we attempt to corroborate our outcomes with the market approach. For the income approach, we use the discounted cash flow method.

• When we estimate the fair value of our Consumer Healthcare reporting unit, we use a combination of approaches and methods. We use the income approach and the market approach, which we weight equally in our analysis. We weight them equally as we have equal confidence in the appropriateness of the approaches for this reporting unit. For the income approach, we use the discounted cash flow method and for the market approach, we use both the guideline public company method and the guideline transaction method, which we weight equally to arrive at our market approach value.

• When we estimate the fair value of our Animal Health reporting unit, we use the income approach, relying exclusively on the discounted cash flow method. We rely exclusively on the income approach as the discounted cash flow method provides a more reliable outlook of the business. However, on a limited basis and as deemed reasonable, we attempt to corroborate our outcomes with the market approach. (See also Notes to Consolidated Financial Statements––Note 19A. Subsequent Events: Zoetis Debt Offering and Initial Public Offering.)

While all reporting units can confront events and circumstances that can lead to impairment, we do not believe that the risk of goodwill impairment for any of our reporting units is significant at this time.

Our Consumer Healthcare reporting unit has the narrowest difference between fair value and book value. However, we estimate that it would take a significant negative change in the undiscounted cash flows, the discount rate and/or the market multiples in the consumer industry for the Consumer Healthcare reporting unit goodwill to be impaired. Our Consumer Healthcare reporting unit performance and consumer healthcare industry market multiples are highly correlated with the overall economy and our specific performance is also dependent on our and our competitors’ innovation and marketing effectiveness, and on regulatory developments affecting claims, formulations and ingredients of our products.

For all of our reporting units, there are a number of future events and factors that may impact future results and that could potentially have an impact on the outcome of subsequent goodwill impairment testing. For a list of these factors, see the “Forward-Looking Information and Factors That May Affect Future Results” section of this Financial Review.

Benefit Plans

The majority of our employees worldwide are covered by defined benefit pension plans, defined contribution plans or both. In the U.S., we have both qualified and supplemental (non-qualified) defined benefit plans, as well as other postretirement benefit plans, consisting primarily of healthcare and life insurance for retirees (see Notes to Consolidated Financial Statements—Note 1P. Basis of Presentation and Significant Accounting Policies: Pension and Postretirement Benefit Plans and Note 11. Pension and Postretirement Benefit Plans and Defined Contribution Plans). Beginning on January 1, 2011, for employees hired in the U.S. and Puerto Rico after December 31,