Common Shareholders’ Equity and Non-controlling Interests Common Shareholders’ Equity and Non-controlling Interests (Tables)

12 Months Ended

Dec. 31, 2016

Noncontrolling Interest [Abstract]

Noncontrolling Interest

The following table details the balance of non-controlling interests included in White Mountains’s total equity and the related percentage of each consolidated entity’s total equity owned by non-controlling shareholders as of December 31, 2016 and 2015:

	December 31, 2016					December 31, 2015
$ in millions	Non-controlling Percentage		Non-controlling Equity			Non-controlling Percentage		Non-controlling Equity
OneBeacon Ltd.	23.9	%	$	244.6		24.5	%	$	245.6
SIG Preference Shares	—		—			100.0		250.0
Other, excluding mutuals and reciprocals
HG Global	3.1		16.6			3.1		17.1
MediaAlpha	40.0		11.7			40.0		14.4
Dewar	18.8		3.9			19.0		3.7
Buzzmove	29.1		2.9			—		—
Wobi	5.0		.7			3.9		.6
Tranzact	—		—			36.8		79.4
Total other, excluding mutuals and reciprocals			35.8					115.2
Mutuals and reciprocals
BAM	100.0		(150.9		)	100.0		(140.0		)
SSIE	100.0		4.4			100.0		(16.0		)
Total mutuals and reciprocals			(146.5		)			(156.0		)
Total non-controlling interests			$	133.9				$	454.8