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	Dec. 31, 2014		Dec. 31, 2013
Cash, cash equivalents and marketable securities [Line Items]
Less: Restricted cash, cash equivalents, and marketable securities	$ (450)	[1]	$ (301)	[1]
Cash, Cash Equivalents, and Short-term Investments	17,416		12,447
Cash
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	4,155		3,008
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Cash, Cash Equivalents, and Short-term Investments	4,155		3,008
Cash, cash equivalents, and marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	17,865		12,746
Gross Unrealized Gains	4		7
Gross Unrealized Losses	(3)		(5)
Cash, Cash Equivalents, and Short-term Investments	17,866		12,748
Level 1 Securities | Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	10,718		5,914
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Cash, Cash Equivalents, and Short-term Investments	10,718		5,914
Level 1 Securities | Equity securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	2		3
Gross Unrealized Gains	2		1
Gross Unrealized Losses	0		0
Cash, Cash Equivalents, and Short-term Investments	4		4
Level 2 Securities | Foreign government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	80		757
Gross Unrealized Gains	0		2
Gross Unrealized Losses	0		(1)
Cash, Cash Equivalents, and Short-term Investments	80		758
Level 2 Securities | U.S. government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	2,407		2,224
Gross Unrealized Gains	1		1
Gross Unrealized Losses	(2)		(3)
Cash, Cash Equivalents, and Short-term Investments	2,406		2,222
Level 2 Securities | Corporate debt securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	401		739
Gross Unrealized Gains	1		3
Gross Unrealized Losses	(1)		(1)
Cash, Cash Equivalents, and Short-term Investments	401		741
Level 2 Securities | Asset-backed securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	69		65
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Cash, Cash Equivalents, and Short-term Investments	69		65
Level 2 Securities | Other fixed income securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	33		36
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Cash, Cash Equivalents, and Short-term Investments	$ 33		$ 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, real estate leases, and amounts due to third-party sellers in certain jurisdictions. We classify cash, cash equivalents 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 8—Commitments and Contingencies.”