Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Quarterly Financial Data [Abstract]
Net sales	$ 4,558	$ 3,914	$ 4,162	$ 4,151	$ 4,971	$ 4,684	$ 4,570	$ 4,147	$ 16,785	$ 18,372	$ 17,408
Gross profit	1,882	1,618	1,750	1,759	2,128	2,001	1,925	1,761	7,009	7,815
Net earnings common stockholders	$ 723	$ 399	$ 517	$ 326	$ 717	$ 604	$ 520	$ 465	$ 1,965	$ 2,306	$ 2,203
Basic earnings per common share	$ 1.21	$ 0.67	$ 0.85	$ 0.53	$ 1.17	$ 0.98	$ 0.85	$ 0.74	$ 3.26	$ 3.74	$ 3.48
Diluted earnings per common share	1.20	0.67	0.84	0.53	1.16	0.97	0.84	0.74	3.24	3.71	3.46
Dividends per common share	$ 0.50	$ 0.50	$ 0.50	$ 0.50	$ 0.49	$ 0.49	$ 0.49	$ 0.49	$ 2.00	$ 1.96	$ 1.94