Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 3,143	$ 3,129	$ 3,102	$ 2,876	$ 2,863	$ 2,743	$ 2,933	$ 2,869	$ 12,250	$ 11,408	$ 11,069
Operating Income	1,249	1,293	1,283	1,044	1,126	868	957	769	4,869	3,720	3,413
Net Earnings	$ 843	$ 894	$ 877	$ 695	$ 4,140	$ 459	$ 510	$ 362	$ 3,309	$ 5,471	$ 1,714
Earnings Per Share, Basic (in dollars per share)	$ 1.02	$ 1.05	$ 1.02	$ 0.78	$ 4.63	$ 0.51	$ 0.55	$ 0.39	$ 3.86	$ 6.01	$ 1.81
Earnings Per Share, Assuming Dilution (in dollars per share)	$ 1.01	$ 1.05	$ 1.01	$ 0.78	$ 4.62	$ 0.51	$ 0.55	$ 0.39	$ 3.84	$ 5.99	$ 1.81
Effect of change in tax rate					$ 3,600					$ 3,600
Effect of change in tax rate (in dollars per share)					$ 3.91					$ 3.91