87	$ 0.87	$ 0.87	$ 0.83	$ 0.83	$ 0.83	$ 2.61	$ 2.49
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
Beginning balance	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365	$ 365
Ending balance	365	365	365	365	365	365	365	365
Capital in Excess of Par Value
Beginning balance	19,495	19,435	19,272	19,341	19,301	19,270	19,272	19,270
Common stock issued for share-based compensation and other plans, net	(9)	(21)	(71)	(9)	(15)	(53)
Share-based compensation	50	56	83	50	55	83
Repurchase of common stock			(150)	(100)
Common stock held in trusts, net	24	(24)
Ending balance	19,511	19,495	19,435	19,282	19,341	19,301	19,511	19,282
Retained Earnings
Beginning balance	14,416	14,233	13,826	13,557	13,522	12,791	13,826	12,791
Net income	360	454	677	525	299	1,003
Common dividends	(248)	(248)	(248)	(239)	(242)	(242)
Preferred dividends	(23)	(23)	(23)	(23)	(23)	(23)
Stockholders' Equity Note, Spinoff Transaction	583
Ending balance	15,088	14,416	14,233	13,821	13,557	13,522	15,088	13,821
Retained Earnings | Effect of change in accounting principles
Effect of change in accounting principles						(9)
Deferred Compensation
Beginning balance	24	24	23	23	23	23	23	23
Common stock issued for share-based compensation and other plans, net		1
Ending balance	24	24	24	23	23	23	24	23
Treasury Stock
Beginning balance	$ (7,866)	$ (7,855)	$ (7,723)	$ (6,132)	$ (6,136)	$ (6,138)	$ (7,723)	$ (6,138)
Beginning balance (shares)	(79,575)	(79,869)	(80,164)	(73,821)	(74,080)	(74,623)	(80,164)	(74,623)
Common stock issued for share-based compensation and other plans, net	$ 5	$ 14	$ 19	$ 5	$ 4	$ 2
Common stock issued for share-based compensation and other plans, net (in shares)	122	284	762	87	234	549
Common stock held in trusts, net (in shares)	9	9	(5)	8	23	(7)
Repurchase of common stock			$ 150	$ (900)
Repurchase of common stock (in shares)			462	(3,724)
Common stock held in trusts, net	$ (24)	$ (24)
Ending balance	$ (7,836)	$ (7,866)	$ (7,855)	$ (7,027)	$ (6,132)	$ (6,136)	$ (7,836)	$ (7,027)
Ending balance (shares)	(79,445)	(79,575)	(79,869)	(77,450)	(73,821)	(74,080)	(79,445)	(77,450)