Subsequent Events (Details)	3 Months Ended
Jun. 30, 2018 USD ($)
Subsequent Events [Abstract]
Agreed Consideration	$ 2,300,000,000.0

The agreed-upon cash payment to be made for the acquisition of AMS upon satisfaction of the terms and subject to the conditions set forth in the Purchase Agreement.

No definition available.

Name:	ipg_AgreedConsideration
Namespace Prefix:	ipg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration