Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value of Assets Measured on Recurring Basis

The following tables present the fair values of the Company’s assets, measured on a recurring basis, as of December 31, 2023 and 2022:

(in millions)	Total		Level 1		Level 2		Level 3
December 31, 2023
Debt securities:
U.S. Treasury bonds	$	199.3	$	—	$	199.3	$	—
Municipal bonds		1,245.8		—		1,245.8		—
Foreign government bonds		219.3		—		219.3		—
Governmental agency bonds		195.4		—		195.4		—
Governmental agency mortgage-backed securities		3,875.7		—		3,875.7		—
U.S. corporate debt securities		958.4		—		958.4		—
Foreign corporate debt securities		463.6		—		463.6		—
		7,157.5		—		7,157.5		—
Equity securities:
Common stocks		424.5		424.5		—		—
Preferred stocks		12.4		12.4		—		—
		436.9		436.9		—		—
Mortgage loans held for sale		13.1		—		11.8		1.3
Total	$	7,607.5	$	436.9	$	7,169.3	$	1.3

(in millions)	Total		Level 1		Level 2		Level 3
December 31, 2022
Debt securities:
U.S. Treasury bonds	$	302.8	$	—	$	302.8	$	—
Municipal bonds		1,478.7		—		1,478.7		—
Foreign government bonds		193.7		—		193.7		—
Governmental agency bonds		228.6		—		228.6		—
Governmental agency mortgage-backed securities		4,602.4		—		4,602.4		—
U.S. corporate debt securities		921.4		—		921.4		—
Foreign corporate debt securities		442.0		—		442.0		—
		8,169.6		—		8,169.6		—
Equity securities:
Common stocks		268.1		268.1		—		—
Preferred stocks		11.4		11.4		—		—
		279.5		279.5		—		—
Mortgage loans held for sale		15.9		—		13.9		2.0
Total	$	8,465.0	$	279.5	$	8,183.5	$	2.0

Carrying Amounts and Estimated Fair Values of Financial Instruments Not Measured at Fair Value

The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments not measured at fair value as of December 31, 2023 and 2022:

	Carrying		Estimated fair value
(in millions)	Amount		Total		Level 1		Level 2		Level 3
December 31, 2023
Assets:
Cash and cash equivalents	$	3,605.3	$	3,605.3	$	3,605.3	$	—	$	—
Deposits with banks	$	55.8	$	55.6	$	4.0	$	51.6	$	—
Notes receivable, net	$	22.4	$	23.2	$	—	$	—	$	23.2
Secured financings receivable	$	636.5	$	636.5	$	—	$	636.5	$	—
Liabilities:
Secured financings payable	$	553.3	$	553.3	$	—	$	553.3	$	—
Notes and contracts payable	$	1,393.9	$	1,219.6	$	—	$	1,215.4	$	4.2

	Carrying		Estimated fair value
(in millions)	Amount		Total		Level 1		Level 2		Level 3
December 31, 2022
Assets:
Cash and cash equivalents	$	1,223.5	$	1,223.5	$	1,223.5	$	—	$	—
Deposits with banks	$	63.4	$	62.7	$	8.5	$	54.2	$	—
Notes receivable, net	$	10.7	$	10.6	$	—	$	—	$	10.6
Secured financings receivable	$	422.7	$	422.7	$	—	$	422.7	$	—
Liabilities:
Secured financings payable	$	366.3	$	366.3	$	—	$	366.3	$	—
Notes and contracts payable	$	1,645.8	$	1,404.4	$	—	$	1,400.6	$	3.8

Assets measured at fair value on a non-recurring basis

	Estimated fair value (3)
(in millions)	Total		Level 1		Level 2		Level 3
December 31, 2023
Non-marketable equity securities (1)	$	95.1	$	—	$	56.5	$	38.6
December 31, 2022
Non-marketable equity securities (2)	$	117.3	$	—	$	107.3	$	10.0

(1)Excludes $129.0 million of non-marketable equity securities for which no observable price changes or impairment charges occurred during the year ended December 31, 2023.

(2)Excludes $278.5 million of non-marketable equity securities for which no observable price changes or impairment charges occurred during the year ended December 31, 2022.

(3)Estimated fair values were determined during the year as of the dates that either an observable transaction occurred or an impairment assessment was made.

Summary of Valuation Techniques and Significant Unobservable Inputs Used in Measuring Fair Value of Non-Marketable Equity Securities

(in millions)	Fair Value		Approach	Input	Range	Weighted Average (1)
Non-marketable equity securities	$	38.6	Market	Revenue Multiple	10.2-12.5	11.7

(1)Weighted average is calculated based on the fair values of the non-marketable equity securities.