SCHEDULE II CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT (Details 3) (USD $)	3 Months Ended								12 Months Ended				1 Months Ended		12 Months Ended							1 Months Ended				12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Lone Tree Insurance Group Ltd	Nov. 30, 2011 Lone Tree Insurance Group Ltd	Dec. 31, 2013 White Mountains Insurance Group Ltd.		Dec. 31, 2012 White Mountains Insurance Group Ltd.		Dec. 31, 2011 White Mountains Insurance Group Ltd.		Dec. 31, 2010 White Mountains Insurance Group Ltd.	Dec. 31, 2013 Fixed maturity investments Lone Tree Insurance Group Ltd	Nov. 30, 2011 Fixed maturity investments Lone Tree Insurance Group Ltd	Nov. 30, 2011 Short-term investments Lone Tree Insurance Group Ltd	Dec. 31, 2013 Cash Lone Tree Insurance Group Ltd	Dec. 31, 2013 Revolving Credit Facility [Member] White Mountains Insurance Group Ltd.
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT
Net income attributable to White Mountains’ common shareholders	$ 117,900,000	$ 57,200,000	$ 26,300,000	$ 120,400,000	$ 68,200,000	$ 19,100,000	$ 26,100,000	$ 94,000,000	$ 321,800,000	$ 207,400,000	$ 767,900,000				$ 321,800,000		$ 207,400,000		$ 767,900,000
Charges (credits) to reconcile net income to net cash (used for) provided from operations:
Net realized and unrealized investment gains									(161,700,000)	(118,200,000)	(74,100,000)				(200,000)		(11,000,000)		(3,100,000)
Undistributed current earnings from subsidiaries															(359,700,000)		(219,300,000)		(806,700,000)
Other non-cash reconciling items including restricted share and option amortization															15,600,000		22,100,000		7,200,000
Net change in other assets and liabilities, net									63,200,000	(52,700,000)	(62,200,000)				(2,900,000)		(10,000,000)		6,500,000
Net cash used for operations									(101,000,000)	(225,800,000)	(114,500,000)				(25,400,000)		(10,800,000)		(28,200,000)
Cash flows from investing activities:
Net decrease in short-term investments									34,800,000	145,300,000	174,500,000				7,500,000	[1]	63,300,000	[1]	267,300,000	[1]
Purchases of investment securities															(26,200,000)	[1],[2]	(706,200,000)	[1],[2]	(237,300,000)	[1],[2]
Sales and maturities of investment securities									4,924,800,000	6,997,500,000	5,034,000,000				61,100,000	[3]	2,009,700,000	[3]	59,000,000	[3]
Issuance of debt (to) from subsidiaries															153,900,000	[4]	(121,000,000)	[4]	0	[4]
Repayment of debt (to) from subsidiaries															(10,300,000)	[1]	28,500,000	[1]	192,500,000	[1]
Payments to subsidiaries															0	[3]	(663,000,000)	[3]	0	[3]
Distributions from subsidiaries															100,000	[2]	0	[2]	7,200,000	[2]
Net cash provided from investing activities									401,800,000	829,600,000	799,600,000				186,100,000		611,300,000		288,700,000
Cash flows from financing activities:
Draw down of revolving line of credit									200,000,000	150,000,000	0				200,000,000	[5]	150,000,000	[5]	0	[5]
Repayment of revolving line of credit									(275,000,000)	(75,000,000)	0				(275,000,000)	[4],[5]	(75,000,000)	[4],[5]	0	[4],[5]						(75,000,000)
Proceeds from issuances of common shares									0	0	900,000				0		0		900,000
Repurchases and retirement of common shares									(79,800,000)	(669,100,000)	(253,000,000)				(79,800,000)	[3],[4]	(669,100,000)	[3],[4]	(253,000,000)	[3],[4]
Dividends paid on common shares									(6,200,000)	(6,600,000)	(8,000,000)				(6,200,000)		(6,600,000)		(8,000,000)
Net cash used for financing activities									(186,500,000)	(648,200,000)	(460,200,000)				(161,000,000)		(600,700,000)		(260,100,000)
Net change in cash during the period									114,100,000	(41,300,000)	223,400,000				(300,000)		(200,000)		400,000
Cash balance at beginning of year	326,700,000				212,600,000				326,700,000	212,600,000	251,900,000	103,600,000			200,000		500,000		700,000		300,000
Cash balance at end of year	326,700,000				212,600,000				326,700,000	212,600,000	251,900,000	103,600,000			200,000		500,000		700,000		300,000
Cash dividends received on warrants													0									0			0
Interest Paid									42,600,000	44,600,000	59,000,000				3,700,000		2,000,000		12,400,000
Noncash distribution received													0
Common shares repurchased and retired during the period										1,329,640
Noncash investments acquired																							0	284.7
Noncash payables acquired														$ 417.5

[1] In November 2011, Lone Tree Insurance Group Ltd., a direct wholly-owned subsidiary of the Registrant, was liquidated into the Registrant. Significant non-cash balances that were transferred to the Registrant as part of the liquidation included fixed maturity investments of $1,146.9, short-term investments of $284.7 and a payable to subsidiary of $417.5.

[2] During 2013, the Company received a distribution of $28.0 from its direct wholly-owned subsidiary Lone Tree Holdings, Ltd. The distribution included $27.9 of fixed maturities and $.1 of cash. Purchases of investment securities excludes the non-cash distribution of $27.9.

[3] During 2012, the Company sold the majority of its fixed maturity investments and used the proceeds to (a) contribute $663.0 to its subsidiaries, the majority of which was used to fund HG Global and (b) repurchase 1,329,640 of its common shares for $669.1.

[4] During 2013, the Company used cash proceeds received from the issuance of debt to repurchase $79.8 of its common shares and repay $75.0 of its revolving line of credit.

[5] The WTM Bank Facility presented in Note 6 - “Debt” is a direct obligation of the Registrant.