Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2020	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Operations of Seaboard Corporation and its Subsidiaries
Percentage of ownership interest held by Seaboard Flour LLC and SFC Preferred LLC	77.00%									77.00%
Change in Accounting Principle
Percentage of LIFO inventory	42.00%									42.00%
Retained earnings	$ 4,287				$ 4,030					$ 4,287	$ 4,030
Impact of the change in consolidated statements of comprehensive income
Total cost of sales and operating expenses	1,768	$ 1,517	$ 1,719	$ 1,548	1,634	$ 1,591	$ 1,676	$ 1,493		6,552	6,394	$ 6,033
Gross income										574	446	550
Operating income (loss)	$ 134	$ 39	$ 9	$ 63	$ 89	$ (8)	$ 63	$ (34)		245	110	236
Income tax expense (benefit)										3	3	8
Net earnings										$ 283	$ 287	$ 3
Earnings per common share	$ 222.52	$ 132.58	$ (23.51)	$ (88.73)	$ 148.75	$ (7.23)	$ 56.26	$ 48.88		$ 244.21	$ 246.62	$ 2.26
impact of the change on consolidated balance sheet
Inventories	$ 1,178				$ 1,086					$ 1,178	$ 1,086
Deferred income taxes	103				93					103	93
Retained earnings	4,287				4,030					4,287	4,030
impact of the change on consollidated statements of cash flows
Net earnings										283	287	$ 3
Deferred income taxes										11	(53)	(13)
Inventories										(99)	(158)	(61)
Goodwill and Other Intangible Assets
Impairment charges										0
Goodwill
Goodwill, beginning balance				$ 164				$ 167		164	167
Acquisition											1
Foreign currency translation										4	(4)
Other adjustments										(1)
Goodwill, ending balance	167				164					167	164	167
Intangible assets
Gross carrying amount	79				78					79	78
Accumulated amortization and currency translation	(25)				(20)					(25)	(20)
Net carrying amount	54				58					54	58
Intangible assets
Amortization of intangible assets										8	8
2021	8									8
2022	8									8
2023	8									8
2024	8									8
2025	8									8
Thereafter	14									14
Changes in the asset retirement obligation
Beginning balance				25				23		25	23
Accretion expense										2	2
Ending balance	27				25					$ 27	25	23
Practical expedient, disclosure of performance obligation										true
Supplemental Non-Cash Transactions
Interest, net of interest capitalized										$ 16	36	43
Income taxes, net of refunds										55	31	35
Operating cash flows from operating leases										142	137
Operating cash flows from finance leases										4	1
Financing cash flows from finance leases										7	2
Operating ROU assets obtained in exchange for new operating lease liabilities										62	95
Finance ROU assets obtained in exchange for new finance lease liabilities										50	46
Capital expenditures included in accounts payable										7
Foreign Currency Transactions and Translation
Period of measurement to determine highly inflationary accounting									3 years
Three-year cumulative inflation rate									100.00%
Foreign currency gains related to the adoption of highly inflationary accounting										1	(3)	9
As Computed Under LIFO
Change in Accounting Principle
Retained earnings	4,243									4,243
Impact of the change in consolidated statements of comprehensive income
Total cost of sales and operating expenses										6,612
Gross income										514
Operating income (loss)										185
Income tax expense (benefit)										(13)
Net earnings										$ 239
Earnings per common share										$ 205.88
impact of the change on consolidated balance sheet
Inventories	1,118									$ 1,118
Deferred income taxes	87									87
Retained earnings	4,243									4,243
impact of the change on consollidated statements of cash flows
Net earnings										239
Deferred income taxes										(5)
Inventories										(39)
As Previously Reported
Change in Accounting Principle
Retained earnings					3,983						3,983
Impact of the change in consolidated statements of comprehensive income
Total cost of sales and operating expenses	1,768	$ 1,527	$ 1,717	1,548	1,632	$ 1,589	$ 1,686	1,493			6,400	6,060
Gross income											440	523
Operating income (loss)	$ 134	$ 29	$ 11	$ 63	$ 91	$ (6)	$ 53	$ (34)			104	209
Income tax expense (benefit)											1	1
Net earnings											$ 283	$ (17)
Earnings per common share	$ 222.52	$ 126.17	$ (22.35)	$ (88.43)	$ 149.91	$ (6.00)	$ 50.13	$ 48.79			$ 242.78	$ (14.61)
impact of the change on consolidated balance sheet
Inventories					$ 1,022						$ 1,022
Deferred income taxes					76						76
Retained earnings					3,983						3,983
impact of the change on consollidated statements of cash flows
Net earnings											283	$ (17)
Deferred income taxes											(55)	(20)
Inventories											(152)	(34)
Impact of Change to FIFO
Change in Accounting Principle
Retained earnings	$ 44				47					44	47		$ 23
Impact of the change in consolidated statements of comprehensive income
Total cost of sales and operating expenses										(60)	(6)	(27)
Gross income										60	6	27
Operating income (loss)										60	6	27
Income tax expense (benefit)										16	2	7
Net earnings										$ 44	$ 4	$ 20
Earnings per common share										$ 38.33	$ 3.84	$ 16.87
impact of the change on consolidated balance sheet
Inventories	60				64					$ 60	$ 64
Deferred income taxes	16				17					16	17
Retained earnings	44				47					44	47		$ 23
impact of the change on consollidated statements of cash flows
Net earnings										44	4	$ 20
Deferred income taxes										16	2	7
Inventories										$ (60)	(6)	(27)
Minimum
Principles of Consolidation and Investments in Affiliates
Time lag for reporting financial information										1 month
Property, Plant and Equipment
Useful Lives										3 years
Maximum
Principles of Consolidation and Investments in Affiliates
Time lag for reporting financial information										3 months
Property, Plant and Equipment
Useful Lives										30 years
Pork
Impact of the change in consolidated statements of comprehensive income
Operating income (loss)										$ 131	60	144
Goodwill
Goodwill, beginning balance				$ 18				$ 18		18	18
Goodwill, ending balance	18				18					18	18	18
CT&M
Impact of the change in consolidated statements of comprehensive income
Operating income (loss)										118	62	46
Goodwill
Goodwill, beginning balance				146				149		146	149
Acquisition											1
Foreign currency translation										4	(4)
Other adjustments										(1)
Goodwill, ending balance	149				146					$ 149	146	149
CT&M | Mimran
Principles of Consolidation and Investments in Affiliates
Time lag for reporting financial information										3 months
Customer relationships
Intangible assets
Gross carrying amount	51				50					$ 51	50
Accumulated amortization and currency translation	(16)				(13)					(16)	(13)
Net carrying amount	35				37					35	37
Trade names
Intangible assets
Gross carrying amount	28				28					28	28
Accumulated amortization and currency translation	(9)				(7)					(9)	(7)
Net carrying amount	19				21					19	21
Allowance for Credit Losses
Movement in valuation and qualifying accounts
Balance at beginning of year				28				33		28	33	29
Provision											5	7
Net deductions										(3)	(10)	(3)
Balance at end of year	28				28					28	28	33
Allowance for Notes Receivable
Movement in valuation and qualifying accounts
Balance at beginning of year				$ 17				$ 17		17	17	16
Provision												1
Balance at end of year	17				17					17	17	$ 17
Cumulative Effect, Period of Adoption, Adjustment | Allowance for Credit Losses
Movement in valuation and qualifying accounts
Transition Adjustment											3
Accounts Receivable | Geographic concentration | Foreign Country
Accounts Receivable
Foreign receivables, excluding receivables due from affiliates	$ 410				$ 390					$ 410	$ 390