Employee Benefits - Contributions to Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Restructuring charges	$ 5	$ 96	$ 25	$ 238
Employer contributions to employee benefit plans	255	4	274	28	$ 44
Total current year projected employer contributions	287		287
Employer discretionary contribution amount	250
Pension
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to employee benefit plans	251	2	266	23	31
Total current year projected employer contributions	274		274
Employer discretionary contribution amount		250
Nonpension postretirement
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to employee benefit plans	4	2	8	5	$ 13
Total current year projected employer contributions	13		13
Employee related costs
Defined Benefit Plan Disclosure [Line Items]
Restructuring charges	$ 1	28	$ 5	$ 135
Employee related costs | Multiemployer Plans
Defined Benefit Plan Disclosure [Line Items]
Restructuring charges		$ 26
Cash Obligation Period		20 years