Significant Transactions (Tables)

3 Months Ended

Mar. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Reconciliation to the increase in book value

A reconciliation of the gain reported in discontinued operations to the impact to White Mountains's book value is as follows:

Gain from sale of Tranzact reported in discontinued operations	$	51.9
Add back reclassification from continuing operations for the release of a tax valuation allowance	30.2
Increase to White Mountains book value from sale of Tranzact	$	82.1