Fair value measurement (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair value of each major class of financial assets and liabilities measured at fair value on a recurring basis

The fair value of each major class of the Company’s financial assets and liabilities measured at fair value on a recurring basis was as follows (in millions):

Fair value measurement as of December 31, 2016, using:	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Assets:
Available-for-sale investments:
U.S. Treasury securities	$	6,614	$	—	$	—	$	6,614
Other government-related debt securities:
U.S.	—		299		—		299
Foreign and other	—		1,759		—		1,759
Corporate debt securities:
Financial	—		8,460		—		8,460
Industrial	—		8,789		—		8,789
Other	—		1,077		—		1,077
Residential mortgage-backed securities	—		1,940		—		1,940
Other mortgage- and asset-backed securities	—		1,719		—		1,719
Money market mutual funds	2,782		—		—		2,782
Other short-term interest-bearing securities	—		4,188		—		4,188
Equity securities	154		—		—		154
Derivatives:
Foreign currency contracts	—		203		—		203
Interest rate swap contracts	—		41		—		41
Total assets	$	9,550	$	28,475	$	—	$	38,025
Liabilities:
Derivatives:
Foreign currency contracts	$	—	$	4	$	—	$	4
Cross-currency swap contracts	—		523		—		523
Interest rate swap contracts	—		7		—		7
Contingent consideration obligations in connection with business combinations	—		—		179		179
Total liabilities	$	—	$	534	$	179	$	713

Fair value measurement as of December 31, 2015, using:	Quoted prices in active markets for identical assets (Level 1)		Significant  other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Assets:
Available-for-sale investments:
U.S. Treasury securities	$	4,274	$	—	$	—	$	4,274
Other government-related debt securities:
U.S.	—		534		—		534
Foreign and other	—		1,739		—		1,739
Corporate debt securities:
Financial	—		7,871		—		7,871
Industrial	—		7,836		—		7,836
Other	—		885		—		885
Residential mortgage-backed securities	—		1,470		—		1,470
Other mortgage- and asset-backed securities	—		2,469		—		2,469
Money market mutual funds	3,370		—		—		3,370
Other short-term interest-bearing securities	—		528		—		528
Equity securities	136		—		—		136
Derivatives:
Foreign currency contracts	—		142		—		142
Interest rate swap contracts	—		71		—		71
Total assets	$	7,780	$	23,545	$	—	$	31,325
Liabilities:
Derivatives:
Foreign currency contracts	$	—	$	8	$	—	$	8
Cross-currency swap contracts	—		250		—		250
Interest rate swap contracts	—		3		—		3
Contingent consideration obligations in connection with business combinations	—		—		188		188
Total liabilities	$	—	$	261	$	188	$	449

Change in carrying amounts of contingent consideration obligations

Changes in the carrying amounts of contingent consideration obligations were as follows (in millions):

	During the years ended December 31,
	2016			2015
Beginning balance	$	188		$	215
Additions from Dezima acquisition	—			110
Payment to former BioVex Group, Inc. shareholders	—			(125		)
Net changes in valuation	(9		)	(12		)
Ending balance	$	179		$	188