Long-Lived Assets by Geographic Area (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 33,344	[1]	$ 19,816	[1]
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	20,985	[1]	15,963	[1]
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 12,359	[1]	$ 3,853	[1]

[1] Includes Home segment.