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Income Taxes - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Operating Loss Carryforwards [Line Items] |  |  |
Decrease in valuation allowance | $ 30.0 |  |
Adjustment to additional paid-in-capital for income tax benefits attributable to employee stock compensation | 126.0 | $ 89.0 | $ 74.0
Deferred tax liabilities from undistributed foreign earnings | 20.0 |  |
Undistributed foreign earnings | 2,200.0 |  |
Benefit realized from tax holiday granted | $ 23.0 | $ 7.0 | $ 3.0
Earnings per share impact of tax holiday | $ 0.08 | $ 0.02 | $ 0.01
Unrecognized tax benefits that would impact effective tax rate | $ 180.0 | $ 154.0 | $ 141.0
Accrued potential interest and penalties | 2.0 | 4.0 | 2.0
Liability recorded for interest and penalties | 33.0 | 31.0 | $ 27.0
U.K. [Member] |  |  |
Operating Loss Carryforwards [Line Items] |  |  |
Operating loss carryforwards | 449.0 | 154.0 |
Capital loss carryforwards | 360.0 | 380.0 |
U.S. Federal [Member] |  |  |
Operating Loss Carryforwards [Line Items] |  |  |
Operating loss carryforwards | 7.5 | 18.0 |
U.S. State [Member] |  |  |
Operating Loss Carryforwards [Line Items] |  |  |
Operating loss carryforwards | 443.0 | 451.0 |
Other [Member] |  |  |
Operating Loss Carryforwards [Line Items] |  |  |
Operating loss carryforwards | 245.0 | 325.0 |
Capital loss carryforwards | $ 206.0 | $ 223.0 |

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- Definition Amount of increase in additional paid in capital (APIC) resulting from a tax benefit associated with share-based compensation plan other than an employee stock ownership plan (ESOP). Includes, but is not limited to, excess tax benefit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 740 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6419406&loc=d3e23524-113945 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 + Details
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