Nature of Operations and Significant Accounting Policies - Restructuring Charges (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 24, 2016	Jun. 30, 2017	Jun. 24, 2016
Restructuring Cost and Reserve [Line Items]
Expense	$ 122		$ 0	$ 295	$ 0
Management Streamlining Initiative
Restructuring Cost and Reserve [Line Items]
Expense	122	$ 173		295
Payments				(129)
Non-cash Items				102
Balance	(64)			(64)
Management Streamlining Initiative | Subtotal Management Workforce Reduction
Restructuring Cost and Reserve [Line Items]
Expense	22	155		177
Payments				(64)
Non-cash Items				78
Balance	(35)			(35)
Management Streamlining Initiative | Severance
Restructuring Cost and Reserve [Line Items]
Expense	10	81		91
Payments				(62)
Balance	(29)			(29)
Management Streamlining Initiative | Pension, Other Post-retirement Benefit and Other Non-cash Charges
Restructuring Cost and Reserve [Line Items]
Expense	10	68		78
Payments				0
Non-cash Items				78
Balance	0			0
Management Streamlining Initiative | Relocation
Restructuring Cost and Reserve [Line Items]
Expense	2	6		8
Payments				(2)
Balance	(6)			(6)
Management Streamlining Initiative | Reimbursement Arrangements
Restructuring Cost and Reserve [Line Items]
Expense	84	0		84
Payments				(55)
Balance	(29)			(29)
Management Streamlining Initiative | Non-cash Executive Equity Awards Proration
Restructuring Cost and Reserve [Line Items]
Expense	16	8		24
Payments				0
Non-cash Items				24
Balance
Management Streamlining Initiative | Advisory Fees Related to Shareholder Matters
Restructuring Cost and Reserve [Line Items]
Expense	0	$ 10		10
Payments				(10)
Balance	$ 0			$ 0