Equity - Narrative (Details) - USD ($)		3 Months Ended
	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2021	Mar. 14, 2019	Sep. 30, 2015
Class of Stock [Line Items]
Quarterly dividend on all classes of common stock (in dollars per share)		$ 0.95	$ 0.88
Capital required for capital adequacy	$ 743,800,000	$ 743,800,000			$ 713,800,000
Capital	1,200,000,000	1,200,000,000			1,200,000,000
Excess capital	$ 488,700,000	$ 488,700,000			$ 486,800,000
Class C non-voting common stock
Class of Stock [Line Items]
Stock authorized for repurchase						$ 10,000,000	$ 25,000,000
Shares repurchased (in shares)	673,000	0		4,000
Shares repurchased	$ 19,800,000			$ 200,000
Remaining authorized amount for repurchase			$ 9,800,000