A summary of property and equipment at October 31 in millions of dollars follows:

* Weighted-averages

Total property and equipment additions in 2012, 2011 and 2010 were $1,376 million, $1,059 million and $802 million and depreciation was $555 million, $516 million and $540 million, respectively. Capitalized interest was $7 million, $8 million and $6 million in the same periods, respectively. The cost of leased property and equipment under capital leases of $47 million and $41 million and accumulated depreciation of $25 million and $23 million at October 31, 2012 and 2011, respectively, is included in property and equipment.

Capitalized software has an estimated useful life of three years. The amounts of total capitalized software costs, including purchased and internally developed software, classified as “Other Assets” at October 31, 2012 and 2011 were $684 million and $592 million, less accumulated amortization of $493 million and $451 million, respectively. Amortization of these software costs was $89 million in 2012, $73 million in 2011 and $68 million in 2010. The cost of leased software assets under capital leases amounting to $42 million and $40 million at October 31, 2012 and 2011, respectively, is included in other assets.

The cost of compliance with foreseeable environmental requirements has been accrued and did not have a material effect on the company’s consolidated financial statements.