Employee Share-Based Incentive Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

The following table presents performance share activity for the years ended December 31, 2020, 2019 and 2018 for performance shares granted under the WTM Incentive Plan:


	Year Ended December 31,
	2020			2019			2018
$ in Millions	Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense
Beginning of period	42,473	$	43.7	40,616	$	31.7	50,515	$	45.8
Shares paid or expired (1)	(14,070)	(27.7)		(13,715)	(18.1)		(23,186)	(28.4)
New grants	14,055	—		15,600	—		14,105	—
Forfeitures (2)	—	(.4)		(28)	(.1)		(818)	.1

Expense recognized	—	40.7		—	30.2		—	14.2
End of period	42,458	$	56.3	42,473	$	43.7	40,616	$	31.7

(1)WTM performance share payments in 2020 for the 2017-2019 performance cycle, which were paid in March 2020, ranged from 174% to 180% of target. WTM performance share payments in 2019 for the 2016-2018 performance cycle, which were paid in March 2019, ranged from 139% to 166% of target. WTM performance share payments in 2018 for the 2015-2017 performance cycle, which were paid in March 2018, ranged from 145% to 147% of target.

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

Schedule of performance shares outstanding and accrued expense for performance shares awarded

The following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of December 31, 2020 for each performance cycle:


$ in Millions	Target Performance Shares Outstanding	Accrued Expense
Performance cycle:
2020 – 2022	14,055	$	9.5
2019 – 2021	15,600	20.7
2018 – 2020	13,450	27.1
Sub-total	43,105	57.3
Assumed forfeitures	(647)	(1.0)
Total	42,458	$	56.3

Schedule of unrecognized compensation costs associated with outstanding 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 years ended December 31, 2020, 2019 and 2018:


	Year Ended December 31,
	2020			2019			2018
$ in Millions	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	43,395	$	16.7	41,510	$	12.5	53,755	$	14.3
Issued	14,055	15.1		15,600	14.5		14,105	11.4
Vested	(14,345)	—		(13,715)	—		(25,381)	—
Forfeited	—	—		—	—		(969)	(.2)

Expense recognized	—	(16.6)		—	(10.3)		—	(13.0)
End of period	43,105	$	15.2	43,395	$	16.7	41,510	$	12.5