Revenue - Impact of Adjustments in Contract Estimates (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 9,094	$ 7,580	$ 25,815	$ 22,696
Operating earnings	$ 1,135	$ 1,063	$ 3,231	$ 3,176
Diluted earnings per share	$ 2.85	$ 2.52	$ 8.12	$ 7.45
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 96	$ 94	$ 302	$ 256
Operating earnings	$ 103	$ 103	$ 283	$ 274
Diluted earnings per share	$ 0.27	$ 0.22	$ 0.75	$ 0.58