Stock Compensation - Stock Options (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	14	15
Granted (in shares)	3	2
Exercised (in shares)	(1)	(1)
Forfeitures and expirations (in shares)	(1)	0
Outstanding, end of period (in shares)	15	16
Exercisable, end of period (in shares)	11	11
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period, weighted-average exercise price (in dollars per share)	$ 64	$ 62
Granted, weighted-average exercise price (in dollars per share)	70	73
Exercised, weighted-average exercise price (in dollars per share)	57	57
Forfeitures and expirations, weighted-average exercise price (in dollars per share)	70	0
Outstanding, end of period, weighted-average exercise price (in dollars per share)	65	64
Exercisable, end of period, weighted-average exercise price (in dollars per share)	$ 63	$ 60
Outstanding, end of period, weighted-average remaining contractual term	6 years 7 months 6 days	7 years
Exercisable, end of period, weighted-average remaining contractual term	5 years 8 months 12 days	6 years 1 month 6 days
Outstanding, end of period, aggregate intrinsic value	$ 92	$ 109
Exercisable, end of period, aggregate intrinsic value	$ 91	$ 104
Weighted-average fair value of options granted (in dollars per share)	$ 10.00	$ 10.14