Employee Share-Based Incentive Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Summary of performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan

The following table presents the performance share activity for the three and six months ended June 30, 2024 and 2023 for performance shares granted under the WTM Incentive Plan:

	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
$ in Millions	Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense
Beginning of period	34,007	$	44.2	37,031	$	36.4	37,031	$	69.4	39,449	$	67.5
Shares paid (1) (2)	—	—		—	—		(13,475)	(44.9)		(13,350)	(40.8)
New grants	1,000	—		—	—		11,405	—		10,895	—
Forfeitures and cancellations (3)	(15)	—		—	(.2)		31	.3		37	.2
Expense recognized	—	7.8		—	8.4		—	27.2		—	17.7
End of period	34,992	$	52.0	37,031	$	44.6	34,992	$	52.0	37,031	$	44.6

(1) WTM performance share payments for the 2021-2023 performance cycle were made in March 2024 at 188% of target.

(2) WTM performance share payments for the 2020-2022 performance cycle were made in March 2023 at 200% of target. 

(3) Amounts include changes in assumed forfeitures, as required under GAAP.

Share-based compensation, performance shares award outstanding activity

The following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of June 30, 2024 for each performance cycle:

	June 30, 2024
$ in Millions	Target Performance Shares Outstanding	Accrued Expense
Performance cycle:
2022 – 2024	13,225	$	39.7
2023 – 2025	10,895	10.7
2024 – 2026	11,405	2.4
Sub-total	35,525	52.8
Assumed forfeitures	(533)	(.8)
Total	34,992	$	52.0

Unrecognized compensation cost for restricted share awards

The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the three and six months ended June 30, 2024 and 2023:

	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
$ in Millions	Restricted Shares	Unamortized Issue Date Fair Value		Restricted Shares	Unamortized Issue Date Fair Value		Restricted Shares	Unamortized Issue Date Fair Value		Restricted Shares	Unamortized Issue Date Fair Value
Non-vested,
Beginning of period	34,525	$	31.3	37,595	$	28.3	37,595	$	16.2	38,350	$	15.5
Issued	1,000	1.7		—	—		11,405	20.0		10,895	16.0
Vested	—	—		—	—		(13,475)	—		(11,650)	—
Forfeited	—	—		—	—		—	—		—	—
Expense recognized	—	(4.2)		—	(4.0)		—	(7.4)		—	(7.2)
End of period	35,525	$	28.8	37,595	$	24.3	35,525	$	28.8	37,595	$	24.3