Commitments and Contingencies (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Lease guarantees	$ 851.7	$ 829.2
Credit facility guarantees	333.8	308.8
Cash pooling guarantees	$ 204.6	$ 182.2

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the credit facilities guarantees or each group of similar guarantees.

No definition available.

Name:	ipg_GuaranteeObligationsCurrentCarryingValueCreditfacilities
Namespace Prefix:	ipg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant