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Income Taxes (Deferred Tax Inventory) (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2012 | Dec. 31, 2011
--- | --- | ---
Deferred income tax assets related to: |  |
Non-U.S. net operating loss carryforwards | $ 509.5 | $ 503.7
U.S. federal net operating and capital loss carryforwards | 165.2 | 102.7
U.S. federal net operating and capital loss carryforwards | 88.6 | 114.2
Unearned premiums | 45.5 | 41.2
Incentive compensation | 36.8 | 43.4
Tax credit carryforwards | 17.0 | 13.5
Deferred compensation | 10.4 | 11.4
Pension and benefit accruals | 10.3 | 8.0
Accrued interest | 8.0 | 8.0
Fixed assets | 2.8 | (0.1)
Other items | 7.7 | 6.4
Total gross deferred income tax assets | 951.1 | 862.8
Less: valuation allowances | (254.0) | (232.6)
Total net deferred income tax assets | 697.1 | 630.2
Deferred income tax liabilities related to: |  |
Safety reserve | 326.7 | 369.6
Deferred acquisition costs | 54.2 | 34.8
Net unrealized investment gains | 49.8 | 48.8
Investment basis difference | 21.0 | (0.9)
Purchase accounting | 9.5 | 0.6
Other items | 7.6 | 5.9
Total deferred income tax liabilities | 468.8 | 458.8
Net deferred tax asset | 228.3 | 171.4
OneBeacon Runoff |  |
Deferred income tax assets related to: |  |
Sale of AutoOne | 49.3 | 0
AutoOne |  |
Deferred income tax assets related to: |  |
Sale of AutoOne | $ 0 | $ 10.4

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