Other Income - Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 30, 2016
Other Income and Expenses [Abstract]
Net Periodic Pension and Postretirement Benefit Credit (Expense)	$ 38	$ 32	$ (24)
Interest Income	32	13	10
Income from Non-operating Real Estate Activities	0	0	27
Miscellaneous Income	4	8	9
Total Other Income - Net	74	53	22
Gross Revenue from Real Estate Operations included above	$ 0	$ 0	$ 56