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

12 Months Ended

Dec. 31, 2021

Stockholders' Equity Note [Abstract]

Schedule of noncontrolling interest

The following table presents 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, 2021 and 2020:

	December 31, 2021				December 31, 2020
$ in Millions	Non-controlling Percentage		Non-controlling Equity		Non-controlling Percentage		Non-controlling Equity
Non-controlling interests, excluding BAM
HG Global	3.1	%	$	8.9	3.1	%	$	13.5
Ark	28.0	%	230.7		—	%	—
NSM	3.5	%	16.7		3.4	%	17.0
Kudu	2.5	%	12.4		.7	%	2.3
Other	various		11.9		various		2.4
Total, excluding BAM			280.6				35.2
BAM	100.0	%	(124.0)		100.0	%	(123.3)
Total non-controlling interests			$	156.6			$	(88.1)