Reconciliation of Pension and OPEB Plan Obligations, Assets and Funded Status (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Benefit obligations
End of period	$ 5,716
Fair value of plan assets
Beginning of period	3,698
End of period	4,501	$ 3,698
Pension Benefits, Defined Benefit
Benefit obligations
Beginning of period	5,423	6,331
Service cost	93	128	$ 130
Interest cost	183	211	242
Participant contributions	5	7
Actuarial (gain)/loss	298	(105)
Benefit payments	(234)	(214)
Settlements	(6)	(3)
Plan amendments		(2)
Separation of Baxalta		(821)
Foreign exchange and other	(45)	(109)
End of period	5,717	5,423	6,331
Fair value of plan assets
Beginning of period	3,698	4,197
Actual return on plan assets	309	(41)
Employer contributions	752	157
Participant contributions	5	7
Benefit payments	(234)	(214)
Settlements	(6)	(3)
Separation of Baxalta		(347)
Foreign exchange and other	(23)	(58)
End of period	4,501	3,698	4,197
Funded status at December 31	(1,216)	(1,725)
Amounts recognized in the consolidated balance sheets
Noncurrent asset	42	47
Current liability	(23)	(22)
Noncurrent liability	(1,235)	(1,750)
Net liability recognized at December 31	(1,216)	(1,725)
Other Postretirement Benefit Plans, Defined Benefit
Benefit obligations
Beginning of period	266	551
Service cost	2	4	5
Interest cost	8	14	25
Actuarial (gain)/loss	10	(261)
Benefit payments	(20)	(21)
Plan amendments	(23)
Separation of Baxalta		(21)
End of period	243	266	$ 551
Fair value of plan assets
Employer contributions	20	21
Benefit payments	(20)	(21)
Funded status at December 31	(243)	(266)
Amounts recognized in the consolidated balance sheets
Current liability	(19)	(19)
Noncurrent liability	(224)	(247)
Net liability recognized at December 31	$ (243)	$ (266)