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Employee Benefits - Weighted-average assumptions used to determine future benefit obligations (Details) | Dec. 31, 2016 | Dec. 31, 2015
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U.K. |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Discount rate | 2.77% | 3.96%
Underlying price inflation | 1.83% | 1.88%
U.K. | Minimum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Rate of compensation increase | 3.70% | 3.63%
U.K. | Maximum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Rate of compensation increase | 4.20% | 4.13%
U.S. | Minimum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Discount rate | 3.53% | 3.69%
U.S. | Maximum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Discount rate | 4.11% | 4.43%
Other | Minimum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Discount rate | 1.85% | 2.43%
Rate of compensation increase | 1.00% | 2.00%
Underlying price inflation | 2.00% | 2.00%
Other | Maximum |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |
Discount rate | 3.81% | 3.96%
Rate of compensation increase | 3.50% | 3.50%
Underlying price inflation | 2.50% | 2.50%

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- Definition Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Underlying Price Inflation + References No definition available. + Details
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- Definition The interest rate used to adjust for the time value of money for the plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
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- Definition Expected rate of compensation increases (for pay-related plans). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(2) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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