Summary of Significant Accounting Policies Earnings Per Share (Policies)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Earnings Per Share

Earnings Per Share (“EPS”)

Basic EPS available to IPG common stockholders equals net income available to IPG common stockholders divided by the weighted-average number of common shares outstanding for the applicable period. Diluted EPS equals net income available to IPG common stockholders adjusted to exclude, if dilutive, preferred stock dividends, allocation to participating securities, interest expense related to potentially dilutive securities calculated using the effective interest rate method and the benefit from the preferred stock repurchased, divided by the weighted-average number of common shares outstanding, plus any additional common shares that would have been outstanding if potentially dilutive shares had been issued. 

Diluted EPS reflect the potential dilution that would occur if certain potentially dilutive securities or debt obligations were exercised or converted into common stock. The potential issuance of common stock is assumed to occur at the beginning of the year (or at the time of issuance of the potentially dilutive instrument, if later) and the incremental shares are included using the treasury stock or “if-converted” method. The proceeds utilized in applying the treasury stock method consist of the amount, if any, to be paid upon exercise and, as it relates to stock-based compensation, the amount of compensation cost attributed to future service not yet recognized and any tax benefits credited to additional paid-in-capital related to the exercise. These proceeds are then assumed to be used to purchase common stock at the average market price of our stock during the period. The incremental shares (difference between the shares assumed to be issued and the shares assumed to be purchased), to the extent they would have been dilutive, are included in the denominator of the diluted EPS calculation.

We may be required to calculate basic EPS using the two-class method, as a result of our redeemable noncontrolling interests. To the extent that the redemption value increases and exceeds the then-current fair value of a redeemable noncontrolling interest, net income available to IPG common stockholders (used to calculate EPS) could be negatively impacted by that increase, subject to certain limitations. The partial or full recovery of these reductions to net income available to IPG common stockholders (used to calculate EPS) is limited to cumulative prior-period reductions. For the years ended December 31, 2011, 2010 and 2009, there was no impact to EPS for adjustments related to our redeemable noncontrolling interests.