Inventories (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
At lower of LIFO cost or market:
Hogs and materials	$ 387	$ 361
Fresh pork and materials	46	36
LIFO adjustment	(64)	(58)
Total inventories at lower of LIFO cost or market	369	339
At lower of FIFO cost and net realizable value:
Grains, oilseeds and other commodities	353	229
Sugar produced and in process	17	17
Other	109	81
Total inventories at lower of FIFO cost and net realizable value	479	327
Grain, flour and feed at lower of weighted average cost and net realizable value	174	149
Total inventories	1,022	815
LIFO method increase (decrease) in earnings	$ (5)	$ (20)	$ (6)
LIFO method increase (decrease) in earnings per share (in dollars per share)	$ (4.10)	$ (16.87)	$ (5.40)
Amount that inventories would have been higher by if the FIFO method had been used	$ 64	$ 58
Reserve for LIFO Valuation
Reserve for LIFO Valuation
Balance at beginning of year	58	31	$ 21
Increase (decrease)	6	27	10
Balance at end of year	$ 64	$ 58	$ 31