Employee Share-Based Incentive Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2023

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 months ended March 31, 2023 and 2022 for performance shares granted under the WTM Incentive Plan:

	Three Months Ended March 31,
	2023			2022
$ in Millions	Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense
Beginning of period	39,449	$	67.5	40,828	$	42.2
Shares paid (1)	(13,350)	(40.8)		(14,625)	(26.4)
New grants	10,895	—		13,075	—
Forfeitures and cancellations (2)	37	.4		24	.3
Expense recognized	—	9.3		—	5.8
End of period	37,031	$	36.4	39,302	$	21.9

(1) WTM performance share payments in 2023 for the 2020-2022 performance cycle, which were paid in March 2023 at 200% of target.

WTM performance share payments in 2022 for the 2019-2021 performance cycle, which were paid in March 2022 at 172% of target. 

(2) 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 March 31, 2023 for each performance cycle:

	March 31, 2023
$ in Millions	Target Performance Shares Outstanding	Accrued Expense
Performance cycle:
2021 – 2023	13,475	$	22.6
2022 – 2024	13,225	14.0
2023 – 2025	10,895	.4
Sub-total	37,595	37.0
Assumed forfeitures	(564)	(.6)
Total	37,031	$	36.4

Summary of restricted shares activity

Restricted shares are grants of a specified number of common shares that generally vest at the end of a 34-month service period. The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the three months ended March 31, 2023 and 2022:

	Three Months Ended March 31,
	2023			2022
$ in Millions	Restricted Shares	Unamortized Issue Date Fair Value		Restricted Shares	Unamortized Issue Date Fair Value
Non-vested,
Beginning of period	38,350	$	15.5	37,850	$	15.9
Issued	10,895	16.0		13,075	13.6
Vested	(11,650)	—		(12,725)	—
Forfeited	—	—		—	—
Expense recognized	—	(3.2)		—	(3.0)
End of period	37,595	$	28.3	38,200	$	26.5