Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 31, 2019
Contract with Customer, Asset and Liability [Abstract]
Accounts receivable, net	$ 1,155		$ 1,155		$ 1,412
Contract assets	1,069		1,069		1,046
Contract liabilities	1,359		1,359		1,449
Non-current contract liabilities	266		266		$ 274
Contract with customer, liability, revenue recognized	349	$ 342	807	$ 783
Contract with customer, performance obligation adjustments	12	26	48	42
Impairment losses	$ 0	$ 0	$ 0	$ 0