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Employee Incentive Plans, Weighted Average Grant Date Fair Value (Details) - $ / shares | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
Restricted Stock [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Weighted-average grant-date fair value per share (in dollars per share) | $ 86.92 | $ 86.11 | $ 86.92 | $ 86.11
Restricted stock units |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Weighted-average grant-date fair value per share (in dollars per share) | 0.00 | 88.27 | 73.14 | 75.57
TSR-Based Performance Shares |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Weighted-average grant-date fair value per share (in dollars per share) | 0.00 | 0.00 | 97.88 | 93.02
CP-Based Performance Shares |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Weighted-average grant-date fair value per share (in dollars per share) | $ 0.00 | $ 0.00 | $ 79.69 | $ 80.46

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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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