Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements

v2.3.0.15
Fair Value Measurements
9 Months Ended
Sep. 30, 2011
Fair Value Measurements [Abstract]  
Fair Value Measurements

7. Fair Value Measurements

We measure the fair value of our derivative financial instruments by applying the income approach, using models with inputs that are classified within Level 2 of the valuation hierarchy. The inputs used for the fair value measurement of our derivative financial instruments are the exercise price, the expiration date, the settlement date, notional quantities, the implied volatility, the discount curve with spreads and published commodity futures prices. As described in Note 5, our derivative financial instruments are reported in the balance sheet at fair value and changes in fair value are recognized currently in earnings.

The fair value of our senior notes is based on quoted prices. The market for our senior notes is not an active market; therefore the fair value is classified within Level 2. The senior notes are reported in the balance sheet at their carrying value and their fair value is reported in Note 6.