Asset Impairments

Pre-tax (non-cash) asset impairment charges were as follows:



	Year Ended December 31,
(millions)	2013		2012		2011
Piceance (Onshore US)	$	—	$	39	$	487
South Raton (Deepwater Gulf of Mexico)	—		34		—
Mari-B (Offshore Israel)	47		31		—
Other Onshore US Properties	39		—		270
Total	$	86	$	104	$	757

2013 Asset Impairments We recorded impairments of the Mari-B field, due to natural field decline, and certain non-core, onshore US properties upon reclassification to assets held for sale. The Mari-B field was written down to its estimated fair value using a discounted cash flow model which included management’s estimates of future oil and gas production, commodity prices based on forward commodity price curves or contract prices as of the date of the estimate, operating and development costs, and discount rates. The fair values of onshore US assets held for sale were based on anticipated sales proceeds less costs to sell.

2012 Asset Impairments Due to declines in realized natural gas prices associated with our Piceance development, onshore US, and declines in near-term crude oil prices associated with our South Raton development in the deepwater Gulf of Mexico, we determined that their carrying amounts were not recoverable from future cash flows and, therefore, were impaired. In addition, due to end-of-field life declines in production of our Mari-B, Noa and Pinnacles fields, offshore Israel, we determined that the carrying amount was not recoverable from future cash flows and, therefore, was impaired. The assets were written down to their estimated fair values, which were determined using discounted cash flow models, as described above.

2011 Asset Impairments Due to a significant decline in spot and five-year forward natural gas prices, specifically during the fourth quarter of 2011, as well as field performance, we determined that the carrying amounts of certain of our onshore US assets were not recoverable from future cash flows and, therefore, were impaired. The assets were written down to their estimated fair values, which were determined using discounted cash flow models, as described above.

See also Note 13. Fair Value Measurements and Disclosures.