Business Combinations - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions		3 Months Ended	9 Months Ended
	Oct. 03, 2016	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 11,598	$ 11,598	$ 10,727
Commercial Solutions [Member]
Business Acquisition [Line Items]
Goodwill		10,099	10,099	9,415
Research & Development Solutions [Member]
Business Acquisition [Line Items]
Goodwill		1,382	1,382	1,196
Integrated Engagement Services [Member]
Business Acquisition [Line Items]
Goodwill		117	117	$ 116
IMS Health Holdings, Inc. [Member]
Business Acquisition [Line Items]
Date of Acquisition	Oct. 03, 2016
Merger agreement date	May 03, 2016
Revenues since acquisition		858	2,459
IMS Health Holdings, Inc. [Member] | Commercial Solutions [Member]
Business Acquisition [Line Items]
Goodwill		9,688	9,688
IMS Health Holdings, Inc. [Member] | Research & Development Solutions [Member]
Business Acquisition [Line Items]
Goodwill		533	533
IMS Health Holdings, Inc. [Member] | Integrated Engagement Services [Member]
Business Acquisition [Line Items]
Goodwill		$ 67	$ 67
IMS Health Holdings, Inc. [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Merger agreement, stock for stock exchange ratio	38.40%
Business acquisition through merger, consideration in stock	$ 10,400
Business acquisition through merger, consideration in stock, shares issued	126.6