Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]

Summary of assets and liabilities measured at fair value

The following table summarizes the types of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in millions):



	March 31, 2018								December 31, 2017
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Available-for-sale debt securities:
Corporate debt securities	$	—	$	11,972	$	—	$	11,972	$	—	$	14,747	$	—	$	14,747
U.S. treasury securities	3,884		—		—		3,884		4,061		—		—		4,061
Residential mortgage and asset-backed securities	—		3,406		—		3,406		—		4,058		—		4,058
U.S. government agencies securities	—		925		—		925		—		926		—		926
Certificates of deposit	—		3,908		—		3,908		—		5,131		—		5,131
Non-U.S. government securities	—		559		—		559		—		664		—		664
Marketable equity securities:
Money market funds	4,674		—		—		4,674		4,714		—		—		4,714
Equity securities	680		—		—		680		635		—		—		635
Deferred compensation plan	126		—		—		126		116		—		—		116
Foreign currency derivative contracts	—		4		—		4		—		13		—		13
Total	$	9,364	$	20,774	$	—	$	30,138	$	9,526	$	25,539	$	—	$	35,065
Liabilities:
Deferred compensation plan	$	126	$	—	$	—	$	126	$	116	$	—	$	—	$	116
Foreign currency derivative contracts	—		110		—		110		—		93		—		93
Total	$	126	$	110	$	—	$	236	$	116	$	93	$	—	$	209

Summary of the Classification of Marketable Equity Securities

The following table summarizes the classification of our marketable equity securities on our Condensed Consolidated Balance Sheets (in millions):



	March 31, 2018		December 31, 2017
Cash and cash equivalents	$	4,674	$	4,714
Prepaid and other current assets	681		637
Other long-term assets	125		114
Total	$	5,480	$	5,465