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, 2015		Dec. 31, 2014
Cash, cash equivalents and marketable securities [Line Items]
Less: Restricted cash, cash equivalents, and marketable securities	$ (222)	[1]	$ (450)	[1]
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	13,781		17,416
Cash
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	3,986
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	3,986		4,155
Cash, cash equivalents, and marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	14,000
Gross Unrealized Gains	5
Gross Unrealized Losses	(2)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	14,003		17,866
Level 1 Securities | Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	6,428
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	6,428		10,718
Level 1 Securities | Equity securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	1
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	2		4
Level 2 Securities | Foreign government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	68
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	68		80
Level 2 Securities | U.S. government and agency securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	3,006
Gross Unrealized Gains	2
Gross Unrealized Losses	(2)
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	3,006		2,406
Level 2 Securities | Corporate debt securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	408
Gross Unrealized Gains	2
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	410		401
Level 2 Securities | Asset-backed securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	72
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	72		69
Level 2 Securities | Other fixed income securities
Cash, cash equivalents and marketable securities [Line Items]
Cost or Amortized Cost	31
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Cash, Cash Equivalents, and Marketable Securities Total Estimated Fair Value	$ 31		$ 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.”