Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

Computation of Earnings Per Share 

	Year Ended December 31,
	2023		2022		2021
	(in millions, except per share amounts)
Basic EPS:
Net income (loss) attributable to AGL	$	739	$	124	389
Less: Distributed and undistributed income (loss) available to nonvested shareholders	6		1		—
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	733	$	123	389
Basic shares	58.4		62.9		73.5
Basic EPS	$	12.54	$	1.95	$	5.29
Diluted EPS:
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	733	$	123	$	389
Plus: Re-allocation of undistributed income (loss) available to nonvested shareholders of AGL and subsidiaries	—		—		—
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, diluted	$	733	$	123	$	389
Basic shares	58.4		62.9		73.5
Dilutive securities:
Restricted stock awards	1.2		1.0		0.8
Diluted shares	59.6		63.9		74.3
Diluted EPS	$	12.30	$	1.92	$	5.23
Potentially dilutive securities excluded from computation of EPS because of antidilutive effect	0.1		0.6		0.1

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

Computation of Earnings Per Share 

	Year Ended December 31,
	2023		2022		2021
	(in millions, except per share amounts)
Basic EPS:
Net income (loss) attributable to AGL	$	739	$	124	389
Less: Distributed and undistributed income (loss) available to nonvested shareholders	6		1		—
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	733	$	123	389
Basic shares	58.4		62.9		73.5
Basic EPS	$	12.54	$	1.95	$	5.29
Diluted EPS:
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	733	$	123	$	389
Plus: Re-allocation of undistributed income (loss) available to nonvested shareholders of AGL and subsidiaries	—		—		—
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, diluted	$	733	$	123	$	389
Basic shares	58.4		62.9		73.5
Dilutive securities:
Restricted stock awards	1.2		1.0		0.8
Diluted shares	59.6		63.9		74.3
Diluted EPS	$	12.30	$	1.92	$	5.23
Potentially dilutive securities excluded from computation of EPS because of antidilutive effect	0.1		0.6		0.1