Information about Segments and Geographic Areas (Long-Lived Assets by Geographic Area) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Long-lived assets:
Long-lived assets	$ 33,884	[1]	$ 33,344	[1]
United States
Long-lived assets:
Long-lived assets	21,645	[1]	20,985	[1]
International
Long-lived assets:
Long-lived assets	$ 12,239	[1]	$ 12,359	[1]

[1] Includes Home segment.