Subsequent Event	12 Months Ended
Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Symetra On February 1, 2016, Symetra closed its definitive merger agreement with Sumitomo Life and White Mountains received proceeds of $658.0 million, or $32.00 per common share.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

No definition available.

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