STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock-based compensation expense

Stock-based compensation expense was as follows:

	Years ended December 31,
	2020		2019		2018
	($ in millions)
Stock-based compensation	$	17.5	$	9.4	$	19.3
Mark-to-market adjustments	4.8		(1.8)		(10.7)
Total expense	$	22.3	$	7.6	$	8.6

Stock Options Activity

Stock option transactions were as follows:

					Exercisable
	Shares	Option Price	Weighted-Average Option Price		Options	Weighted-Average Exercise Price
Outstanding at January 1, 2020	7,210,551	$13.14-32.94	$	24.95	4,648,574	$	23.07
Granted	2,663,100	17.33-17.33	17.33
Exercised	(190,295)	13.14-18.78	17.42
Canceled	(555,981)	13.14-32.94	22.03
Outstanding at December 31, 2020	9,127,375	$13.14-32.94	$	23.06	5,671,371	$	24.57

Stock Options Exercisable, Exercise Price Range

The following table provides certain information with respect to stock options exercisable at December 31, 2020:

Range of Exercise Prices	Options Exercisable	Weighted-Average Exercise Price		Options Outstanding	Weighted-Average Exercise Price
Under $22.00	1,570,673	$	15.14	3,936,073	$	16.45
$22.00 - $28.00	2,096,617	25.77		2,953,235	25.91
Over $28.00	2,004,081	30.70		2,238,067	30.93
	5,671,371			9,127,375

Common shares reserved and available for grant or purchase

At December 31, 2020, common shares reserved for issuance and available for grant or purchase under the following plans consisted of:

	Number of Shares
Stock Option Plans	Reserved for Issuance	Available for Grant or Purchase(1)
2000 long term incentive plan	18,666	—
2003 long term incentive plan	178,284	—
2006 long term incentive plan	93,190	—
2009 long term incentive plan	1,510,954	—
2014 long term incentive plan	1,784,213	—
2016 long term incentive plan	1,967,666	—
2018 long term incentive plan	9,933,512	4,834,380
Total under stock option plans	15,486,485	4,834,380

	Number of Shares
Stock Purchase Plans	Reserved for Issuance	Available for Grant or Purchase
1997 stock plan for non-employee directors	453,323	176,088

(1)All available to be issued as stock options, but includes a sub-limit for all types of stock awards of 472,630 shares.

Performance Shares Transactions

Performance share transactions were as follows:

	To Settle in Cash			To Settle in Shares
	Shares	Weighted-Average Fair Value per Share		Shares	Weighted-Average Fair Value per Share
Outstanding at January 1, 2020	317,710	$	17.18	304,075	$	28.91
Granted	238,050	17.33		238,050	17.33
Paid/Issued	(69,639)	17.18		(64,970)	29.75
Converted from shares to cash	22,952	25.10		(22,952)	25.10
Canceled	(115,868)	21.29		(108,773)	27.83
Outstanding at December 31, 2020	393,205	$	24.84	345,430	$	21.37
Total vested at December 31, 2020	216,955	$	24.84	168,230	$	23.41

Summary of Unvested Performance Shares

The summary of the status of our unvested performance shares to be settled in cash were as follows:

	Shares	Weighted-Average Fair Value per Share
Unvested at January 1, 2020	125,567	$	17.18
Granted	238,050	17.33
Vested	(120,982)	24.84
Canceled	(66,385)	19.61
Unvested at December 31, 2020	176,250	$	24.84