Pension and Other Postretirement Benefits, Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 25	$ 22	$ 77	$ 72
Interest cost	36	35	108	106
Expected return on plan assets	(56)	(48)	(168)	(146)
Amortization of prior service costs (credits)	(1)	1	(1)	1
Amortization of net loss (gains)	18	14	55	45
Curtailment losses	0	2	0	2
Net periodic benefit cost	22	26	71	80
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0	1	1	2
Interest cost	2	2	4	4
Expected return on plan assets	(2)	(1)	(4)	(3)
Amortization of prior service costs (credits)	(1)	(1)	(1)	(1)
Amortization of net loss (gains)	0	(1)	(2)	(2)
Curtailment losses	0	0	0	0
Net periodic benefit cost	$ (1)	0	$ (2)	$ 0
ISRS [Member] | Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Curtailment losses		$ 2