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		Jun. 30, 2015	Dec. 31, 2014
Cash, cash equivalents and marketable securities [Line Items]
Less: Restricted cash, cash equivalents, and marketable securities	[1]	$ (168)	$ (450)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		14,001	17,416
Cash
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		4,368
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		4,368	4,155
Cash, cash equivalents, and marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		14,151
Gross Unrealized Gains		21
Gross Unrealized Losses		(3)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		14,169	17,866
Level 1 Securities | Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		6,056
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		6,056	10,718
Level 1 Securities | Equity securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		4
Gross Unrealized Gains		18
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		22	4
Level 2 Securities | Foreign government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		63
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		63	80
Level 2 Securities | U.S. government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		3,037
Gross Unrealized Gains		2
Gross Unrealized Losses		(2)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		3,037	2,406
Level 2 Securities | Corporate debt securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		468
Gross Unrealized Gains		1
Gross Unrealized Losses		(1)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		468	401
Level 2 Securities | Asset-backed securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		111
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		111	69
Level 2 Securities | Other fixed income securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost		44
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value		$ 44	$ 33

[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 3 — Commitments and Contingencies.”