Unaudited Selected Quarterly Data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unaudited Selected Quarterly Data (Table Amounts) [Abstract]
Sales	$ 8,156	$ 8,085	$ 7,119	$ 6,735	$ 6,552	$ 6,569	$ 6,473	$ 6,410	$ 30,095	$ 26,004	$ 24,706
Operating income	943	1,172	817	848	672	829	864	853	3,780	3,218	3,277
Net earnings	$ 356	$ 1,244	$ 789	$ 840	$ 672	$ 750	$ 677	$ 770	$ 3,229	$ 2,869	$ 2,043
Basic earnings per share	$ 2.07	$ 7.15	$ 4.52	$ 4.82	$ 3.86	$ 4.31	$ 3.88	$ 4.41	$ 18.59	$ 16.45	$ 11.42
Diluted earnings per share	$ 2.06	$ 7.11	$ 4.50	$ 4.79	$ 3.83	$ 4.28	$ 3.86	$ 4.37	$ 18.49	$ 16.34	$ 11.32
Weighted-average common shares outstanding	171.8	174.1	174.5	174.3	174.2	174.2	174.5	174.8	173.7	174.4	178.9
Weighted-average diluted shares outstanding	172.6	174.9	175.4	175.4	175.5	175.3	175.5	176.1	174.6	175.6	180.5