Mueller Industries (MLI) 10-K 28 Feb 24 2023 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 30, 2023	Feb. 22, 2024	Jul. 01, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 30, 2023
Current Fiscal Year End Date	--12-30
Document Transition Report	false
Entity File Number	1-6770
Entity Registrant Name	MUELLER INDUSTRIES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	25-0790410
Entity Address, Address Line One	150 Schilling Boulevard
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Collierville
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	38017
City Area Code	901
Local Phone Number	753-3200
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	MLI
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 4,824,036,270
Entity Common Stock, Shares Outstanding		113,634,944
Documents Incorporated by Reference	Portions of the following document are incorporated by reference into this Report: Registrant’s Definitive Proxy Statement for the 2024 Annual Meeting of Stockholders, scheduled to be mailed on or about March 22, 2024 (Part III).
Entity Central Index Key	0000089439
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 30, 2023
Audit Information [Abstract]
Auditor Name	Ernst & Young LLP
Auditor Location	Memphis, Tennessee
Auditor Firm ID	42

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Income Statement [Abstract]
Net sales	$ 3,420,345	$ 3,982,455	$ 3,769,345
Cost of goods sold	2,433,511	2,864,862	2,938,989
Depreciation and amortization	39,954	43,731	45,390
Selling, general, and administrative expense	208,172	203,086	184,052
Gain on sale of businesses	(4,137)	0	(57,760)
Gain on sale of assets, net	0	(6,373)	0
Impairment charges	6,258	0	2,829
Gain on insurance settlement	(19,466)	0	0
Operating income	756,053	877,149	655,845
Interest expense	(1,221)	(810)	(7,709)
Interest income	38,208	6,457	353
Realized and unrealized gains on short-term investments	41,865	2,918	0
Gain on extinguishment of NMTC liability	7,534	0	0
Redemption premium	0	0	(5,674)
Environmental expense	(825)	(1,298)	(5,053)
Pension plan termination expense	0	(13,100)	0
Other income, net	3,618	4,715	3,377
Income before income taxes	845,232	876,031	641,139
Income tax expense	(220,762)	(223,322)	(165,858)
(Loss) income from unconsolidated affiliates, net of foreign tax	(14,821)	10,111	(157)
Consolidated net income	609,649	662,820	475,124
Net income attributable to noncontrolling interests	(6,752)	(4,504)	(6,604)
Net income attributable to Mueller Industries, Inc.	$ 602,897	$ 658,316	$ 468,520
Weighted average shares for basic earnings per share (in shares)	111,420	111,558	112,022
Effect of dilutive stock-based awards (in shares)	2,242	1,552	1,574
Adjusted weighted average shares for diluted earnings per share (in shares)	113,662	113,110	113,596
Basic earnings per share (in dollars per share)	$ 5.41	$ 5.90	$ 4.18
Diluted earnings per share (in dollars per share)	5.30	5.82	4.12
Dividends per share (in dollars per share)	$ 0.60	$ 0.50	$ 0.26

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 609,649	$ 662,820	$ 475,124
Other comprehensive income (loss), net of tax:
Foreign currency translation	21,943	(30,382)	(6,730)
Net change with respect to derivative instruments and hedging activities, net of tax of $373, $(200), and $47	(1,273)	683	(181)
Net change in pension and postretirement obligation adjustments, net of tax of $1,308, $(4,381), and $(1,379)	(3,852)	12,722	5,703
Attributable to unconsolidated affiliates, net of tax of $(266), $(784), and $(284)	917	2,702	978
Total other comprehensive income (loss), net	17,735	(14,275)	(230)
Consolidated comprehensive income	627,384	648,545	474,894
Comprehensive income attributable to noncontrolling interests	(7,533)	(1,057)	(4,838)
Comprehensive income attributable to Mueller Industries, Inc.	$ 619,851	$ 647,488	$ 470,056

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Statement of Comprehensive Income [Abstract]
Net change with respect to derivative instruments and hedging activities, net of tax	$ 373	$ (200)	$ 47
Net change in pension and postretirement obligation adjustments, net of tax	1,308	(4,381)	(1,379)
Attributable to unconsolidated affiliates, net of tax	$ (266)	$ (784)	$ (284)

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 1,170,893	$ 461,018
Short-term investments	98,146	217,863
Accounts receivable, less allowance for doubtful accounts of $2,830 in 2023 and $2,687 in 2022	351,561	380,352
Inventories	380,248	448,919
Other current assets	39,173	26,501
Total current assets	2,040,021	1,534,653
Property, plant, and equipment, net	385,165	379,950
Operating lease right-of-use assets	35,170	22,892
Goodwill, net	151,820	157,588
Intangible assets, net	46,208	54,785
Investment in unconsolidated affiliates	83,436	72,364
Other noncurrent assets	17,481	20,167
Total Assets	2,759,301	2,242,399
Current liabilities:
Current portion of debt	796	811
Accounts payable	120,485	128,000
Accrued wages and other employee costs	55,644	61,915
Current portion of operating lease liabilities	7,893	4,942
Other current liabilities	132,320	152,627
Total current liabilities	317,138	348,295
Long-term debt, less current portion	185	1,218
Pension liabilities	2,832	4,078
Postretirement benefits other than pensions	9,230	8,977
Environmental reserves	15,030	16,380
Deferred income taxes	19,134	16,258
Noncurrent operating lease liabilities	26,683	16,880
Other noncurrent liabilities	10,353	16,349
Total liabilities	400,585	428,435
Mueller Industries, Inc. stockholders' equity:
Preferred stock - $1.00 par value; shares authorized 5,000,000; none outstanding	0	0
Common stock - $.01 par value; shares authorized 250,000,000 in 2023 and 100,000,000 in 2022; issued 160,366,008; outstanding 114,157,918 in 2023 and 114,003,234 in 2022	1,604	802
Additional paid-in capital	312,171	297,270
Retained earnings	2,594,300	2,059,796
Accumulated other comprehensive loss	(47,221)	(64,175)
Treasury common stock, at cost	(523,409)	(502,779)
Total Mueller Industries, Inc. stockholders' equity	2,337,445	1,790,914
Noncontrolling interests	21,271	23,050
Total equity	2,358,716	1,813,964
Commitments and contingencies	0	0
Total Liabilities and Equity	$ 2,759,301	$ 2,242,399

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2,830	$ 2,687
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	250,000,000
Common stock, issued (in shares)	160,366,008	160,366,008
Common stock, outstanding (in shares)	114,157,918	114,003,234
Common stock, authorized (in shares)	250,000,000
Previously Reported
Statement of Financial Position [Abstract]
Common stock, authorized (in shares)		100,000,000
Common stock, authorized (in shares)		100,000,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Operating activities:
Consolidated net income	$ 609,649	$ 662,820	$ 475,124
Reconciliation of consolidated net income to net cash provided by operating activities:
Depreciation	34,949	38,157	39,120
Amortization of intangibles	5,005	5,574	6,270
Amortization of debt issuance costs	870	357	265
Loss (income) from unconsolidated affiliates	14,821	(10,111)	157
Insurance proceeds - noncapital related	9,854	1,646	0
Redemption premium	0	0	5,674
Gain on sale of securities	(17,100)	0	0
Gain on insurance settlement	(19,466)	0	0
Stock-based compensation expense	23,131	17,801	9,822
Provision for doubtful accounts receivable	(84)	323	1,216
Gain on disposals of assets	(1)	(6,373)	(769)
Gain on sale of businesses	(4,137)	0	(57,760)
Unrealized gain on short-term investments	(24,765)	0	0
Impairment charges	6,258	0	2,829
Gain on extinguishment of NMTC liability	(7,534)	0	0
Deferred income tax expense (benefit)	4,790	(3,880)	7,413
Changes in assets and liabilities, net of effects of businesses acquired and sold:
Receivables	30,915	82,713	(124,708)
Inventories	67,903	(24,189)	(119,514)
Other assets	(20,700)	(8,971)	919
Current liabilities	(40,606)	(26,633)	73,755
Other liabilities	(3,497)	(7,564)	(5,467)
Other, net	2,511	2,273	(2,645)
Net cash provided by operating activities	672,766	723,943	311,701
Investing activities:
Proceeds from sale of assets, net of cash transferred	279	7,850	2,302
Purchase of short-term investments	(106,231)	(217,863)	0
Acquisition of businesses, net of cash acquired	0	0	(30,206)
Proceeds from sale of business, net of cash sold	0	0	81,884
Capital expenditures	(54,025)	(37,639)	(31,833)
Payment received for (issuance of) notes receivable	0	0	8,539
Insurance proceeds - capital related	24,646	3,354	0
Proceeds from the sale of securities	55,454	0	0
Proceeds from the maturity of short-term investments	217,863	0	0
Dividends from unconsolidated affiliates	1,093	2,295	0
Investments in unconsolidated affiliates	(3,999)	0	(1,613)
Net cash provided by (used in) investing activities	135,080	(242,003)	29,073
Financing activities:
Dividends paid to stockholders of Mueller Industries, Inc.	(66,868)	(55,787)	(29,137)
Dividends paid to noncontrolling interests	(9,312)	(7,248)	(9,722)
Issuance of long-term debt	0	0	595,000
Repayments of long-term debt	(241)	(204)	(920,610)
(Repayment) issuance of debt by consolidated joint ventures, net	(30)	67	(5,113)
Repurchase of common stock	(19,303)	(38,054)	(4,864)
Payment of contingent consideration	0	0	(1,250)
Net cash (used) received to settle stock-based awards	(8,755)	(1,429)	85
Debt issuance costs	0	0	(1,111)
Net cash used in financing activities	(104,509)	(102,655)	(376,722)
Effect of exchange rate changes on cash	5,590	(4,365)	(1,052)
Increase (decrease) in cash, cash equivalents, and restricted cash	708,927	374,920	(37,000)
Cash, cash equivalents, and restricted cash at the beginning of the year	465,296	90,376	127,376
Cash, cash equivalents, and restricted cash at the end of the year	$ 1,174,223	$ 465,296	$ 90,376

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss	Treasury stock	Noncontrolling interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)		160,366,000
Balance at beginning of year at Dec. 26, 2020		$ 802	$ 280,051	$ 1,019,694	$ (54,883)	$ (468,919)	$ 24,315
Treasury stock beginning balance (in shares) at Dec. 26, 2020						46,192,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under two-for-one stock split (in shares)		0
Issuance of shares under two-for-one stock split		$ 0	0
Acquisition of shares under incentive stock option plans			720			$ (636)
Stock-based compensation expense			9,822
Issuance of restricted stock			(4,385)			$ 4,385
Net income attributable to Mueller Industries, Inc.	$ 468,520			468,520
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(29,725)
Total other comprehensive income (loss) attributable to Mueller Industries, Inc.	(230)				1,536
Issuance of shares under incentive stock option plans (in shares)						(176,000)
Repurchase of common stock (in shares)						194,000
Repurchase of common stock						$ (4,864)
Issuance of restricted stock (in shares)						(436,000)
Purchase of Mueller Middle East							15,414
Dividends paid to noncontrolling interests							(9,722)
Net income attributable to noncontrolling interests	(6,604)						6,604
Foreign currency translation	(6,730)						(1,766)
Treasury stock ending balance (in shares) at Dec. 25, 2021						45,774,000
Balance at end of year at Dec. 25, 2021		$ 802	286,208	1,458,489	(53,347)	$ (470,034)	34,845
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)		160,366,000
Issuance of shares under two-for-one stock split (in shares)		0
Issuance of shares under two-for-one stock split		$ 0	0
Acquisition of shares under incentive stock option plans			830			(2,260)
Stock-based compensation expense			17,801
Issuance of restricted stock			(7,569)			$ 7,569
Net income attributable to Mueller Industries, Inc.	658,316			658,316
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(57,009)
Total other comprehensive income (loss) attributable to Mueller Industries, Inc.	(14,275)				(10,828)
Issuance of shares under incentive stock option plans (in shares)						(153,000)
Repurchase of common stock (in shares)						1,438,000
Repurchase of common stock						$ (38,054)
Issuance of restricted stock (in shares)						(696,000)
Purchase of Mueller Middle East							(5,604)
Dividends paid to noncontrolling interests							(7,248)
Net income attributable to noncontrolling interests	(4,504)						4,504
Foreign currency translation	(30,382)						(3,447)
Treasury stock ending balance (in shares) at Dec. 31, 2022						46,363,000
Balance at end of year at Dec. 31, 2022	$ 1,813,964	$ 802	297,270	2,059,796	(64,175)	$ (502,779)	23,050
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)	114,003,234	160,366,000
Issuance of shares under two-for-one stock split (in shares)		0
Issuance of shares under two-for-one stock split		$ 802	(802)
Acquisition of shares under incentive stock option plans			786			(9,541)
Stock-based compensation expense			23,131
Issuance of restricted stock			(8,214)			$ 8,214
Net income attributable to Mueller Industries, Inc.	$ 602,897			602,897
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(68,393)
Total other comprehensive income (loss) attributable to Mueller Industries, Inc.	17,735				16,954
Issuance of shares under incentive stock option plans (in shares)						57,000
Repurchase of common stock (in shares)						516,000
Repurchase of common stock						$ (19,303)
Issuance of restricted stock (in shares)						(728,000)
Purchase of Mueller Middle East							0
Dividends paid to noncontrolling interests							(9,312)
Net income attributable to noncontrolling interests	(6,752)						6,752
Foreign currency translation	$ 21,943						781
Treasury stock ending balance (in shares) at Dec. 30, 2023	15,000,000					46,208,000
Balance at end of year at Dec. 30, 2023	$ 2,358,716	$ 1,604	$ 312,171	$ 2,594,300	$ (47,221)	$ (523,409)	$ 21,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)	114,157,918	160,366,000

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical)		12 Months Ended
	Sep. 26, 2023	Dec. 30, 2023
Statement of Stockholders' Equity [Abstract]
Stock split ratio, common stock	2	2

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Nature of Operations The principal business of Mueller Industries, Inc. is the manufacture and sale of copper tube and fittings; line sets; steel nipples; brass rod, bar, and shapes; aluminum and brass forgings; aluminum impact extrusions; compressed gas valves; refrigeration valves and fittings; pressure vessels; coaxial heat exchangers; and insulated flexible duct systems. The Company also resells brass and plastic plumbing valves, plastic fittings, malleable iron fittings, faucets, and plumbing specialty products. The Company markets its products to the HVAC, plumbing, refrigeration, hardware, and other industries. Mueller’s operations are located throughout the United States and in Canada, Mexico, Great Britain, South Korea, the Middle East, and China. Fiscal Years The Company’s fiscal year ends on the last Saturday of December and consisted of 52 weeks in 2023, 53 weeks in 2022, and 52 weeks in 2021. These dates were December 30, 2023, December 31, 2022, and December 25, 2021. Basis of Presentation The Consolidated Financial Statements include the accounts of Mueller Industries, Inc. and its majority-owned subsidiaries. The noncontrolling interests represent a private ownership interest of 40 percent of Jungwoo Metal Ind. Co., LTD (Jungwoo-Mueller) and 45 percent of Mueller Middle East WLL (Mueller Middle East). The Company records the results of Jungwoo-Mueller one month in arrears in the Consolidated Financial Statements. Certain prior year balances have been reclassified to conform to current year presentation. Common Stock Split On September 26, 2023, the Company’s shareholders approved an amendment to the Company’s Restated Certificate of Incorporation to increase the total number of authorized shares of Common Stock from 100,000,000 to 250,000,000. Subsequently, the Company’s Board of Directors announced a two-for-one stock split of its common stock effected in the form of a stock dividend of one share for each outstanding share. The record date for the stock split was October 6, 2023, and the additional shares were distributed on October 20, 2023. Shares authorized in prior periods are not adjusted. All other references to share and per share amounts presented in the Consolidated Financial Statements and this Annual Report on Form 10-K have been adjusted retroactively to reflect the stock split. Revenue Recognition Given the nature of the Company’s business and product offerings, sales transactions with customers are generally comprised of a single performance obligation that involves delivery of the products identified in the contracts with customers. Performance obligations are generally satisfied at the point in time of shipment and payment is generally due within 60 days. Variable consideration is estimated for future rebates on certain product lines and product returns. The Company records variable consideration as an adjustment to the transaction price in the period it is incurred. Since variable consideration is settled within a short period of time, the time value of money is not significant. The cost of shipping product to customers is expensed as incurred as a component of cost of goods sold. The Company’s Domestic Piping Systems Group engages in certain transactions where it acts as an agent. Revenue from these transactions is recorded on a net basis. See “ Note 3 – Segment Information ” for additional information on disaggregation of revenue from contracts with customers. Acquisitions Accounting for acquisitions requires the Company to recognize separately from goodwill the assets acquired and liabilities assumed at their acquisition date fair values. Goodwill is measured as the excess of the purchase price over the net amount allocated to the identifiable assets acquired and liabilities assumed. While management uses its best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date, the estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. The operating results generated by the acquired businesses are included in the Consolidated Statements of Income from their respective dates of acquisition. Acquisition related costs are expensed as incurred. See “ Note 2 – Acquisitions & Dispositions ” for additional information. Cash Equivalents and Restricted Cash Temporary investments with original maturities of three months or less are considered to be cash equivalents. These investments are stated at cost. At December 30, 2023 and December 31, 2022, temporary investments consisted of money market mutual funds, commercial paper, bank repurchase agreements, and U.S. and foreign government securities totaling approximately $1.01 billion and $329.4 million, respectively. Amounts included in restricted cash relate to required deposits in brokerage accounts that facilitate the Company’s hedging activities as well as imprest funds for the Company’s self-insured workers’ compensation program. See “ Note 4 – Cash, Cash Equivalents, and Restricted Cash ” for additional information. Short-Term Investments The fair value of short-term investments at December 30, 2023, consisting of marketable securities, approximates the carrying value on that date. These marketable securities are stated at fair value and classified as level 1 within the fair value hierarchy. This classification is defined as a fair value determined using observable inputs that reflect quoted prices in active markets for identical assets. During 2023, the Company recognized gains of $41.9 million on short-term investments, of which $17.1 million was realized on the sale of marketable securities and the remaining $24.8 million represents unrealized gains relating to the excess fair value over the related cost basis of the marketable securities as of December 30, 2023. The fair value of short-term investments at December 31, 2022, consisting of U.S. treasury bills with maturities exceeding three months at the time of purchase, approximates the carrying value on that date. These treasury bills are stated at fair value and are classified as trading securities. The fair value of treasury bills is classified as level 1 within the fair value hierarchy. This classification is defined as a fair value determined using observable inputs that reflect quoted prices in active markets for identical assets. Allowance for Doubtful Accounts The Company routinely grants credit to many of its customers without collateral. The risk of credit loss in trade receivables is substantially mitigated by the credit evaluation process. The Company provides an allowance for receivables that may not be fully collected. In circumstances where the Company is aware of a customer’s inability to meet their financial obligations (e.g., bankruptcy filings or substantial credit rating downgrades), it records an allowance for doubtful accounts against amounts due to reduce the net recognized receivable to the amount it believes most likely will be collected. For all other customers, the Company recognizes an allowance for doubtful accounts based on its historical collection experience and the impact of current economic conditions. If circumstances change (e.g., greater than expected defaults or an unexpected material change in a major customer’s ability to meet their financial obligations), the Company could change its estimate of the recoverability of amounts due by a material amount. Historically, credit losses have been within management’s expectations. The balance for uncollectible accounts was $2.8 million and $2.7 million as of December 30, 2023 and December 31, 2022, respectively. Inventories The Company’s inventories are valued at the lower-of-cost-or-market. The material component of its U.S. copper tube and copper fittings inventories is valued on a LIFO basis and the non-material components of U.S. copper tube and copper fittings inventories are valued on a FIFO basis. The material component of its U.K. and Canadian copper tube inventories are valued on a FIFO basis. The material component of its brass rod and forgings inventories are valued on a FIFO basis. Certain inventories are valued on an average cost basis. Elements of cost in finished goods inventory in addition to the cost of material include depreciation, amortization, utilities, maintenance, production wages, and transportation costs. The market price of copper cathode and scrap is subject to volatility. During periods when open market prices decline below net book value, the Company may need to provide an allowance to reduce the carrying value of its inventory. In addition, certain items in inventory may be considered obsolete and, as such, the Company may establish an allowance to reduce the carrying value of those items to their net realizable value. Changes in these estimates related to the value of inventory, if any, may result in a materially adverse impact on the Company’s reported financial position or results of operations. The Company recognizes the impact of any changes in estimates, assumptions, and judgments in income in the period in which it is determined. See “ Note 5 – Inventories ” for additional information. Leases The Company leases certain manufacturing facilities, distribution centers, office space, and equipment. Leases with an initial term of twelve months or less are not recorded on the balance sheet; expense for these leases is recognized on a straight line-basis over the term of the lease. Most of the Company’s leases include one or more options to renew up to five years and have remaining terms of one The Company has certain vehicle leases that are financing; however, these leases are deemed immaterial for disclosure. See “ Note 8 – Leases ” for additional information. Property, Plant, and Equipment Property, plant, and equipment is stated at cost less accumulated depreciation. Expenditures for major additions and improvements are capitalized, while minor replacements, maintenance, and repairs are charged to expense as incurred. Depreciation of buildings, machinery, and equipment is provided on the straight-line method over the estimated useful lives ranging from 20 to 40 years for buildings and five The Company continually evaluates these assets to determine whether events or changes in circumstances have occurred that may warrant revision of the estimated useful life or whether the remaining balance should be evaluated for possible impairment. See “ Note 9 – Property, Plant, and Equipment, Net ” for additional information. Goodwill Goodwill is recognized for the excess of the purchase price over the fair value of tangible and identifiable intangible net assets of businesses acquired. Several factors give rise to goodwill in business acquisitions, such as the expected benefit from synergies of the combination and the existing workforce of the acquired business. Goodwill is evaluated annually for possible impairment as of the first day of the fourth quarter unless circumstances indicate the need to accelerate the timing of the evaluation. In the evaluation of goodwill impairment, management performs a qualitative assessment to determine if it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the qualitative assessment is not conclusive, management compares the fair value of a reporting unit with its carrying amount and will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, not to exceed the total amount of goodwill allocated to the reporting unit. Fair value for the Company’s reporting units is determined using a combination of the income and market approaches (level 3 within the fair value hierarchy), incorporating market participant considerations and management’s assumptions on revenue growth rates, operating margins, discount rates and expected capital expenditures. The market approach measures the fair value of a business through the analysis of publicly traded companies or recent sales of similar businesses. The income approach uses a discounted cash flow model to estimate the fair value of reporting units based on expected cash flows (adjusted for capital investment required to support operations) and a terminal value. This cash flow stream is discounted to its present value to arrive at a fair value for each reporting unit. Future earnings are estimated using the Company’s most recent annual projections, applying a growth rate to future periods. Those projections are directly impacted by the condition of the markets in which the Company’s businesses participate. The discount rate selected for the reporting units is generally based on rates of return available for comparable companies at the date of valuation. Fair value determinations may include both internal and third-party valuations. See “ Note 10 – Goodwill and Other Intangible Assets ” for additional information. Investments in Unconsolidated Affiliates Tecumseh The Company owns a 50 percent interest in an unconsolidated affiliate that acquired Tecumseh Products Company (Tecumseh) and an entity that provides financing to Tecumseh. This investment is recorded using the equity method of accounting, as the Company can exercise significant influence but does not own a majority equity interest or otherwise control the entity. Under the equity method of accounting, this investment is stated at initial cost and is adjusted for subsequent additional investments and the Company’s proportionate share of earnings or losses and distributions. The Company records its proportionate share of the investee’s net income or loss, net of foreign taxes, one quarter in arrears as income (loss) from unconsolidated affiliates, net of foreign tax, in the Consolidated Statements of Income. The Company’s proportionate share of the investee’s other comprehensive income (loss), net of income taxes, is recorded in the Consolidated Statements of Comprehensive Income and Consolidated Statements of Changes in Equity. The U.S. tax effect of the Company’s proportionate share of Tecumseh’s income or loss is recorded in income tax expense in the Consolidated Statements of Income. In general, the equity investment in unconsolidated affiliates is equal to the current equity investment less the investee’s net accumulated losses. Retail Distribution The Company owns a 28 percent noncontrolling equity interest in a limited liability company in the retail distribution business. This investment is recorded using the equity method of accounting. The Company records its proportionate share of the investee’s net income or loss one month in arrears as income (loss) from unconsolidated affiliates in the Consolidated Statements of Income. The Company’s proportionate share of the investee’s other comprehensive income (loss), net of income taxes, is recorded in the Consolidated Statements of Comprehensive Income and Consolidated Statements of Changes in Equity. The investments in unconsolidated affiliates are assessed periodically for impairment and written down when the carrying amount is not considered fully recoverable. See “ Note 11 – Investments in Unconsolidated Affiliates ” for additional information. Self-Insurance Accruals The Company is primarily self-insured for workers’ compensation claims and benefits paid under certain employee health care programs. Accruals are primarily based on estimated undiscounted cost of claims, which includes incurred but not reported claims, and are classified as accrued wages and other employee costs. Pension Benefit Plans The Company sponsors qualified and nonqualified pension benefit plans in certain foreign locations. The Company recognizes the overfunded or underfunded status of the plans as an asset or liability in the Consolidated Balance Sheets with changes in the funded status recorded through comprehensive income in the year in which those changes occur. The obligations for these plans are determined by actuaries and affected by the assumptions, including discount rates, expected long-term return on plan assets for defined benefit pension plans, and certain employee-related factors, such as retirement age and mortality. The Company evaluates its assumptions periodically and makes adjustments as necessary. The expected return on plan assets is determined using the market value of plan assets. Differences between assumed and actual returns are amortized to the market value of assets on a straight-line basis over the average remaining service period of the plan participants using the corridor approach. The corridor approach defers all actuarial gains and losses resulting from variances between actual results and actuarial assumptions. These unrecognized gains and losses are amortized when the net gains and losses exceed 10 percent of the greater of the market value of the plan assets or the projected benefit obligation. The amount in excess of the corridor is amortized over the average remaining service period of the plan participants. For 2023, the average remaining service period for the pension plans was 11 years. We determine the discount rate (which is required to be the rate at which the projected benefit obligation could be effectively settled as of the measurement date) with the assistance of actuaries, who calculate the yield available on high quality corporate bonds of a term that reflects the maturity and duration of expected benefit payments. See “ Note 14 – Benefit Plans ” for additional information. Environmental Reserves and Environmental Expenses The Company recognizes an environmental liability when it is probable the liability exists and the amount is reasonably estimable. The Company estimates the duration and extent of its remediation obligations based upon reports of outside consultants, internal and third party estimates and analyses of cleanup costs and ongoing monitoring costs, communications with regulatory agencies, and changes in environmental law. If the Company were to determine that its estimates of the duration or extent of its environmental obligations were no longer accurate, it would adjust environmental liabilities accordingly in the period that such determination is made. Estimated future expenditures for environmental remediation are not discounted to their present value. Environmental expenses that relate to ongoing operations are included as a component of cost of goods sold. Environmental expenses related to non-operating properties Note 15 – Commitments and Contingencies ” for additional information. Earnings Per Share Basic earnings per share is computed based on the weighted average number of common shares outstanding. Diluted earnings per share reflects the increase in weighted average common shares outstanding that would result from the assumed exercise of outstanding stock options and vesting of restricted stock awards calculated using the treasury stock method. There were approximately 98 thousand stock-based awards excluded from the computation of diluted earnings per share for the year ended December 30, 2023 because they were antidilutive. Income Taxes Deferred income tax assets and liabilities are recognized when differences arise between the treatment of certain items for financial statement and tax purposes. Realization of certain components of deferred tax assets is dependent upon the occurrence of future events. The Company records valuation allowances to reduce its deferred tax assets to the amount it believes is more likely than not to be realized. These valuation allowances can be impacted by changes in tax laws, changes to statutory tax rates, and future taxable income levels and are based on the Company’s judgment, estimates, and assumptions regarding those future events. In the event the Company was to determine that it would not be able to realize all or a portion of the net deferred tax assets in the future, it would increase the valuation allowance through a charge to income tax expense in the period that such determination is made. Conversely, if it was to determine that it would be able to realize its deferred tax assets in the future, in excess of the net carrying amounts, the Company would decrease the recorded valuation allowance through a decrease to income tax expense in the period that such determination is made. The Company provides for uncertain tax positions and the related interest and penalties, if any, based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. Tax benefits for uncertain tax positions that are recognized in the financial statements are measured as the largest amount of benefit, determined on a cumulative probability basis, that is more likely than not to be realized upon ultimate settlement. To the extent the Company prevails in matters for which a liability for an uncertain tax position is established or is required to pay amounts in excess of the liability, the Company’s effective tax rate in a given financial statement period may be affected. These estimates are highly subjective and could be affected by changes in business conditions and other factors. Changes in any of these factors could have a material impact on future income tax expense. See “ Note 16 – Income Taxes ” for additional information. Taxes Collected from Customers and Remitted to Governmental Authorities Taxes assessed by a governmental authority that are directly imposed on a revenue producing transaction between the Company and its customers, primarily value added taxes in foreign jurisdictions, are accounted for on a net (excluded from revenues and costs) basis. Stock-Based Compensation The Company has in effect stock incentive plans under which stock-based awards have been granted to certain employees and members of its Board of Directors. Stock-based compensation expense is recognized in the Consolidated Statements of Income as a component of selling, general, and administrative expense based on the grant date fair value of the awards. See “ Note 18 – Stock-Based Compensation ” for additional information. Concentrations of Credit and Market Risk Concentrations of credit risk with respect to accounts receivable are limited due to the large number of customers comprising the Company’s customer base, and their dispersion across different geographic areas and different industries, including HVAC, plumbing, refrigeration, hardware, automotive, OEMs, and others. The Company minimizes its exposure to base metal price fluctuations through various strategies. Generally, it prices an equivalent amount of copper raw material, under flexible pricing arrangements it maintains with its suppliers, at the time it determines the selling price of finished products to its customers. Derivative Instruments and Hedging Activities The Company’s earnings and cash flows are subject to fluctuations due to changes in commodity prices, foreign currency exchange rates, and interest rates. The Company uses derivative instruments such as commodity futures contracts, foreign currency forward contracts, and interest rate swaps to manage these exposures. All derivatives are recognized in the Consolidated Balance Sheets at their fair value. On the date the derivative contract is entered into, it is either a) designated as a hedge of (i) a forecasted transaction or the variability of cash flow to be paid (cash flow hedge) or (ii) the fair value of a recognized asset or liability (fair value hedge), or b) not designated in a hedge accounting relationship, even though the derivative contract was executed to mitigate an economic exposure (economic hedge), as the Company does not enter into derivative contracts for trading purposes. Changes in the fair value of a derivative that is qualified, designated, and highly effective as a cash flow hedge are recorded in stockholders’ equity within accumulated other comprehensive income (AOCI), to the extent effective, until they are reclassified to earnings in the same period or periods during which the hedged transaction affects earnings. Changes in the fair value of undesignated derivative instruments executed as economic hedges are reported in current earnings. The Company documents all relationships between derivative instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivative instruments that are designated as fair value hedges to specific assets and liabilities in the Consolidated Balance Sheets and linking cash flow hedges to specific forecasted transactions or variability of cash flow. The Company also assesses, both at the hedge’s inception and on an ongoing basis, whether the designated derivative instruments that are used in hedging transactions are highly effective in offsetting changes in cash flow or fair values of hedged items. When a derivative instrument is determined not to be highly effective as a hedge or the underlying hedged transaction is no longer probable of occurring, hedge accounting is discontinued prospectively in accordance with the derecognition criteria for hedge accounting. The Company primarily executes derivative contracts with major financial institutions. These counterparties expose the Company to credit risk in the event of non-performance. The amount of such exposure is limited to the fair value of the contract plus the unpaid portion of amounts due to the Company pursuant to terms of the derivative instruments, if any. If a downgrade in the credit rating of these counterparties occurs, management believes that this exposure is mitigated by provisions in the derivative arrangements which allow for the legal right of offset of any amounts due to the Company from the counterparties with any amounts payable to the counterparties by the Company. As a result, management considers the risk of loss from counterparty default to be minimal. See “ Note 7 – Derivative Instruments and Hedging Activities ” for additional information. Fair Value of Financial Instruments The carrying amounts for cash and cash equivalents, accounts receivable, and accounts payable approximate fair value due to the short-term maturity of these instruments. The fair value of long-term debt at December 30, 2023 approximates the carrying value on that date. The estimated fair values were determined based on quoted market prices and the current rates offered for debt with similar terms and maturities. The fair value of long-term debt is classified as level 2 within the fair value hierarchy. This classification is defined as a fair value determined using market-based inputs other than quoted prices that are observable for the liability, either directly or indirectly. Foreign Currency Translation For foreign subsidiaries for which the functional currency is not the U.S. dollar, balance sheet accounts are translated at exchange rates in effect at the end of the year and income statement accounts are translated at average exchange rates for the year. Translation gains and losses are included in equity as a component of AOCI. Transaction gains and losses that arise from exchange rate fluctuations on transactions denominated in a currency other than the functional currency are recognized in selling, general, and administrative expense in the Consolidated Statements of Income. Included in the Consolidated Statements of Income were net transaction losses of $4.4 million in 2023, gains of $1.0 million in 2022, and losses of $0.6 million in 2021. Use of and Changes in Estimates The preparation of financial statements in conformity with generally accepted accounting principles in the United States (U.S. GAAP) requires management to make estimates, assumptions, and judgments that affect the amounts reported in the financial statements and accompanying notes. Management makes its best estimate of the ultimate outcome for these items based on historical trends and other information available when the financial statements are prepared. Changes in estimates are recognized in accordance with the accounting rules for the estimate, which is typically in the period when new information becomes available to management. Areas where the nature of the estimate makes it reasonably possible that actual results could materially differ from amounts estimated include but are not limited to: pension and other postretirement benefit plan obligations, tax liabilities, loss contingencies, litigation claims, environmental reserves, and impairment assessments of long-lived assets (including goodwill). Recently Adopted Accounting Standards In October 2021, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2021-08, Business Combinations (Topic 805): An Amendment of the FASB Accounting Standards Codification . The new guidance was issued to improve accounting for acquired revenue contracts with customers in a business combination by addressing diversity in practice and inconsistency related to the (i) recognition of an acquired contract liability, and (ii) payment terms and their effect on subsequent revenue recognized by the acquirer. The ASU is effective for fiscal years beginning after December 15, 2022 for public entities. The updated guidance requires prospective adoption, and early adoption is permitted. The Company adopted the ASU during the first quarter of 2023. The adoption of the ASU did not have a material impact on the Company’s Consolidated Financial Statements. Recently Issued Accounting Standards In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . The new guidance requires a public entity to disclose significant segment expenses and other segment items on an annual and interim basis and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. The guidance applies to all public entities and is effective for fiscal years beginning after December 15, 2023, and for interim periods beginning after December 15, 2024. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Consolidated Financial Statements. In June 2022, the FASB issued ASU No. 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The new guidance was issued to clarify existing guidance measuring the fair value of an equity security subject to contractual restrictions that prohibit the sale of an equity security and introduce new disclosure requirements for applicable equity securities. The ASU is effective for fiscal years beginning after December 15, 2023 for public entities. The updated guidance requires prospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Consolidated Financial Statements.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions 2021 Acquisitions Mueller Middle East On December 7, 2021, the Company entered into an agreement providing for the purchase of an additional 15 percent equity interest in Mueller Middle East for a total of 55 percent, for approximately $20.0 million. The total purchase price consisted of $15.8 million in cash paid at closing (net of cash acquired), a gain recognized on the settlement of preexisting relationships of $2.6 million, a contingent consideration arrangement of $1.0 million, and the fair value of the Company’s existing investment in the joint venture of $0.7 million. Mueller Middle East, which manufactures copper tube, is headquartered in Bahrain. This business complements the Company’s existing copper tube businesses in the Piping Systems segment. Prior to entering into this agreement, the Company was the technical and marketing lead with a 40 percent ownership in a joint venture with Cayan Ventures and Bahrain Mumtalakat Holding Company and accounted for this investment under the equity method of accounting. The Company began consolidating this business for financial reporting purposes in December 2021. Mueller Middle East manufactures and sells copper coils to certain Mueller subsidiaries. Total sales to Mueller subsidiaries were approximately $48.2 million for the period in 2021 prior to consolidation. H&C Flex On December 20, 2020, the Company entered into an asset purchase agreement with Hart & Cooley LLC. The transaction closed on January 29, 2021, whereby the Company purchased the Hart & Cooley flexible duct business, which included inventory, manufacturing equipment, and related assets for approximately $15.3 million. The total purchase price consisted of $14.0 million in cash paid at closing and a contingent consideration arrangement of $1.3 million, which was paid in Q3 2021. The Company treated this as a business combination. The acquired business, H&C Flex, is a manufacturer and distributor of insulated HVAC flexible duct systems. It is reported within and complements the Company’s existing businesses in the Climate segment. Purchase Price Allocations These acquisitions were accounted for using the acquisition method of accounting whereby the total purchase price was allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values. The following table summarizes the allocation of the purchase price to acquire these businesses, which were financed by available cash balances, as well as the assets acquired and liabilities assumed at the respective acquisition dates. The purchase price allocations for all acquisitions have been finalized as of December 30, 2023. (In thousands) Mueller Middle East H&C Flex Total consideration $ 20,017 $ 15,279 Allocated to: Accounts receivable 10,652 — Inventories 4,727 4,511 Other current assets 1,744 — Property, plant, and equipment 26,664 10,813 Operating lease right-of-use assets 935 — Goodwill 864 — Intangible assets 452 — Total assets acquired 46,038 15,324 Accounts payable 4,593 — Other current liabilities 10,941 45 Other noncurrent liabilities 692 — Total liabilities assumed 16,226 45 Noncontrolling interest 9,795 — Net assets acquired $ 20,017 $ 15,279 The following details the total intangible assets identified in the allocation of the purchase price at the respective acquisition dates: (In thousands) Estimated Useful Life Mueller Middle East Intangible asset type: Customer relationships 20 years $ 452 Total intangible assets $ 452 2023 Dispositions Heatlink Group Effective July 3, 2023, the Company transferred 100 percent of the outstanding shares of Heatlink Group, Inc. and Heatlink Group USA, LLC for an additional 11 percent equity interest in the limited liability company in the retail distribution business. This equity interest, combined with the 17 percent equity interest acquired with the contribution of Die-Mold in 2021, gives the Company a 28 percent equity interest in the limited liability company. Heatlink Group produces a complete line of products for PEX plumbing and radiant systems in Canada and sells these products in Canada and the U.S. and was included in the Piping Systems segment. Heatlink Group reported net sales of $15.6 million and operating income of $1.7 million for the year ended December 30, 2023 compared to net sales of $39.1 million and operating income of $7.2 million for the year ended December 31, 2022. As a result of the transaction, the Company recognized a gain of $4.1 million in the third quarter of 2023 based on the excess of the fair value of the consideration received (the 11 percent equity interest) over the carrying value of Heatlink Group. The Company equally weighted an income discounted cash flow approach and market comparable companies approach using an EBITDA multiple to determine the fair value of the consideration received of $26.0 million, which is recognized within the Investments in unconsolidated affiliates line of the Consolidated Balance Sheet. The excess of the fair value of the deconsolidated subsidiary over its carrying value resulted in the gain. 2021 Dispositions Copper Bar On October 25, 2021, the Company sold its Copper Bar business for approximately $10.1 million. This business manufactured copper bar products used primarily by OEMs in the U.S. and was included in the Industrial Metals segment. The carrying value of the assets disposed totaled $3.6 million, consisting primarily of inventories and long-lived assets. As a result of the transaction, the Company recognized a pre-tax gain of $6.5 million on the sale of the business in the Consolidating Financial Statements in 2021. Die-Mold On September 2, 2021, the Company entered into a contribution agreement with a limited liability company in the retail distribution business, pursuant to which the Company exchanged the outstanding common stock of Die-Mold for a 17 percent equity interest in the limited liability company. Die-Mold manufactures PEX and other plumbing-related fittings and plastic injection tooling in Canada and sells these products in Canada and the U.S. and was included in the Piping Systems Segment. Die-Mold reported net sales of $10.9 million and operating income of $2.2 million for the year ended December 25, 2021. As a result of the transaction, the Company recognized a gain of $4.7 million based on the excess of the fair value of the consideration received (the 17 percent equity interest) over the carrying value of Die-Mold in 2021. The Company utilized a combination of income and market comparable companies approaches using an EBITDA multiple to determine the fair value of the consideration received of $22.8 million, which is recognized within the Investments in unconsolidated affiliates line of the Consolidated Balance Sheet. The excess of the fair value of the deconsolidated subsidiary over its carrying value resulted in the gain. Fabricated Tube Products and Shoals Tubular, Inc. On July 28, 2021, the Company entered into a purchase agreement with J.W. Harris Co., Inc. and Lincoln Electric Holdings, Inc., pursuant to which the Company sold the assets of Fabricated Tube Products (FTP) and all of the outstanding stock of STI for approximately $75.7 million. These businesses manufacture and fabricate valves and assemblies, brazed manifolds, headers, and distributor assemblies used primarily by manufacturers of residential heating and air conditioning units in the U.S. and were included in the Climate segment. They reported combined net sales of $37.0 million and operating income of $5.5 million for the year ended December 25, 2021. The carrying value of the assets disposed totaled $32.7 million, consisting primarily of accounts receivable, inventories, and long-lived assets. The carrying value of the liabilities disposed totaled $3.6 million, consisting primarily of accounts payable. As a result of the transaction, the Company recognized a pre-tax gain of $46.6 million on the sale of these businesses in the Consolidating Financial Statements in 2021.

Segment Information

Segment Information	12 Months Ended
	Dec. 30, 2023
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s reportable segments are Piping Systems, Industrial Metals, and Climate. Each of the reportable segments is composed of certain operating segments that are aggregated primarily by the nature of products offered as follows: Piping Systems Piping Systems is composed of the following operating segments: Domestic Piping Systems Group, Great Lakes Copper, European Operations, Trading Group, Jungwoo-Mueller (the Company’s South Korean joint venture), and Mueller Middle East (our Bahraini joint venture). The Domestic Piping Systems Group manufactures and distributes copper tube, fittings, and line sets. These products are manufactured in the U.S., sold in the U.S., and exported to markets worldwide. Outside the U.S., Great Lakes Copper manufactures copper tube and line sets in Canada and sells the products primarily in the U.S. and Canada. European Operations manufactures copper tube in the U.K. which is sold primarily in Europe. The Trading Group manufactures pipe nipples and resells brass and plastic plumbing valves, malleable iron fittings, faucets, and plumbing specialty products in the U.S. and Mexico. Jungwoo-Mueller manufactures copper-based joining products that are sold worldwide. Mueller Middle East manufactures copper tube and serves markets in the Middle East and Northern Africa. The Piping Systems segment’s products are sold primarily to plumbing, refrigeration, and air-conditioning wholesalers, hardware wholesalers and co-ops, building product retailers, and air-conditioning OEMs. Beginning in fiscal year 2022, the results of Precision Tube are included in the Industrial Metals segment prospectively as the impact to prior periods was not material. The business was previously reported in the Piping Systems segment. This change was made to reflect the Company’s internal management reporting structure. As disclosed in “ Note 2 – Acquisitions & Dispositions ,” during 2023 the Company exchanged the outstanding common stock of Heatlink Group for an additional equity interest in a limited liability company in the retail distribution business, resulting in the deconsolidation of Heatlink Group and the recognition of a $4.1 million gain. This gain is reported within Corporate and Eliminations. The results of Heatlink Group, prior to deconsolidation, were included within the Piping Systems segment. During 2021, the Company exchanged the outstanding common stock of Die-Mold for an equity interest in a limited liability company in the retail distribution business, resulting in the deconsolidation of Die-Mold and the recognition of a $4.7 million gain. This gain is reported within Corporate and Eliminations. The results of Die-Mold, prior to deconsolidation, were included within the Piping Systems segment. Industrial Metals Industrial Metals is composed of the following operating segments: Brass Rod, Impacts & Micro Gauge, Brass Value-Added Products, and Precision Tube. These businesses manufacture brass rod, impact extrusions and forgings, specialty copper, copper alloy, and aluminum tube, as well as a wide variety of end products including plumbing brass, automotive components, valves, fittings, and gas assemblies. These products are manufactured in the U.S. and sold primarily to OEMs in the U.S., many of which are in the industrial, transportation, construction, heating, ventilation, and air-conditioning, plumbing, refrigeration, and energy markets. During 2021, the segment recognized a gain of $6.5 million on the sale of the Copper Bar business. Climate Climate is composed of the following operating segments: Refrigeration Products, Westermeyer, Turbotec, Flex Duct, and Linesets, Inc. These domestic businesses manufacture and fabricate valves, assemblies, high pressure components, coaxial heat exchangers, insulated HVAC flexible duct systems, line sets, brazed manifolds, headers, and distributor assemblies primarily for the heating, ventilation, air-conditioning, and refrigeration markets in the U.S. During 2023 the Company settled the insurance claim related to the August 2022 fire in its Bluffs, Illinois manufacturing operation, resulting in a gain of $19.5 million recognized in the segment. As disclosed in “ Note 2 – Acquisitions & Dispositions ,” during 2021 the Company sold the assets of FTP and all of the outstanding stock of STI, resulting in a gain of $46.6 million. This gain is reported within Corporate and Eliminations. The results of FTP and STI, prior to the sale, were included within the Climate segment. During 2021, the segment recognized impairment charges on goodwill and long-lived assets of $2.8 million. Performance of segments is generally evaluated by their operating income. Summarized product line, geographic, and segment information is shown in the following tables. Geographic sales data indicates the location from which products are shipped. Unallocated expenses include general corporate expenses, plus certain charges or credits not included in segment activity. During 2023, 2022, and 2021, no single customer exceeded 10 percent of worldwide sales. The following tables represent a disaggregation of revenue from contracts with customers, along with the reportable segment for each category: For the Year Ended December 30, 2023 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,926,975 $ — $ — $ 1,926,975 Brass rod and forgings — 454,246 — 454,246 OEM components and valves — 79,879 120,923 200,802 Valves and plumbing specialties 455,598 — — 455,598 Flex duct and other HVAC components — — 379,867 379,867 Other — 43,750 — 43,750 $ 2,382,573 $ 577,875 $ 500,790 $ 3,461,238 Intersegment sales (40,893) Net sales $ 3,420,345 Disaggregation of revenue from contracts with customers (continued): For the Year Ended December 31, 2022 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 2,211,963 $ — $ — $ 2,211,963 Brass rod and forgings — 510,865 — 510,865 OEM components, tube & assemblies — 74,647 121,004 195,651 Valves and plumbing specialties 518,121 — — 518,121 Flex duct and other HVAC components — — 529,303 529,303 Other — 59,177 — 59,177 $ 2,730,084 $ 644,689 $ 650,307 $ 4,025,080 Intersegment sales (42,625) Net sales $ 3,982,455 For the Year Ended December 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 2,055,639 $ — $ — $ 2,055,639 Brass rod and forgings — 565,870 — 565,870 OEM components, tube & assemblies 32,557 48,572 137,564 218,693 Valves and plumbing specialties 511,834 — — 511,834 Flex duct and other HVAC components — — 357,850 357,850 Other — 88,921 — 88,921 $ 2,600,030 $ 703,363 $ 495,414 $ 3,798,807 Intersegment sales (29,462) Net sales $ 3,769,345 Summarized segment information is as follows: For the Year Ended December 30, 2023 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,382,573 $ 577,875 $ 500,790 $ (40,893) $ 3,420,345 Cost of goods sold 1,686,792 480,510 311,875 (45,666) 2,433,511 Depreciation and amortization 20,461 7,273 7,567 4,653 39,954 Selling, general, and administrative expense 99,823 13,713 28,950 65,686 208,172 Gain on sale of businesses — — — (4,137) (4,137) Impairment charges 6,258 — — — 6,258 Gain on insurance settlement — — (19,466) — (19,466) Operating income 569,239 76,379 171,864 (61,429) 756,053 Interest expense (1,221) Interest income 38,208 Realized and unrealized gains on short-term investments 41,865 Gain on extinguishment of NMTC liability 7,534 Environmental expense (825) Other income, net 3,618 Income before income taxes $ 845,232 For the Year Ended December 31, 2022 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,730,084 $ 644,689 $ 650,307 $ (42,625) $ 3,982,455 Cost of goods sold 1,943,174 543,004 416,953 (38,269) 2,864,862 Depreciation and amortization 22,193 7,647 9,174 4,717 43,731 Selling, general, and administrative expense 93,655 11,574 36,113 61,744 203,086 Gain on sale of assets — — — (6,373) (6,373) Operating income 671,062 82,464 188,067 (64,444) 877,149 Interest expense (810) Interest income 6,457 Pension plan termination expense (13,100) Realized and unrealized gains on short-term investments 2,918 Environmental expense (1,298) Other income, net 4,715 Income before income taxes $ 876,031 Segment information (continued): For the Year Ended December 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,600,030 $ 703,363 $ 495,414 $ (29,462) $ 3,769,345 Cost of goods sold 1,996,610 605,715 367,343 (30,679) 2,938,989 Depreciation and amortization 23,384 6,929 10,379 4,698 45,390 Selling, general, and administrative expense 93,749 11,698 29,327 49,278 184,052 Gain on sale of businesses — (6,454) — (51,306) (57,760) Impairment charges — — 2,829 — 2,829 Operating income 486,287 85,475 85,536 (1,453) 655,845 Interest expense (7,709) Interest income 353 Redemption premium (5,674) Environmental expense (5,053) Other income, net 3,377 Income before income taxes $ 641,139 Summarized geographic information is as follows: (In thousands) 2023 2022 2021 Net sales: United States $ 2,572,141 $ 2,965,053 $ 2,791,571 United Kingdom 270,128 297,582 330,908 Canada 339,682 410,679 469,652 Asia and the Middle East 153,816 217,750 83,217 Mexico 84,578 91,391 93,997 $ 3,420,345 $ 3,982,455 $ 3,769,345 Long-lived assets: 2023 2022 2021 United States $ 273,604 $ 266,571 $ 272,903 United Kingdom 40,045 36,474 36,529 Canada 18,152 23,354 26,422 Asia and the Middle East 50,725 51,193 48,742 Mexico 2,639 2,358 966 $ 385,165 $ 379,950 $ 385,562 (In thousands) 2023 2022 2021 Expenditures for long-lived assets (including those resulting from business acquisitions): Piping Systems $ 19,118 $ 20,694 $ 43,429 Industrial Metals 9,406 6,905 5,744 Climate 15,407 2,611 12,428 General Corporate 10,094 7,429 3,521 $ 54,025 $ 37,639 $ 65,122 (In thousands) 2023 2022 2021 Segment assets: Piping Systems $ 1,029,821 $ 1,088,940 $ 1,160,272 Industrial Metals 157,761 160,702 173,290 Climate 252,561 279,940 250,107 General Corporate 1,319,158 712,817 145,267 $ 2,759,301 $ 2,242,399 $ 1,728,936

Cash, Cash Equivalents, and Res

Cash, Cash Equivalents, and Restricted Cash	12 Months Ended
	Dec. 30, 2023
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash (In thousands) 2023 2022 Cash & cash equivalents $ 1,170,893 $ 461,018 Restricted cash included within other current assets 3,228 4,176 Restricted cash included within other assets 102 102 Total cash, cash equivalents, and restricted cash $ 1,174,223 $ 465,296

Inventories

Inventories	12 Months Ended
	Dec. 30, 2023
Inventory Disclosure [Abstract]
Inventories	Inventories (In thousands) 2023 2022 Raw materials and supplies $ 111,843 $ 133,189 Work-in-process 61,793 64,177 Finished goods 220,629 265,842 Valuation reserves (14,017) (14,289) Inventories $ 380,248 $ 448,919 Inventories valued using the LIFO method totaled $20.2 million at December 30, 2023 and $16.5 million at December 31, 2022. At December 30, 2023 and December 31, 2022, the approximate FIFO cost of such inventories was $122.9 million and $117.3 million, respectively. At the end of 2023 and 2022, the FIFO value of inventory consigned to others was $19.8 million and $14.3 million, respectively.

Consolidated Financial Statemen

Consolidated Financial Statement Details	12 Months Ended
	Dec. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidated Financial Statement Details	Consolidated Financial Statement Details Other Current Liabilities Included in other current liabilities Other Income, Net (In thousands) 2023 2022 2021 Net periodic benefit income $ 765 $ 3,168 $ 1,903 Accounts payable discounts 1,502 1,609 1,385 Other 1,351 (62) 89 Other income, net $ 3,618 $ 4,715 $ 3,377

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company’s earnings and cash flows are subject to fluctuations due to changes in commodity prices, foreign currency exchange rates, and interest rates. The Company uses derivative instruments such as commodity futures contracts, foreign currency forward contracts, and interest rate swaps to manage these exposures. Commodity Futures Contracts Copper and brass represent the largest component of the Company’s variable costs of production. The cost of these materials is subject to global market fluctuations caused by factors beyond the Company’s control. The Company occasionally enters into forward fixed-price arrangements with certain customers; the risk of these arrangements is generally managed with commodity futures contracts. These futures contracts have been designated as cash flow hedges. At December 30, 2023, the Company held open futures contracts to purchase approximately $5.8 million of copper over the next twelve months related to fixed price sales orders. The fair value of those futures contracts was a $0.1 million net gain position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy). In the next 12 months, the Company will reclassify into earnings realized gains or losses relating to cash flow hedges. At December 30, 2023, this amount was approximately $0.1 million of deferred net gains, net of tax. The Company may also enter into futures contracts to protect the value of inventory against market fluctuations. At December 30, 2023, the Company held open futures contracts to sell approximately $61.3 million of copper over the next twelve months related to copper inventory. The fair value of those futures contracts was a $0.2 million net loss position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy). The Company presents its derivative assets and liabilities in the Consolidated Balance Sheets on a net basis by counterparty. The following table summarizes the location and fair value of the derivative instruments and disaggregates the net derivative assets and liabilities into gross components on a contract-by-contract basis: Asset Derivatives Liability Derivatives Fair Value Fair Value (In thousands) Balance Sheet Location 2023 2022 Balance Sheet Location 2023 2022 Commodity contracts - gains Other current assets $ 589 $ 3,746 Other current liabilities $ 16 $ — Commodity contracts - losses Other current assets (281) (1,483) Other current liabilities (383) — Total derivatives (1) $ 308 $ 2,263 $ (367) $ — (1) Does not include the impact of cash collateral provided to counterparties . The following table summarizes the effects of derivative instruments on the Consolidated Statements of Income: (In thousands) Location 2023 2022 Undesignated derivatives: (Loss) gain on commodity contracts (nonqualifying) Cost of goods sold $ (1,071) $ 20,659 The following tables summarize amounts recognized in and reclassified from AOCI during the period: For the Year Ended December 30, 2023 (In thousands) Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 1,180 Cost of goods sold $ (2,419) Other (34) Other — Total $ 1,146 Total $ (2,419) For the Year Ended December 31, 2022 (In thousands) (Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ (7,066) Cost of goods sold $ 7,666 Other 83 Other — Total $ (6,983) Total $ 7,666 The Company primarily enters into International Swaps and Derivatives Association master netting agreements with major financial institutions that permit the net settlement of amounts owed under their respective derivative contracts. Under these master netting agreements, net settlement generally permits the Company or the counterparty to determine the net amount payable for contracts due on the same date and in the same currency for similar types of derivative transactions. The master netting agreements generally also provide for net settlement of all outstanding contracts with the counterparty in the case of an event of default or a termination event. The Company does not offset fair value amounts for derivative instruments and fair value amounts recognized for the right to reclaim cash collateral. At December 30, 2023 and December 31, 2022, the Company had recorded restricted cash in other current assets of $3.2 million and $4.0 million, respectively, as collateral related to open derivative contracts under the master netting arrangements.

Leases

Leases	12 Months Ended
	Dec. 30, 2023
Leases [Abstract]
Leases	Leases The Company leases certain facilities, vehicles, and equipment which expire on various dates through 2041. The following table includes supplemental information with regards to the Company’s operating leases: (In thousands, except lease term and discount rate) 2023 2022 Operating lease right-of-use assets $ 35,170 $ 22,892 Current portion of operating lease liabilities 7,893 4,942 Noncurrent operating lease liabilities 26,683 16,880 Total operating lease liabilities $ 34,576 $ 21,822 Weighted average discount rate 3.55 % 3.35 % Weighted average remaining lease term (in years) 5.24 6.03 Some of the Company’s leases include variable lease costs such as taxes, insurance, etc. These costs are immaterial for disclosure. The following table presents certain information related to operating lease costs and cash paid during the period: For the Year Ended (In thousands) December 30, 2023 December 31, 2022 Operating lease costs $ 9,705 $ 8,220 Short term lease costs 3,843 4,086 Total lease costs $ 13,548 $ 12,306 Cash paid for amounts included in the measurement of lease liabilities $ 9,276 $ 7,787 Maturities of the Company’s operating leases are as follows: (In thousands) Amount 2024 $ 8,909 2025 8,124 2026 7,110 2027 6,210 2028 3,222 2029 and thereafter 4,646 Total lease payments 38,221 Less imputed interest (3,645) Total lease obligations 34,576 Less current obligations (7,893) Noncurrent lease obligations $ 26,683

Property, Plant, and Equipment,

Property, Plant, and Equipment, Net	12 Months Ended
	Dec. 30, 2023
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment, Net	Property, Plant, and Equipment, Net (In thousands) 2023 2022 Land and land improvements $ 33,127 $ 32,707 Buildings 232,169 234,480 Machinery and equipment 654,079 653,997 Construction in progress 82,552 54,748 1,001,927 975,932 Less accumulated depreciation (616,762) (595,982) Property, plant, and equipment, net $ 385,165 $ 379,950

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill The changes in the carrying amount of goodwill by segment were as follows: (In thousands) Piping Systems Industrial Metals Climate Total Goodwill $ 192,316 $ 8,854 $ 21,652 $ 222,822 Accumulated impairment charges (40,552) (8,853) (2,087) (51,492) Balance at December 25, 2021: 151,764 1 19,565 171,330 Reductions (1) (11,216) — — (11,216) Currency translation (2,526) — — (2,526) Balance at December 31, 2022: 138,022 1 19,565 157,588 Reductions (2) (7,007) — — (7,007) Currency translation 1,239 — — 1,239 Balance at December 30, 2023: Goodwill 172,806 8,854 21,652 203,312 Accumulated impairment charges (40,552) (8,853) (2,087) (51,492) Goodwill, net $ 132,254 $ 1 $ 19,565 $ 151,820 (1) Includes finalization of the purchase price allocation adjustment for Mueller Middle East of $11.2 million. (2) Includes disposal of Heatlink Group business. Reporting units with recorded goodwill include Domestic Piping Systems Group, B&K LLC, Great Lakes, European Operations, Jungwoo-Mueller, Mueller Middle East, Westermeyer, and Flex Duct . Several factors give rise to goodwill in the Company’s acquisitions, such as the expected benefit from synergies of the combination and the existing workforce of the acquired businesses. With the exception of the Turbotec reporting unit, there were no impairment charges resulting from the 2023, 2022, or 2021 annual impairment tests as the estimated fair value of each of the reporting units exceeded its carrying value. During the third quarter of 2021, the Company recognized an impairment charge of $2.1 million related to Turbotec, reported within the Climate segment. Other Intangible Assets The carrying amount of intangible assets at December 30, 2023 was as follows: (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 50,009 $ (17,535) $ 32,474 Non-compete agreements 2,325 (2,325) — Patents and technology 16,681 (8,119) 8,562 Trade names and licenses 12,092 (6,920) 5,172 Other 1,715 (1,715) — Other intangible assets $ 82,822 $ (36,614) $ 46,208 The carrying amount of intangible assets at December 31, 2022 was as follows: (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 53,156 $ (15,658) $ 37,498 Non-compete agreements 2,333 (2,333) — Patents and technology 18,032 (7,570) 10,462 Trade names and licenses 13,374 (6,697) 6,677 Other 1,676 (1,528) 148 Other intangible assets $ 88,571 $ (33,786) $ 54,785 Amortization expense for intangible assets was $5.0 million in 2023, $5.6 million in 2022, and $6.3 million in 2021. Future amortization expense is estimated as follows: (In thousands) Amount 2024 $ 4,623 2025 4,505 2026 4,357 2027 4,356 2028 4,117 Thereafter 24,250 Expected amortization expense $ 46,208

Investment in Unconsolidated Af

Investment in Unconsolidated Affiliates	12 Months Ended
	Dec. 30, 2023
Equity Method Investments and Joint Ventures [Abstract]
Investment in Unconsolidated Affiliates	Investments in Unconsolidated Affiliates Tecumseh The Company owns a 50 percent interest in an unconsolidated affiliate that acquired Tecumseh and an entity that provides financing to Tecumseh. Tecumseh is a global manufacturer of hermetically sealed compressors for residential and specialty air conditioning, household refrigerators and freezers, and commercial refrigeration applications, including air conditioning and refrigeration compressors, as well as condensing units, heat pumps, and complete refrigeration systems. The Company’s income ( loss) from unconsolidated affiliates, net of foreign tax, for 2023, 2022, and 2021 included net losses of $22.7 million, net gains of $5.2 million, and net losses of $1.7 million, respectively, for Tecumseh. Retail Distribution The Company owns a 28 percent noncontrolling equity interest in a limited liability company in the retail distribution business. The Company’s income ( loss) from unconsolidated affiliates, net of foreign tax, for 2023, 2022, and 2021 included net gains of $7.9 million, $4.9 million, and $0.8 million, respectively, for the retail distribution business.

Debt

Debt	12 Months Ended
	Dec. 30, 2023
Debt Disclosure [Abstract]
Debt	Debt Credit Agreement The Company’s Credit Agreement provides for an unsecured $400.0 million revolving credit facility that matures on March 31, 2026. There were no borrowings outstanding under the Credit Agreement as of December 30, 2023 or December 31, 2022. Borrowings under the Revolving Credit Facility bear interest, at the Company’s option, at the Eurocurrency Rate which is determined by the underlying currency of the Credit Extension or the Base Rate as defined by the Credit Agreement, plus a variable premium. Advances may be based upon the one, three, or six-month interest period. The variable premium is based upon the Company’s debt to total capitalization ratio, and can range from 112.5 to 162.5 basis points for Eurocurrency Rate loans and 12.5 to 62.5 basis points for Base Rate loans. At December 30, 2023, the premium was 112.5 basis points for Eurocurrency Rate loans and 12.5 basis points for Base Rate loans. Additionally, a commitment fee is payable quarterly on the total commitment less any outstanding loans or issued letters of credit, and varies from 15.0 to 30.0 basis points based upon the Company’s debt to total capitalization ratio. Availability of funds under the Revolving Credit Facility is reduced by the amount of certain outstanding letters of credit, which are used to secure the Company’s payment of insurance deductibles, certain retiree health benefits, and other corporate obligations, totaling approximately $28.7 million at December 30, 2023. Terms of the letters of credit are generally renewable annually. Subordinated Debentures During the first quarter of 2021, the Company announced the redemption of its Subordinated Debentures due 2027. The full redemption of outstanding debentures occurred on April 15, 2021 for a total of $291.4 million in principal plus accrued interest and a redemption premium of $5.7 million that was expensed during the second quarter. Jungwoo-Mueller Jungwoo-Mueller has several secured revolving credit arrangements with a total borrowing capacity of KRW 20.0 billion (or approximately $15.3 million). Borrowings are secured by the real property and equipment of Jungwoo-Mueller. Covenants contained in the Company’s financing obligations require, among other things, the maintenance of minimum levels of tangible net worth and the satisfaction of certain minimum financial ratios. At December 30, 2023, the Company was in compliance with all debt covenants. There was no interest paid in 2023 or 2022. Interest paid in 2021 was $13.9 million.

New Markets Tax Credit Transact

New Markets Tax Credit Transactions	12 Months Ended
	Dec. 30, 2023
New Markets Tax Credit Transaction [Abstract]
New Markets Tax Credit Transactions	Note 13 – New Markets Tax Credit Transactions On October 18, 2016, the Company entered into a financing transaction with Wells Fargo Community Investment Holdings, LLC (Wells Fargo) related to an equipment modernization project at the Company’s copper tube and line sets production facilities in Fulton, MS. Wells Fargo made a capital contribution and the Company made a loan to MCTC Investment Fund, LLC (Investment Fund) under a qualified New Markets Tax Credit (NMTC) program. The NMTC program was provided for in the Community Renewal Tax Relief Act of 2000 (CRTR Act) and is intended to induce capital investment in qualified lower income communities. The CRTR Act permits taxpayers to claim credits against their Federal income taxes for up to 39 percent of qualified investments in the equity of community development entities (CDEs). CDEs are privately managed investment institutions that are certified to make qualified low-income community investments. In connection with the financing, Wells Fargo contributed to the Investment Fund, and as such, Wells Fargo is entitled to substantially all of the benefits derived from the NMTCs. The Investment Fund then contributed the proceeds to certain CDEs, which, in turn, loaned the funds on similar terms as the Leverage Loan to Mueller Copper Tube Company, Inc. (MCTC), an indirect, wholly-owned subsidiary of the Company. The proceeds of the loans from the CDEs, including loans representing the capital contribution made by Wells Fargo, net of syndication fees, are restricted for use on the modernization project. The NMTC is subject to 100 percent recapture for a period of seven years as provided in the Internal Revenue Code. The Company was required to comply with various regulations and contractual provisions that apply to the NMTC arrangement. Non-compliance with applicable requirements could result in projected tax benefits not being realized and, therefore, require the Company to indemnify Wells Fargo for any loss or recapture of NMTCs related to the financing until such time as the Company’s obligation to deliver tax benefits is relieved. This transaction also included a put/call provision whereby the Company may be obligated or entitled to repurchase Wells Fargo’s interest in the Investment Fund. The Company previously determined the financing arrangement with the Investment Fund and CDEs is a variable interest entity (VIE), and that it is the primary beneficiary of the VIE and has included the VIE in the Company’s Consolidated Financial Statements. In December 2023, Wells Fargo exercised the put option, and as such the Company recognized a gain on the extinguishment of the liability representing Wells Fargo’s interest in the Investment Fund of $7.5 million.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 30, 2023
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans Pension and Other Postretirement Plans The Company sponsors several qualified and nonqualified pension plans and other postretirement benefit plans for certain employees. The information disclosed below does not include the pension plan in South Korea, as it it immaterial to the Company’s Consolidated Financial Statements. The following tables provide a reconciliation of the changes in the most significant plans’ benefit obligations and the fair value of the plans’ assets for 2023 and 2022, and a statement of the plans’ aggregate funded status: Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Change in benefit obligation: Obligation at beginning of year $ 50,761 $ 84,283 $ 9,240 $ 11,825 Service cost — — 183 291 Interest cost 2,454 1,450 439 346 Actuarial loss (gain) 1,508 (24,154) (105) (2,604) Plan amendments/transference — — 101 — Benefit payments (3,582) (2,512) (686) (547) Foreign currency translation adjustment 3,294 (8,306) 385 (71) Obligation at end of year 54,435 50,761 9,557 9,240 Change in fair value of plan assets: Fair value of plan assets at beginning of year 62,298 79,478 — — Actual return on plan assets 410 (6,371) — — Employer contributions — — 686 547 Benefit payments (3,582) (2,512) (686) (547) Foreign currency translation adjustment 3,745 (8,297) — — Fair value of plan assets at end of year 62,871 62,298 — — Funded (underfunded) status at end of year $ 8,436 $ 11,537 $ (9,557) $ (9,240) The following represents amounts recognized in AOCI (before the effect of income taxes): Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Unrecognized net actuarial loss (gain) $ 7,728 $ 2,870 $ (3,863) $ (4,149) Unrecognized prior service credit — — (5) (19) As of December 30, 2023, $0.2 million of the actuarial net gain and the remainder of the prior service credit will, through amortization, be recognized as components of net periodic benefit cost in 2024. The aggregate status of all overfunded plans is recognized as an asset and the aggregate status of all underfunded plans is recognized as a liability in the Consolidated Balance Sheets. The amounts recognized as a liability are classified as current or long-term on a plan-by-plan basis. Liabilities are classified as current to the extent the actuarial present value of benefits payable within the next 12 months exceeds the fair value of plan assets, with all remaining amounts classified as long-term. As of December 30, 2023 and December 31, 2022, the total funded status of the plans recognized in the Consolidated Balance Sheets was as follows: Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Long-term asset $ 8,436 $ 11,537 $ — $ — Current liability $ — $ — $ (1,041) $ (1,068) Long-term liability — — (8,516) (8,172) Total funded (underfunded) status $ 8,436 $ 11,537 $ (9,557) $ (9,240) The components of net periodic benefit cost (income) are as follows: (In thousands) 2023 2022 2021 Pension benefits: Interest cost $ 2,454 $ 1,450 $ 1,272 Expected return on plan assets (3,260) (3,568) (3,671) Amortization of net loss — 897 1,536 Settlement charge — — — Net periodic benefit income $ (806) $ (1,221) $ (863) Other benefits: Service cost $ 183 $ 291 $ 258 Interest cost 439 346 281 Amortization of prior service credit (2) (198) (470) Amortization of net gain (449) (220) (103) Curtailment gain — (1,756) — Net periodic benefit cost (income) $ 171 $ (1,537) $ (34) During 2022, the Company recognized a curtailment gain of $1.8 million related to one of its postretirement benefit plans. The components of net periodic benefit cost (income) other than the service cost component are included in other income, net in the Consolidated Statements of Income. The weighted average assumptions used in the measurement of the Company’s benefit obligations are as follows: Pension Benefits Other Benefits 2023 2022 2023 2022 Discount rate 4.40 % 4.80 % 5.96 % 6.08 % Expected long-term return on plan assets 4.30 % 5.51 % N/A N/A Rate of compensation increases N/A N/A 5.00 % 5.00 % Rate of inflation 3.20 % 3.30 % N/A N/A The weighted average assumptions used in the measurement of the Company’s net periodic benefit cost are as follows: Pension Benefits Other Benefits 2023 2022 2021 2023 2022 2021 Discount rate 4.80 % 1.90 % 1.40 % 6.08 % 3.73 % 2.92 % Expected long-term return on plan assets 5.51 % 4.96 % 4.69 % N/A N/A N/A Rate of compensation increases N/A N/A N/A 5.00 % 5.00 % 5.00 % Rate of inflation 3.30 % 3.70 % 3.20 % N/A N/A N/A The Company’s Mexican postretirement plans use the rate of compensation increase in the benefit formulas. Past service in the U.K. pension plan will be adjusted for the effects of inflation. All other pension and postretirement plans use benefit formulas based on length of service. The annual assumed rate of increase in the per capita cost of covered benefits (i.e., health care cost trend rate) is assumed to range from 4.9 to 8.2 percent for 2024, gradually decrease to 4.1 percent through 2040, and remain at that level thereafter. The health care cost trend rate assumption does not have a significant effect on the amounts reported. Pension Assets The weighted average asset allocation of the Company’s pension fund assets are as follows: Pension Plan Assets Asset category 2023 2022 Pooled liability investments 99 % — % Equity securities (includes equity mutual funds) — 67 Multi-asset securities — 22 Cash and equivalents (includes money market funds) 1 1 Alternative investments — 10 Total 100 % 100 % The pension plan obligations are long-term and, accordingly, the plan assets are invested for the long-term. Plan assets are monitored periodically. Based upon results, investment managers and/or asset classes are redeployed when considered necessary. None of the plans’ assets are expected to be returned to the Company during the next fiscal year. The assets of the plans do not include investments in securities issued by the Company. The estimated rates of return on plan assets are the expected future long-term rates of earnings on plan assets and are forward-looking assumptions that materially affect pension cost. Establishing the expected future rates of return on pension assets is a judgmental matter. The Company reviews the expected long-term rates of return on an annual basis and revises as appropriate. The expected long-term rate of return on plan assets was 4.30 percent for 2023 and 5.51 percent in 2022. The Company’s investments for its pension plans are reported at fair value. The following methods and assumptions were used to estimate the fair value of the Company’s plan asset investments: Cash and money market funds – Valued at cost, which approximates fair value. Pooled liability investments – These funds are primarily invested in U.K. government bonds and highly rated corporate bonds. The level 2 fair value is determined utilizing observable inputs of the underlying assets. Mutual funds – Valued at the net asset value of shares held by the plans, based upon quoted market prices. Limited partnerships – Limited partnerships comprise a diversified portfolio of real estate investments which are classified as Level 3 due to a lack of observable inputs existing at the measurement date. Accordingly, the estimated fair values may differ significantly from the values that would have been used had a ready market existed for these investments. Limited partnership investments are recorded at estimated fair value based on financial information received from the investment manager. The investment manager determines fair value based upon, among other things, property valuations received from valuation specialists at regular intervals. The following table sets forth by level, within the fair value hierarchy, the assets of the plans at fair value: Fair Value Measurements at December 30, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash and money market funds $ 502 $ — $ — $ 502 Pooled liability investments — 62,369 — 62,369 Total $ 502 $ 62,369 $ — $ 62,871 Fair Value Measurements at December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash and money market funds $ 829 $ — $ — $ 829 Mutual funds (1) — 55,441 — 55,441 Limited partnerships — — 6,028 6,028 Total $ 829 $ 55,441 $ 6,028 $ 62,298 (1) Approximately 78 percent of mutual funds are actively managed funds and approximately 22 percent of mutual funds are index funds. Additionally, 24 percent of the mutual funds’ assets are invested in non-U.S. multi-asset securities and 76 percent in non-U.S. equities. The table below reflects the changes in the assets of the plan measured at fair value on a recurring basis using significant unobservable inputs (level 3 of fair value hierarchy) during the year ended December 30, 2023: (In thousands) Limited Partnerships Balance, December 31, 2022 $ 6,028 Liquidation (6,028) Balance, December 30, 2023 $ — Contributions and Benefit Payments The Company does not expect to contribute to the U.K. pension plan, other than to reimburse expenses, and expects to contribute $1.0 million to its other postretirement benefit plans in 2024. The Company expects future benefits to be paid from the plans as follows: (In thousands) Pension Benefits Other Benefits 2024 $ 3,418 $ 1,042 2025 3,540 1,045 2026 3,667 1,080 2027 3,798 877 2028 3,934 922 2028-2032 21,886 4,146 Total $ 40,243 $ 9,112 401(k) Plans The Company sponsors voluntary employee savings plans that qualify under Section 401(k) of the Internal Revenue Code of 1986. Compensation expense for the Company’s matching contribution to the 401(k) plans was $4.9 million in 2023, $4.9 million in 2022, and $4.5 million in 2021. The Company match is a cash contribution. Participants direct the investment of their account balances by allocating among a range of asset classes including mutual funds (equity, fixed income, and balanced funds) and money market funds. The plans do not allow direct investment in securities issued by the Company. U. K. Pension Plan

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Environmental The Company is subject to federal, state, local, and foreign environmental laws and regulations. For all properties, the Company has provided and charged to expense $0.7 million in 2023, $1.4 million in 2022, and $5.0 million in 2021 for pending environmental matters. Environmental reserves Non-operating Properties Southeast Kansas Sites The Kansas Department of Health and Environment (KDHE) has contacted the Company regarding environmental contamination at three former smelter sites in Kansas (Altoona, East La Harpe, and Lanyon). The Company is not a successor to the companies that operated these smelter sites, but has explored possible settlement with KDHE and other potentially responsible parties (PRP) in order to avoid litigation. In February 2022, the Company reached a settlement with another PRP relating to these three sites. Under the terms of that agreement, the Company paid $5.6 million, which was previously reserved, in exchange for the other PRP’s agreement to conduct or fund any required remediation with the geographic boundaries of the three sites (namely, the parcel(s) on which the former smelters were located), plus coverage of certain off-site areas (namely, contamination that migrated by surface water runoff or air emissions from the Altoona or East La Harpe site, and smelter materials located within 50 feet of the geographic boundary of each site). The settlement does not cover certain matters, including potential liability related to the remediation of the town of Iola which is not estimable at this time. The other PRP has also provided an indemnity that would cover third-party cleanup claims for those sites, subject to a time limit and a cap. Altoona. Another PRP conducted a site investigation of the Altoona site under a consent decree with KDHE and submitted a removal site evaluation report recommending a remedy. The remedial design plan, which covers both on-site and certain off-site cleanup costs, was approved by the KDHE in 2016. Construction of the remedy was completed in 2018. Under the terms of the settlement with the other PRP, the Company expects the operations and maintenance costs for this remedy to be paid for entirely by the other PRP. East La Harpe. At the East La Harpe site, the Company and two other PRPs conducted a site study evaluation under KDHE supervision and prepared a site cleanup plan approved by KDHE. In December 2018, KDHE provided a draft agreement which contemplates the use of funds KDHE obtained from two other parties (Peabody Energy and Blue Tee) to fund part of the remediation, and removes Blue Tee from the PRPs’ agreement with KDHE. Pursuant to the terms of the settlement with the other PRP noted above, the Company expects the remediation to be conducted and paid for entirely by the other PRP, and for that other PRP to negotiate and enter into an agreement with KDHE. Lanyon. With respect to the Lanyon Site, in 2016, the Company received a general notice letter from the United States Environmental Protection Agency (EPA) asserting that the Company is a PRP, which the Company has denied. EPA issued an interim record of decision in 2017 and has been remediating properties at the site. According to EPA, 1,371 properties were to be remediated. In August 2023, EPA issued a five-year review indicating that the cleanup of approximately 300 remaining residential properties would be completed in 2026. A record of decision concerning the cleanup is scheduled for May 2025. Shasta Area Mine Sites Mining Remedial Recovery Company (MRRC), a wholly owned subsidiary, owns certain inactive mines in Shasta County, California. MRRC has continued a program, begun in the late 1980s, of implementing various remedial measures, including sealing mine portals with concrete plugs in portals that were discharging water. The sealing program achieved significant reductions in the metal load in discharges from these adits; however, additional reductions are required pursuant to an order issued by the California Regional Water Quality Control Board (QCB). In response to a 1996 QCB Order, MRRC completed a feasibility study in 1997 describing measures designed to mitigate the effects of acid rock drainage. In December 1998, the QCB modified the 1996 order extending MRRC’s time to comply with water quality standards. In September 2002, the QCB adopted a new order requiring MRRC to adopt Best Management Practices (BMP) to control discharges of acid mine drainage, and again extended the time to comply with water quality standards until September 2007. During that time, implementation of BMP further reduced impacts of acid rock drainage; however, full compliance has not been achieved. The QCB is presently renewing MRRC’s discharge permit and will concurrently issue a new order. It is expected that the new 10-year permit will include an order requiring continued implementation of BMP through 2034 to address residual discharges of acid rock drainage. At this site, MRRC spent approximately $1.2 million from 2021 through 2023 for remediation, and currently estimates that it will spend between approximately $14.1 million and $16.1 million over the next 30 years and has accrued a reserve at the low end of this range. Lead Refinery Site U.S.S. Lead Refinery, Inc. (Lead Refinery), a non-operating wholly owned subsidiary of MRRC, has conducted corrective action and interim remedial activities (collectively, Site Activities) at Lead Refinery’s East Chicago, Indiana site pursuant to the Resource Conservation and Recovery Act since December 1996. Although the Site Activities have been substantially concluded, Lead Refinery is required to perform monitoring and maintenance-related activities pursuant to a post-closure permit issued by the Indiana Department of Environmental Management effective as of March 2, 2013. Lead Refinery spent approximately $0.6 million from 2021 through 2023 with respect to this site. Approximate costs to comply with the post-closure permit, including associated general and administrative costs, are estimated at between $1.6 million and $2.2 million over the next 13 years. The Company has recorded a reserve at the low end of this range. On April 9, 2009, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the U.S. Environmental Protection Agency (EPA) added the Lead Refinery site and surrounding properties to the National Priorities List (NPL). On July 17, 2009, Lead Refinery received a written notice from the EPA indicating that it may be a PRP under CERCLA due to the release or threat of release of hazardous substances including lead into properties surrounding the Lead Refinery NPL site. The EPA identified two other PRPs in connection with that matter. In November 2012, the EPA adopted a remedy for the surrounding properties and in September 2014, the EPA announced that it had entered into a settlement with the two other PRPs whereby they will pay approximately $26.0 million to fund the cleanup of approximately 300 properties surrounding the Lead Refinery NPL site (zones 1 and 3 of operable unit 1) and perform certain remedial action tasks. On November 8, 2016, the Company, its subsidiary Arava Natural Resources Company, Inc. (Arava), and Arava’s subsidiary MRRC each received general notice letters from the EPA asserting that they may be PRPs in connection with the Lead Refinery NPL site. The Company, Arava, and MRRC have denied liability for any remedial action and response costs associated with the Lead Refinery NPL site. In June 2017, the EPA requested that Lead Refinery conduct, and the Company fund, a remedial investigation and feasibility study of operable unit 2 of the Lead Refinery NPL site pursuant to a proposed administrative settlement agreement and order on consent. The Company and Lead Refinery entered into that agreement in September 2017. The Company has made a capital contribution to Lead Refinery to conduct the remedial investigation and feasibility study with respect to operable unit 2 and has provided financial assurance in the amount of $1.0 million. The remedial investigation and feasibility study remain ongoing. The EPA has also asserted its position that the Company is a responsible party for the Lead Refinery NPL site, and accordingly is responsible for a share of remedial action and response costs at the site and in the adjacent residential area. In January 2018, the EPA issued two unilateral administrative orders (UAOs) directing the Company, Lead Refinery, and four other PRPs to conduct soil and interior remediation of certain residences at the Lead Refinery NPL site (zones 2 and 3 of operable unit 1). Subsequent thereto, the Company and Lead Refinery reached agreement with the four other PRPs to implement these two UAOs, with the Company agreeing to pay, on an interim basis, (i) an estimated $4.5 million (subject to potential change through a future reallocation process) of the approximately $25.0 million the PRPs then estimated it would cost to implement the UAOs, which estimate is subject to change, and (ii) $2.0 million relating to past costs incurred by other PRPs for work conducted at the site, as well as the possibility of up to $0.7 million in further payments for ongoing work by those PRPs. As of year-end, the Company has made payments of approximately $7.6 million related to the aforementioned agreement with the other PRPs. The Company disputes that it was properly named in the UAOs. In March 2022, Lead Refinery entered into an administrative settlement agreement and order on consent with the EPA, along with the four other PRPs, which involves payment of certain past and future costs relating to operable unit 1, in exchange for certain releases and contribution protection for the Company, Lead Refinery, and their respective affiliates relating to that operable unit. The settlement became effective in September 2022. The Company reserved $3.3 million for this settlement at the end of 2021. In March 2018, a group of private plaintiffs sued the Company, Arava, MRRC, and Lead Refinery, along with other defendants, in civil tort action relating to the site. The Company, Arava, and MRRC have been voluntarily dismissed from that litigation without prejudice. Lead Refinery subsequently answered plaintiffs’ amended complaint, but has filed a motion for partial judgment on the pleadings which remains pending. At this juncture, the Company is unable to determine the likelihood of a material adverse outcome or the amount or range of a potential loss in excess of the current reserve with respect to any remedial action or litigation relating to the Lead Refinery NPL site, either at Lead Refinery’s former operating site (operable unit 2) or the adjacent residential area (operable unit 1), including, but not limited to, EPA oversight costs for which the EPA may attempt to seek reimbursement from the Company, and past costs for which other PRPs may attempt to seek contribution from the Company. Bonita Peak Mining District Following an August 2015 spill from the Gold King Mine into the Animas River near Silverton, Colorado, the EPA listed the Bonita Peak Mining District on the NPL. Said listing was finalized in September 2016. The Bonita Peak Mining District encompasses 48 mining sites within the Animas River watershed, including the Sunnyside Mine, the American Tunnel, and the Sunbank Group. On or about July 25, 2017, Washington Mining Company (Washington Mining) (a wholly-owned subsidiary of the Company’s wholly-owned subsidiary, Arava), received a general notice letter from the EPA stating that Washington Mining may be a PRP under CERCLA in connection with the Bonita Peak Mining District site and therefore responsible for the remediation of certain portions of the site, along with related costs incurred by the EPA. Shortly thereafter, the Company received a substantively identical letter asserting that it may be a PRP at the site and similarly responsible for the cleanup of certain portions of the site. The general notice letters identify one other PRP at the site, and do not require specific action by Washington Mining or the Company at this time. At this juncture, the Company is unable to determine the likelihood of a materially adverse outcome or the amount or range of a potential loss with respect to any remedial action related to the Bonita Peak Mining District NPL site. Operating Properties Mueller Copper Tube Products, Inc. In 1999, Mueller Copper Tube Products, Inc. (MCTP), a wholly owned subsidiary, commenced a cleanup and remediation of soil and groundwater at its Wynne, Arkansas plant to remove trichloroethylene, a cleaning solvent formerly used by MCTP. On August 30, 2000, MCTP received approval of its Final Comprehensive Investigation Report and Storm Water Drainage Investigation Report addressing the treatment of soils and groundwater from the Arkansas Department of Environmental Quality (ADEQ). The Company established a reserve for this project in connection with the acquisition of MCTP in 1998. Effective November 17, 2008, MCTP entered into a Settlement Agreement and Administrative Order by Consent to submit a Supplemental Investigation Work Plan (SIWP) and subsequent Final Remediation Work Plan (RWP) for the site. By letter dated January 20, 2010, ADEQ approved the SIWP as submitted, with changes acceptable to the Company. On December 16, 2011, MCTP entered into an amended Administrative Order by Consent to prepare and implement a revised RWP regarding final remediation for the Site. The remediation system was activated in February 2014. Costs to implement the work plans, including associated general and administrative costs, are estimated to approximate $0.4 million over the next two years. United States Department of Commerce Antidumping Review On December 24, 2008, the Department of Commerce (DOC) initiated an antidumping administrative review of the antidumping duty order covering circular welded non-alloy steel pipe and tube from Mexico for the November 1, 2007 through October 31, 2008 period of review. The DOC selected Mueller Comercial as a respondent in the review. On April 19, 2010, the DOC published the final results of the review and assigned Mueller Comercial an antidumping duty rate of 48.33 percent. On May 25, 2010, the Company appealed the final results to the U.S. Court of International Trade (CIT). On December 16, 2011, the CIT issued a decision remanding the Department’s final results. While the matter was still pending, the Company and the United States reached an agreement to settle the appeal. Subject to the conditions of the agreement, the Company anticipated that certain of its subsidiaries would incur antidumping duties on subject imports made during the period of review and, as such, established a reserve for this matter. After the lapse of the statutory period of time during which U.S. Customs and Border Protection (CBP) was required, but failed, to liquidate the entries at the settled rate, the Company released the reserve. Between October 30, 2015 and November 27, 2015, CBP sent a series of invoices to Southland Pipe Nipples Co., Inc. (Southland), requesting payment of approximately $3.0 million in duties and interest in connection with 795 import entries made during the November 1, 2007 through October 31, 2008 period. On January 26, 2016 and January 27, 2016, Southland filed protests with CBP in connection with these invoices, noting that CBP’s asserted claims were not made in accordance with applicable law, including statutory provisions governing deemed liquidation. The Company believes in the merits of the legal objections raised in Southland’s protests, and CBP’s response to Southland’s protests is currently pending. Given the procedural posture and issues raised by this legal dispute, the Company cannot estimate the amount of potential duty liability, if any, that may result from CBP’s asserted claims. Guarantees Guarantees, in the form of letters of credit, are issued by the Company generally to assure the payment of insurance deductibles, certain retiree health benefits, and debt at certain unconsolidated affiliates. The terms of the guarantees are generally one year but are renewable annually as required. These letters are primarily backed by the Company’s revolving credit facility. The maximum payments that the Company could be required to make under its guarantees at December 30, 2023 were $28.7 million. Insurance Claims In August 2022, a portion of the Company’s Bluffs, Illinois manufacturing operation was damaged by fire. Certain inventories, production equipment, and building structures were extensively damaged. During the second quarter of 2023, the Company settled the claim with its insurer for total proceeds of $29.5 million, net of the deductible of $250 thousand. As a result of the settlement with the insurer, all proceeds received and all costs previously deferred (which were recorded as other current liabilities in prior periods) were recognized, resulting in a pre-tax gain of $19.5 million in the second quarter of 2023, or 13 cents per diluted share after tax. The Company received proceeds of $24.5 million and $5.0 million in 2023 and 2022, respectively. In March 2023, a portion of the Company’s Covington, Tennessee manufacturing operation was damaged by a tornado. The extent of the damage to inventories, production equipment, and building structures is currently being assessed. The total value of the loss, including business interruption, cannot be determined at this time, but is expected to be covered by property and business interruption insurance subject to customary deductibles. Any gain resulting from insurance proceeds for property damage in excess of the net book value of the related property will be recognized in income upon settlement of the claim. In addition, the Company has deferred recognition of direct, identifiable costs associated with this matter. These costs will also be recognized upon settlement of the insurance claim. As of December 30, 2023, the Company has received advances totaling $10.0 million from the insurance company for this claim. Other The Company is involved in certain litigation as a result of claims that arose in the ordinary course of business, which management believes will not have a material adverse effect on the Company’s financial position, results of operations, or cash flows. It may also realize the benefit of certain legal claims and litigation in the future; these gain contingencies are not recognized in the Consolidated Financial Statements.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of income before income taxes were taxed under the following jurisdictions: (In thousands) 2023 2022 2021 Domestic $ 722,153 $ 737,538 $ 518,080 Foreign 123,079 138,493 123,059 Income before income taxes $ 845,232 $ 876,031 $ 641,139 Income tax expense consists of the following: (In thousands) 2023 2022 2021 Current tax expense: Federal $ 144,111 $ 149,269 $ 107,804 Foreign 39,167 36,719 34,455 State and local 32,694 41,214 16,186 Current tax expense 215,972 227,202 158,445 Deferred tax expense (benefit): Federal 4,806 (3,312) (3,504) Foreign 270 (192) 2,572 State and local (286) (376) 8,345 Deferred tax expense (benefit) 4,790 (3,880) 7,413 Income tax expense $ 220,762 $ 223,322 $ 165,858 The difference between the reported income tax expense and a tax determined by applying the applicable U.S. federal statutory income tax rate to income before income taxes is reconciled as follows: (In thousands) 2023 2022 2021 Expected income tax expense $ 177,499 $ 183,967 $ 134,639 State and local income tax, net of federal benefit 25,542 32,184 21,132 Effect of foreign statutory rates different from U.S. and other foreign adjustments 14,519 7,443 11,185 Investment in unconsolidated affiliates 1,226 206 (679) Other, net 1,976 (478) (419) Income tax expense $ 220,762 $ 223,322 $ 165,858 The Company continues to assert that a portion of the undistributed earnings of its foreign subsidiaries are permanently reinvested. No taxes have been accrued with respect to these undistributed earnings or any outside basis differences. The Company has accrued appropriate taxes for any undistributed earnings that are not considered permanently reinvested. The Company has elected to provide for the tax expense related to global intangible low-taxed income (GILTI) in the year the tax is incurred. The Company includes interest and penalties related to income tax matters as a component of income tax expense, none of which was material in 2023, 2022, and 2021. During 2021, the Internal Revenue Service completed its audit of the Company’s 2015 and 2017 tax returns, the results of which were immaterial to the Consolidated Financial Statements. The statute of limitations is open for the Company’s federal tax return for 2020 and all subsequent years, and some state and foreign returns are also open for some earlier tax years due to differing statute periods. While the Company believes that it is adequately reserved for possible audit adjustments, the final resolution of these examinations cannot be determined with certainty and could result in final settlements that differ from current estimates. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: (In thousands) 2023 2022 Deferred tax assets: Inventories $ 19,162 $ 16,829 Other postretirement benefits and accrued items 10,174 7,260 Other reserves 6,956 8,046 Foreign tax attributes 4,862 5,750 State tax attributes, net of federal benefit 6,728 8,063 Stock-based compensation 4,502 5,249 Lease liability 7,354 4,540 Basis difference in unconsolidated affiliates 11,509 6,881 Total deferred tax assets 71,247 62,618 Less valuation allowance (23,078) (21,505) Deferred tax assets, net of valuation allowance 48,169 41,113 Deferred tax liabilities: Property, plant, and equipment 42,980 44,001 Lease asset 7,776 4,970 Other liabilities 10,884 2,918 Total deferred tax liabilities 61,640 51,889 Net deferred tax liabilities $ (13,471) $ (10,776) As of December 30, 2023, after consideration of the federal impact, the Company had state income tax credit carryforwards of $1.3 million, all of which expire by 2024, and state net operating loss (NOL) carryforwards with potential tax benefits of $5.6 million, after consideration of the federal impact, expiring between 2027 and 2036. The state tax credit and NOL carryforwards were fully offset by valuation allowances. As of December 30, 2023, the Company had other foreign tax attributes with potential tax benefits of $3.8 million, which have an unlimited life, and attributes with potential benefits of $1.0 million that expire between 2035 and 2039; all of these foreign attributes were fully offset by a valuation allowance. The Company has also recorded a valuation allowance against deferred tax assets related to the book-tax differences in investments in unconsolidated affiliates. Income taxes paid were approximately $219.6 million in 2023, $238.3 million in 2022, and $132.9 million in 2021.

Equity

Equity	12 Months Ended
	Dec. 30, 2023
Equity [Abstract]
Equity	Equity The Company’s Board of Directors has extended, until July 2024, its authorization to repurchase up to 40 million shares of the Company’s common stock through open market transactions or through privately negotiated transactions. The Company has no obligation to purchase any shares and may cancel, suspend, or extend the time period for the purchase of shares at any time. Any purchases will be funded primarily through existing cash and cash from operations. The Company may hold any shares purchased in treasury or use a portion of the repurchased shares for its stock-based compensation plans, as well as for other corporate purposes. From its initial authorization in 1999 through December 30, 2023, the Company has repurchased approximately 15.0 million shares under this authorization.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company has in effect stock incentive plans under which stock-based awards have been granted to certain employees and members of its Board of Directors. Under these existing plans, the Company may grant stock options, restricted stock awards, and performance stock awards. Approximately 1.1 million shares were available for future stock incentive awards at December 30, 2023, comprised of 564 thousand and 561 thousand shares available under the 2019 Incentive Plan and 2014 Stock Incentive Plan, respectively. During the years ended December 30, 2023, December 31, 2022, and December 25, 2021, the Company recognized stock-based compensation, as a component of selling, general, and administrative expense, in its Consolidated Statements of Income of $23.1 million, $17.8 million, and $9.8 million, respectively. The total compensation expense not yet recognized related to stock incentive awards at December 30, 2023 was $52.9 million, with an average expense recognition period of 2.8 years. The Company generally issues treasury shares when stock options are exercised, or when restricted stock awards or performance stock awards are granted. A summary of the activity and related information follows: Stock Options Restricted Stock Awards Performance Stock Awards (Shares in thousands) Shares Weighted Average Exercise Price Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Beginning of period 884 $ 14.60 982 $ 18.29 1,722 $ 22.04 Granted — N/A 93 36.88 535 (2) 37.64 Added by Performance Factor — N/A — N/A 100 14.81 Exercised/Released (258) 14.16 (410) 18.89 (455) 15.40 Forfeited — N/A (1) 33.80 — N/A End of period 626 $ 14.78 664 $ 20.51 1,902 (1) $ 27.63 (1) Of the performance stock awards outstanding, there are 856 thousand awards granted in 2021 and 2022 that have the potential to vest at maximum, up to 200% of target. These awards are represented at 100% target and would increase the performance awards outstanding by 856 thousand if they vest at maximum. (2) Performance awards granted in 2023 are represented at 200% target. Restricted Stock Awards The fair value of each restricted stock award equals the fair value of the Company’s stock on the grant date and is amortized into compensation expense on a straight-line or accrual basis over its vesting period based on its vesting schedule. The weighted average grant-date fair value of awards granted during 2023, 2022, and 2021 was $36.88, $31.90, and $22.04, respectively. The aggregate intrinsic value of outstanding and unvested awards was $31.3 million at December 30, 2023. The total fair value of awards that vested was $7.7 million, $4.9 million, and $7.0 million in 2023, 2022, and 2021, respectively. Performance Stock Awards Performance stock awards require achievement of certain performance criteria which are predefined by the Compensation Committee of the Board of Directors at the time of grant. The fair value of each performance stock award equals the fair value of the Company’s stock on the grant date. Performance stock awards are vested and released at the end of the performance period if the predefined performance criteria are achieved. For all performance stock awards, in the event the certified results equal the predefined performance criteria, the Company will grant the number of shares equal to the target award. In the event the certified results exceed the predefined performance criteria, additional shares up to the maximum award will be granted. In the event the certified results fall below the predefined performance criteria but above the minimum threshold, a reduced number of shares will be granted. If the certified results fall below the minimum threshold, no shares will be granted. In the period it becomes probable that the minimum threshold specified in the award will be achieved, the Company recognizes expense for the proportionate share of the total fair value of the performance stock awards related to the vesting period that has already lapsed for the shares expected to vest and be released. The remaining fair value of the shares expected to vest and be released is expensed on a straight-line basis over the balance of the vesting period. In the event the Company determines it is no longer probable that it will achieve the minimum threshold specified in the award, all of the previously recognized compensation expense is reversed in the period such a determination is made. The weighted average grant-date fair value of awards granted during 2023, 2022, and 2021 was $37.63, $32.74, and $21.73, respectively. The aggregate intrinsic value of outstanding and unvested awards was $89.7 million at December 30, 2023. The total fair value of awards that vested was $7.0 million and $1.7 million in 2023 and 2022, respectively. Stock Options Stock options are generally granted to purchase shares of common stock at an exercise price equal to the average of the high and low market price of the Company’s stock on the grant date. Generally, the awards vest within five years from the grant date. Any unexercised options expire after not more than ten years. The fair value of each option is estimated as a single award and amortized into compensation expense on a straight-line or accrual basis over its vesting period based on its vesting schedule. The Company estimates the fair value of all stock option awards as of the grant date by applying the Black-Scholes-Merton option pricing model. The use of this valuation model in the determination of compensation expense involves certain assumptions that are judgmental and/or highly sensitive including the expected life of the option, stock price volatility, risk-free interest rate, and dividend yield. Additionally, forfeitures are not estimated at the time of valuation; they are recognized as they occur. The weighted average of key assumptions used in determining the fair value of options granted and a discussion of the methodology used to develop each assumption are as follows: 2023 2022 2021 Fair value of stock options on grant date N/A N/A $ 15.6 Expected term N/A N/A 7.9 years Expected price volatility N/A N/A 33.6 % Risk-free interest rate N/A N/A 1.3 % Dividend yield N/A N/A 1.1 % Expected term – This is the period of time estimated based on historical experience over which the options granted are expected to remain outstanding. An increase in the expected term will increase compensation expense. Expected price volatility – This is a measure of the amount by which a price has fluctuated or is expected to fluctuate. The Company uses actual historical changes in the market value of its stock to calculate the volatility assumption. Daily market value changes from the grant date over a past period representative of the expected term of the options are used. An increase in the expected price volatility rate will increase compensation expense. Risk-free interest rate – This is the U.S. Treasury rate for the week of the grant, having a term representative of the expected term of the options. An increase in the risk-free rate will increase compensation expense. Dividend yield – This rate is the annual dividends per share as a percentage of the Company’s stock price. An increase in the dividend yield will decrease compensation expense. The total intrinsic value of options exercised was $6.5 million, $5.9 million, and $3.8 million in 2023, 2022, and 2021, respectively. The total fair value of options that vested was $1.0 million, $1.1 million, and $0.4 million in 2023, 2022, and 2021.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 30, 2023
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) AOCI includes certain foreign currency translation adjustments from those subsidiaries not using the U.S. dollar as their functional currency, net deferred gains and losses on certain derivative instruments accounted for as cash flow hedges, adjustments to pension and other post-employment benefit liabilities, and other comprehensive income attributable to unconsolidated affiliates. The following table provides changes in AOCI by component, net of taxes and noncontrolling interest (amounts in parentheses indicate debits to AOCI): (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/ Attributable to Unconsol. Affiliates Total Balance at December 25, 2021 $ (42,303) $ 803 $ (11,500) $ (347) $ (53,347) Other comprehensive (loss) income before reclassifications (26,935) (6,983) 13,667 2,702 (17,549) Amounts reclassified from AOCI — 7,666 (945) — 6,721 Balance at December 31, 2022 (69,238) 1,486 1,222 2,355 (64,175) Other comprehensive income (loss) before reclassifications 21,162 1,146 (3,499) 917 19,726 Amounts reclassified from AOCI — (2,419) (353) — (2,772) Balance at December 30, 2023 $ (48,076) $ 213 $ (2,630) $ 3,272 $ (47,221) Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI (In thousands) 2023 2022 2021 Affected Line Item Unrealized losses (gains) on derivatives: Commodity contracts $ (3,109) $ 9,891 $ (3,848) Cost of goods sold 690 (2,225) 1,306 Income tax expense (benefit) $ (2,419) $ 7,666 $ (2,542) Net of tax and noncontrolling interests Amortization of net loss (gain) and prior service cost on employee benefit plans $ (451) $ (1,277) $ 963 Other income, net 98 332 (159) Income tax expense (benefit) $ (353) $ (945) $ 804 Net of tax and noncontrolling interests

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 30, 2023
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Quarterly Financial Information (Unaudited) (1) (In thousands, except per share data) First Second Third Fourth 2023 Net sales $ 971,192 $ 896,984 $ 819,792 $ 732,377 Gross profit (2) 292,394 257,712 240,734 195,994 Consolidated net income 175,093 179,551 135,709 119,296 Net income attributable to Mueller Industries, Inc. 173,239 177,711 132,709 119,238 Basic earnings per share 1.56 1.60 1.19 1.07 Diluted earnings per share 1.54 1.56 1.17 1.05 Dividends per share 0.15 0.15 0.15 0.15 2022 Net sales $ 1,010,002 $ 1,150,042 $ 944,830 $ 877,581 Gross profit (2) 265,491 329,128 266,193 256,781 Consolidated net income 159,248 207,524 155,813 140,235 Net income attributable to Mueller Industries, Inc. 158,316 206,552 154,542 138,906 Basic earnings per share 1.41 1.85 1.39 1.25 Diluted earnings per share 1.39 1.83 1.37 1.23 Dividends per share 0.125 0.125 0.125 0.125 (1) The sum of quarterly amounts may not equal the annual amounts reported due to rounding. In addition, the earnings per share amounts are computed independently for each quarter, while the full year is based on the weighted average shares outstanding. (2) Gross profit is net sales less cost of goods sold, which excludes depreciation and amortization.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The non-controlling interest in the Company’s South Korean joint venture owns 100 percent of a copper tube mill which supplies Mueller affiliates. These affiliates purchased $15.5 million and $22.2 million of product from the supplier in 2023 and 2022, respectively. Payables related to these sales as of December 30, 2023 were $0.8 million.

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
	Dec. 30, 2023
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation And Qualifying Accounts	MUELLER INDUSTRIES, INC. SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS Years Ended December 30, 2023, December 31, 2022, and December 25, 2021 Additions (In thousands) Balance at beginning of year Charged to costs and expenses Other additions Deductions Balance at end 2023 Allowance for doubtful accounts $ 2,687 $ (84) $ 227 $ — $ 2,830 Environmental reserves $ 20,534 $ 652 $ — $ 2,246 $ 18,940 Valuation allowance for deferred tax assets $ 21,504 $ 4,939 $ 267 $ 3,632 $ 23,078 2022 Allowance for doubtful accounts $ 2,590 $ 323 $ — $ 226 $ 2,687 Environmental reserves $ 27,426 $ 1,367 $ — $ 8,259 $ 20,534 Valuation allowance for deferred tax assets $ 26,624 $ (1,648) $ 509 $ 3,981 $ 21,504 2021 Allowance for doubtful accounts $ 1,538 $ 1,216 $ — $ 164 $ 2,590 Environmental reserves $ 24,001 $ 4,964 $ — $ 1,539 $ 27,426 Valuation allowance for deferred tax assets $ 27,199 $ 108 $ 642 $ 1,325 $ 26,624

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Pay vs Performance Disclosure
Net income attributable to Mueller Industries, Inc.	$ 119,238	$ 132,709	$ 177,711	$ 173,239	$ 138,906	$ 154,542	$ 206,552	$ 158,316	$ 602,897	$ 658,316	$ 468,520

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 30, 2023
Accounting Policies [Abstract]
Fiscal Years	Fiscal Years The Company’s fiscal year ends on the last Saturday of December and consisted of 52 weeks in 2023, 53 weeks in 2022, and 52 weeks in 2021. These dates were December 30, 2023, December 31, 2022, and December 25, 2021.
Basis of Presentation	Basis of Presentation The Consolidated Financial Statements include the accounts of Mueller Industries, Inc. and its majority-owned subsidiaries. The noncontrolling interests represent a private ownership interest of 40 percent of Jungwoo Metal Ind. Co., LTD (Jungwoo-Mueller) and 45 percent of Mueller Middle East WLL (Mueller Middle East).
Reclassifications	Certain prior year balances have been reclassified to conform to current year presentation.
Revenue Recognition	Revenue Recognition Given the nature of the Company’s business and product offerings, sales transactions with customers are generally comprised of a single performance obligation that involves delivery of the products identified in the contracts with customers. Performance obligations are generally satisfied at the point in time of shipment and payment is generally due within 60 days. Variable consideration is estimated for future rebates on certain product lines and product returns. The Company records variable consideration as an adjustment to the transaction price in the period it is incurred. Since variable consideration is settled within a short period of time, the time value of money is not significant. The cost of shipping product to customers is expensed as incurred as a component of cost of goods sold.
Acquisitions	Acquisitions Accounting for acquisitions requires the Company to recognize separately from goodwill the assets acquired and liabilities assumed at their acquisition date fair values. Goodwill is measured as the excess of the purchase price over the net amount allocated to the identifiable assets acquired and liabilities assumed. While management uses its best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date, the estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the
Cash Equivalents and Restricted Cash	Cash Equivalents and Restricted Cash Temporary investments with original maturities of three months or less are considered to be cash equivalents. These investments are stated at cost. At December 30, 2023 and December 31, 2022, temporary investments consisted of money market mutual funds, commercial paper, bank repurchase agreements, and U.S. and foreign government securities totaling approximately $1.01 billion and $329.4 million, respectively.
Short-Term Investments and Investments in Unconsolidated Affiliate	Short-Term Investments The fair value of short-term investments at December 30, 2023, consisting of marketable securities, approximates the carrying value on that date. These marketable securities are stated at fair value and classified as level 1 within the fair value hierarchy. This classification is defined as a fair value determined using observable inputs that reflect quoted prices in active markets for identical assets. During 2023, the Company recognized gains of $41.9 million on short-term investments, of which $17.1 million was realized on the sale of marketable securities and the remaining $24.8 million represents unrealized gains relating to the excess fair value over the related cost basis of the marketable securities as of December 30, 2023. The fair value of short-term investments at December 31, 2022, consisting of U.S. treasury bills with maturities exceeding three months at the time of purchase, approximates the carrying value on that date. These treasury bills are stated at fair value and are classified as trading securities. The fair value of treasury bills is classified as level 1 within the fair value hierarchy. This classification is defined as a fair value determined using observable inputs that reflect quoted prices in active markets for identical assets. Investments in Unconsolidated Affiliates Tecumseh The Company owns a 50 percent interest in an unconsolidated affiliate that acquired Tecumseh Products Company (Tecumseh) and an entity that provides financing to Tecumseh. This investment is recorded using the equity method of accounting, as the Company can exercise significant influence but does not own a majority equity interest or otherwise control the entity. Under the equity method of accounting, this investment is stated at initial cost and is adjusted for subsequent additional investments and the Company’s proportionate share of earnings or losses and distributions. The Company records its proportionate share of the investee’s net income or loss, net of foreign taxes, one quarter in arrears as income (loss) from unconsolidated affiliates, net of foreign tax, in the Consolidated Statements of Income. The Company’s proportionate share of the investee’s other comprehensive income (loss), net of income taxes, is recorded in the Consolidated Statements of Comprehensive Income and Consolidated Statements of Changes in Equity. The U.S. tax effect of the Company’s proportionate share of Tecumseh’s income or loss is recorded in income tax expense in the Consolidated Statements of Income. In general, the equity investment in unconsolidated affiliates is equal to the current equity investment less the investee’s net accumulated losses. Retail Distribution The Company owns a 28 percent noncontrolling equity interest in a limited liability company in the retail distribution business. This investment is recorded using the equity method of accounting. The Company records its proportionate share of the investee’s net income or loss one month in arrears as income (loss) from unconsolidated affiliates in the Consolidated Statements of Income. The Company’s proportionate share of the investee’s other comprehensive income (loss), net of income taxes, is recorded in the Consolidated Statements of Comprehensive Income and Consolidated Statements of Changes in Equity.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
Inventories	Inventories The Company’s inventories are valued at the lower-of-cost-or-market. The material component of its U.S. copper tube and copper fittings inventories is valued on a LIFO basis and the non-material components of U.S. copper tube and copper fittings inventories are valued on a FIFO basis. The material component of its U.K. and Canadian copper tube inventories are valued on a FIFO basis. The material component of its brass rod and forgings inventories are valued on a FIFO basis. Certain inventories are valued on an average cost basis. Elements of cost in finished goods inventory in addition to the cost of material include depreciation, amortization, utilities, maintenance, production wages, and transportation costs. The market price of copper cathode and scrap is subject to volatility. During periods when open market prices decline below net book value, the Company may need to provide an allowance to reduce the carrying value of its inventory. In addition, certain items in inventory may be considered obsolete and, as such, the Company may establish an allowance to reduce the carrying value of those items to their net realizable value. Changes in these estimates related to the value of inventory, if any,
Leases	Leases The Company leases certain manufacturing facilities, distribution centers, office space, and equipment. Leases with an initial term of twelve months or less are not recorded on the balance sheet; expense for these leases is recognized on a straight line-basis over the term of the lease. Most of the Company’s leases include one or more options to renew up to five years and have remaining terms of one
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment is stated at cost less accumulated depreciation. Expenditures for major additions and improvements are capitalized, while minor replacements, maintenance, and repairs are charged to expense as incurred. Depreciation of buildings, machinery, and equipment is provided on the straight-line method over the estimated useful lives ranging from 20 to 40 years for buildings and five
Goodwill	Goodwill Goodwill is recognized for the excess of the purchase price over the fair value of tangible and identifiable intangible net assets of businesses acquired. Several factors give rise to goodwill in business acquisitions, such as the expected benefit from synergies of the combination and the existing workforce of the acquired business. Goodwill is evaluated annually for possible impairment as of the first day of the fourth quarter unless circumstances indicate the need to accelerate the timing of the evaluation. In the evaluation of goodwill impairment, management performs a qualitative assessment to determine if it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the qualitative assessment is not conclusive, management compares the fair value of a reporting unit with its carrying amount and will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, not to exceed the total amount of goodwill allocated to the reporting unit. Fair value for the Company’s reporting units is determined using a combination of the income and market approaches (level 3 within the fair value hierarchy), incorporating market participant considerations and management’s assumptions on revenue growth rates, operating margins, discount rates and expected capital expenditures. The market approach measures the fair value of a business through the analysis of publicly traded companies or recent sales of similar businesses. The income approach uses a discounted cash flow model to estimate the fair value of reporting units based on expected cash flows (adjusted for capital investment required to support operations) and a terminal value. This cash flow stream is discounted to its present value to arrive at a fair value for each reporting unit. Future earnings are estimated using the Company’s most recent annual projections, applying a growth rate to future periods. Those projections are directly impacted by the condition of the markets in which the Company’s businesses participate. The discount rate selected for the reporting units is generally based on rates of return available for comparable companies at the date of valuation.
Self-Insurance Accruals	Self-Insurance Accruals The Company is primarily self-insured for workers’ compensation claims and benefits paid under certain employee health care programs. Accruals are primarily based on estimated undiscounted cost of claims, which includes incurred but not reported claims, and are classified as accrued wages and other employee costs.
Pension Benefit Plans	Pension Benefit Plans The Company sponsors qualified and nonqualified pension benefit plans in certain foreign locations. The Company recognizes the overfunded or underfunded status of the plans as an asset or liability in the Consolidated Balance Sheets with changes in the funded status recorded through comprehensive income in the year in which those changes occur. The obligations for these plans are determined by actuaries and affected by the assumptions, including discount rates, expected long-term return on plan assets for defined benefit pension plans, and certain employee-related factors, such as retirement age and mortality. The Company evaluates its assumptions periodically and makes adjustments as necessary. The expected return on plan assets is determined using the market value of plan assets. Differences between assumed and actual returns are amortized to the market value of assets on a straight-line basis over the average remaining service period of the plan participants using the corridor approach. The corridor approach defers all actuarial gains and losses resulting from variances between actual results and actuarial assumptions. These unrecognized gains and losses are amortized when the net gains and losses exceed 10 percent of the greater of the market value of the plan assets or the projected benefit obligation. The amount in excess of the corridor is amortized over the average remaining service period of the plan participants. For 2023, the average remaining service period for the pension plans was 11 years.
Environmental Reserves and Environmental Expenses	Environmental Reserves and Environmental Expenses The Company recognizes an environmental liability when it is probable the liability exists and the amount is reasonably estimable. The Company estimates the duration and extent of its remediation obligations based upon reports of outside consultants, internal and third party estimates and analyses of cleanup costs and ongoing monitoring costs, communications with regulatory agencies, and changes in environmental law. If the Company were to determine that its estimates of the duration or extent of its environmental obligations were no longer accurate, it would adjust environmental liabilities accordingly in the period that such determination is made. Estimated future expenditures for environmental remediation are not discounted to their present value. Environmental expenses related to non-operating properties
Earnings Per Share	Earnings Per Share
Income Taxes	Income Taxes Deferred income tax assets and liabilities are recognized when differences arise between the treatment of certain items for financial statement and tax purposes. Realization of certain components of deferred tax assets is dependent upon the occurrence of future events. The Company records valuation allowances to reduce its deferred tax assets to the amount it believes is more likely than not to be realized. These valuation allowances can be impacted by changes in tax laws, changes to statutory tax rates, and future taxable income levels and are based on the Company’s judgment, estimates, and assumptions regarding those future events. In the event the Company was to determine that it would not be able to realize all or a portion of the net deferred tax assets in the future, it would increase the valuation allowance through a charge to income tax expense in the period that such determination is made. Conversely, if it was to determine that it would be able to realize its deferred tax assets in the future, in excess of the net carrying amounts, the Company would decrease the recorded valuation allowance through a decrease to income tax expense in the period that such determination is made. The Company provides for uncertain tax positions and the related interest and penalties, if any, based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. Tax benefits for uncertain tax positions that are recognized in the financial statements are measured as the largest amount of benefit, determined on a cumulative probability basis, that is more likely than not to be realized upon ultimate settlement. To the extent the Company prevails in matters for which a liability for an uncertain tax position is established or is required to pay amounts in excess of the liability, the Company’s effective tax rate in a given financial statement period may be affected.
Taxes Collected from Customers and Remitted to Governmental Authorities	Taxes Collected from Customers and Remitted to Governmental Authorities Taxes assessed by a governmental authority that are directly imposed on a revenue producing transaction between the Company and its customers, primarily value added taxes in foreign jurisdictions, are accounted for on a net (excluded from revenues and costs) basis.
Stock-Based Compensation	Stock-Based Compensation
Concentrations of Credit and Market Risk	Concentrations of Credit and Market Risk Concentrations of credit risk with respect to accounts receivable are limited due to the large number of customers comprising the Company’s customer base, and their dispersion across different geographic areas and different industries, including HVAC, plumbing, refrigeration, hardware, automotive, OEMs, and others. The Company minimizes its exposure to base metal price fluctuations through various strategies. Generally, it prices an equivalent amount of copper raw material, under flexible pricing arrangements it maintains with its suppliers, at the time it determines the selling price of finished products to its customers.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company’s earnings and cash flows are subject to fluctuations due to changes in commodity prices, foreign currency exchange rates, and interest rates. The Company uses derivative instruments such as commodity futures contracts, foreign currency forward contracts, and interest rate swaps to manage these exposures. All derivatives are recognized in the Consolidated Balance Sheets at their fair value. On the date the derivative contract is entered into, it is either a) designated as a hedge of (i) a forecasted transaction or the variability of cash flow to be paid (cash flow hedge) or (ii) the fair value of a recognized asset or liability (fair value hedge), or b) not designated in a hedge accounting relationship, even though the derivative contract was executed to mitigate an economic exposure (economic hedge), as the Company does not enter into derivative contracts for trading purposes. Changes in the fair value of a derivative that is qualified, designated, and highly effective as a cash flow hedge are recorded in stockholders’ equity within accumulated other comprehensive income (AOCI), to the extent effective, until they are reclassified to earnings in the same period or periods during which the hedged transaction affects earnings. Changes in the fair value of undesignated derivative instruments executed as economic hedges are reported in current earnings. The Company documents all relationships between derivative instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivative instruments that are designated as fair value hedges to specific assets and liabilities in the Consolidated Balance Sheets and linking cash flow hedges to specific forecasted transactions or variability of cash flow. The Company also assesses, both at the hedge’s inception and on an ongoing basis, whether the designated derivative instruments that are used in hedging transactions are highly effective in offsetting changes in cash flow or fair values of hedged items. When a derivative instrument is determined not to be highly effective as a hedge or the underlying hedged transaction is no longer probable of occurring, hedge accounting is discontinued prospectively in accordance with the derecognition criteria for hedge accounting.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts for cash and cash equivalents, accounts receivable, and accounts payable approximate fair value due to the short-term maturity of these instruments.
Foreign Currency Translation	Foreign Currency Translation
Use of and Changes in Estimates	Use of and Changes in Estimates The preparation of financial statements in conformity with generally accepted accounting principles in the United States (U.S. GAAP) requires management to make estimates, assumptions, and judgments that affect the amounts reported in the financial statements and accompanying notes. Management makes its best estimate of the ultimate outcome for these items based on historical trends and other information available when the financial statements are prepared. Changes in estimates are recognized in accordance with the accounting rules for the estimate, which is typically in the period when new information becomes available to management. Areas where the nature of the estimate makes it reasonably possible that actual results could materially differ from amounts estimated include but are not limited to: pension and other postretirement benefit plan obligations, tax liabilities, loss contingencies, litigation claims, environmental reserves, and impairment assessments of long-lived assets (including goodwill).
Recently Adopted and Issued Accounting Standards	Recently Adopted Accounting Standards In October 2021, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2021-08, Business Combinations (Topic 805): An Amendment of the FASB Accounting Standards Codification . The new guidance was issued to improve accounting for acquired revenue contracts with customers in a business combination by addressing diversity in practice and inconsistency related to the (i) recognition of an acquired contract liability, and (ii) payment terms and their effect on subsequent revenue recognized by the acquirer. The ASU is effective for fiscal years beginning after December 15, 2022 for public entities. The updated guidance requires prospective adoption, and early adoption is permitted. The Company adopted the ASU during the first quarter of 2023. The adoption of the ASU did not have a material impact on the Company’s Consolidated Financial Statements. Recently Issued Accounting Standards In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . The new guidance requires a public entity to disclose significant segment expenses and other segment items on an annual and interim basis and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. The guidance applies to all public entities and is effective for fiscal years beginning after December 15, 2023, and for interim periods beginning after December 15, 2024. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Consolidated Financial Statements. In June 2022, the FASB issued ASU No. 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The new guidance was issued to clarify existing guidance measuring the fair value of an equity security subject to contractual restrictions that prohibit the sale of an equity security and introduce new disclosure requirements for applicable equity securities. The ASU is effective for fiscal years beginning after December 15, 2023 for public entities. The updated guidance requires prospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Consolidated Financial Statements.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule of Final Valuation of the Long-Lived Assets	The following table summarizes the allocation of the purchase price to acquire these businesses, which were financed by available cash balances, as well as the assets acquired and liabilities assumed at the respective acquisition dates. The purchase price allocations for all acquisitions have been finalized as of December 30, 2023. (In thousands) Mueller Middle East H&C Flex Total consideration $ 20,017 $ 15,279 Allocated to: Accounts receivable 10,652 — Inventories 4,727 4,511 Other current assets 1,744 — Property, plant, and equipment 26,664 10,813 Operating lease right-of-use assets 935 — Goodwill 864 — Intangible assets 452 — Total assets acquired 46,038 15,324 Accounts payable 4,593 — Other current liabilities 10,941 45 Other noncurrent liabilities 692 — Total liabilities assumed 16,226 45 Noncontrolling interest 9,795 — Net assets acquired $ 20,017 $ 15,279
Schedule of Intangible Assets Identified in the Allocation of the Purchase Price	The following details the total intangible assets identified in the allocation of the purchase price at the respective acquisition dates: (In thousands) Estimated Useful Life Mueller Middle East Intangible asset type: Customer relationships 20 years $ 452 Total intangible assets $ 452

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 30, 2023
Segment Reporting [Abstract]
Schedule of Net sales by Major Product Line	The following tables represent a disaggregation of revenue from contracts with customers, along with the reportable segment for each category: For the Year Ended December 30, 2023 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,926,975 $ — $ — $ 1,926,975 Brass rod and forgings — 454,246 — 454,246 OEM components and valves — 79,879 120,923 200,802 Valves and plumbing specialties 455,598 — — 455,598 Flex duct and other HVAC components — — 379,867 379,867 Other — 43,750 — 43,750 $ 2,382,573 $ 577,875 $ 500,790 $ 3,461,238 Intersegment sales (40,893) Net sales $ 3,420,345 Disaggregation of revenue from contracts with customers (continued): For the Year Ended December 31, 2022 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 2,211,963 $ — $ — $ 2,211,963 Brass rod and forgings — 510,865 — 510,865 OEM components, tube & assemblies — 74,647 121,004 195,651 Valves and plumbing specialties 518,121 — — 518,121 Flex duct and other HVAC components — — 529,303 529,303 Other — 59,177 — 59,177 $ 2,730,084 $ 644,689 $ 650,307 $ 4,025,080 Intersegment sales (42,625) Net sales $ 3,982,455 For the Year Ended December 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 2,055,639 $ — $ — $ 2,055,639 Brass rod and forgings — 565,870 — 565,870 OEM components, tube & assemblies 32,557 48,572 137,564 218,693 Valves and plumbing specialties 511,834 — — 511,834 Flex duct and other HVAC components — — 357,850 357,850 Other — 88,921 — 88,921 $ 2,600,030 $ 703,363 $ 495,414 $ 3,798,807 Intersegment sales (29,462) Net sales $ 3,769,345
Schedule of Segment Information	Summarized segment information is as follows: For the Year Ended December 30, 2023 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,382,573 $ 577,875 $ 500,790 $ (40,893) $ 3,420,345 Cost of goods sold 1,686,792 480,510 311,875 (45,666) 2,433,511 Depreciation and amortization 20,461 7,273 7,567 4,653 39,954 Selling, general, and administrative expense 99,823 13,713 28,950 65,686 208,172 Gain on sale of businesses — — — (4,137) (4,137) Impairment charges 6,258 — — — 6,258 Gain on insurance settlement — — (19,466) — (19,466) Operating income 569,239 76,379 171,864 (61,429) 756,053 Interest expense (1,221) Interest income 38,208 Realized and unrealized gains on short-term investments 41,865 Gain on extinguishment of NMTC liability 7,534 Environmental expense (825) Other income, net 3,618 Income before income taxes $ 845,232 For the Year Ended December 31, 2022 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,730,084 $ 644,689 $ 650,307 $ (42,625) $ 3,982,455 Cost of goods sold 1,943,174 543,004 416,953 (38,269) 2,864,862 Depreciation and amortization 22,193 7,647 9,174 4,717 43,731 Selling, general, and administrative expense 93,655 11,574 36,113 61,744 203,086 Gain on sale of assets — — — (6,373) (6,373) Operating income 671,062 82,464 188,067 (64,444) 877,149 Interest expense (810) Interest income 6,457 Pension plan termination expense (13,100) Realized and unrealized gains on short-term investments 2,918 Environmental expense (1,298) Other income, net 4,715 Income before income taxes $ 876,031 Segment information (continued): For the Year Ended December 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 2,600,030 $ 703,363 $ 495,414 $ (29,462) $ 3,769,345 Cost of goods sold 1,996,610 605,715 367,343 (30,679) 2,938,989 Depreciation and amortization 23,384 6,929 10,379 4,698 45,390 Selling, general, and administrative expense 93,749 11,698 29,327 49,278 184,052 Gain on sale of businesses — (6,454) — (51,306) (57,760) Impairment charges — — 2,829 — 2,829 Operating income 486,287 85,475 85,536 (1,453) 655,845 Interest expense (7,709) Interest income 353 Redemption premium (5,674) Environmental expense (5,053) Other income, net 3,377 Income before income taxes $ 641,139
Schedule of Geographic Information	Summarized geographic information is as follows: (In thousands) 2023 2022 2021 Net sales: United States $ 2,572,141 $ 2,965,053 $ 2,791,571 United Kingdom 270,128 297,582 330,908 Canada 339,682 410,679 469,652 Asia and the Middle East 153,816 217,750 83,217 Mexico 84,578 91,391 93,997 $ 3,420,345 $ 3,982,455 $ 3,769,345 Long-lived assets: 2023 2022 2021 United States $ 273,604 $ 266,571 $ 272,903 United Kingdom 40,045 36,474 36,529 Canada 18,152 23,354 26,422 Asia and the Middle East 50,725 51,193 48,742 Mexico 2,639 2,358 966 $ 385,165 $ 379,950 $ 385,562
Schedule of Segment Information by Assets	(In thousands) 2023 2022 2021 Expenditures for long-lived assets (including those resulting from business acquisitions): Piping Systems $ 19,118 $ 20,694 $ 43,429 Industrial Metals 9,406 6,905 5,744 Climate 15,407 2,611 12,428 General Corporate 10,094 7,429 3,521 $ 54,025 $ 37,639 $ 65,122 (In thousands) 2023 2022 2021 Segment assets: Piping Systems $ 1,029,821 $ 1,088,940 $ 1,160,272 Industrial Metals 157,761 160,702 173,290 Climate 252,561 279,940 250,107 General Corporate 1,319,158 712,817 145,267 $ 2,759,301 $ 2,242,399 $ 1,728,936

Cash, Cash Equivalents, and R_2

Cash, Cash Equivalents, and Restricted Cash (Tables)	12 Months Ended
	Dec. 30, 2023
Cash and Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	(In thousands) 2023 2022 Cash & cash equivalents $ 1,170,893 $ 461,018 Restricted cash included within other current assets 3,228 4,176 Restricted cash included within other assets 102 102 Total cash, cash equivalents, and restricted cash $ 1,174,223 $ 465,296
Schedule of Cash, Cash Equivalents and Restricted Cash	(In thousands) 2023 2022 Cash & cash equivalents $ 1,170,893 $ 461,018 Restricted cash included within other current assets 3,228 4,176 Restricted cash included within other assets 102 102 Total cash, cash equivalents, and restricted cash $ 1,174,223 $ 465,296

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventories	(In thousands) 2023 2022 Raw materials and supplies $ 111,843 $ 133,189 Work-in-process 61,793 64,177 Finished goods 220,629 265,842 Valuation reserves (14,017) (14,289) Inventories $ 380,248 $ 448,919

Consolidated Financial Statem_2

Consolidated Financial Statement Details (Tables)	12 Months Ended
	Dec. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Other Income, Net	Other Income, Net (In thousands) 2023 2022 2021 Net periodic benefit income $ 765 $ 3,168 $ 1,903 Accounts payable discounts 1,502 1,609 1,385 Other 1,351 (62) 89 Other income, net $ 3,618 $ 4,715 $ 3,377

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments Designated as Cash Flow Hedges Reflected in the Financial Statements	The following table summarizes the location and fair value of the derivative instruments and disaggregates the net derivative assets and liabilities into gross components on a contract-by-contract basis: Asset Derivatives Liability Derivatives Fair Value Fair Value (In thousands) Balance Sheet Location 2023 2022 Balance Sheet Location 2023 2022 Commodity contracts - gains Other current assets $ 589 $ 3,746 Other current liabilities $ 16 $ — Commodity contracts - losses Other current assets (281) (1,483) Other current liabilities (383) — Total derivatives (1) $ 308 $ 2,263 $ (367) $ — (1) Does not include the impact of cash collateral provided to counterparties .
Schedule of Fair Value Hedges	The following table summarizes the effects of derivative instruments on the Consolidated Statements of Income: (In thousands) Location 2023 2022 Undesignated derivatives: (Loss) gain on commodity contracts (nonqualifying) Cost of goods sold $ (1,071) $ 20,659
Schedule of Activities Related to Derivative Instruments Classified as Cash Flow Hedges	The following tables summarize amounts recognized in and reclassified from AOCI during the period: For the Year Ended December 30, 2023 (In thousands) Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 1,180 Cost of goods sold $ (2,419) Other (34) Other — Total $ 1,146 Total $ (2,419) For the Year Ended December 31, 2022 (In thousands) (Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ (7,066) Cost of goods sold $ 7,666 Other 83 Other — Total $ (6,983) Total $ 7,666

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 30, 2023
Leases [Abstract]
Schedule of Supplemental Information Regarding Operating Leases	The following table includes supplemental information with regards to the Company’s operating leases: (In thousands, except lease term and discount rate) 2023 2022 Operating lease right-of-use assets $ 35,170 $ 22,892 Current portion of operating lease liabilities 7,893 4,942 Noncurrent operating lease liabilities 26,683 16,880 Total operating lease liabilities $ 34,576 $ 21,822 Weighted average discount rate 3.55 % 3.35 % Weighted average remaining lease term (in years) 5.24 6.03
Schedule of Operating Lease Cost and Payments	The following table presents certain information related to operating lease costs and cash paid during the period: For the Year Ended (In thousands) December 30, 2023 December 31, 2022 Operating lease costs $ 9,705 $ 8,220 Short term lease costs 3,843 4,086 Total lease costs $ 13,548 $ 12,306 Cash paid for amounts included in the measurement of lease liabilities $ 9,276 $ 7,787
Schedule of Maturities of Operating Leases	Maturities of the Company’s operating leases are as follows: (In thousands) Amount 2024 $ 8,909 2025 8,124 2026 7,110 2027 6,210 2028 3,222 2029 and thereafter 4,646 Total lease payments 38,221 Less imputed interest (3,645) Total lease obligations 34,576 Less current obligations (7,893) Noncurrent lease obligations $ 26,683

Property, Plant, and Equipmen_2

Property, Plant, and Equipment, Net (Tables)	12 Months Ended
	Dec. 30, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant, and Equipment, Net	(In thousands) 2023 2022 Land and land improvements $ 33,127 $ 32,707 Buildings 232,169 234,480 Machinery and equipment 654,079 653,997 Construction in progress 82,552 54,748 1,001,927 975,932 Less accumulated depreciation (616,762) (595,982) Property, plant, and equipment, net $ 385,165 $ 379,950

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in the Carrying Amount of Goodwill	The changes in the carrying amount of goodwill by segment were as follows: (In thousands) Piping Systems Industrial Metals Climate Total Goodwill $ 192,316 $ 8,854 $ 21,652 $ 222,822 Accumulated impairment charges (40,552) (8,853) (2,087) (51,492) Balance at December 25, 2021: 151,764 1 19,565 171,330 Reductions (1) (11,216) — — (11,216) Currency translation (2,526) — — (2,526) Balance at December 31, 2022: 138,022 1 19,565 157,588 Reductions (2) (7,007) — — (7,007) Currency translation 1,239 — — 1,239 Balance at December 30, 2023: Goodwill 172,806 8,854 21,652 203,312 Accumulated impairment charges (40,552) (8,853) (2,087) (51,492) Goodwill, net $ 132,254 $ 1 $ 19,565 $ 151,820 (1) Includes finalization of the purchase price allocation adjustment for Mueller Middle East of $11.2 million. (2) Includes disposal of Heatlink Group business.
Schedule of Carrying Amount of Intangible Assets	The carrying amount of intangible assets at December 30, 2023 was as follows: (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 50,009 $ (17,535) $ 32,474 Non-compete agreements 2,325 (2,325) — Patents and technology 16,681 (8,119) 8,562 Trade names and licenses 12,092 (6,920) 5,172 Other 1,715 (1,715) — Other intangible assets $ 82,822 $ (36,614) $ 46,208 The carrying amount of intangible assets at December 31, 2022 was as follows: (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 53,156 $ (15,658) $ 37,498 Non-compete agreements 2,333 (2,333) — Patents and technology 18,032 (7,570) 10,462 Trade names and licenses 13,374 (6,697) 6,677 Other 1,676 (1,528) 148 Other intangible assets $ 88,571 $ (33,786) $ 54,785
Schedule of Amortization Expense for Intangible Assets	Future amortization expense is estimated as follows: (In thousands) Amount 2024 $ 4,623 2025 4,505 2026 4,357 2027 4,356 2028 4,117 Thereafter 24,250 Expected amortization expense $ 46,208

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 30, 2023
Retirement Benefits [Abstract]
Schedule of Reconciliation of the Changes in the Plans' Benefit Obligations and the Fair Value of the Plans Assets	The following tables provide a reconciliation of the changes in the most significant plans’ benefit obligations and the fair value of the plans’ assets for 2023 and 2022, and a statement of the plans’ aggregate funded status: Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Change in benefit obligation: Obligation at beginning of year $ 50,761 $ 84,283 $ 9,240 $ 11,825 Service cost — — 183 291 Interest cost 2,454 1,450 439 346 Actuarial loss (gain) 1,508 (24,154) (105) (2,604) Plan amendments/transference — — 101 — Benefit payments (3,582) (2,512) (686) (547) Foreign currency translation adjustment 3,294 (8,306) 385 (71) Obligation at end of year 54,435 50,761 9,557 9,240 Change in fair value of plan assets: Fair value of plan assets at beginning of year 62,298 79,478 — — Actual return on plan assets 410 (6,371) — — Employer contributions — — 686 547 Benefit payments (3,582) (2,512) (686) (547) Foreign currency translation adjustment 3,745 (8,297) — — Fair value of plan assets at end of year 62,871 62,298 — — Funded (underfunded) status at end of year $ 8,436 $ 11,537 $ (9,557) $ (9,240)
Schedule of Amounts Recognized in Accumulated OCI (Before the Effect of Income Taxes)	The following represents amounts recognized in AOCI (before the effect of income taxes): Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Unrecognized net actuarial loss (gain) $ 7,728 $ 2,870 $ (3,863) $ (4,149) Unrecognized prior service credit — — (5) (19)
Schedule of Funded Status of the Plans Recognized	As of December 30, 2023 and December 31, 2022, the total funded status of the plans recognized in the Consolidated Balance Sheets was as follows: Pension Benefits Other Benefits (In thousands) 2023 2022 2023 2022 Long-term asset $ 8,436 $ 11,537 $ — $ — Current liability $ — $ — $ (1,041) $ (1,068) Long-term liability — — (8,516) (8,172) Total funded (underfunded) status $ 8,436 $ 11,537 $ (9,557) $ (9,240)
Schedule of Components of Net Periodic Benefit Costs	The components of net periodic benefit cost (income) are as follows: (In thousands) 2023 2022 2021 Pension benefits: Interest cost $ 2,454 $ 1,450 $ 1,272 Expected return on plan assets (3,260) (3,568) (3,671) Amortization of net loss — 897 1,536 Settlement charge — — — Net periodic benefit income $ (806) $ (1,221) $ (863) Other benefits: Service cost $ 183 $ 291 $ 258 Interest cost 439 346 281 Amortization of prior service credit (2) (198) (470) Amortization of net gain (449) (220) (103) Curtailment gain — (1,756) — Net periodic benefit cost (income) $ 171 $ (1,537) $ (34)
Schedule of Weighted Average Assumptions Used in the Measurement of the Company's Benefit Obligation and Net Periodic Benefit Cost are as Follows	The weighted average assumptions used in the measurement of the Company’s benefit obligations are as follows: Pension Benefits Other Benefits 2023 2022 2023 2022 Discount rate 4.40 % 4.80 % 5.96 % 6.08 % Expected long-term return on plan assets 4.30 % 5.51 % N/A N/A Rate of compensation increases N/A N/A 5.00 % 5.00 % Rate of inflation 3.20 % 3.30 % N/A N/A The weighted average assumptions used in the measurement of the Company’s net periodic benefit cost are as follows: Pension Benefits Other Benefits 2023 2022 2021 2023 2022 2021 Discount rate 4.80 % 1.90 % 1.40 % 6.08 % 3.73 % 2.92 % Expected long-term return on plan assets 5.51 % 4.96 % 4.69 % N/A N/A N/A Rate of compensation increases N/A N/A N/A 5.00 % 5.00 % 5.00 % Rate of inflation 3.30 % 3.70 % 3.20 % N/A N/A N/A
Schedule of Weighted Average Asset Allocation of the Company’s Pension Fund Assets are as Follows	The weighted average asset allocation of the Company’s pension fund assets are as follows: Pension Plan Assets Asset category 2023 2022 Pooled liability investments 99 % — % Equity securities (includes equity mutual funds) — 67 Multi-asset securities — 22 Cash and equivalents (includes money market funds) 1 1 Alternative investments — 10 Total 100 % 100 %
Schedule of Plan Assets at Fair Value Within the Fair Value Hierarchy, by Level	The following table sets forth by level, within the fair value hierarchy, the assets of the plans at fair value: Fair Value Measurements at December 30, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash and money market funds $ 502 $ — $ — $ 502 Pooled liability investments — 62,369 — 62,369 Total $ 502 $ 62,369 $ — $ 62,871 Fair Value Measurements at December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash and money market funds $ 829 $ — $ — $ 829 Mutual funds (1) — 55,441 — 55,441 Limited partnerships — — 6,028 6,028 Total $ 829 $ 55,441 $ 6,028 $ 62,298 (1) Approximately 78 percent of mutual funds are actively managed funds and approximately 22 percent of mutual funds are index funds. Additionally, 24 percent of the mutual funds’ assets are invested in non-U.S. multi-asset securities and 76 percent in non-U.S. equities.
Schedule of Plan Assets Measured at Fair Value Using Significant Unobservable Inputs	The table below reflects the changes in the assets of the plan measured at fair value on a recurring basis using significant unobservable inputs (level 3 of fair value hierarchy) during the year ended December 30, 2023: (In thousands) Limited Partnerships Balance, December 31, 2022 $ 6,028 Liquidation (6,028) Balance, December 30, 2023 $ —
Schedule of Future Benefit Plans Payments	The Company expects future benefits to be paid from the plans as follows: (In thousands) Pension Benefits Other Benefits 2024 $ 3,418 $ 1,042 2025 3,540 1,045 2026 3,667 1,080 2027 3,798 877 2028 3,934 922 2028-2032 21,886 4,146 Total $ 40,243 $ 9,112

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 30, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income Before Income Taxes	The components of income before income taxes were taxed under the following jurisdictions: (In thousands) 2023 2022 2021 Domestic $ 722,153 $ 737,538 $ 518,080 Foreign 123,079 138,493 123,059 Income before income taxes $ 845,232 $ 876,031 $ 641,139
Schedule of Components of Income Tax Expense	Income tax expense consists of the following: (In thousands) 2023 2022 2021 Current tax expense: Federal $ 144,111 $ 149,269 $ 107,804 Foreign 39,167 36,719 34,455 State and local 32,694 41,214 16,186 Current tax expense 215,972 227,202 158,445 Deferred tax expense (benefit): Federal 4,806 (3,312) (3,504) Foreign 270 (192) 2,572 State and local (286) (376) 8,345 Deferred tax expense (benefit) 4,790 (3,880) 7,413 Income tax expense $ 220,762 $ 223,322 $ 165,858
Schedule of Income Tax Reconciliation	The difference between the reported income tax expense and a tax determined by applying the applicable U.S. federal statutory income tax rate to income before income taxes is reconciled as follows: (In thousands) 2023 2022 2021 Expected income tax expense $ 177,499 $ 183,967 $ 134,639 State and local income tax, net of federal benefit 25,542 32,184 21,132 Effect of foreign statutory rates different from U.S. and other foreign adjustments 14,519 7,443 11,185 Investment in unconsolidated affiliates 1,226 206 (679) Other, net 1,976 (478) (419) Income tax expense $ 220,762 $ 223,322 $ 165,858
Schedule of Components of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: (In thousands) 2023 2022 Deferred tax assets: Inventories $ 19,162 $ 16,829 Other postretirement benefits and accrued items 10,174 7,260 Other reserves 6,956 8,046 Foreign tax attributes 4,862 5,750 State tax attributes, net of federal benefit 6,728 8,063 Stock-based compensation 4,502 5,249 Lease liability 7,354 4,540 Basis difference in unconsolidated affiliates 11,509 6,881 Total deferred tax assets 71,247 62,618 Less valuation allowance (23,078) (21,505) Deferred tax assets, net of valuation allowance 48,169 41,113 Deferred tax liabilities: Property, plant, and equipment 42,980 44,001 Lease asset 7,776 4,970 Other liabilities 10,884 2,918 Total deferred tax liabilities 61,640 51,889 Net deferred tax liabilities $ (13,471) $ (10,776)

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Share-Based Payment Arrangement, Activity	A summary of the activity and related information follows: Stock Options Restricted Stock Awards Performance Stock Awards (Shares in thousands) Shares Weighted Average Exercise Price Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Beginning of period 884 $ 14.60 982 $ 18.29 1,722 $ 22.04 Granted — N/A 93 36.88 535 (2) 37.64 Added by Performance Factor — N/A — N/A 100 14.81 Exercised/Released (258) 14.16 (410) 18.89 (455) 15.40 Forfeited — N/A (1) 33.80 — N/A End of period 626 $ 14.78 664 $ 20.51 1,902 (1) $ 27.63 (1) Of the performance stock awards outstanding, there are 856 thousand awards granted in 2021 and 2022 that have the potential to vest at maximum, up to 200% of target. These awards are represented at 100% target and would increase the performance awards outstanding by 856 thousand if they vest at maximum. (2) Performance awards granted in 2023 are represented at 200% target.
Schedule of Weighted Average Assumptions Used in Calculating Fair Value of Stock Options	The weighted average of key assumptions used in determining the fair value of options granted and a discussion of the methodology used to develop each assumption are as follows: 2023 2022 2021 Fair value of stock options on grant date N/A N/A $ 15.6 Expected term N/A N/A 7.9 years Expected price volatility N/A N/A 33.6 % Risk-free interest rate N/A N/A 1.3 % Dividend yield N/A N/A 1.1 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 30, 2023
Equity [Abstract]
Schedule of Changes in AOCI by Component, Net of taxes and Noncontrolling Interest	The following table provides changes in AOCI by component, net of taxes and noncontrolling interest (amounts in parentheses indicate debits to AOCI): (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/ Attributable to Unconsol. Affiliates Total Balance at December 25, 2021 $ (42,303) $ 803 $ (11,500) $ (347) $ (53,347) Other comprehensive (loss) income before reclassifications (26,935) (6,983) 13,667 2,702 (17,549) Amounts reclassified from AOCI — 7,666 (945) — 6,721 Balance at December 31, 2022 (69,238) 1,486 1,222 2,355 (64,175) Other comprehensive income (loss) before reclassifications 21,162 1,146 (3,499) 917 19,726 Amounts reclassified from AOCI — (2,419) (353) — (2,772) Balance at December 30, 2023 $ (48,076) $ 213 $ (2,630) $ 3,272 $ (47,221)
Schedule of Reclassification Adjustments Out of AOCI	Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI (In thousands) 2023 2022 2021 Affected Line Item Unrealized losses (gains) on derivatives: Commodity contracts $ (3,109) $ 9,891 $ (3,848) Cost of goods sold 690 (2,225) 1,306 Income tax expense (benefit) $ (2,419) $ 7,666 $ (2,542) Net of tax and noncontrolling interests Amortization of net loss (gain) and prior service cost on employee benefit plans $ (451) $ (1,277) $ 963 Other income, net 98 332 (159) Income tax expense (benefit) $ (353) $ (945) $ 804 Net of tax and noncontrolling interests

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 30, 2023
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information (Unaudited)	(In thousands, except per share data) First Second Third Fourth 2023 Net sales $ 971,192 $ 896,984 $ 819,792 $ 732,377 Gross profit (2) 292,394 257,712 240,734 195,994 Consolidated net income 175,093 179,551 135,709 119,296 Net income attributable to Mueller Industries, Inc. 173,239 177,711 132,709 119,238 Basic earnings per share 1.56 1.60 1.19 1.07 Diluted earnings per share 1.54 1.56 1.17 1.05 Dividends per share 0.15 0.15 0.15 0.15 2022 Net sales $ 1,010,002 $ 1,150,042 $ 944,830 $ 877,581 Gross profit (2) 265,491 329,128 266,193 256,781 Consolidated net income 159,248 207,524 155,813 140,235 Net income attributable to Mueller Industries, Inc. 158,316 206,552 154,542 138,906 Basic earnings per share 1.41 1.85 1.39 1.25 Diluted earnings per share 1.39 1.83 1.37 1.23 Dividends per share 0.125 0.125 0.125 0.125 (1) The sum of quarterly amounts may not equal the annual amounts reported due to rounding. In addition, the earnings per share amounts are computed independently for each quarter, while the full year is based on the weighted average shares outstanding. (2) Gross profit is net sales less cost of goods sold, which excludes depreciation and amortization.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Thousands		12 Months Ended
	Sep. 26, 2023 shares	Dec. 30, 2023 USD ($) renewal_option shares	Dec. 31, 2022 USD ($)	Dec. 25, 2021 USD ($)	Sep. 25, 2023 shares
Noncontrolling Interest [Line Items]
Common stock, authorized (in shares) | shares	250,000,000	250,000,000			100,000,000
Stock split ratio, common stock	2	2
Performance obligation payment term		60 days
Temporary investments		$ 1,010,000	$ 329,400
Gain on short term investments		41,900
Marketable securities, realized gain		17,100
Marketable securities, unrealized gain		24,800
Allowance for doubtful accounts		$ 2,830	2,687
Number of operating lease renewal options | renewal_option		1
Operating lease renewal term		5 years
Specified percentage over which unrecognized gains and losses are amortized		10%
Average remaining service period for the pension plans		11 years
Stock-based awards excluded from the computation of diluted earnings per share (in shares) | shares		98,000
Foreign currency transaction gains (losses)		$ (4,400)	$ 1,000	$ (600)
Environmental Remediation Expense, Statement of Income or Comprehensive Income [Extensible Enumeration]		Environmental Remediation Expense, Non-Operating Properties
Tecumseh Products Holdings LLC
Noncontrolling Interest [Line Items]
Equity method investment, ownership percentage		50%
Retail Distribution Business
Noncontrolling Interest [Line Items]
Equity method investment, ownership percentage		28%
Minimum
Noncontrolling Interest [Line Items]
Operating lease, lease term		1 year
Maximum
Noncontrolling Interest [Line Items]
Operating lease, lease term		15 years
Buildings | Minimum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life		20 years
Buildings | Maximum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life		40 years
Machinery and equipment | Minimum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life		5 years
Machinery and equipment | Maximum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life		20 years
Jungwoo Metal Ind. Co., LTD
Noncontrolling Interest [Line Items]
Non-controlling ownership interest		40%
Mueller Middle East BSC
Noncontrolling Interest [Line Items]
Non-controlling ownership interest		45%

Acquisitions and Dispositions -

Acquisitions and Dispositions - Narrative (Details) - USD ($) $ in Thousands

3 Months Ended

11 Months Ended

12 Months Ended

Jul. 03, 2023

Dec. 07, 2021

Sep. 02, 2021

Jul. 28, 2021

Jan. 29, 2021

Sep. 30, 2023

Sep. 24, 2022

Dec. 06, 2021

Dec. 30, 2023

Dec. 31, 2022

Dec. 25, 2021

Oct. 25, 2021

Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Exchange | Heatlink Group, Inc.

Business Acquisition [Line Items]

Ownership interest transferred (as a percent)

100%

Net sales of disposed of business

$ 15,600

$ 39,100

Operating income of disposed business

$ 1,700

7,200

Consideration for sale of businesses

$ 26,000

Gain (loss) on disposal of businesses

$ 4,100

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Die-Mold

Business Acquisition [Line Items]

Net sales of disposed of business

$ 10,900

Consideration for sale of businesses

$ 22,800

Net income of disposed business

$ 2,200

Gain (loss) on disposal of businesses

$ 4,700

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Copper Bar

Business Acquisition [Line Items]

Consideration for sale of businesses

$ 10,100

Assets

$ 3,600

Gain (loss) on disposal of businesses

6,500

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Fabricated Tube Products and Shoals Tubular, Inc.

Business Acquisition [Line Items]

Net sales of disposed of business

37,000

Consideration for sale of businesses

$ 75,700

Assets

32,700

Net income of disposed business

$ 5,500

Carrying value of the liabilities disposed

3,600

Gain (loss) on disposal of businesses

$ 46,600

Mueller Middle East

Business Acquisition [Line Items]

Ownership interest acquired (as a percent)

55%

Total consideration paid

$ 20,017

Cash paid for acquisition

15,800

Debt assumed

2,600

Payment for contingent consideration liability

1,000

Equity interest issued or issuable

$ 700

Asset acquisition, pro forma revenue from acquiree

$ 48,200

Hart & Cooley Flexible Duct Business

Business Acquisition [Line Items]

Total consideration paid

$ 15,300

Cash paid for acquisition

$ 14,000

Payment for contingent consideration liability

$ 1,300

Retail Distribution Business

Business Acquisition [Line Items]

Ownership interest acquired (as a percent)

11%

28%

17%

Retail Distribution Business | Die-Mold

Business Acquisition [Line Items]

Ownership interest acquired (as a percent)

17%

Mueller Middle East

Business Acquisition [Line Items]

Interest in the joint venture, ownership percentage

15%

Mueller Middle East | Joint Venture

Business Acquisition [Line Items]

Interest in the joint venture, ownership percentage

40%

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 07, 2021	Jan. 29, 2021	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Business Acquisition [Line Items]
Goodwill			$ 151,820	$ 157,588	$ 171,330
Mueller Middle East
Business Acquisition [Line Items]
Total consideration	$ 20,017
Accounts receivable	10,652
Inventories	4,727
Other current assets	1,744
Property, plant, and equipment	26,664
Operating lease right-of-use assets	935
Goodwill	864
Intangible assets	452
Total assets acquired	46,038
Accounts payable	4,593
Other current liabilities	10,941
Other noncurrent liabilities	692
Total liabilities assumed	16,226
Noncontrolling interest	9,795
Net assets acquired	$ 20,017
H&C Flex
Business Acquisition [Line Items]
Total consideration		$ 15,279
Accounts receivable		0
Inventories		4,511
Other current assets		0
Property, plant, and equipment		10,813
Operating lease right-of-use assets		0
Goodwill		0
Intangible assets		0
Total assets acquired		15,324
Accounts payable		0
Other current liabilities		45
Other noncurrent liabilities		0
Total liabilities assumed		45
Noncontrolling interest		0
Net assets acquired		$ 15,279

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Schedule of Intangible Assets Identified (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 07, 2021
Mueller Middle East
Business Acquisition [Line Items]
Intangible assets		$ 452
Customer relationships
Business Acquisition [Line Items]
Intangible assets, useful life	20 years
Customer relationships | Mueller Middle East
Business Acquisition [Line Items]
Intangible assets		$ 452

Segment Information - Narrative

Segment Information - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended	12 Months Ended
	Sep. 02, 2021	Jul. 28, 2021	Sep. 30, 2023	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Revenue from External Customer [Line Items]
Gain on sale of businesses				$ 4,137	$ 0	$ 57,760
Disposal Group Not Discontinued Operation Gain Loss On Disposal Statement Of Income Extensible List Not Disclosed Flag					Corporate and Eliminations
Impairment charges				6,258	$ 0	2,829
Industrial Metals | Operating Segments
Revenue from External Customer [Line Items]
Gain on sale of businesses				0		6,500
Impairment charges				0		0
Climate | Operating Segments
Revenue from External Customer [Line Items]
Gain on sale of businesses				0
Impairment charges				$ 0	$ 2,800	$ 2,829
Die-Mold | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Revenue from External Customer [Line Items]
Gain (loss) on disposal of businesses	$ 4,700
Fabricated Tube Products and Shoals Tubular, Inc. | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Revenue from External Customer [Line Items]
Gain (loss) on disposal of businesses		$ 46,600
Heatlink Group, Inc. | Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Exchange
Revenue from External Customer [Line Items]
Gain (loss) on disposal of businesses			$ 4,100

Segment Information - Summary o

Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales	$ 732,377	$ 819,792	$ 896,984	$ 971,192	$ 877,581	$ 944,830	$ 1,150,042	$ 1,010,002	$ 3,420,345	$ 3,982,455	$ 3,769,345
Cost of goods sold									2,433,511	2,864,862	2,938,989
Depreciation and amortization									39,954	43,731	45,390
Selling, general, and administrative expense									208,172	203,086	184,052
Gain on sale of assets, net									0	(6,373)	0
Gain on insurance settlement									19,466	0	0
Gain on sale of businesses									(4,137)	0	(57,760)
Impairment charges									6,258	0	2,829
Operating income									756,053	877,149	655,845
Interest expense									(1,221)	(810)	(7,709)
Interest income									38,208	6,457	353
Redemption premium									0	0	(5,674)
Pension plan termination expense									0	(13,100)	0
Realized and unrealized gains on short-term investments									41,865	2,918	0
Gain on extinguishment of NMTC liability									7,534	0	0
Environmental expense									(825)	(1,298)	(5,053)
Other income, net									3,618	4,715	3,377
Income before income taxes									845,232	876,031	641,139
Expenditures for long-lived assets									54,025	37,639	65,122
Segment assets	2,759,301				2,242,399				2,759,301	2,242,399	1,728,936
Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									3,461,238	4,025,080	3,798,807
Intersegment sales
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									(40,893)	(42,625)	(29,462)
Corporate and Eliminations
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									(40,893)	(42,625)	(29,462)
Cost of goods sold									(45,666)	(38,269)	(30,679)
Depreciation and amortization									4,653	4,717	4,698
Selling, general, and administrative expense									65,686	61,744	49,278
Gain on sale of assets, net										(6,373)	(51,306)
Gain on sale of businesses									(4,137)
Impairment charges									0		0
Operating income									(61,429)	(64,444)	(1,453)
Expenditures for long-lived assets									10,094	7,429	3,521
Segment assets	1,319,158				712,817				1,319,158	712,817	145,267
Corporate and Eliminations
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Gain on insurance settlement									0
Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									2,382,573	2,730,084	2,600,030
Cost of goods sold									1,686,792	1,943,174	1,996,610
Depreciation and amortization									20,461	22,193	23,384
Selling, general, and administrative expense									99,823	93,655	93,749
Gain on sale of assets, net										0	0
Gain on insurance settlement									0
Gain on sale of businesses									0
Impairment charges									6,258		0
Operating income									569,239	671,062	486,287
Expenditures for long-lived assets									19,118	20,694	43,429
Segment assets	1,029,821				1,088,940				1,029,821	1,088,940	1,160,272
Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									577,875	644,689	703,363
Cost of goods sold									480,510	543,004	605,715
Depreciation and amortization									7,273	7,647	6,929
Selling, general, and administrative expense									13,713	11,574	11,698
Gain on sale of assets, net										0	(6,454)
Gain on insurance settlement									0
Gain on sale of businesses									0		(6,500)
Impairment charges									0		0
Operating income									76,379	82,464	85,475
Expenditures for long-lived assets									9,406	6,905	5,744
Segment assets	157,761				160,702				157,761	160,702	173,290
Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									500,790	650,307	495,414
Cost of goods sold									311,875	416,953	367,343
Depreciation and amortization									7,567	9,174	10,379
Selling, general, and administrative expense									28,950	36,113	29,327
Gain on sale of assets, net										0	0
Gain on insurance settlement									19,466
Gain on sale of businesses									0
Impairment charges									0	2,800	2,829
Operating income									171,864	188,067	85,536
Expenditures for long-lived assets									15,407	2,611	12,428
Segment assets	$ 252,561				$ 279,940				252,561	279,940	250,107
Tube and fittings | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									1,926,975	2,211,963	2,055,639
Tube and fittings | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									1,926,975	2,211,963	2,055,639
Tube and fittings | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Tube and fittings | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Brass rod and forgings | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									454,246	510,865	565,870
Brass rod and forgings | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Brass rod and forgings | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									454,246	510,865	565,870
Brass rod and forgings | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
OEM components, tube & assemblies | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									200,802	195,651	218,693
OEM components, tube & assemblies | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	32,557
OEM components, tube & assemblies | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									79,879	74,647	48,572
OEM components, tube & assemblies | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									120,923	121,004	137,564
Valves and plumbing specialties | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									455,598	518,121	511,834
Valves and plumbing specialties | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									455,598	518,121	511,834
Valves and plumbing specialties | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Valves and plumbing specialties | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Flex duct and other HVAC components | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									379,867	529,303	357,850
Flex duct and other HVAC components | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Flex duct and other HVAC components | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Flex duct and other HVAC components | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									379,867	529,303	357,850
Other | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									43,750	59,177	88,921
Other | Piping Systems | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									0	0	0
Other | Industrial Metals | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									43,750	59,177	88,921
Other | Climate | Operating Segments
Segment Reporting Information, Income (Loss) before Income Taxes [Abstract]
Net sales									$ 0	$ 0	$ 0

Segment Information - Summary_2

Segment Information - Summary of Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 732,377	$ 819,792	$ 896,984	$ 971,192	$ 877,581	$ 944,830	$ 1,150,042	$ 1,010,002	$ 3,420,345	$ 3,982,455	$ 3,769,345
Long-lived assets:	385,165				379,950				385,165	379,950	385,562
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									2,572,141	2,965,053	2,791,571
Long-lived assets:	273,604				266,571				273,604	266,571	272,903
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									270,128	297,582	330,908
Long-lived assets:	40,045				36,474				40,045	36,474	36,529
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									339,682	410,679	469,652
Long-lived assets:	18,152				23,354				18,152	23,354	26,422
Asia and the Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									153,816	217,750	83,217
Long-lived assets:	50,725				51,193				50,725	51,193	48,742
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									84,578	91,391	93,997
Long-lived assets:	$ 2,639				$ 2,358				$ 2,639	$ 2,358	$ 966

Cash, Cash Equivalents, and R_3

Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021	Dec. 26, 2020
Cash and Cash Equivalents [Abstract]
Cash & cash equivalents	$ 1,170,893	$ 461,018
Restricted cash included within other current assets	3,228	4,176
Restricted cash included within other assets	102	102
Total cash, cash equivalents, and restricted cash	$ 1,174,223	$ 465,296	$ 90,376	$ 127,376

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 111,843	$ 133,189
Work-in-process	61,793	64,177
Finished goods	220,629	265,842
Valuation reserves	(14,017)	(14,289)
Inventories	$ 380,248	$ 448,919

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	Dec. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
LIFO inventory amount	$ 20.2	$ 16.5
FIFO cost of inventories	122.9	117.3
FIFO value of inventory consigned to others	$ 19.8	$ 14.3

Consolidated Financial Statem_3

Consolidated Financial Statement Details (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Other Current Liabilities [Abstract]
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities
Accrued discounts and allowances	$ 78,800	$ 82,300
Taxes payable, current	22,800	24,600
Environmental expense, non operating properties	3,900	4,200
Pension withdrawal liability, current		13,100
Other (Expense) Income, Net [Abstract]
Net periodic benefit income	765	3,168	$ 1,903
Accounts payable discounts	1,502	1,609	1,385
Other	1,351		89
Other		(62)
Other income, net	$ 3,618	$ 4,715	$ 3,377

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Restricted cash in other current assets as collateral related to open derivative contracts	$ 3.2	$ 4
Commodity Contract
Derivative [Line Items]
Deferred net gains (losses), net of tax, included in AOCI	$ 0.1
Cash Flow Hedging | Commodity Contract | Long
Derivative [Line Items]
Time period for open copper future contract	12 months
Fair value of future contracts with gain (loss) position	$ 0.1
Cash Flow Hedging | Commodity Contract | Long | Options Held
Derivative [Line Items]
Open future contracts to purchase copper	5.8
Fair Value Hedging | Commodity Contract | Short
Derivative [Line Items]
Fair value of future contracts with gain (loss) position	(0.2)
Open future contracts to sell copper	$ 61.3
Time period for open copper future contract sales	12 months

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Summary of Location and Fair Value (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Total derivative assets	$ 308	$ 2,263
Total derivative liabilities	367	0
Other current assets | Commodity contracts
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	589	3,746
Other current assets: Loss positions	(281)	(1,483)
Other current liabilities | Commodity contracts
Derivatives, Fair Value [Line Items]
Other current liability: Gain positions	16	0
Other current liability: Loss positions	$ (383)	$ 0

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities - Effects of Derivative Instruments on Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Commodity Contract | Not Designated as Hedging Instrument | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on commodity contracts (nonqualifying)	$ (1,071)	$ 20,659

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities - Amounts Recognized In and Reclassified From AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	$ (1,273)	$ 683	$ (181)
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	1,146	(6,983)
Gain Reclassified from AOCI (Effective Portion), Net of Tax	(2,419)	7,666
Commodity contracts | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	1,180	(7,066)
Commodity contracts | Cost of goods sold | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain Reclassified from AOCI (Effective Portion), Net of Tax	(2,419)	7,666
Other | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	(34)	83
Gain Reclassified from AOCI (Effective Portion), Net of Tax	$ 0	$ 0

Leases - Summary of Supplementa

Leases - Summary of Supplemental Operating Lease Information (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease right-of-use assets	$ 35,170	$ 22,892
Current portion of operating lease liabilities	7,893	4,942
Noncurrent operating lease liabilities	26,683	16,880
Total lease obligations	$ 34,576	$ 21,822
Weighted average discount rate (as a percent)	3.55%	3.35%
Weighted average remaining lease term (in years)	5 years 2 months 26 days	6 years 10 days

Leases - Schedule of Operating

Leases - Schedule of Operating Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease costs	$ 9,705	$ 8,220
Short term lease costs	3,843	4,086
Total lease costs	13,548	12,306
Cash paid for amounts included in the measurement of lease liabilities	$ 9,276	$ 7,787

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Operating Leases (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 8,909
2025	8,124
2026	7,110
2027	6,210
2028	3,222
2029 and thereafter	4,646
Total lease payments	38,221
Less imputed interest	(3,645)
Total lease obligations	34,576	$ 21,822
Less current obligations	(7,893)	(4,942)
Noncurrent lease obligations	$ 26,683	$ 16,880

Property, Plant, and Equipmen_3

Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,001,927	$ 975,932
Less accumulated depreciation	(616,762)	(595,982)
Property, plant, and equipment, net	385,165	379,950
Depreciation	34,949	38,157	$ 39,120
Land and land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	33,127	32,707
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	232,169	234,480
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	654,079	653,997
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 82,552	$ 54,748

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 25, 2021	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Goodwill [Roll Forward]
Goodwill			$ 222,822,000
Accumulated impairment charges, beginning of year			(51,492,000)
Goodwill, net, beginning balance		$ 157,588,000	171,330,000
Reductions		(7,007,000)	(11,216,000)
Currency translation		1,239,000	(2,526,000)
Goodwill		203,312,000		$ 222,822,000
Accumulated impairment charges, end of year		(51,492,000)		(51,492,000)
Goodwill, net, ending balance		151,820,000	157,588,000	171,330,000
Impairment charges, excluding Turbotec		0	0	0
Impairment charges	$ 2,100,000
Mueller Middle East
Goodwill [Roll Forward]
Decrease in goodwill			(11,200,000)
Piping Systems
Goodwill [Roll Forward]
Goodwill			192,316,000
Accumulated impairment charges, beginning of year			(40,552,000)
Goodwill, net, beginning balance		138,022,000	151,764,000
Reductions		(7,007,000)	(11,216,000)
Currency translation		1,239,000	(2,526,000)
Goodwill		172,806,000		192,316,000
Accumulated impairment charges, end of year		(40,552,000)		(40,552,000)
Goodwill, net, ending balance		132,254,000	138,022,000	151,764,000
Industrial Metals
Goodwill [Roll Forward]
Goodwill			8,854,000
Accumulated impairment charges, beginning of year			(8,853,000)
Goodwill, net, beginning balance		1,000	1,000
Reductions		0	0
Currency translation		0	0
Goodwill		8,854,000		8,854,000
Accumulated impairment charges, end of year		(8,853,000)		(8,853,000)
Goodwill, net, ending balance		1,000	1,000	1,000
Climate
Goodwill [Roll Forward]
Goodwill			21,652,000
Accumulated impairment charges, beginning of year			(2,087,000)
Goodwill, net, beginning balance		19,565,000	19,565,000
Reductions		0	0
Currency translation		0	0
Goodwill		21,652,000		21,652,000
Accumulated impairment charges, end of year		(2,087,000)		(2,087,000)
Goodwill, net, ending balance		$ 19,565,000	$ 19,565,000	$ 19,565,000

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Carrying amount of intangible assets [Abstract]
Expected amortization expense	$ 46,208
Amortization	5,000	$ 5,600	$ 6,300
Customer relationships
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	50,009	53,156
Accumulated Amortization	(17,535)	(15,658)
Expected amortization expense	32,474	37,498
Non-compete agreements
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	2,325	2,333
Accumulated Amortization	(2,325)	(2,333)
Expected amortization expense	0	0
Patents and technology
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	16,681	18,032
Accumulated Amortization	(8,119)	(7,570)
Expected amortization expense	8,562	10,462
Trade names and licenses
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	12,092	13,374
Accumulated Amortization	(6,920)	(6,697)
Expected amortization expense	5,172	6,677
Other
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	1,715	1,676
Accumulated Amortization	(1,715)	(1,528)
Expected amortization expense	0	148
Other intangible assets
Carrying amount of intangible assets [Abstract]
Gross Carrying Amount	82,822	88,571
Accumulated Amortization	(36,614)	(33,786)
Expected amortization expense	$ 46,208	$ 54,785

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Schedule of Future Amortization Expense (Details) $ in Thousands	Dec. 30, 2023 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2024	$ 4,623
2025	4,505
2026	4,357
2027	4,356
2028	4,117
Thereafter	24,250
Expected amortization expense	$ 46,208

Investment in Unconsolidated _2

Investment in Unconsolidated Affiliates - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Schedule of Equity Method Investments [Line Items]
Net gain (loss)	$ 119,296	$ 135,709	$ 179,551	$ 175,093	$ 140,235	$ 155,813	$ 207,524	$ 159,248	$ 609,649	$ 662,820	$ 475,124
Retail Distribution Business
Schedule of Equity Method Investments [Line Items]
Net gain (loss)									7,900	4,900	800
Tecumseh Products Holdings LLC
Schedule of Equity Method Investments [Line Items]
Net gain (loss)									$ (22,700)	$ 5,200	$ (1,700)
Tecumseh Products Holdings LLC
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50%								50%
Retail Distribution Business
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	28%								28%

Debt - Narrative (Details)

Debt - Narrative (Details)		12 Months Ended
	Apr. 15, 2021 USD ($)	Dec. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 25, 2021 USD ($)	Dec. 30, 2023 KRW (₩)
Debt Instrument [Line Items]
Redemption premium		$ 0	$ 0	$ 5,674,000
Interest paid		0	0	$ 13,900,000
Subordinated Debt
Debt Instrument [Line Items]
Repayments of debt	$ 291,400,000
Redemption premium	$ 5,700,000
Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity		400,000,000
Credit Agreement
Debt Instrument [Line Items]
Outstanding letters of credit		$ 28,700,000
Credit Agreement | Minimum
Debt Instrument [Line Items]
Credit facility commitment fee		0.15%
Credit Agreement | Maximum
Debt Instrument [Line Items]
Credit facility commitment fee		0.30%
Credit Agreement | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.125%
Credit Agreement | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.125%
Credit Agreement | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate		1.625%
Credit Agreement | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.125%
Credit Agreement | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		0.125%
Credit Agreement | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate		0.625%
Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding borrowings		$ 0	$ 0
Jungwoo-Mueller
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity		$ 15,300,000			₩ 20,000,000,000

New Markets Tax Credit Transa_2

New Markets Tax Credit Transactions (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 18, 2016	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Variable Interest Entity [Line Items]
Percentage of qualifying investments on tax credits	39%
Percentage of recapture to the tax credits	100%
Compliance period	7 years
Gain on extinguishment of NMTC liability		$ 7,534	$ 0	$ 0
Wells Fargo [Member]
Variable Interest Entity [Line Items]
Gain on extinguishment of NMTC liability		$ 7,500

Benefit Plans - Benefit Plan In

Benefit Plans - Benefit Plan Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Change in fair value of plan assets:
Beginning balance	$ 62,298
Ending balance	62,871	$ 62,298
Pension Benefits
Change in benefit obligation:
Obligation at beginning of year	50,761	84,283
Service cost	0	0
Interest cost	2,454	1,450	$ 1,272
Actuarial loss (gain)	1,508	(24,154)
Benefit payments	(3,582)	(2,512)
Plan amendments/transference	0	0
Foreign currency translation adjustment	3,294	(8,306)
Obligation at end of year	54,435	50,761	84,283
Change in fair value of plan assets:
Beginning balance	62,298	79,478
Actual return on plan assets	410	(6,371)
Employer contributions	0	0
Benefit payments	(3,582)	(2,512)
Foreign currency translation adjustment	3,745	(8,297)
Ending balance	62,871	62,298	79,478
Funded (underfunded) status at end of year	8,436	11,537
Other Benefits
Change in benefit obligation:
Obligation at beginning of year	9,240	11,825
Service cost	183	291	258
Interest cost	439	346	281
Actuarial loss (gain)	(105)	(2,604)
Benefit payments	(686)	(547)
Plan amendments/transference	101	0
Foreign currency translation adjustment	385	(71)
Obligation at end of year	9,557	9,240	11,825
Change in fair value of plan assets:
Beginning balance	0	0
Actual return on plan assets	0	0
Employer contributions	686	547
Benefit payments	(686)	(547)
Foreign currency translation adjustment	0	0
Ending balance	0	0	$ 0
Funded (underfunded) status at end of year	$ (9,557)	$ (9,240)

Benefit Plans - Amounts Recogni

Benefit Plans - Amounts Recognized in Accumulated OCI (Before the Effect of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized net actuarial loss (gain)	$ 7,728	$ 2,870
Unrecognized prior service credit	0	0
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized net actuarial loss (gain)	(3,863)	(4,149)
Unrecognized prior service credit	$ (5)	$ (19)

Benefit Plans - Narrative (Deta

Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial net loss	$ (200)
Payable maximum period to be considered current	12 months
Ultimate health care cost trend rate	4.10%
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual assumed rate of increase in the per capita cost of covered benefits	4.90%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual assumed rate of increase in the per capita cost of covered benefits	8.20%
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total plan assets (as a percent)	100%	100%
Expected long-term rate of return on plan assets	4.30%	5.51%
Pension Benefits | Equity securities (includes equity mutual funds)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total plan assets (as a percent)	0%	67%
Pension Benefits | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total plan assets (as a percent)	0%	10%
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment gain	$ 0	$ 1,756	$ 0

Benefit Plans - Total Funded St

Benefit Plans - Total Funded Status of the Plans Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Long-term asset	$ 8,436	$ 11,537
Current liability	0	0
Long-term liability	0	0
Total funded (underfunded) status	8,436	11,537
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Long-term asset	0	0
Current liability	(1,041)	(1,068)
Long-term liability	(8,516)	(8,172)
Total funded (underfunded) status	$ (9,557)	$ (9,240)

Benefit Plans - Components of N

Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Components of net periodic benefit cost (income) [Abstract]
Net periodic benefit income	$ (765)	$ (3,168)	$ (1,903)
Pension Benefits
Components of net periodic benefit cost (income) [Abstract]
Interest cost	2,454	1,450	1,272
Expected return on plan assets	(3,260)	(3,568)	(3,671)
Amortization of net loss (gain)	0	897	1,536
Settlement charge	0	0	0
Service cost	0	0
Net periodic benefit income	(806)	(1,221)	(863)
Other Benefits
Components of net periodic benefit cost (income) [Abstract]
Interest cost	439	346	281
Amortization of net loss (gain)	(449)	(220)	(103)
Service cost	183	291	258
Amortization of prior service credit	(2)	(198)	(470)
Curtailment gain	0	(1,756)	0
Net periodic benefit income	$ 171	$ (1,537)	$ (34)

Benefit Plans - Weighted Averag

Benefit Plans - Weighted Average Assumptions Used in the Measurement of the Company's Benefit Obligation and Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Pension Benefits
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate	4.40%	4.80%
Expected long-term return on plan assets	4.30%	5.51%
Rate of inflation	3.20%	3.30%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate	4.80%	1.90%	1.40%
Expected long-term return on plan assets	5.51%	4.96%	4.69%
Rate of inflation	3.30%	3.70%	3.20%
Other Benefits
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate	5.96%	6.08%
Rate of compensation increases	5%	5%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate	6.08%	3.73%	2.92%
Rate of compensation increases	5%	5%	5%

Benefit Plans - Pension Assets

Benefit Plans - Pension Assets by Percentage (Details) - Pension Benefits	Dec. 30, 2023	Dec. 31, 2022
Asset category
Total plan assets (as a percent)	100%	100%
Pooled liability investments
Asset category
Total plan assets (as a percent)	99%	0%
Equity securities (includes equity mutual funds)
Asset category
Total plan assets (as a percent)	0%	67%
Multi-asset securities
Asset category
Total plan assets (as a percent)	0%	22%
Cash and equivalents (includes money market funds)
Asset category
Total plan assets (as a percent)	1%	1%
Alternative investments
Asset category
Total plan assets (as a percent)	0%	10%

Benefit Plans - Pension Asset_2

Benefit Plans - Pension Assets by Fair Value Level (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 62,871	$ 62,298
Approximate percentage of mutual funds actively managed		78%
Approximate percentage of mutual funds indexed funds		22%
Percentage of mutual funds' assets invested in U.S equities		24%
Percent of mutual funds assets invested in non US equities		76%
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	502	$ 829
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	62,369	55,441
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	6,028
Cash and money market funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	502	829
Cash and money market funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	502	829
Cash and money market funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Cash and money market funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Pooled liability investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	62,369
Pooled liability investments | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0
Pooled liability investments | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	62,369
Pooled liability investments | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 0
Mutual funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		55,441
Mutual funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Mutual funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		55,441
Mutual funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Limited partnerships
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		6,028
Limited partnerships | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Limited partnerships | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Limited partnerships | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		$ 6,028

Benefit Plans - Assets of the P

Benefit Plans - Assets of the Plan Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) $ in Thousands	12 Months Ended
	Dec. 30, 2023 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 62,298
Ending balance	62,871
Pension Benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	62,298
Ending balance	62,871
Fair Value, Inputs, Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	6,028
Ending balance	0
Fair Value, Inputs, Level 3 | Pension Benefits | Limited Partner
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	6,028
Liquidation	(6,028)
Ending balance	$ 0

Benefit Plans - Contributions a

Benefit Plans - Contributions and Benefit Payments (Details) $ in Thousands	Dec. 30, 2023 USD ($)
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2024	$ 3,418
2025	3,540
2026	3,667
2027	3,798
2028	3,934
2028-2032	21,886
Total	40,243
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company's expected contribution to benefit plans in next fiscal year	1,000
2024	1,042
2025	1,045
2026	1,080
2027	877
2028	922
2028-2032	4,146
Total	$ 9,112

Benefit Plans - Contributions_2

Benefit Plans - Contributions and Benefit Payments, Multiemployer Plan, 401(k) Plans and UMWA Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
401 (k) Plan [Abstract]
Compensation expense for the Company's matching contribution	$ 4.9	$ 4.9	$ 4.5

Commitments and Contingencies (

Commitments and Contingencies (Details) $ / shares in Units, $ in Thousands

1 Months Ended

3 Months Ended

12 Months Ended

36 Months Ended

Mar. 31, 2022 potentially_responsible_party

Feb. 28, 2022 USD ($) smelter_site ft

Jan. 31, 2018 USD ($) unilateralAdministrativeOrder potentially_responsible_party

Nov. 27, 2015 USD ($)

Aug. 31, 2015 mining_site

Jul. 01, 2023 USD ($) $ / shares

Dec. 30, 2023 USD ($) property potentially_responsible_party smelter_site

Dec. 31, 2022 USD ($)

Dec. 25, 2021 USD ($)

Oct. 31, 2008 import_entry

Dec. 30, 2023 USD ($) potentially_responsible_party property smelter_site

Dec. 28, 2019 potentially_responsible_party

Nov. 08, 2016 USD ($)

Apr. 19, 2010

Loss Contingencies [Line Items]

Environmental expense

$ 700

$ 1,400

$ 5,000

Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]

Environmental reserves, Other current liabilities

Environmental reserves, Other current liabilities

Environmental reserves

$ 18,900

20,500

$ 18,900

Expected environmental expenditures for 2024

3,800

3,800

Expected environmental expenditures for 2025

800

800

Expected environmental expenditures for 2026

600

600

Expected environmental expenditures for 2027

700

700

Expected environmental expenditures for 2028

700

700

Expected environmental expenditures after 2028

12,300

12,300

Proceeds from Insurance Settlement, Gross

$ 29,500

Insurance deductible

250

Insured event, gain (loss), pretax

$ 19,500

Insured event, gain per diluted share, after tax (in USD per share) | $ / shares

$ 0.13

Proceeds from insurance settlement

24,500

$ 5,000

Insurance advances, net

$ 10,000

Letter of Credit

Loss Contingencies [Line Items]

Term of guarantees

1 year

Letter of Credit | Revolving Credit Facility

Loss Contingencies [Line Items]

Payments required to be made under guarantees, maximum

$ 28,700

$ 28,700

United States Department of Commerce Antidumping Review

Loss Contingencies [Line Items]

Assignment of antidumping duty rate on U.S. imports by Company subsidiaries (as a percent)

48.33%

Payment for interest and duties

$ 3,000

Number of import entries | import_entry

795

East La Harpe

Loss Contingencies [Line Items]

Number of parties involved in settlement negotiations | smelter_site

3

3

Southeast Kansas Sites

Loss Contingencies [Line Items]

Accrual for environmental loss contingencies, gross

$ 5,600

Geographic boundary of sites | ft

50

Southeast Kansas Sites | Non operating Properties

Loss Contingencies [Line Items]

Number of parties involved in settlement negotiations | smelter_site

3

Southeast Kansas Sites - East La Harpe | Non operating Properties

Loss Contingencies [Line Items]

Number of parties involved in settlement negotiations | potentially_responsible_party

2

2

2

Southeast Kansas Sites - Lanyon | Operating Properties

Loss Contingencies [Line Items]

Number of properties in remediation | property

1,371

1,371

Number of surrounding properties | property

300

Shasta Area Mine Sites

Loss Contingencies [Line Items]

Period of permit, implementation of Best Management Practices

10 years

Environmental remediation expense spending

$ 1,200

Estimated remediation costs, term

30 years

Shasta Area Mine Sites | Minimum

Loss Contingencies [Line Items]

Estimated remediation costs

$ 14,100

Shasta Area Mine Sites | Maximum

Loss Contingencies [Line Items]

Estimated remediation costs

$ 16,100

Lead Refinery Site

Loss Contingencies [Line Items]

Environmental expense

$ 600

Number of surrounding properties | property

300

Amount other PRPs will pay to fund cleanup

$ 26,000

Financial guarantee

$ 1,000

Lead Refinery Site | Minimum

Loss Contingencies [Line Items]

Estimated remediation costs

1,600

Lead Refinery Site | Maximum

Loss Contingencies [Line Items]

Estimated remediation costs

$ 2,200

Lead Refinery Site | Non operating Properties

Loss Contingencies [Line Items]

Number of parties involved in settlement negotiations | potentially_responsible_party

2

2

Estimated remediation costs, term

13 years

Lead Refinery NPL Site

Loss Contingencies [Line Items]

Environmental reserves

$ 4,500

Number of UAOs | unilateralAdministrativeOrder

2

Number of PRPs | potentially_responsible_party

4

4

Site contingency, total costs

$ 25,000

Site contingency, amount agreed upon to pay PRPs for past costs

2,000

Site contingency, additional reimbursement of past costs

$ 700

Contingency charge

$ 7,600

Reserve for settlement

$ 3,300

Bonita Peak Mining District

Loss Contingencies [Line Items]

Number of mining sites | mining_site

48

Mueller Copper Tube Products, Inc. | Operating Properties

Loss Contingencies [Line Items]

Estimated remediation costs, term

2 years

Mueller Copper Tube Products, Inc. | Operating Properties | Minimum

Loss Contingencies [Line Items]

Estimated remediation costs

$ 400

Income Taxes - Components of In

Income Taxes - Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Income Tax Disclosure [Abstract]
Domestic	$ 722,153	$ 737,538	$ 518,080
Foreign	123,079	138,493	123,059
Income before income taxes	$ 845,232	$ 876,031	$ 641,139

Income Taxes - Components of _2

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Current tax expense:
Federal	$ 144,111	$ 149,269	$ 107,804
Foreign	39,167	36,719	34,455
State and local	32,694	41,214	16,186
Current tax expense	215,972	227,202	158,445
Deferred tax expense (benefit):
Federal	4,806	(3,312)	(3,504)
Foreign	270	(192)	2,572
State and local	(286)	(376)	8,345
Deferred tax expense (benefit)	4,790	(3,880)	7,413
Income tax expense	$ 220,762	$ 223,322	$ 165,858

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Income Tax Disclosure [Abstract]
Expected income tax expense	$ 177,499	$ 183,967	$ 134,639
State and local income tax, net of federal benefit	25,542	32,184	21,132
Effect of foreign statutory rates different from U.S. and other foreign adjustments	14,519	7,443	11,185
Investment in unconsolidated affiliates	1,226	206	(679)
Other, net	1,976	(478)	(419)
Income tax expense	$ 220,762	$ 223,322	$ 165,858

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 30, 2023	Dec. 31, 2022
Deferred tax assets:
Inventories	$ 19,162	$ 16,829
Other postretirement benefits and accrued items	10,174	7,260
Other reserves	6,956	8,046
Foreign tax attributes	4,862	5,750
State tax attributes, net of federal benefit	6,728	8,063
Stock-based compensation	4,502	5,249
Lease liability	7,354	4,540
Basis difference in unconsolidated affiliates	11,509	6,881
Total deferred tax assets	71,247	62,618
Less valuation allowance	(23,078)	(21,505)
Deferred tax assets, net of valuation allowance	48,169	41,113
Deferred tax liabilities:
Property, plant, and equipment	42,980	44,001
Lease asset	7,776	4,970
Other liabilities	10,884	2,918
Total deferred tax liabilities	61,640	51,889
Net deferred tax liabilities	$ (13,471)	$ (10,776)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Income Tax Disclosure [Abstract]
State income tax credit carryforwards with expiration	$ 1.3
State net operating loss carryforwards with potential tax benefits	5.6
Federal and foreign tax attributes with unlimited life	3.8
Federal and foreign tax attributes with potential tax benefits	1
Income taxes paid	$ 219.6	$ 238.3	$ 132.9

Equity (Details)

Equity (Details)	Dec. 30, 2023 shares
Equity [Abstract]
Authorization to repurchase shares of common stock (in shares)	40,000,000
Shares repurchased (in shares)	15,000,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 23.1	$ 17.8	$ 9.8
Compensation for stock awards not yet recognized	$ 52.9
Compensation recognition period	2 years 9 months 18 days
2019 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	564
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	561
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	1,100
Weighted average grant-date fair value of options granted (in dollars per share)			$ 15.6
Total intrinsic value of options exercised	$ 6.5	5.9	$ 3.8
Total fair value of options, vested	1	$ 1.1	$ 0.4
Aggregate intrinsic value of all outstanding options	$ 20.3
Weighted average remaining contractual term of all outstanding options	3 years 6 months
Weighted average exercise price (in dollars per share)	$ 14.78
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	5 years
Stock options expiration period	10 years
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of awards granted (in dollars per share)	$ 36.88	$ 31.90	$ 22.04
Aggregate intrinsic value	$ 31.3
Fair value of options vested	$ 7.7	$ 4.9	$ 7
Performance Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of awards granted (in dollars per share)	$ 37.64
Aggregate intrinsic value	$ 89.7
Fair value of options vested	$ 7	$ 1.7
Weighted average grant-date fair value of options granted (in dollars per share)	$ 37.63	$ 32.74	$ 21.73

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Award Activity (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Stock Options
Shares
Beginning balance (in shares)	884
Granted (in shares)	0
Exercised/Released (in shares)	(258)
Forfeited (in shares)	0
Ending balance (in shares)	626	884
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 14.60
Exercised/Released (in dollars per share)	14.16
Ending balance (in dollars per share)	$ 14.78	$ 14.60
Shares
Added by Performance Factor (in share)	0
Restricted Stock Awards
Shares
Beginning balance (in shares)	982
Granted (in shares)	93
Added by Performance Factor (in share)	0
Exercised/Released (in shares)	(410)
Forfeited (in shares)	(1)
Ending balance (in shares)	664	982
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 18.29
Granted (in dollars per share)	36.88	$ 31.90	$ 22.04
Exercised/Released (in dollars per share)	18.89
Forfeited (in dollars per share)	33.80
Ending balance (in dollars per share)	$ 20.51	$ 18.29
Performance Stock Awards
Shares
Granted (in shares)		856	856
Shares
Beginning balance (in shares)	1,722
Granted (in shares)	535
Exercised/Released (in shares)	(455)
Forfeited (in shares)	0
Ending balance (in shares)	1,902	1,722
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 22.04
Granted (in dollars per share)	37.64
Exercised/Released (in dollars per share)	15.40
Ending balance (in dollars per share)	$ 27.63	$ 22.04
Award vesting percentage (as a percent)	200%
Performance Stock Awards | Maximum
Shares
Granted (in shares)	856
Weighted Average Grant Date Fair Value
Award vesting percentage (as a percent)	100%	200%	200%
Performance Stock Awards
Shares
Added by Performance Factor (in share)	100
Weighted Average Grant Date Fair Value
Added by Performance Factor (in dollars per share)	$ 14.81

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions in Determining Fair Value of Options Granted (Details) - Stock Options	12 Months Ended
	Dec. 25, 2021 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of stock options on grant date (in dollars per share)	$ 15.6
Expected term (in years)	7 years 10 months 24 days
Expected price volatility (as a percent)	33.60%
Risk-free interest rate (as a percent)	1.30%
Dividend yield (as a percent)	1.10%

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Changes in AOCI by Component, Net of Taxes and Noncontrolling Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	$ 1,813,964
Other comprehensive (loss) income before reclassifications	19,726	$ (17,549)
Amounts reclassified from AOCI	(2,772)	6,721
Balance at end of year	2,358,716	1,813,964
Total
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	(64,175)	(53,347)
Balance at end of year	(47,221)	(64,175)
Cumulative Translation Adjustment
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	(69,238)	(42,303)
Other comprehensive (loss) income before reclassifications	21,162	(26,935)
Amounts reclassified from AOCI	0	0
Balance at end of year	(48,076)	(69,238)
Unrealized Gain (Loss) on Derivatives
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	1,486	803
Other comprehensive (loss) income before reclassifications	1,146	(6,983)
Amounts reclassified from AOCI	(2,419)	7,666
Balance at end of year	213	1,486
Pension/ OPEB Liability Adjustment
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	1,222	(11,500)
Other comprehensive (loss) income before reclassifications	(3,499)	13,667
Amounts reclassified from AOCI	(353)	(945)
Balance at end of year	(2,630)	1,222
Attributable to Unconsol. Affiliates
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of year	2,355	(347)
Other comprehensive (loss) income before reclassifications	917	2,702
Amounts reclassified from AOCI	0	0
Balance at end of year	$ 3,272	$ 2,355

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Reclassification Adjustments out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Affected Line Item
Income tax expense (benefit)									$ 220,762	$ 223,322	$ 165,858
Net of tax and noncontrolling interests	$ (119,238)	$ (132,709)	$ (177,711)	$ (173,239)	$ (138,906)	$ (154,542)	$ (206,552)	$ (158,316)	(602,897)	(658,316)	(468,520)
Other income, net									(3,618)	(4,715)	(3,377)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Amount Reclassified from AOCI
Affected Line Item
Income tax expense (benefit)									690	(2,225)	1,306
Net of tax and noncontrolling interests									(2,419)	7,666	(2,542)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent | Amount Reclassified from AOCI
Affected Line Item
Income tax expense (benefit)									98	332	(159)
Net of tax and noncontrolling interests									(353)	(945)	804
Other income, net									(451)	(1,277)	963
Commodity contracts | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Amount Reclassified from AOCI
Affected Line Item
Cost of goods sold									$ (3,109)	$ 9,891	$ (3,848)

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Sep. 24, 2022	Jun. 25, 2022	Mar. 26, 2022	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 732,377	$ 819,792	$ 896,984	$ 971,192	$ 877,581	$ 944,830	$ 1,150,042	$ 1,010,002	$ 3,420,345	$ 3,982,455	$ 3,769,345
Gross profit	195,994	240,734	257,712	292,394	256,781	266,193	329,128	265,491
Consolidated net income	119,296	135,709	179,551	175,093	140,235	155,813	207,524	159,248	609,649	662,820	475,124
Net income attributable to Mueller Industries, Inc.	$ 119,238	$ 132,709	$ 177,711	$ 173,239	$ 138,906	$ 154,542	$ 206,552	$ 158,316	$ 602,897	$ 658,316	$ 468,520
Basic earnings per share (in dollars per share)	$ 1.07	$ 1.19	$ 1.60	$ 1.56	$ 1.25	$ 1.39	$ 1.85	$ 1.41	$ 5.41	$ 5.90	$ 4.18
Diluted earnings per share (in dollars per share)	1.05	1.17	1.56	1.54	1.23	1.37	1.83	1.39	5.30	5.82	4.12
Dividends per share (in dollars per share)	$ 0.15	$ 0.15	$ 0.15	$ 0.15	$ 0.125	$ 0.125	$ 0.125	$ 0.125	$ 0.60	$ 0.50	$ 0.26

Related Party Transactions (Det

Related Party Transactions (Details) - Non-Controlling Interest in South Korean Joint Venture - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Ownership of copper mill (as a percent)	100%
Related party purchases	$ 15.5	$ 22.2
Related party payables	$ 0.8

Schedule II - Valuation And Q_2

Schedule II - Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 2,687	$ 2,590	$ 1,538
Charged to costs and expenses	(84)	323	1,216
Other additions	227	0	0
Deductions	0	226	164
Balance at end of year	2,830	2,687	2,590
Environmental reserves
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	20,534	27,426	24,001
Charged to costs and expenses	652	1,367	4,964
Other additions	0	0	0
Deductions	2,246	8,259	1,539
Balance at end of year	18,940	20,534	27,426
Valuation allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	21,504	26,624	27,199
Charged to costs and expenses	4,939	(1,648)	108
Other additions	267	509	642
Deductions	3,632	3,981	1,325
Balance at end of year	$ 23,078	$ 21,504	$ 26,624