Unaudited Selected Quarterly Data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unaudited Selected Quarterly Data (Table Amounts) [Abstract]
Total sales	$ 6,634	$ 6,527	$ 6,375	$ 6,267	$ 6,397	$ 6,155	$ 6,000	$ 5,956	$ 25,803	$ 24,508	$ 23,526
Operating income	767	845	855	832	831	826	797	739	3,299	3,193	3,076
Net earnings	$ 178	$ 645	$ 552	$ 640	$ 525	$ 602	$ 517	$ 556	$ 2,015	$ 2,200	$ 1,990
Basic earnings per share	$ 1.02	$ 3.70	$ 3.16	$ 3.66	$ 2.98	$ 3.38	$ 2.87	$ 3.07	$ 11.55	$ 12.30	$ 10.51
Diluted earnings per share	$ 1.01	$ 3.68	$ 3.15	$ 3.63	$ 2.96	$ 3.35	$ 2.85	$ 3.03	$ 11.47	$ 12.19	$ 10.39
Weighted-average common shares outstanding	174.2	174.2	174.5	174.8	176.0	178.1	180.1	181.3	174.4	178.9	189.4
Weighted-average diluted shares outstanding	175.5	175.3	175.5	176.1	177.6	179.6	181.5	183.4	175.6	180.5	191.6