Revenue (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended
	Mar. 29, 2019	Mar. 29, 2019	Mar. 30, 2018	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue, OTLs and STLs		$ 107	$ 97
Revenue, remaining performance obligation	$ 1,900	1,900
Revenue, remaining performance obligation, expected satisfaction in next 12 months, percent	43.00%
Revenue, remaining performance obligation, expected satisfaction in subsequent 12 months, percent	27.00%
Contract with customer, asset, net	$ 97	97		$ 82
Contract with customer, liability	$ 838	838		$ 799
Contract with customer, liability, revenue recognized		$ 287	$ 265