Goodwill and Other Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in Goodwill and Intangible Assets

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

	Three Months Ended June 30,
	2018								2017
Millions	Goodwill		Other intangible assets			Total Goodwill and other intangible assets			Goodwill		Other intangible assets			Total Goodwill and other intangible assets
Beginning balance	$	25.9	$	33.3		$	59.2		$	25.9	$	17.0		$	42.9
Amortization, including foreign currency translation	—		(2.6		)	(2.6		)	—		(2.6		)	(2.6		)
Subtotal	$	25.9	$	30.7		$	56.6		$	25.9	$	14.4		$	40.3
Acquisition of businesses						436.2								—
Ending balance						$	492.8							$	40.3

	Six Months Ended June 30,
	2018								2017
Millions	Goodwill		Other intangible assets			Total Goodwill and other intangible assets			Goodwill		Other intangible assets			Total Goodwill and other intangible assets
Beginning balance	$	25.9	$	36.2		$	62.1		$	25.9	$	19.3		$	45.2
Amortization, including foreign currency translation	—		(5.5		)	(5.5		)	—		(4.9		)	(4.9		)
Subtotal	$	25.9	$	30.7		$	56.6		$	25.9	$	14.4		$	40.3
Acquisition of businesses						436.2								—
Ending balance						$	492.8							$	40.3

Schedule of Intangible Assets and Goodwill

The following table presents the goodwill and other intangible assets as of June 30, 2018 and December 31, 2017:

Millions	June 30, 2018			December 31, 2017
Goodwill and other intangible assets:
NSM	$	436.2		$	—
MediaAlpha	48.3			53.7
Other	8.3			8.4
Total goodwill and other intangible assets	492.8			62.1
Goodwill and other intangible assets attributed to non-controlling interests	(41.7		)	(21.1		)
Goodwill and other intangible assets included in White Mountains’s common shareholders’ equity	$	451.1		$	41.0