Per Share Information (Tables)

3 Months Ended

Mar. 31, 2023

Earnings Per Share [Abstract]

Schedule Of Earnings Per Share Diluted By Common Class

The following table sets forth the computation of basic and diluted income per common share: 

(In millions, except per share amounts)	Three months ended March 31,
	2023		2022
Numerator:
Numerator for basic income per common share –
Net income attributable to ATI	$	70.1	$	30.9
Effect of dilutive securities:
4.75% Convertible Senior Notes due 2022	—		1.1
3.5% Convertible Senior Notes due 2025	2.6		2.9
Numerator for diluted net income per common share –
Net income attributable to ATI after assumed conversions	$	72.7	$	34.9
Denominator:
Denominator for basic net income per common share – weighted average shares	128.5		126.4
Effect of dilutive securities:
Share-based compensation	2.8		1.8
4.75% Convertible Senior Notes due 2022	—		5.8
3.5% Convertible Senior Notes due 2025	18.8		18.8
Denominator for diluted net income per common share – adjusted weighted average shares and assumed conversions	150.1		152.8
Basic net income attributable to ATI per common share	$	0.55	$	0.24
Diluted net income attributable to ATI per common share	$	0.48	$	0.23