Goodwill and Other Intangible Assets (Carrying Amount of Goodwill) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Change in carrying amount of goodwill
December 31, 2011	$ 3,623	[1]
Currency translation adjustment	5
March 31, 2012	3,628
U.S. Morning Foods and Kashi [Member]
Change in carrying amount of goodwill
December 31, 2011	80
Currency translation adjustment	0
March 31, 2012	80
U.S. Snacks [Member]
Change in carrying amount of goodwill
December 31, 2011	3,257
Currency translation adjustment	0
March 31, 2012	3,257
North America Other [Member]
Change in carrying amount of goodwill
December 31, 2011	202
Currency translation adjustment	0
March 31, 2012	202
Europe [Member]
Change in carrying amount of goodwill
December 31, 2011	57
Currency translation adjustment	5
March 31, 2012	62
Asia Pacific [Member]
Change in carrying amount of goodwill
December 31, 2011	27
Currency translation adjustment	0
March 31, 2012	$ 27

[1] * Condensed from audited financial statements.