Retirement Benefits (Tables)

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

Schedule of defined benefit plans

The components of pension and other postretirement benefit expense for the Company’s defined benefit plans included the following:

	Pension Benefits						Other Postretirement Benefits
(In millions)	2020		2019		2018		2020		2019		2018
Service cost—benefits earned during the year	$	12.7	$	12.7	$	16.4	$	2.3	$	1.9	$	2.5
Interest cost on benefits earned in prior years	86.3		105.5		104.8		10.7		14.8		12.7
Expected return on plan assets	(134.5)		(131.3)		(157.9)		—		—		—
Amortization of prior service cost (credit)	0.7		0.3		0.3		(3.8)		(2.9)		(2.9)
Amortization of net actuarial loss	74.5		73.7		65.9		10.8		13.5		10.6
Curtailment loss (gain)	—		—		0.4		(0.2)		—		—
Termination benefits	10.9		—		—		6.7		—		—
Total retirement benefit expense	$	50.6	$	60.9	$	29.9	$	26.5	$	27.3	$	22.9

Schedule of assumptions used

Actuarial assumptions used to develop the components of defined benefit pension expense and other postretirement benefit expense were as follows:

	Pension Benefits						Other Postretirement Benefits
	2020		2019		2018		2020		2019		2018
Discount rate	3.40	%	4.40	%	3.85	%	3.25	%	4.35	%	3.80	%
Rate of increase in future compensation levels	1.0	%	0.5% - 1.0%		0.5% - 1.0%		—		—		—
Weighted average expected long-term rate of return on assets	7.16	%	7.52	%	7.75	%	—	%	4.0	%	4.0	%

Schedule of assumptions used for year end valuation

Actuarial assumptions used for the valuation of defined benefit pension and other postretirement benefit obligations at the end of the respective periods were as follows:

	Pension Benefits				Other Postretirement Benefits
	2020		2019		2020		2019
Discount rate	2.60	%	3.40	%	2.45	%	3.25	%
Rate of increase in future compensation levels	1.0	%	0.5%- 1.0%		—		—

Schedule of changes in projected benefit obligations

A reconciliation of the funded status for the Company’s defined benefit pension and other postretirement benefit plans at December 31, 2020 and 2019 was as follows:

	Pension Benefits				Other Postretirement Benefits
(In millions)	2020		2019		2020		2019
Change in benefit obligations:
Benefit obligation at beginning of year	$	2,633.9	$	2,497.7	$	345.3	$	359.1
Service cost	12.7		12.7		2.3		1.9
Interest cost	86.3		105.5		10.7		14.8
Benefits paid	(258.0)		(274.6)		(30.4)		(37.7)
Subsidy received	—		—		0.8		—
Effect of currency rates	4.3		2.8		—		—
Net actuarial (gains) losses – discount rate change	235.3		266.0		25.5		30.5
– other	(5.3)		14.3		(0.8)		(18.1)
Plan curtailments	—		—		(2.5)		—
Plan amendments	—		9.5		—		(5.2)
Termination benefits	10.9		—		6.7		—
Benefit obligation at end of year	$	2,720.1	$	2,633.9	$	357.6	$	345.3

Schedule of changes in fair value of plan assets

	Pension Benefits				Other Postretirement Benefits
(In millions)	2020		2019		2020		2019
Change in plan assets:
Fair value of plan assets at beginning of year	$	1,902.1	$	1,772.2	$	0.1	$	0.1
Actual returns on plan assets and plan expenses	258.9		248.2		(0.1)		—
Employer contributions	138.8		153.4		—		—
Effect of currency rates	4.6		2.9		—		—
Benefits paid	(258.0)		(274.6)		—		—
Fair value of plan assets at end of year	$	2,046.4	$	1,902.1	$	—	$	0.1

Schedule of amounts recognized in balance sheet

Assets (liabilities) recognized in the consolidated balance sheets:
	Pension Benefits				Other Postretirement Benefits
	2020		2019		2020		2019
Noncurrent assets	$	5.4	$	4.8	$	—	$	—
Current liabilities	(5.5)		(5.1)		(30.9)		(32.7)
Noncurrent liabilities	(673.6)		(731.5)		(326.7)		(312.5)
Total amount recognized	$	(673.7)	$	(731.8)	$	(357.6)	$	(345.2)

Schedule of amounts recognized in other comprehensive income

Changes to accumulated other comprehensive loss related to pension and other postretirement benefit plans in 2020 and 2019 were as follows:

	Pension Benefits				Other Postretirement Benefits
(In millions)	2020		2019		2020		2019
Beginning of year accumulated other comprehensive loss	$	(1,569.7)	$	(1,470.3)	$	(103.5)	$	(107.0)
Amortization of net actuarial loss	74.5		73.7		10.8		13.5
Amortization of prior service cost (credit)	0.7		0.3		(3.8)		(2.9)
Remeasurements	(105.8)		(173.4)		(22.6)		(7.1)
End of year accumulated other comprehensive loss	$	(1,600.3)	$	(1,569.7)	$	(119.1)	$	(103.5)
Net change in accumulated other comprehensive loss	$	(30.6)	$	(99.4)	$	(15.6)	$	3.5

Schedule of net periodic benefit cost not yet recognized

Amounts included in accumulated other comprehensive loss at December 31, 2020 and 2019 were as follows:

	Pension Benefits				Other Postretirement Benefits
(In millions)	2020		2019		2020		2019
Prior service (cost) credit	$	(10.6)	$	(11.2)	$	7.0	$	11.0
Net actuarial loss	(1,589.7)		(1,558.5)		(126.1)		(114.5)
Accumulated other comprehensive loss	(1,600.3)		(1,569.7)		(119.1)		(103.5)
Deferred tax effect	561.4		555.7		38.1		34.4
Accumulated other comprehensive loss, net of tax	$	(1,038.9)	$	(1,014.0)	$	(81.0)	$	(69.1)

Schedule of amounts in accumulated other comprehensive income to be recognized

Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost in 2021 are:

(In millions)	Pension Benefits		Other Postretirement Benefits		Total
Amortization of prior service cost (credit)	$	0.6	$	(2.5)	$	(1.9)
Amortization of net actuarial loss	75.6		13.2		88.8
Amortization of accumulated other comprehensive loss	$	76.2	$	10.7	$	86.9

Schedule of accumulated benefit obligations in excess of fair value of plan assets

Additional information for pension plans with accumulated benefit obligations and projected benefit obligations in excess of plan assets:

	Pension Benefits
(In millions)	2020		2019
Projected benefit obligation	$	2,611.8	$	2,538.9
Accumulated benefit obligation	$	2,595.6	$	2,526.1
Fair value of plan assets	$	1,932.8	$	1,802.4

Schedule of expected benefit payments

The following table summarizes expected benefit payments from the Company’s various pension and other postretirement defined benefit plans through 2030, and also includes estimated Medicare Part D subsidies projected to be received during this period based on currently available information. Pension benefit payments for the U.S. qualified defined benefit pension plans and the U.K. defined benefit plan are made from pension plan assets.

(In millions)	Pension Benefits		Other Postretirement Benefits		Medicare Part D Subsidy
2021	$	167.2	$	30.9	$	0.1
2022	165.0		29.7		0.1
2023	164.1		30.1		0.1
2024	161.5		28.5		0.1
2025	158.8		26.5		0.1
2026-2030	747.4		107.2		0.3

Schedule of allocation of plan assets

The fair values of the Company’s pension plan assets are determined using net asset value (NAV) as a practical expedient, or by information categorized in the fair value hierarchy level based on the inputs used to determine fair value, as further discussed in Note 15. The fair values at December 31, 2020 were as follows:

(In millions)					Quoted Prices in Active Markets for Identical Assets		Significant Observable Inputs		Significant Unobservable  Inputs
Asset category	Total		NAV		(Level 1)		(Level 2)		(Level 3)
Equity securities:
U.S. equities	$	452.0	$	264.7	$	187.3	$	—	$	—
International equities	477.1		448.7		28.4		—		—
Debt securities and cash:
Fixed income and cash equivalents	588.0		306.3		80.3		201.4		—
Floating rate	47.4		47.4		—		—		—
Private equity	130.0		130.0		—		—		—
Hedge funds	325.0		325.0		—		—		—
Real estate and other	26.9		26.9		—		—		—
Total assets	$	2,046.4	$	1,549.0	$	296.0	$	201.4	$	—

The fair values of the Company’s pension plan assets at December 31, 2019 were as follows:

(In millions)					Quoted Prices in Active Markets for Identical Assets		Significant Observable Inputs		Significant Unobservable  Inputs
Asset category	Total		NAV		(Level 1)		(Level 2)		(Level 3)
Equity securities:
U.S. equities	$	443.6	$	254.7	$	188.9	$	—	$	—
International equities	326.1		299.6		26.5		—		—
Debt securities and cash:
Fixed income and cash equivalents	650.7		419.9		58.7		172.1		—
Floating rate	51.0		51.0		—		—		—
Private equity	129.0		129.0		—		—		—
Hedge funds	263.9		263.9		—		—		—
Real estate and other	37.8		37.8		—		—		—
Total assets	$	1,902.1	$	1,455.9	$	274.1	$	172.1	$	—

Schedule of target asset allocations for pension plans

The target asset allocations for ATI Pension Plan for 2021, by major investment category, are:

Asset category	Target asset allocation range
U.S. equity	18% - 40%
Global equity	10% - 30%
Debt securities and cash	15% - 40%
Private equity	0% - 15%
Hedge funds	10% - 20%
Real estate and other	0%  - 10.0%

Schedule of multiemployer plans

The Company’s participation in multiemployer plans for the years ended December 31, 2020, 2019 and 2018 is reported in the following table.

		Pension Protection Act Zone Status (1)		FIP / RP Status Pending / Implemented (2)	in millions							Expiration Dates of Collective Bargaining Agreements
	EIN / Pension Plan Number				Company Contributions						Surcharge Imposed (3)
Pension Fund		2020	2019		2020		2019		2018
Steelworkers Western Independent Shops Pension Plan	90-0169564 / 001	Green	Green	N/A	$	0.7	$	0.9	$	0.8	No	2/28/2021
Boilermakers-Blacksmiths National Pension Trust	48-6168020 / 001	Yellow	Red	Yes	2.1		2.5		2.5		No	9/30/2026
IAM National Pension Fund	51-6031295 / 002	Red	Red	Yes	2.0		2.2		2.1		Yes	Various between 2021-2022 (4)
Total contributions					$	4.8	$	5.6	$	5.4

(1)The most recent Pension Protection Act Zone Status is based on information provided to ATI and other participating employers by each plan, as certified by the plan’s actuary. A plan in the “deep red” zone had been determined to be in “critical and declining status”, based on criteria established by the Internal Revenue Code (Code), and is in critical status (as defined by the “red” zone) and is projected to become insolvent (run out of money to pay benefits) within 15 years (or within 20 years if a special rule applies). A plan in the “red” zone had been determined to be in “critical status”, based on criteria established by the Code, and is generally less than 65% funded. A plan in the “yellow” zone has been determined to be in “endangered status”, based on criteria established under the Code, and is generally less than 80% funded. A plan in the “green” zone has been determined to be neither in “critical status” nor in “endangered status”, and is generally at least 80% funded. Additionally, a plan may voluntarily place itself into a rehabilitation plan.

In April 2019, the Company received notification from the IAM National Pension Fund (IAM Fund) that its’ actuary certified the IAM Fund as “endangered status” for the plan year beginning January 1, 2019, and that the IAM Fund was voluntarily placing itself in “red” zone status and implementing a rehabilitation plan. In April 2020, the Company received notification from the IAM Fund that it was certified by its actuary as being in “red” zone status for the plan year beginning January 1, 2020. A 5% contribution surcharge was imposed as of June 1, 2019 for the rest of 2019, increasing to a 10% surcharge rate beginning January 1, 2020 in addition to the contribution rate specified in the applicable collective bargaining agreements. The contribution surcharge ends when an employer begins contributing under a collective bargaining agreement that includes terms consistent with the rehabilitation plan.

In April 2019, the Company received notifications from the Boilermakers-Blacksmiths National Pension Trust (Blacksmiths Trust) that it was certified by its actuary as being in “red” zone status for the plan year beginning January 1, 2019. A rehabilitation plan has been adopted for the Blacksmiths Trust, and the Company and the Blacksmiths union agreed to adopt the rehabilitation plan in 2019 prior to a contribution surcharge being imposed. In April 2020, the funding status improved for the Blacksmiths Trust as it was certified by its actuary as being in the “yellow” zone for the plan year beginning January 1, 2020.

(2)The “FIP / RP Status Pending / Implemented” column indicates whether a Funding Improvement Plan, as required under the Code by plans in the “yellow” zone, or a Rehabilitation Plan, as required under the Code to be adopted by plans in the “red” or “deep red” zones, is pending or has been implemented as of the end of the plan year that ended in 2020.

(3)The “Surcharge Imposed” column indicates whether ATI’s contribution rate for 2020 included an amount in addition to the contribution rate specified in the applicable collective bargaining agreement, as imposed by a plan in “critical status” or “critical and declining status”, in accordance with the requirements of the Code.

(4)The Company is party to five separate bargaining agreements that require contributions to this plan. Expiration dates of these collective bargaining agreements range between November 14, 2021 and July 14, 2022.