Asset Impairment Charges And Exit Costs (Asset Impairment Charges And Exit Costs) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Sep. 30, 2012 Gruma S.A.B. de C.V. [Member]	Dec. 31, 2012 Agricultural Services [Member]	Mar. 31, 2012 Corporate [Member]	Dec. 31, 2011 Corporate [Member]	Dec. 31, 2011 Corporate [Member]	Jun. 30, 2012 Corporate [Member]	Mar. 31, 2012 Corn Processing [Member]	Dec. 31, 2011 Corn Processing [Member]	Dec. 31, 2011 Corn Processing [Member]	Jun. 30, 2012 Corn Processing [Member]
Employee-related costs			$ 71
Facility exit and other related costs	146	352	366	146	146	4	13	13	17	14	339	339	349
Total asset impairment, exit and restructuring costs	146	352	437
Remeasurement charge			$ 34