CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Earned insurance and reinsurance premiums	$ 490.6	$ 498.1	$ 1,436.7	$ 1,772.9
Net investment income	42.8	48.9	138.1	157.4
Net realized and unrealized investment gains	1.7	11.6	78.3	104.7
Other revenue	(33.8)	(7.6)	(68.6)	(21.1)
Total revenues	501.3	551.0	1,584.5	2,013.9
Expenses:
Loss and loss adjustment expenses	277.1	253.4	914.0	1,175.9
Insurance and reinsurance acquisition expenses	107.0	102.1	296.2	370.9
Other underwriting expenses	67.0	75.0	211.5	245.9
General and administrative expenses	36.2	32.1	120.4	119.5
Interest expense on debt	12.8	13.2	38.8	44.2
Total expenses	500.1	475.8	1,580.9	1,956.4
Pre-tax income (loss) from continuing operations	1.2	75.2	3.6	57.5
Income tax (expense) benefit	0.6	(11.7)	(1.9)	(10.3)
Net income (loss) from continuing operations	1.8	63.5	1.7	47.2
Loss from sale of discontinued operations, net of tax	(18.2)		(18.2)
Net (loss) income from discontinued operations, net of tax	(11.9)	3.6	(10.7)	1.2
(Loss) income before equity in earnings of unconsolidated affiliates	(28.3)	67.1	(27.2)	48.4
Equity in earnings of unconsolidated affiliates	1.5	7.9	16.1	1.6
Net (loss) income	(26.8)	75.0	(11.1)	50.0
Net income (loss) attributable to noncontrolling interests	11.0	(24.3)	(21.2)	(36.4)
Net (loss) income attributable to White Mountains' common shareholders	(15.8)	50.7	(32.3)	13.6
Comprehensive income (loss), net of tax:
Change in equity in net unrealized gains from investments in unconsolidated affiliates	55.1	43.1	77.2	126.4
Change in foreign currency translation and other	(81.8)	126.9	(25.3)	45.9
Comprehensive (loss) income	(42.5)	220.7	19.6	185.9
Comprehensive income attributable to noncontrolling interests	0		0
Comprehensive (loss) income attributable to White Mountains' common shareholders	$ (42.5)	$ 220.7	$ 19.6	$ 185.9
Basic income (loss) per share
Continuing operations (in dollars per share)	$ 1.81	$ 5.58	$ (0.43)	$ 1.44
Discontinued operations (in dollars per share)	$ (3.81)	$ 0.43	$ (3.63)	$ 0.13
Diluted income (loss) per share
Continuing operations (in dollars per share)	$ 1.81	$ 5.58	$ (0.43)	$ 1.44
Discontinued operations (in dollars per share)	$ (3.81)	$ 0.43	$ (3.63)	$ 0.13
Dividends declared and paid per White Mountains' common share (in dollars per share)			$ 1.00	$ 1.00