Cash, Cash Equivalents, and Marketable Securities - Summary by Major Security Type Cash Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis and Categorized Using Fair Value Hierarchy (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Cash, cash equivalents and marketable securities [Line Items]
Total Estimated Fair Value	$ 8,666		$ 12,447
Less: Restricted cash, cash equivalents, and marketable securities	(336)	[1]	(301)	[1]
Cash
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	2,902
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Total Estimated Fair Value	2,902		3,008
Cash, cash equivalents, and marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	8,998
Gross Unrealized Gains	7
Gross Unrealized Losses	(3)
Total Estimated Fair Value	9,002		12,748
Level 1 Securities | Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	2,490
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Total Estimated Fair Value	2,490		5,914
Level 1 Securities | Equity securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	3
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Total Estimated Fair Value	3		4
Level 2 Securities | Foreign government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	617
Gross Unrealized Gains	2
Gross Unrealized Losses	(1)
Total Estimated Fair Value	618		758
Level 2 Securities | U.S. government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	2,128
Gross Unrealized Gains	2
Gross Unrealized Losses	(2)
Total Estimated Fair Value	2,128		2,222
Level 2 Securities | Corporate debt securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	755
Gross Unrealized Gains	3
Gross Unrealized Losses	0
Total Estimated Fair Value	758		741
Level 2 Securities | Asset-backed securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	69
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Total Estimated Fair Value	69		65
Level 2 Securities | Other fixed income securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	34
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Total Estimated Fair Value	$ 34		$ 36

[1] We are required to pledge or otherwise restrict a portion of our cash, cash equivalents, and marketable securities as collateral for standby and trade letters of credit, guarantees, debt, and real estate lease agreements. We classify cash and marketable securities with use restrictions of less than twelve months as “Accounts receivable, net and other” and of twelve months or longer as non-current “Other assets” on our consolidated balance sheets. See “Note 3 — Commitments and Contingencies.”