Cash Cash Equivalents and Marketable Securities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011	Dec. 31, 2010
Cash, cash equivalents and marketable securities [Line Items]
Cash and cash equivalents	$ 15,437		$ 9,983		$ 10,320	$ 13,630
Marketable securities	27,685		34,643
Total cash, cash equivalents, and marketable securities	43,122		44,626
Time deposits
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	404		495
U.S. government agencies
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	2,184		6,226
U.S. government notes
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	8,933		11,579
Foreign government bonds
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	1,606		1,629
Municipal securities
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	1,382		1,794
Corporate debt securities
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	6,118		6,112
Agency residential mortgage-backed securities
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	6,942		6,501
Marketable equity securities
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities	116		307
Cash
Cash, cash equivalents and marketable securities [Line Items]
Cash and cash equivalents	7,463		4,712
Cash equivalents | Time deposits
Cash, cash equivalents and marketable securities [Line Items]
Cash and cash equivalents	436		534
Cash equivalents | Money market and other funds
Cash, cash equivalents and marketable securities [Line Items]
Cash and cash equivalents	7,538	[1]	4,462	[1]
Cash equivalents | U.S. government agencies
Cash, cash equivalents and marketable securities [Line Items]
Cash and cash equivalents	$ 0		$ 275

[1] The balances at December 31, 2011 and June 30, 2012 included $1.3 billion and $1.4 billion of cash collateral received in connection with our securities lending program, which was invested in reverse repurchase agreements maturing within three months. See below for further discussion on this program.