Financial Information for Subsidiary and Guarantor Parent Financial Information for Subsidiary and Guarantor Parent (Narrative) (Details) (Allegheny Ludlum 6.95% debentures due 2025, USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Allegheny Ludlum 6.95% debentures due 2025
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 150.0	$ 150.0
Interest rate	6.95%