Fair Value Measurements - Schedule of Pension Plan Assets at Fair Value by Level (Details) - USD ($) $ in Millions	Dec. 30, 2016	Dec. 25, 2015
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 2,539	$ 2,309
Total investments in the fair value hierarchy	1,616	1,393
Alternative Investments, Fair Value Disclosure	923	916
Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1,806	1,626
Common Stock
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	940	738
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	665	641
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	12	15
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1	8
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	497	480
Government Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	141	132
Asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	14	14
Derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	11	6
Level 1
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	953	761
Total investments in the fair value hierarchy	953	761
Level 1 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	940	738
Level 1 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	12	15
Level 1 | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1	8
Level 1 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 | Government Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 | Asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 | Derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	663	632
Total investments in the fair value hierarchy	663	632
Level 2 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	497	480
Level 2 | Government Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	141	132
Level 2 | Asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	14	14
Level 2 | Derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	11	6
Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Total investments in the fair value hierarchy	0	0
Level 3 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Government Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Asset-backed securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 | Derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 0	$ 0