Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of debt

Debt at December 31, 2020 and 2019 was as follows:

(In millions)	2020		2019
Allegheny Technologies $500 million 5.875% Senior Notes due 2023 (a)	$	500.0	$	500.0
Allegheny Technologies $350 million 5.875% Senior Notes due 2027	350.0		350.0
Allegheny Technologies $291.4 million 3.5% Convertible Senior Notes due 2025	291.4		—
Allegheny Technologies $287.5 million 4.75% Convertible Senior Notes due 2022	84.2		287.5
Allegheny Ludlum 6.95% Debentures due 2025 (b)	150.0		150.0
Term Loan due 2024	200.0		100.0
U.S. revolving credit facility	—		—
Foreign credit agreements	5.5		4.9
Finance leases and other	48.0		18.8
Debt issuance costs	(14.5)		(12.3)
Equity component of convertible debt	(46.8)		—
Total short-term and long-term debt	1,567.8		1,398.9
Short-term debt and current portion of long-term debt	17.8		11.5
Total long-term debt	$	1,550.0	$	1,387.4

(a)Bearing interest at 7.875% effective February 15, 2016.

(b)The payment obligations of these debentures issued by Allegheny Ludlum, LLC are fully and unconditionally guaranteed by ATI.