CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Total Equity	Common Shares and Paid-in Surplus	Retained Earnings	AOCL, After-tax	Total	Non-controlling Interests
Beginning balance at Dec. 31, 2018		$ 2,718.2	$ 584.0	$ 2,264.9	$ (5.8)	$ 2,843.1	$ (124.9)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	$ 376.6	376.6		414.5		414.5	(37.9)
Net change in foreign currency translation and other		(1.4)			(1.4)	(1.4)
Comprehensive income (loss)		375.2		414.5	(1.4)	413.1	(37.9)
Dividends declared on common shares		(3.2)		(3.2)		(3.2)
Dividends to non-controlling interests		(2.0)					(2.0)
Issuances of common shares		2.2	2.2			2.2
Repurchases and retirements of common shares	(4.9)	(4.9)	(1.1)	(3.8)		(4.9)
BAM member surplus contribution, net of tax		57.6					57.6
Amortization of restricted share awards		10.6	10.6			10.6
Recognition of equity-based compensation expense of subsidiaries		1.5	1.5			1.5
Net contributions and dilution from other non-controlling interests		1.5	(0.9)			(0.9)	2.4
Acquisition of non-controlling interests		1.8					1.8
Deconsolidation of non-controlling interests associated with the MediaAlpha Transaction		(13.8)					(13.8)
Ending balance at Dec. 31, 2019		3,144.7	596.3	2,672.4	(7.2)	3,261.5	(116.8)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	663.4	663.4		708.7		708.7	(45.3)
Net change in foreign currency translation and other		7.3			6.8	6.8	0.5
Comprehensive income (loss)		670.7		708.7	6.8	715.5	(44.8)
Dividends declared on common shares		(3.2)		(3.2)		(3.2)
Dividends to non-controlling interests		(2.1)					(2.1)
Issuances of common shares		1.5	1.5			1.5
Repurchases and retirements of common shares	(85.1)	(85.2)	(18.5)	(66.7)		(85.2)
BAM member surplus contribution, net of tax		68.9					68.9
Amortization of restricted share awards		16.6	16.6			16.6
Recognition of equity-based compensation expense of subsidiaries		2.4	2.3			2.3	0.1
Net contributions and dilution from other non-controlling interests		2.3	(3.0)			(3.0)	5.3
Acquisition of non-controlling interests		1.3					1.3
Ending balance at Dec. 31, 2020	3,817.9	3,817.9	595.2	3,311.2	(0.4)	3,906.0	(88.1)
Increase (Decrease) in Shareholders' Equity
Net income (loss)	(321.9)	(321.9)		(275.4)		(275.4)	(46.5)
Net change in foreign currency translation and other		2.1			2.1	2.1
Comprehensive income (loss)		(319.8)		(275.4)	2.1	(273.3)	(46.5)
Dividends declared on common shares		(3.1)		(3.1)		(3.1)
Dividends to non-controlling interests		(2.3)					(2.3)
Issuances of common shares		1.9	1.9			1.9
Issuances of shares of non-controlling interests		6.5					6.5
Repurchases and retirements of common shares	(107.5)	(107.5)	(18.9)	(88.6)		(107.5)
BAM member surplus contribution, net of tax		62.2					62.2
Amortization of restricted share awards		14.7	14.7			14.7
Recognition of equity-based compensation expense of subsidiaries		3.5	3.0			3.0	0.5
Net contributions and dilution from other non-controlling interests		0.4	(7.0)	13.4		6.4	(6.0)
Acquisition of non-controlling interests		230.3					230.3
Ending balance at Dec. 31, 2021	$ 3,704.7	$ 3,704.7	$ 588.9	$ 2,957.5	$ 1.7	$ 3,548.1	$ 156.6