Employee Benefit Plans - Schedule of Pre-tax Change in Other Comprehensive Loss (Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 30, 2016
Pension Benefits
Recognized in the Balance Sheet
Losses (Gains)	$ 223	$ (131)
Expense (Income) Recognized in the Income Statement
Amortization of Net Loss	41	41	$ 48
Settlement (Gain) Loss	(1)	11	(1)
Curtailment Loss	0	4
Amortization of Prior Service Costs	0	0	0
Amortization of net losses estimated to be expensed in next fiscal year	43
Post-retirement Benefits
Recognized in the Balance Sheet
Losses (Gains)	(112)	(17)
Expense (Income) Recognized in the Income Statement
Amortization of Net Loss	0	0	3
Settlement (Gain) Loss	0	0	0
Curtailment Loss	0	0
Amortization of Prior Service Costs	$ (2)	$ 0	$ 0