CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CONSOLIDATED STATEMENTS OF OPERATIONS
Sales									$ 5,183.0	$ 4,047.8	$ 3,054.9
Costs and expenses:
Cost of sales									4,369.8	3,557.5	2,646.5
Selling and administrative expenses									382.1	304.9	315.7
Income (loss) before interest, other income and income taxes									431.1	185.4	92.7
Interest expense, net									(92.3)	(62.7)	(19.3)
Debt extinguishment costs									0	0	(9.2)
Other income, net									0.6	3.0	0.7
Income before income tax provision (benefit)									339.4	125.7	64.9
Income tax provision (benefit)									116.3	47.0	26.9
Net income (loss)									223.1	78.7	38.0
Less: Net income (loss) attributable to noncontrolling interests									8.8	8.0	6.3
Net income (loss) attributable to ATI	$ 31.7	$ 62.3	$ 64.0	$ 56.3	$ 15.1	$ 1.0	$ 36.4	$ 18.2	$ 214.3	$ 70.7	$ 31.7
Basic net income (loss) attributable to ATI per common share	$ 0.30	$ 0.59	$ 0.63	$ 0.58	$ 0.16	$ 0.01	$ 0.37	$ 0.19	$ 2.09	$ 0.73	$ 0.33
Diluted net income (loss) attributable to ATI per common share	$ 0.29	$ 0.56	$ 0.59	$ 0.54	$ 0.15	$ 0.01	$ 0.36	$ 0.18	$ 1.97	$ 0.72	$ 0.32