Pension And Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2021
Pension And Other Postretirement Benefits [Abstract]
Pension And Other Postretirement Benefits	13. PENSION AND OTHER POSTRETIREMENT BENEFITS We have a noncontributory defined benefit pension plan (the "Pension Plan") covering substantially all employees first hired prior to July 1, 2015 after the completion of one year of service and 1,000 hours of service.  The Pension Plan provides retirement benefits based on an employee’s final average earnings and years of service.  A supplemental benefit plan provides nonqualified pension benefits for compensation in excess of the IRS compensation limits applicable to the Pension Plan and eligible compensation deferred by a participant. Our funding policy is to make contributions to the Pension Plan, provided that the total annual contributions will not be less than ERISA and the Pension Protection Act of 2006 minimums or greater than the maximum tax-deductible amount, to review the contribution and funding strategy on a regular basis, and to allow discretionary contributions to be made by us from time to time.  The assets of the Pension Plan are invested primarily in fixed income investments and equity securities. We pay nonqualified pension benefits when they are due according to the terms of the supplemental benefit plan. We provide certain postretirement healthcare and life insurance benefits to retired employees.  Substantially all of our employees hired or rehired prior to 2014 may become eligible for postretirement medical benefits if they reach the age and service requirements of the retiree medical plan and retire on a pension (except a deferred pension) under the Pension Plan.  Medical benefits are self-insured and claims are administered through a third party administrator. The cost of coverage is determined based on the annual projected plan costs. The participant's premium or cost is determined based on Company guidelines. Postretirement life insurance benefits are insured through an insurance company. We fund postretirement benefits as incurred, and accordingly, there were no assets held in the postretirement benefits plan at December 31, 2021 and 2020. The following table sets forth information regarding the funded status of our pension and other postretirement benefits as of December 31, 2021 and 2020: Pension Benefits Postretirement Benefits 2021 2020 2021 2020Change in Benefit Obligation: Benefit obligation at beginning of period$ 921.8 $ 825.1 $ 80.9 $ 76.2Service cost 30.2 29.2 2.2 2.1Interest cost 23.9 26.7 1.7 2.4Actuarial (gain) loss (11.6) 134.7 (5.0) 4.9Benefits paid from plan assets (2.5) (2.1) — —Benefits paid from Company assets (1.6) (1.8) (5.6) (5.8)Plan participants' contributions — — 0.9 1.1Administrative expenses paid (1.5) (3.2) — —Settlements (116.8) (86.8) — —Benefit Obligation at End of Period 841.9 921.8 75.1 80.9Change in Plan Assets: Fair value of plan assets at beginning of period 722.0 658.4 — —Actual return on plan assets 39.5 115.7 — —Employer contributions(A) 41.6 41.8 4.7 4.7Plan participants' contributions — — 0.9 1.1Benefits paid(A) (4.1) (3.9) (5.6) (5.8)Administrative expenses paid (1.5) (3.2) — —Settlements (116.8) (86.8) — —Fair Value of Plan Assets at End of Period 680.7 722.0 — —Unfunded Status$ 161.2 $ 199.8 $ 75.1 $ 80.9 (A) Includes $1.6 million and $1.8 million paid from our assets for unfunded nonqualified pension benefits in fiscal years 2021 and 2020, respectively. The accumulated benefit obligation for our Pension Plan was $774.7 million and $844.0 million at December 31, 2021 and 2020, respectively. Amounts recognized in the consolidated balance sheet for the years ended December 31 consist of the following: Pension Benefits Postretirement Benefits 2021 2020 2021 2020Current accrued benefit cost$ 2.1 $ 1.9 $ 6.6 $ 6.8Non-current accrued benefit cost 159.1 197.9 68.5 74.1Net amount recognized$ 161.2 $ 199.8 $ 75.1 $ 80.9  Current accrued benefit cost for both pension benefits and postretirement benefits is included in other current liabilities in the consolidated balance sheets. Non-current accrued benefit cost for pension benefits and postretirement benefits are included in pension liability and postretirement benefits liability, respectively, in the consolidated balance sheets. Amounts recognized in accumulated other comprehensive loss for the years ended December 31, net of tax, consist of the following: Pension Benefits Postretirement Benefits 2021 2020 2021 2020Net actuarial loss$ 166.1 $ 227.9 $ 9.3 $ 13.6Prior service cost — — 0.1 0.1Accumulated other comprehensive loss$ 166.1 $ 227.9 $ 9.4 $ 13.7 The actuarial gain for the Pension Plan in 2021 was primarily related to increases in the discount rate compared to 2020. The actuarial loss for the Pension Plan in 2020 was primarily related to decreases in the discount rate and changes to the lump-sum interest rates used to measure the benefit obligations compared to 2019. Weighted-average assumptions used to determine the actuarial present value of the pension and postretirement benefit obligations as of December 31 are: Pension BenefitsPostretirement Benefits 2021 2020 2021 2020 Discount rate 2.86% 2.62% 2.71% 2.22%Rate of compensation increase 4.38% 4.49% — — Healthcare cost trend on covered charges — — 5.00% 5.00% The net periodic benefit cost for the years ended December 31, 2021, 2020, and 2019 included the following components: Pension Benefits Postretirement BenefitsComponents of Net Periodic Benefit Cost2021 2020 2019 2021 2020 2019Selling, general and administrative expenses: Service cost$ 30.2 $ 29.2 $ 25.6 $ 2.2 $ 2.1 $ 2.0Total selling, general and administrative expenses$ 30.2 $ 29.2 $ 25.6 $ 2.2 $ 2.1 $ 2.0Non-operating expenses: Interest cost 23.9 26.7 30.0 1.7 2.4 2.9Expected return on plan assets (30.6) (32.8) (34.1) — — —Amortization of: Net actuarial loss 32.3 30.2 19.1 0.8 0.7 0.3Settlement charge 30.4 27.7 — — — —Total non-operating expenses$ 56.0 $ 51.8 $ 15.0 $ 2.5 $ 3.1 $ 3.2Net periodic benefit cost$ 86.2 $ 81.0 $ 40.6 $ 4.7 $ 5.2 $ 5.2 During 2021, we made lump-sum pension benefit distributions and purchased nonparticipating annuity contracts exceeding the cumulative amount of service and interest cost components of the net periodic pension cost for the year, which is the settlement accounting threshold. During 2020, we made lump-sum pension benefit distributions exceeding the settlement accounting threshold. Accordingly, we recorded a non-cash pension settlement charge of $30.4 million and $27.7 million in non-operating expenses on our consolidated statements of income for the year ended December 31, 2021 and 2020, respectively. This settlement charge represented the immediate recognition into expense of a portion of the unrecognized loss within accumulated other comprehensive loss in proportion to the share of the projected benefit obligation that was settled by the lump-sum pension benefit distributions and purchases of the nonparticipating annuity contracts. Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31 were: Pension Benefits Postretirement Benefits 2021 2020 2019 2021 2020 2019 Discount rate2.62% / 2.72% 3.38% / 2.72% 4.31% 2.22% 3.19% 4.16%Expected return on plan assets5.00% 5.50% 5.75% — — — Rate of compensation increase4.32% 4.24% 4.36% — — — Healthcare cost trend on covered charges— — — 5.00% 5.00% 5.00% A discount rate of 2.62% was used as of January 1, 2021 to determine the net periodic benefit cost for the Pension Plan, which was increased to 2.72% effective September 30, 2021 for the remeasurement of the plan liability upon triggering settlement accounting. A discount rate of 3.38% was used as of January 1, 2020 to determine the net periodic benefit cost for the Pension Plan, which was lowered to 2.72% effective September 30, 2020 for the remeasurement of the plan liability upon triggering settlement accounting. The expected return on plan assets assumption for the Pension Plan is a long-term assumption and was determined after evaluating input from both the plan’s actuary and pension fund investment advisors, consideration of macroeconomic conditions, historical rates of return on plan assets, and anticipated current and long-term rates of return on the various classes of assets in which the plan invests. For measurement of the postretirement benefits net periodic cost, a 5.00% annual rate of increase in per capita cost of covered healthcare benefits was assumed for 2021.  The rate was assumed to remain at 5.00% in 2022 and to remain at that level thereafter. We expect to fund $2.0 million for nonqualified pension benefits during 2022. Pension contributions are expected to be $40.0 million in 2022; however, additional contributions may be made at our discretion. Estimated future defined benefit pension and other postretirement benefit plan payments to plan participants for the years ending December 31 are as follows: YearPension‎Benefits Postretirement‎Benefits 2022$ 58.6 $ 6.6 2023 59.3 6.9 2024 58.9 7.3 2025 59.0 7.4 2026 59.2 7.3 2027 to 2031 288.6 31.8 The investment objective of our Pension Plan is to ensure that there are sufficient assets to fund regular pension benefits payable to employees over the long-term life of the plan.  Our Pension Plan seeks to allocate plan assets in a manner that is closely duration-matched with the actuarial projected cash flow liabilities, consistent with prudent standards for preservation of capital, tolerance of investment risk, and maintenance of liquidity. Assets of the qualified pension plan are held by Comerica Bank (the "Trustee"). Our Pension Plan utilizes a liability-driven investment (“LDI”) approach to help meet these objectives. The LDI strategy employs a structured fixed-income portfolio designed to reduce volatility in the plan's future funding requirements and funding status. This is accomplished by using a blend of long duration government, quasi-governmental and corporate fixed-income securities, as well as appropriate levels of equity and alternative investments designed to optimize the plan's liability hedge ratio. Derivatives may also be used on fixed-income investments to manage interest rate exposure, volatility, duration, credit exposures, and asset class allocation. Derivatives are not allowed if the position creates economic portfolio leverage beyond the portfolio’s investment objectives or if used for speculative purposes. In practice, the value of an asset portfolio constructed primarily of fixed income securities is inversely correlated to changes in market interest rates, primarily offsetting changes in the value of the pension benefit obligation caused by changes in the interest rate used to discount plan liabilities. Asset allocation information for the Pension Plan at December 31, 2021 and 2020 is as follows: Investment2021‎Actual‎Allocation 2021‎Target‎Allocation‎Range2020‎Actual‎Allocation 2020‎Target‎Allocation‎RangeEquity securities - U.S. 6%3-10 % 7%3-10 %Equity securities - International 6%2-10 % 10%2-10 %Fixed income investments 55%40-80 % 66%40-80 %Hedge funds 6%2-8 % 5%2-8 %Real assets 5%2-10 % 5%0-15 %Private equity 5%2-8 % 2%0-15 %Other investments 5%0-8 % 4%0-8 %Short-term investments 12%1-10 % 1%1-10 %Total 100%100 % 100%100 % Actual asset allocation may occasionally fall outside of the target allocation range until rebalancing occurs. Certain reclassifications have been made to the classes of plan assets in prior year to conform to the December 31, 2021 presentation due to a change in our investment policy in 2021. The following is a description of the valuation methodologies used for assets held by the Pension Plan measured at fair value: Equity securities - U.S.Equity securities - U.S. consist of investments in U.S. corporate stocks and U.S. equity mutual funds. U.S. equity mutual funds include publicly traded mutual funds and a bank collective fund for ERISA plans. U.S. corporate stocks and U.S. equity mutual funds are primarily large-capitalization stocks (defined as companies with market capitalization of more than $10 billion). U.S. corporate stocks and publicly traded mutual funds are valued at the closing price reported on the active public market in which the individual securities are traded and are classified as Level 1. The bank collective fund for ERISA plans is valued at the net asset value ("NAV") of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Equity securities – InternationalEquity securities - International consist of investments in international corporate stocks, publicly traded mutual funds, and a collective investment trust, and are primarily investments within developed and emerging markets. Investments other than the collective investment trust are valued at the closing price reported on the active public market in which the individual securities are traded and are classified as Level 1. The collective investment trust is valued at the NAV of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Audited financial statements are produced on an annual basis for the collective investment trust. Fixed income investmentsFixed income investments consist of U.S. and international corporate bonds, government and government agency bonds, derivatives, as well as a collective trust that invests in U.S. government debt securities. U.S. and international corporate bonds and government and government agency bonds are valued by independent pricing services using market-based cash flow generators and pricing spread models on both primary and secondary market transactions. As the significant inputs used are observable market inputs, these investments are classified as Level 2. Derivatives could include, but are not limited to, instruments such as U.S. Treasury futures, total returns swaps, and credit default swaps. Derivatives are valued by independent pricing services using direct and observable market inputs and are thus classified as Level 2. The collective trust is valued at the NAV of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Hedge fundsHedge funds consist of investments in various hedge funds structured as fund-of-funds (defined as a single fund that invests in multiple funds). The hedge funds use various investment strategies in an attempt to generate non-correlated returns. A fund-of-funds is designed to help diversify and reduce the risk of the overall portfolio. The hedge funds are valued at the NAV of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Audited financial statements are produced on an annual basis for the hedge funds. Real assets Real assets consist of a diversified mutual fund, and two limited partnerships (“LP”) that invest in real estate. The diversified mutual fund is valued using quoted prices in an active market, and is therefore classified as Level 1. The LP investments are valued at the NAV of units of the trust. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Audited financial statements are produced on an annual basis for the LP investments. Private equityPrivate equity is an asset class that is generally characterized as requiring long-term commitments and where liquidity is typically limited. Private equity investments do not have an actively traded market with readily observable prices. The investments are limited partnerships and are diversified across typical private equity strategies including: buyouts, co-investments, secondary offerings, venture capital, and special situations. Valuations are developed using a variety of proprietary model methodologies. Valuations may be derived from publicly available sources as well as information obtained from each fund's general partner based upon public market conditions and returns. All private equity investments are classified as Level 3, other than a limited partnership valued at the NAV of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. Audited financial statements are produced on an annual basis for the private equity investments. Other investmentsOther investments consist of investments in a private debt fund and a high-yield bond fund. The private debt fund is valued using unobservable inputs with limited trading activity, and is therefore classified as Level 3. The high-yield bond fund is valued using the NAV based on the fair value of the underlying investments held by the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. Audited financial statements are produced on an annual basis for the private debt fund and the high-yield bond fund. Short-term investmentsShort-term investments consist of cash and cash equivalents in a short-term fund which is valued at the NAV of units of the fund. The NAV, as provided by the Trustee, is used as a practical expedient to estimate fair value. The NAV is based on the fair value of the underlying investments held by the fund. The methods described above may produce fair value calculations that may not be indicative of net realizable value or reflective of future fair values.  Furthermore, while we believe our Pension Plan valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. There have been no changes in the methodologies for determining fair value at December 31, 2021 or 2020. The following tables set forth, by level within the fair value hierarchy, the Pension Plan assets measured at fair value as of December 31, 2021 and 2020: December 31, 2021InvestmentInvestments‎Measured at‎NAV Level 1 Level 2 Level 3 TotalEquity securities - U.S.$ 13.6 $ 27.3 $ — $ — $ 40.9Equity securities - International 13.9 28.4 — — 42.3Fixed income investments 96.1 — 279.7 — 375.8Hedge funds 41.8 — — — 41.8Real assets 16.4 20.3 — — 36.7Private equity 8.2 — — 21.7 29.9Other investments 20.1 — — 11.4 31.5Short-term investments 81.8 — — — 81.8Total$ 291.9 $ 76.0 $ 279.7 $ 33.1 $ 680.7 December 31, 2020InvestmentInvestments‎Measured at‎NAV Level 1 Level 2 Level 3 TotalEquity securities - U.S.$ 17.3 $ 30.6 $ — $ — $ 47.9Equity securities - International 24.9 45.4 — — 70.3Fixed income investments 317.4 — 162.5 — 479.9Hedge funds 36.0 — — — 36.0Real assets 13.6 21.2 — — 34.8Private equity 2.0 — — 13.8 15.8Other investments 22.1 — — 11.4 33.5Short-term investments 3.8 — — — 3.8Total$ 437.1 $ 97.2 $ 162.5 $ 25.2 $ 722.0 Certain reclassifications have been made to the fair value hierarchy in prior year to conform to the December 31, 2021 presentation. The tables below set forth a summary of changes in the fair value of the Pension Plan's Level 3 assets for the years ended December 31, 2021 and 2020: December 31, 2021 Private Equity Other Investments TotalBalance, beginning of year$ 13.8 $ 11.4 $ 25.2Realized gains 0.8 0.2 1.0Unrealized gains 9.2 1.1 10.3Purchases 0.1 — 0.1Sales (2.2) (1.3) (3.5)Balance, end of year$ 21.7 $ 11.4 $ 33.1 December 31, 2020 Private Equity Other Investments TotalBalance, beginning of year$ 11.0 $ 11.4 $ 22.4Unrealized gains 1.0 0.6 1.6Purchases 2.5 — 2.5Sales (0.7) (0.6) (1.3)Balance, end of year$ 13.8 $ 11.4 $ 25.2