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Significant Accounting Policies (Tables) | 12 Months Ended
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Dec. 31, 2014
Accounting Policies [Abstract] |
Estimated lives of useful depreciable assets | Operating Assets and Facilities We state operating assets, facilities, and capitalized improvements at cost. We include assets we acquire under capital leases in operating assets, and we record the related obligations as liabilities. We depreciate operating assets and facilities over their estimated useful lives or lease terms to estimated residual values using the straight-line method. We depreciate leasehold improvements over the shorter of their useful lives or the lease term. Our estimated depreciable lives of operating assets and facilities are as follows:
Railcars | 27–42 years
Locomotives | 10–20 years
Buildings | 40–50 years
Leasehold improvements | 5–15 years
Marine vessels | 30–65 years
Other equipment | 5–30 years
Net gain on disposition of assets | The following table presents the net gain on asset dispositions for the years ending December 31 (in millions):
| 2014 |  | 2013 |  | 2012
Disposition gains | $ | 63.1 |  |  | $ | 60.0 |  |  | $ | 42.7 |
Residual sharing income | 9.4 |  |  | 10.8 |  |  | 22.6 |
Non-remarketing disposition gains | 16.0 |  |  | 20.7 |  |  | 19.2 |
Asset impairment losses | (1.3 | ) |  | (5.9 | ) |  | (5.0 | )
Net Gain on Asset Dispositions | $ | 87.2 |  |  | $ | 85.6 |  |  | $ | 79.5 |

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- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph b -Article 5 + Details
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