| Income Statement [Abstract] | |
| REVENUE | 2.06B |
| OPERATING EXPENSES: | |
| Salaries and related expenses | 1.13B |
| Office and general expenses | 519.6M |
| Restructuring and other reorganization-related charges, net | |
| Total operating expenses | 1.65B |
| OPERATING INCOME | 409.9M |
| EXPENSES AND OTHER INCOME: | |
| Interest expense | -36.6M |
| Interest income | 8.1M |
| Other income (expense), net | 95.4M |
| Total (expenses) and other income | 66.9M |
| Income before income taxes | 476.8M |
| Provision for income taxes | 140.5M |
| Income of consolidated companies | 336.3M |
| Equity in net income (loss) of unconsolidated affiliates | 800K |
| NET INCOME | 337.1M |
| Net (income) loss attributable to noncontrolling interests | -20.9M |
| NET INCOME ATTRIBUTABLE TO IPG | 316.2M |
| Dividends on preferred stock | -2.9M |
| Benefit from preferred stock repurchased | |
| NET INCOME AVAILABLE TO IPG COMMON STOCKHOLDERS | 313.3M |
| Earnings Per Share | |
| Basic | |
| Diluted | |
| Weighted-average number of common shares outstanding: | |
| Basic | |
| Diluted | |
| Dividends declared per common share | 0.06 |