XML 108 R89.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Pension Plans and Other Postretirement Benefits (Details 11) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
--- | --- | --- | ---
Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 1,962.3 |  | $ 2,204.4 |  | $ 2,329.8
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 287.5 |  | 409.5 |  |
Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 874.6 |  | 985.2 |  |
Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 800.2 |  | 809.7 |  | 655.3
Equity Securities: ATI common stock [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 33.2 |  | 102.7 |  |
Equity Securities: ATI common stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 33.2 |  | 102.7 |  |
Equity Securities: ATI common stock [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Equity Securities: ATI common stock [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 0.0 |  | $ 0.0 |  |
Equity Securities: Other U.S. equities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of co-mingled funds comprised of large-cap investments | 90.00% |  | 90.00% |  |
Percentage of co-mingled funds comprised of small-cap investments | 10.00% |  | 10.00% |  |
Equity Securities: Other U.S. equities [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 522.0 | [1] | $ 673.8 | [2] |
Equity Securities: Other U.S. equities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 254.1 | [1] | 306.1 | [2] |
Equity Securities: Other U.S. equities [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 267.9 | [1] | 367.7 | [2] |
Equity Securities: Other U.S. equities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 0.0 | [1] | $ 0.0 | [2] |
Equity Securities: International equities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of co-mingled funds comprised of developed countries investments | 90.00% |  | 80.00% |  |
Percentage of co-mingled funds comprised of emerging market investments | 10.00% |  | 20.00% |  |
Equity Securities: International equities [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 239.8 | [3] | $ 238.2 | [4] |
Equity Securities: International equities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 | [3] | 0.0 | [4] |
Equity Securities: International equities [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 239.8 | [3] | 238.2 | [4] |
Equity Securities: International equities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 | [3] | 0.0 | [4] |
Fixed income and cash equivalents [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 369.7 | [5] | 383.5 | [6] |
Fixed income and cash equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.2 | [5] | 0.7 | [6] |
Fixed income and cash equivalents [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 361.0 | [5] | 373.9 | [6] |
Fixed income and cash equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 8.5 | [5] | 8.9 | [6] | 0.8
Floating rate [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 358.0 | [5] | 392.3 | [6] |
Floating rate [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 | [5] | 0.0 | [6] |
Floating rate [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 | [5] | 0.0 | [6] |
Floating rate [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 358.0 | [5] | 392.3 | [6] | 294.5
Private equity [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 201.2 |  | 172.6 |  |
Private equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Private equity [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Private equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 201.2 |  | 172.6 |  | 123.0
Hedge funds [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 51.9 |  | 84.7 |  |
Hedge funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Hedge funds [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Hedge funds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 51.9 |  | 84.7 |  | 111.2
Real estate and other [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 186.5 |  | 156.6 |  |
Real estate and other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 0.0 |  | 0.0 |  |
Real estate and other [Member] | Significant Observable Inputs (Level 2) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | 5.9 |  | 5.4 |  |
Real estate and other [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pension Benefits [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined Benefit Plan Fair Value Of Plan Assets | $ 180.6 |  | $ 151.2 |  | $ 125.8
[1] | Includes investments in commingled funds that invest in U.S. equity securities, comprised of approximately 90% large-cap U.S. companies and 10% small-cap U.S. companies.
[2] | Includes investments in commingled funds that invest in U.S. equity securities, comprised of approximately 90% large-cap U.S. companies and 10% small-cap U.S. companies.
[3] | Includes investments in commingled funds that invest in non-U.S. equity securities, comprised of approximately 90% developed countries and 10% emerging market economies.
[4] | Includes investments in commingled funds that invest in non-U.S. equity securities, comprised of approximately 80% developed countries and 20% emerging market economies.
[5] | Global debt securities include both fixed interest rate and floating interest rate instruments. These are comprised of actively managed investments which include U.S. government and U.S. government agency securities, foreign government securities, corporate bonds, mortgage-backed securities and other debt securities, and include both investment grade and non-investment grade debt, public and private debt, and secured and unsecured debt investments. To mitigate risk, investment managers have limitations regarding the amount of investment in particular securities and the credit quality of such investments.
[6] | Global debt securities include both fixed interest rate and floating interest rate instruments. These are comprised of actively managed investments which include U.S. government and U.S. government agency securities, foreign government securities, corporate bonds, mortgage-backed securities and other debt securities, and include both investment grade and non-investment grade debt, public and private debt, and secured and unsecured debt investments. To mitigate risk, investment managers have limitations regarding the amount of investment in particular securities and the credit quality of such investments.

X
- Definition Defined Benefit Plan, Investment, Co-mingled Funds, Percentage Comprised of Developed Countries Investments + References No definition available. + Details
Name: | ati_DefinedBenefitPlanInvestmentComingledFundsPercentageComprisedofDevelopedCountriesInvestments
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Benefit Plan, Investment, Co-mingled Funds, Percentage Comprised of Emerging Market Investments + References No definition available. + Details
Name: | ati_DefinedBenefitPlanInvestmentComingledFundsPercentageComprisedofEmergingMarketInvestments
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Benefit Plan, Investment, Co-mingled Funds, Percentage Comprised of Large-cap Investments + References No definition available. + Details
Name: | ati_DefinedBenefitPlanInvestmentComingledFundsPercentageComprisedofLargecapInvestments
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Benefit Plan, Investment, Co-mingled Funds, Percentage Comprised of Small-cap Investments + References No definition available. + Details
Name: | ati_DefinedBenefitPlanInvestmentComingledFundsPercentageComprisedofSmallcapInvestments
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ati_EquitySecuritiesAtiCommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ati_EquitySecuritiesUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ati_EquitySecuritiesNonUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ati_FixedIncomeAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=ati_FloatingRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_HedgeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |