Cash, Cash Equivalents, and Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Fair Value by Major Security Type

The following table summarizes, by major security type, our cash, cash equivalents, and marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in millions):

	December 31, 2016			September 30, 2017
	Total Estimated Fair Value			Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Total Estimated Fair Value
Cash	$	6,883		$	8,658	$	—	$	—		$	8,658
Level 1 securities:
Money market funds	11,940			4,625		—		—			4,625
Equity securities	51			34		33		—			67
Level 2 securities:
Foreign government and agency securities	337			807		—		—			807
U.S. government and agency securities	4,816			5,400		2		(9		)	5,393
Corporate debt securities	2,104			4,403		2		(3		)	4,402
Asset-backed securities	353			853		—		(2		)	851
Other fixed income securities	97			701		—		—			701
	$	26,581		$	25,481	$	37	$	(14	)	$	25,504
Less: Restricted cash, cash equivalents, and marketable securities (1)	(600		)								(1,194		)
Total cash, cash equivalents, and marketable securities	$	25,981									$	24,310

___________________

(1) We are required to pledge or otherwise restrict a portion of our cash, cash equivalents, and marketable securities as collateral for real estate leases, workers’ compensation obligations, amounts due to third-party sellers in certain jurisdictions, debt, and standby and trade letters of credit.

(2) 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.”

Investments Classified by Contractual Maturity Date

The following table summarizes the contractual maturities of our cash equivalents and marketable fixed-income securities as of September 30, 2017 (in millions):

	Amortized Cost		Estimated Fair Value
Due within one year	$	11,305	$	11,303
Due after one year through five years	4,355		4,351
Due after five years through ten years	317		316
Due after ten years	812		809
Total	$	16,789	$	16,779