Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets and Goodwill [Table Text Block]

The following table shows the economic lives, acquisition date values, accumulated amortization and net carrying values for other intangible assets and goodwill, for each company acquired:

Millions	Weighted Average Economic  life (in years)	December 31, 2014						December 31, 2013
		Acquisition date fair value		Accumulated amortization		Net carrying value		Acquisition date fair value		Accumulated amortization		Net carrying value
Tranzact:
Domain and trade names	6	$	25.6	$	.9	$	24.7	$	—	$	—	$	—
Customer relationships	10	107.5		2.1		105.4		—		—		—
Information technology	5	12.7		.5		12.2		—		—		—
Other	7	.5		—		.5		—		—		—
Subtotal		146.3		3.5		142.8		—		—		—
QuoteLab:
Customer relationships	4	6.5		1.2		5.3		—		—		—
Information technology	5	32.0		4.8		27.2		—		—		—
Subtotal		38.5		6.0		32.5		—		—		—
Wobi:
Trademark	8	2.1		.2		1.9		—		—		—
Information technology	3	.8		.2		.6		—		—		—
Subtotal		2.9		.4		2.5		—		—		—
Star & Shield:
Customer relationship	3	1.2		.4		.8		—		—		—
OneBeacon (EBI)	10	9.4		5.7		3.7		9.4		4.3		5.1
Sirius (WM Solutions) - Licenses	Indefinite	15.2		—		15.2		15.6		—		15.6
Total other intangible assets		213.5		16.0		197.5		25.0		4.3		20.7
Goodwill:
Tranzact	N/A	145.1		—		145.1		—		—		—
Quote Lab	N/A	18.3		—		18.3		—		—		—
Wobi	N/A	5.5		—		5.5		—		—		—
Total goodwill		168.9		—		168.9		—		—		—
Total goodwill and other intangible assets		$	382.4	$	16.0	$	366.4	$	25.0	$	4.3	$	20.7

Schedule of Goodwill and Intangible Assets Rollforward

The following table shows the change in goodwill and other intangible assets:

	December 31,
Millions	2014					2013
	Goodwill		Other intangible assets			Goodwill		Other intangible assets
Beginning balance	$	—	$	20.7		$	—	$	16.9
Acquisitions of businesses	168.9		188.9			—		5.2
Dispositions of businesses	—		(.4		)	—		—
Amortization, including foreign currency translation	—		(11.7		)	—		(1.4		)
Ending balance	$	168.9	$	197.5		$	—	$	20.7

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

White Mountains expects to recognize amortization expense in each of the next five years as follows:

Millions	Amortization expense
2015	$	27.1
2016	27.0
2017	26.4
2018	24.6
2019	16.5
Total	$	121.6