Per Share Information (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Schedule earnings per share

The following table sets forth the computation of basic and diluted income (loss) from continuing operations per common share:

(In millions, except per share amounts)

For the Years Ended December 31,	2015			2014			2013
Numerator:
Numerator for basic loss from continuing operations per common share -
Loss from continuing operations attributable to ATI	$	(377.9	)	$	(2.0	)	$	(98.8	)
Redeemable noncontrolling interest (Note 18)	(0.3		)	(0.3		)	—
Effect of dilutive securities:
4.25% Convertible Senior Notes due 2014	—			—			—
Numerator for diluted net loss per common share -
Loss from continuing operations attributable to ATI after assumed conversions	$	(378.2	)	$	(2.3	)	$	(98.8	)
Denominator:
Denominator for basic net loss per common share—weighted average shares	107.3			107.1			106.8
Effect of dilutive securities:
Share-based compensation	—			—			—
4.25% Convertible Senior Notes due 2014	—			—			—
Denominator for diluted net loss per common share—adjusted weighted average shares and assumed conversions	107.3			107.1			106.8
Basic loss from continuing operations attributable to ATI per common share	$	(3.53	)	$	(0.02	)	$	(0.93	)
Diluted loss from continuing operations attributable to ATI per common share	$	(3.53	)	$	(0.02	)	$	(0.93	)