Contract Assets and Contract Liabilities (Net Contract Assets (Liabilities)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Contract with Customer, Asset and Liability [Abstract]
Contract assets	$ 6,122	$ 5,594
Change in contract assets	$ 528
Percent change in contract assets	9.40%
Contract liabilities—current	$ (3,267)	(3,309)
Change in contract liabilities, current	$ 42
Percent change in contract liabilities, current	1.30%
Contract liabilities—noncurrent	$ (143)	(150)
Change in contract liabilities, noncurrent	$ 7
Percent change in contract liabilities, noncurrent	4.70%
Net contract assets (liabilities)	$ 2,712	$ 2,135
Change in net contract assets (liabilities)	$ 577
Percent change in net contract assets (liabilities)	27.00%