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Income Taxes (Deferred Tax Inventory) (Details) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | ---
Deferred income tax assets related to: |  |
U.S. federal net operating and capital loss carryforwards | $ 186.6 | $ 152.3
Unearned premiums | 37.5 | 38.3
Non-U.S. net operating loss carryforwards | 33.8 | 33.1
Loss reserve discount | 26.8 | 41.4
Tax credit carryforwards | 16.9 | 13.4
Fixed assets | 1.7 | 2.3
Accrued interest | 1.3 | 5.0
Other items | 3.0 | 2.8
Total gross deferred income tax assets | 371.8 | 348.1
Less: valuation allowances | (156.8) | (140.5)
Total net deferred income tax assets | 215.0 | 207.6
Deferred income tax liabilities related to: |  |
Deferred acquisition costs | 34.9 | 32.0
Net unrealized investment gains | 28.2 | 31.1
Noncurrent deferred tax liabilities | 3.5 | 2.5
Investment basis difference | 13.8 | 17.0
Other items | 0.5 | 0.1
Total deferred income tax liabilities | 109.2 | 93.0
Net deferred tax asset | 105.8 | 114.6
OneBeacon Runoff |  |
Deferred income tax assets related to: |  |
Runoff Transaction | 12.6 | 12.6
Purchase Accounting [Member] |  |
Deferred income tax liabilities related to: |  |
Noncurrent deferred tax liabilities | 9.3 | 0.0
Members Surplus Contributions [Member] |  |
Deferred income tax liabilities related to: |  |
Noncurrent deferred tax liabilities | 19.0 | 10.3
Incentive Compensation [Member] |  |
Deferred income tax assets related to: |  |
Compensation | 45.4 | 40.2
Deferred Compensation, Share-based Payments [Member] |  |
Deferred income tax assets related to: |  |
Compensation | 6.2 | $ 6.7
UNITED STATES |  |
Deferred income tax assets related to: |  |
Tax credit carryforwards | $ 14.6 |

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