Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of fair value, assets and liabilities measured on recurring basis

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):



	December 31, 2017								December 31, 2016
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Corporate debt securities	$	—	$	14,747	$	—	$	14,747	$	—	$	12,603	$	—	$	12,603
Certificates of deposit	—		5,131		—		5,131		—		943		—		943
Money market funds	4,714		—		—		4,714		5,464		—		—		5,464
U.S. treasury securities	4,061		—		—		4,061		5,529		—		—		5,529
Residential mortgage and asset-backed securities	—		4,058		—		4,058		—		3,602		—		3,602
U.S. government agencies securities	—		926		—		926		—		975		—		975
Non-U.S. government securities	—		664		—		664		—		720		—		720
Municipal debt securities	—		—		—		—		—		27		—		27
Equity securities	635				—		635		428		—		—		428
Deferred compensation plan	116		—		—		116		84		—		—		84
Foreign currency derivative contracts	—		13		—		13		—		336		—		336
Total	$	9,526	$	25,539	$	—	$	35,065	$	11,505	$	19,206	$	—	$	30,711

Liabilities:
Deferred compensation plan	$	116	$	—	$	—	$	116	$	84	$	—	$	—	$	84
Foreign currency derivative contracts	—		93		—		93		—		37		—		37
Contingent consideration	—		—		15		15		—		—		25		25
Total	$	116	$	93	$	15	$	224	$	84	$	37	$	25	$	146