Retirement Plans - Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Change in fair value of plan assets
Valuation of owned properties period	3 years
Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	$ 8,772	$ 8,413	$ 7,943
Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	5,477	5,006
Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	679	753
Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	479	508
Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	2,137	2,146
Cash and equivalents | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	159	231
Cash and equivalents | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	1	1
Cash and equivalents | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Cash and equivalents | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Domestic equity securities | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	3,151	2,754
Domestic equity securities | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Domestic equity securities | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Domestic equity securities | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	307	299
International equity securities | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	1,028	1,061
International equity securities | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
International equity securities | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
International equity securities | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	290	281
Mutual funds | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	194	117
Mutual funds | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Mutual funds | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
National, state and local governments | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	899	679
National, state and local governments | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	60	142
National, state and local governments | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
National, state and local governments | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	13	88
Corporate debt | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	46	164
Corporate debt | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	618	610
Corporate debt | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Corporate debt | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	148	90
Private investment partnerships | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Private investment partnerships | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Private investment partnerships | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Private investment partnerships | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	974	1,000
Real estate | Level 1 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Real estate | Level 2 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	0	0
Real estate | Level 3
Change in fair value of plan assets
Fair value of total pension plan assets	479	508	$ 569
Real estate | Level 3 | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	479	508
Real estate | Not Subject to Leveling | Pension Benefits
Change in fair value of plan assets
Fair value of total pension plan assets	$ 405	$ 388