Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule of computation of basic and diluted earnings per share

Computation of Earnings Per Share

	Second Quarter				Six Months
	2018		2017		2018		2017
	(in millions)
Basic Earnings Per Share (EPS):
Net income (loss) attributable to AGL	$	75	$	153	$	272	$	470
Less: Distributed and undistributed income (loss) available to nonvested shareholders	0		0		0		0
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	75	$	153	$	272	$	470
Basic shares	111.7		121.3		113.4		123.3
Basic EPS	$	0.67	$	1.26	$	2.39	$	3.81
Diluted EPS:
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	75	$	153	$	272	$	470
Plus: Re-allocation of undistributed income (loss) available to nonvested shareholders of AGL and subsidiaries	0		0		0		0
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, diluted	$	75	$	153	$	272	$	470
Basic shares	111.7		121.3		113.4		123.3
Dilutive securities:
Options and restricted stock awards	1.2		1.4		1.4		1.6
Diluted shares	112.9		122.7		114.8		124.9
Diluted EPS	$	0.67	$	1.24	$	2.37	$	3.76
Potentially dilutive securities excluded from computation of EPS because of antidilutive effect	0.1		0.1		0.2		0.1

Schedule of antidilutive securities excluded from computation of earnings per share

Computation of Earnings Per Share

	Second Quarter				Six Months
	2018		2017		2018		2017
	(in millions)
Basic Earnings Per Share (EPS):
Net income (loss) attributable to AGL	$	75	$	153	$	272	$	470
Less: Distributed and undistributed income (loss) available to nonvested shareholders	0		0		0		0
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	75	$	153	$	272	$	470
Basic shares	111.7		121.3		113.4		123.3
Basic EPS	$	0.67	$	1.26	$	2.39	$	3.81
Diluted EPS:
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, basic	$	75	$	153	$	272	$	470
Plus: Re-allocation of undistributed income (loss) available to nonvested shareholders of AGL and subsidiaries	0		0		0		0
Distributed and undistributed income (loss) available to common shareholders of AGL and subsidiaries, diluted	$	75	$	153	$	272	$	470
Basic shares	111.7		121.3		113.4		123.3
Dilutive securities:
Options and restricted stock awards	1.2		1.4		1.4		1.6
Diluted shares	112.9		122.7		114.8		124.9
Diluted EPS	$	0.67	$	1.24	$	2.37	$	3.76
Potentially dilutive securities excluded from computation of EPS because of antidilutive effect	0.1		0.1		0.2		0.1