Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Accounting Standards Update and Change in Accounting Principle

The following table reflects the effect of the change in the accounting principle on the 2021 consolidated financial statements:

For the Year Ending December 31, 2021	As Computed under LIFO		As Computed under Current Cost Method		Effect of Change
(dollars in millions, except per share data)
Statement of Operations
Cost of sales	$	2,559.2	$	2,466.6	$	(92.6)
Gross profit	$	240.6	$	333.2	$	92.6
Operating income	$	25.0	$	117.6	$	92.6
Income (loss) before income taxes	$	(82.0)	$	10.6	$	92.6
Net loss	$	(108.8)	$	(16.2)	$	92.6
Net loss attributable to ATI	$	(130.8)	$	(38.2)	$	92.6
Basic net loss per common share	$	(1.03)	$	(0.30)	$	0.73
Diluted net loss per common share	$	(1.03)	$	(0.30)	$	0.73
Statement of Comprehensive Income
Net loss	$	(108.8)	$	(16.2)	$	92.6
Comprehensive income	$	127.9	$	220.5	$	92.6
Comprehensive income attributable to ATI	$	101.1	$	193.7	$	92.6
Balance Sheet
Inventories, net	$	953.7	$	1,046.3	$	92.6
Total current assets	$	2,214.1	$	2,306.7	$	92.6
Total assets	$	4,192.6	$	4,285.2	$	92.6
Retained earnings (deficit)	$	(19.9)	$	72.7	$	92.6
Total ATI stockholders’ equity	$	593.0	$	685.6	$	92.6
Total stockholders’ equity	$	740.1	$	832.7	$	92.6
Total liabilities and stockholders’ equity	$	4,192.6	$	4,285.2	$	92.6
Statement of Cash Flows
Net loss	$	(108.8)	$	(16.2)	$	92.6
Adjustments to reconcile net loss to net cash provided by operating activities:
Inventories	$	38.7	$	(53.9)	$	(92.6)

The following tables reflect the impact to the financial statement line items as a result of the change in accounting principle for the prior periods presented in the accompanying financial statements:

For the Year Ending December 31, 2019	As Reported		Adjustments		As Adjusted
(dollars in millions, except per share data)
Statement of Operations
Cost of sales	$	3,484.7	$	(0.2)	$	3,484.5
Gross profit	$	637.8	$	0.2	$	638.0
Operating income	$	366.1	$	0.2	$	366.3
Other income, net	$	69.7	$	(5.3)	$	64.4
Income before income taxes	$	241.6	$	(5.1)	$	236.5
Net income	$	270.1	$	(5.1)	$	265.0
Net income attributable to ATI	$	257.6	$	(5.1)	$	252.5
Basic net income per common share	$	2.05	$	(0.04)	2.01
Diluted net income per common share	$	1.85	$	(0.04)	1.81
Statement of Comprehensive Income
Net income	$	270.1	$	(5.1)	$	265.0
Comprehensive income	$	200.9	$	(5.1)	$	195.8
Comprehensive income attributable to ATI	$	189.7	$	(5.1)	$	184.6
Statement of Cash Flows
Net income	$	270.1	$	(5.1)	$	265.0
Adjustments to reconcile net income to net cash provided by operating activities:
Net loss from sales of businesses	$	1.8	$	5.3	$	7.1
Inventories	$	25.4	$	(0.2)	$	25.2