Amphenol (APH) 10-Q 3 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document and Entity Information
Entity Registrant Name	AMPHENOL CORP /DE/
Entity Central Index Key	820,313
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		301,435,822
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 1,000.2	$ 1,719.1
Short-term investments	24.1	34.6
Total cash, cash equivalents and short-term investments	1,024.3	1,753.7
Accounts receivable, less allowance for doubtful accounts of $23.9 and $23.0, respectively	1,515.8	1,598.6
Inventories	1,166.8	1,106.9
Other current assets	230.2	196.8
Total current assets	3,937.1	4,656
Property, plant and equipment, less accumulated depreciation of $1,257.4 and $1,200.1, respectively	839.3	816.8
Goodwill	4,146.5	4,042.6
Intangibles, net and other long-term assets	480.8	488.5
Total assets	9,403.7	10,003.9
Current Liabilities:
Accounts payable	798.2	875.6
Accrued salaries, wages and employee benefits	141.3	151.6
Accrued income taxes	166.3	154.2
Accrued dividends	57.4	58.1
Other accrued expenses	271.6	338.8
Current portion of long-term debt	749.9	1.1
Total current liabilities	2,184.7	1,579.4
Long-term debt, less current portion	2,489.4	3,541.5
Accrued pension and postretirement benefit obligations	190.5	272
Deferred income taxes	243.3	241.2
Other long-term liabilities	327.9	326.4
Equity:
Common stock	0.3	0.3
Additional paid-in capital	1,282.4	1,249
Retained earnings	2,770.9	2,941.5
Accumulated other comprehensive loss	(139.7)	(201)
Total shareholders' equity attributable to Amphenol Corporation	3,913.9	3,989.8
Noncontrolling interests	54	53.6
Total equity	3,967.9	4,043.4
Total liabilities and equity	$ 9,403.7	$ 10,003.9

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts	$ 23.9	$ 23
Accumulated depreciation	$ 1,257.4	$ 1,200.1

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Net sales	$ 1,866.9	$ 1,560.1
Cost of sales	1,260	1,044.2
Gross profit	606.9	515.9
Selling, general and administrative expenses	230	201.8
Operating income	376.9	314.1
Interest expense	(24.5)	(19.3)
Other income, net	2.3	3.6
Income before income taxes	354.7	298.4
Provision for income taxes	(86.4)	(71.1)
Net income	268.3	227.3
Less: Net income attributable to noncontrolling interests	(2.7)	(2.4)
Net income attributable to Amphenol Corporation	$ 265.6	$ 224.9
Net income per common share — Basic (in dollars per share)	$ 0.87	$ 0.73
Weighted average common shares outstanding — Basic (in shares)	303.7	306.6
Net income per common share — Diluted (in dollars per share)	$ 0.84	$ 0.71
Weighted average common shares outstanding — Diluted (in shares)	316	316.4
Dividends declared per share (in dollars per share)	$ 0.19	$ 0.16

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 268.3	$ 227.3
Total other comprehensive income, net of tax:
Foreign currency translation adjustments	58.7	62.9
Unrealized gain (loss) on cash flow hedges	(0.9)	0.1
Defined benefit plan adjustment, net of tax of ($1.6) and ($2.2), respectively	5	4.2
Total other comprehensive income, net of tax	62.8	67.2
Total comprehensive income	331.1	294.5
Less: Comprehensive income attributable to noncontrolling interests	(4.2)	(2.9)
Comprehensive income attributable to Amphenol Corporation	$ 326.9	$ 291.6

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Defined benefit plan adjustment, tax	$ (1.6)	$ (2.2)

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash from operating activities:
Net income	$ 268.3	$ 227.3
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	60.5	54.1
Stock-based compensation expense	12.7	12.1
Deferred income tax (benefit) provision	(0.2)	4.5
Net change in components of working capital	(133.3)	(66.8)
Net change in other long-term assets and liabilities	(77.8)	6.6
Net cash provided by operating activities	130.2	237.8
Cash from investing activities:
Capital expenditures	(54.9)	(48.7)
Proceeds from disposals of property, plant and equipment	0.8	0.3
Purchases of short-term investments	(6.8)	(18.2)
Sales and maturities of short-term investments	18.1	122.1
Acquisitions, net of cash acquired	(99.5)	(46.6)
Net cash (used in) provided by investing activities	(142.3)	8.9
Cash from financing activities:
(Repayments) borrowings under commercial paper program, net	(304.8)	225.3
Proceeds from exercise of stock options	20.6	23.7
Distributions to shareholders of noncontrolling interests	(3.9)	(4.2)
Purchase and retirement of treasury stock	(382)	(249.2)
Dividend payments	(58.1)	(49.3)
Net cash used in financing activities	(728.2)	(53.7)
Effect of exchange rate changes on cash and cash equivalents	21.4	15.3
Net change in cash and cash equivalents	(718.9)	208.3
Cash and cash equivalents balance, beginning of period	1,719.1	1,034.6
Cash and cash equivalents balance, end of period	1,000.2	1,242.9
Cash paid for:
Interest	41	32.4
Income taxes	$ 75.9	$ 77.4

Basis of Presentation and Princ

Basis of Presentation and Principles of Consolidation	3 Months Ended
	Mar. 31, 2018
Basis of Presentation and Principles of Consolidation
Basis of Presentation and Principles of Consolidation	AMPHENOL CORPORATION NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Unaudited) (dollars in millions, except per share data) Note 1—Basis of Presentation and Principles of Consolidation The condensed consolidated balance sheets as of March 31, 2018 and December 31, 2017, and the related condensed consolidated statements of income, condensed consolidated statements of comprehensive income, and condensed consolidated statements of cash flow for the three months ended March 31, 2018 and 2017 include the accounts of Amphenol Corporation and its subsidiaries ( “Amphenol”, the “Company”, “we”, “our”, or “us” ). All material intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated financial statements included herein are unaudited. In the opinion of management, all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation in conformity with accounting principles generally accepted in the United States of America have been included. The results of operations for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the full year. These condensed consolidated financial statements and the related notes should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 (the “2017 Annual Report”). Deferred income tax (benefit) provision has been presented as a separate line item within net cash provided by operating activities for the prior period in the Company’s Condensed Consolidated Statements of Cash Flow, in order to conform to the current period presentation, which had no impact on our consolidated results of operations, financial position or cash flows.

New Accounting Pronouncements

New Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements
New Accounting Pronouncements	Note 2—New Accounting Pronouncements Recently Adopted Accounting Standards Revenue Recognition In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”, and collectively with its related subsequent amendments, “Topic 606”). Topic 606 supersedes previous revenue recognition guidance and requires entities to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for such goods or services. The Company adopted Topic 606 as of January 1, 2018 using the modified retrospective transition method applied to those contracts which were not completed as of January 1, 2018. Under this transition method, the Company’s results in the Condensed Consolidated Statements of Income for the three months ended March 31, 2018 are presented under Topic 606, while the comparative results for the three months ended March 31, 2017 were not retrospectively adjusted as such results were recognized in accordance with the revenue recognition policy discussed under Summary of Significant Accounting Policies in Note 1 of the Company’s 2017 Annual Report. The vast majority of our sales continue to be recognized when products are shipped from our facilities or delivered to our customers, depending on the respective contractual terms. For a nominal portion of our contracts where the accounting did change, the adoption of Topic 606 resulted in an increase to the opening balance of retained earnings of approximately $3.2 as of January 1, 2018. This impact was primarily due to the acceleration of net sales and associated net income related to certain uncompleted contracts for the manufacture of goods with no alternative use and for which we have an enforceable right to payment, including a reasonable profit margin, from the customer for performance completed to date. For these such contracts, we now recognize revenue over time as control of the goods transfers, rather than when the goods are delivered, and title, risk and reward of ownership are passed to the customer, as under previous guidance. The adoption of Topic 606 did not have a material impact on our condensed consolidated financial statements as of the adoption date and as of and for the three months ended March 31, 2018. Refer to Note 3 herein for further discussion regarding revenue recognition and related policies. Other Recently Adopted Accounting Standards In March 2017, the FASB issued ASU 2017‑07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (“ASU 2017‑07”), requiring employers to provide more details about the components of costs related to retirement benefits. Specifically, ASU 2017‑07 requires employers to report the service costs for providing pensions to employees in the same line item as other employee compensation costs, while requiring other pension-related costs, such as interest costs, amortization of pension-related costs from prior periods, and the gains or losses on plan assets, to be reported separately and outside of the subtotal of operating income. ASU 2017‑07 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company adopted ASU 2017‑07 in the first quarter of 2018, which did not have a material impact on our consolidated financial statements. In May 2017, the FASB issued ASU 2017‑09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017‑09”), which provides guidance to determine which changes to the terms or conditions of share-based payment awards require an entity to apply modification accounting in Topic 718. ASU 2017‑09 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted, and requires prospective application to changes in terms or conditions of awards occurring on or after the adoption date. The Company adopted ASU 2017‑09 in the first quarter of 2018, which did not have any impact on our consolidated financial statements. In March 2018, the FASB issued ASU 2018‑05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 (“ASU 2018-05”) , which addresses the application of U.S. GAAP when preparing the initial accounting for the income tax effects of a change in tax laws or rates. SEC Staff Accounting Bulletin No. 118 (“SAB 118”) was issued in December 2017 to provide immediate accounting guidance resulting from the enactment of the Tax Cuts and Jobs Act (“Tax Act”) on December 22, 2017. ASU 2018-05 codifies the guidance of SAB 118 within FASB ASC Topic 740, Income Taxes (“ASC 740”), including guidance allowing for the recognition of provisional amounts in situations where the related accounting is not complete and reasonable estimates can be made at the time that financial statements are issued covering the reporting period that includes the enactment date of the Tax Act, as well as allowing for a measurement period of up to one year from the enactment date to finalize the accounting related to the Tax Act. Previously, ASC 740 did not directly address incomplete accounting for the effects of a change in tax laws or rates. The Company followed the guidance under SAB 118 in the fourth quarter of 2017 when we estimated and recorded a provisional income tax charge (“Tax Act Charge”) associated with the Tax Act. Refer to Note 14 herein for further details regarding the Tax Act. Accounting Standards Issued But Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016‑02”), which amends, among other things, the existing guidance by requiring lessees to recognize lease assets (right-to-use) and liabilities (for reasonably certain lease payments) arising from operating leases on the balance sheet. For leases with a term of twelve months or less, ASU 2016‑02 permits an entity to make an accounting policy election to recognize such leases as lease expense, generally on a straight-line basis over the lease term. ASU 2016‑02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. Entities are required to adopt ASU 2016-02 using a modified retrospective approach, which requires prior periods to be presented under this new standard with various practical expedients allowed. The Company has begun evaluating ASU 2016‑02, including the review of the necessary changes to our existing processes and controls and the implementation of a new system that will facilitate the adoption of this new standard, in order to determine its impact on our consolidated financial statements and related disclosures. In February 2018, the FASB issued ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (“ASU 2018-02”), which amends the standard on comprehensive income by providing an option for an entity to reclassify stranded tax effects of the Tax Act from accumulated other comprehensive income directly to retained earnings. The stranded tax effects result from the remeasurement of net deferred tax positions that were originally recorded in comprehensive income but whose remeasurement was reflected in the income statement in 2017. ASU 2018-02 only applies to the effects of the Tax Act and is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. ASU 2018-02 may be applied either in the period of adoption or on a retrospective basis to any period in which the impacts of the Tax Act are recognized. The Company is currently evaluating ASU 2018-02, and we currently anticipate that ASU 2018-02 will not have a material impact on our consolidated financial statements.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2018
Revenue Recognition
Revenue Recognition	Note 3—Revenue Recognition Prior to the adoption of Topic 606, the Company’s revenue recognition policy was in accordance with ASC Topic 605, Revenue Recognition . Effective January 1, 2018, the Company adopted Topic 606 using the modified retrospective transition method, resulting in accounting policy changes surrounding revenue recognition which replace certain related policies discussed under Critical Accounting Policies and Estimates (in Item 7) and Summary of Significant Accounting Policies (in Note 1) of the Company’s 2017 Annual Report. The adoption of Topic 606 did not have a material impact on the Company’s condensed consolidated financial statements. The following is a summary of the Company’s revenue recognition and related accounting policies and disclosures resulting from the adoption of Topic 606. Our revenues consist of product sales to either end customers and their appointed contract manufacturers (including original equipment manufacturers or OEM) or to distributors, and the vast majority of our sales are recognized at a point-in-time under the core principle of recognizing revenue when control transfers to the customer. Our revenues are derived from contracts with customers, which in most cases are customer purchase orders that may be governed by master sales agreements. For each contract, the promise to transfer the control of the products, each of which is individually distinct, is considered to be the identified performance obligation. As part of the consideration promised in each contract, the Company evaluates the customer’s credit risk. Our contracts do not have any significant financing components, as payment terms are generally due net 30 to 120 days after delivery. Although products are almost always sold at fixed prices, in determining the transaction price, we evaluate whether the price is subject to refund (due to returns) or adjustment (due to volume discounts, rebates, or price concessions) to determine the net consideration we expect to be entitled to. We allocate the transaction price to each distinct product based on its relative standalone selling price. Taxes assessed by governmental authorities and collected from the customer are not included in the transaction price. With limited exceptions, the Company recognizes revenue at the point in time when we ship or deliver the product from our manufacturing facility to our customers, when our customer accepts and has legal title of the goods, and the Company has a present right to payment for such goods. Based on the respective contract terms, most of our contracts’ revenues are recognized either (i) upon shipment based on free on board (“FOB”) shipping point, (ii) when the product arrives at its destination or (iii) when the products are pulled from consignment inventory. Less than 5% of our net sales are recognized over time, as the associated contracts relate to the sale of goods with no alternative use as they are only sold to a single customer and whose underlying contract terms provide the Company with an enforceable right to payment, including a reasonable profit margin, for performance completed to date, in the event of customer termination. For the contracts recognized over time, we typically record revenue using the input method, based on the materials and labor costs incurred to date relative to the contract’s total estimated costs. This method reasonably depicts when and as control of the goods transfers to the customer, since it measures our progress in producing the goods which is generally commensurate with this transfer of control. Since we typically invoice our customers at the same time that we satisfy our performance obligations, we do not have significant contract assets or contract liabilities related to our contracts with customers recorded in the Condensed Consolidated Balance Sheets. The Company receives customer orders negotiated with multiple delivery dates that may extend across more than one reporting period until the contract is fulfilled, the end of the order period is reached, or a pre-determined maximum order value has been reached. Orders typically fluctuate from quarter to quarter based on customer demand and general business conditions, and it is generally expected that a substantial portion of our remaining performance obligations will be fulfilled within three months. Nearly all of our performance obligations are fulfilled within one year. Since our performance obligations are part of contracts that generally have original durations of one year or less, we have elected not to disclose the aggregate amount of transaction prices associated with unsatisfied or partially unsatisfied performance obligations as of March 31, 2018. Sales to Distributors and Resellers Sales to certain distributors and resellers are made under terms allowing certain price adjustments and limited rights of return of the Company’s products held in their inventory or upon sale to their end customers. The Company maintains a reserve for unprocessed and estimated future price adjustment claims and returns as a refund liability. The reserve is recorded as a reduction to revenue in the same period that the related revenue is recorded and is calculated based on an analysis of historical claims and returns over a period of time to appropriately account for current pricing and business trends. Similarly, sales returns and allowances are recorded based on historical return rates, as a reduction to revenue with a corresponding reduction to cost of sales for the estimated cost of inventory that is expected to be returned. These reserves were not significant upon the adoption of Topic 606 nor were they significant in the Condensed Consolidated Balance Sheet as of March 31, 2018. Warranty Standard product warranty coverage which provides assurance that our products will conform to the contractually agreed-upon specifications for a limited period from the date of shipment is typically offered, while extended or separately-priced warranty coverage is typically not offered. The warranty claim is generally limited to a credit equal to the purchase price or a promise to repair or replace the product for a specified period of time at no additional charge. We estimate our warranty liability based on historical experience, product history, and current trends, and record warranty expense in cost of sales in the Condensed Consolidated Statements of Income. Warranty liabilities and related warranty expense have not been and were not significant in the accompanying Condensed Consolidated Financial Statements as of and for the three months ended March 31, 2018. Shipping and Handling Costs The Company accounts for shipping and handling activities related to contracts with customers as a cost to fulfill our promise to transfer control of the related product, including any such costs incurred after the customer has obtained control of the goods. Shipping and handling costs are generally charged to and paid by the majority of our customers as part of the contract. For a nominal portion of our customer contracts, primarily for certain customers in the broadband communications market (a market primarily in the Cable Products and Solutions segment), such costs are not separately charged to the customers. Shipping and handling costs are included in Cost of sales in the accompanying Condensed Consolidated Statements of Income. Contract Assets and Contract Liabilities The Company records contract assets or contract liabilities depending on the timing of revenue recognition, billings and cash collections on a contract-by-contract basis. Contract assets represent unbilled receivables, which generally arise when revenue recognized over time exceed amounts billed to customers. Contract liabilities represent billings or advanced consideration received from customers in excess of revenue recognized to date. As the Company’s performance obligations are typically less than one year, these amounts are generally recorded as current in the accompanying Condensed Consolidated Balance Sheets within Other current assets or Other accrued expenses as of March 31, 2018. Contract assets and contract liabilities recorded in the Company’s Condensed Consolidated Balance Sheets were not significant both at the date of adoption and as of March 31, 2018. Contract Costs The Company’s policy is to capitalize any incremental costs incurred to obtain a customer contract, only to the extent that such costs are explicitly chargeable to the customer and the benefit associated with the costs is expected to be longer than one year. Otherwise, such costs are expensed as incurred and recorded within Selling, general and administrative expenses in the accompanying Condensed Consolidated Statements of Income. Incremental costs to fulfill customer orders, which are mostly comprised of pre-production and set-up costs, are generally capitalized to the extent such costs are contractually guaranteed to be reimbursed by the customer. Otherwise, such costs are expensed as incurred. Capitalized contract costs to obtain a contract or to fulfill a contract that are not accounted for under other existing accounting standards are recorded as either other current or long-term assets on the accompanying Condensed Consolidated Balance Sheets, depending on the timing of when the Company expects to recognize the expense, and are generally amortized consistent with the timing of when transfer of control of the related goods occurs. Such capitalized contract costs were not significant both at the date of adoption and as of March 31, 2018, and the related amortization expense was not significant for the three months ended March 31, 2018. Disaggregation of Net Sales The following table shows our net sales disaggregated into categories the Company considers meaningful to depict how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors: Three months ended March 31, 2018 Interconnect Cable Products and Products and Total Reportable Assemblies Solutions Business Segments Net sales by: Sales channel: End customers and contract manufacturers $ 1,515.6 $ 70.0 $ 1,585.6 Distributors and resellers 254.4 26.9 281.3 $ 1,770.0 $ 96.9 $ 1,866.9 Geography: United States $ 479.2 $ 47.8 $ 527.0 China 527.2 0.8 528.0 Other international locations 763.6 48.3 811.9 $ 1,770.0 $ 96.9 $ 1,866.9 Net sales by geographic area are based on the customer location to which the product is shipped.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventories
Inventories	Note 4—Inventories Inventories consist of: March 31, December 31, 2018 2017 Raw materials and supplies $ 432.2 $ 386.2 Work in process 381.6 358.0 Finished goods 353.0 362.7 $ 1,166.8 $ 1,106.9

Reportable Business Segments

Reportable Business Segments	3 Months Ended
	Mar. 31, 2018
Reportable Business Segments
Reportable Business Segments	Note 5—Reportable Business Segments The Company has two reportable business segments: (i) Interconnect Products and Assemblies and (ii) Cable Products and Solutions. The Company organizes its reportable business segments based upon similar economic characteristics and business groupings of products, services and customers. These reportable business segments are determined based upon how the Company reviews its businesses, assesses operating performance and makes investing and resource allocation decisions. The Interconnect Product and Assemblies segment primarily designs, manufactures and markets a broad range of connector and connector systems, value-add products and other products, including antennas and sensors, used in a broad range of applications in a diverse set of end markets. The Cable Products and Solutions segment primarily designs, manufactures and markets cable, value-add products and components for use primarily in the broadband communications and information technology markets as well as certain applications in other markets. The accounting policies of the segments are the same as those for the Company as a whole and are described in Note 1 of the notes to the consolidated financial statements in the Company’s 2017 Annual Report. The Company evaluates the performance of business units on, among other things, profit or loss from operations before interest, headquarters’ expense allocations, stock-based compensation expense, income taxes, amortization related to certain intangible assets and nonrecurring gains and losses. The segment results for the three months ended March 31, 2018 and 2017 are as follows: Interconnect Products Cable Products Total Reportable and Assemblies and Solutions Business Segments Three Months Ended March 31: 2018 2017 2018 2017 2018 2017 Net sales: External $ 1,770.0 $ 1,463.5 $ 96.9 $ 96.6 $ 1,866.9 $ 1,560.1 Intersegment 2.6 2.3 8.9 10.2 11.5 12.5 Segment operating income 391.1 323.9 11.3 13.7 402.4 337.6 A reconciliation of segment operating income to consolidated income before income taxes for the three months ended March 31, 2018 and 2017 is summarized as follows: Three Months Ended March 31, 2018 2017 Segment operating income $ 402.4 $ 337.6 Interest expense (24.5) (19.3) Other income, net 2.3 3.6 Stock-based compensation expense (12.7) (12.1) Other operating expenses (12.8) (11.4) Income before income taxes $ 354.7 $ 298.4

Shareholders' Equity and Noncon

Shareholders' Equity and Noncontrolling Interests	3 Months Ended
	Mar. 31, 2018
Shareholders' Equity and Noncontrolling Interests
Shareholders' Equity and Noncontrolling Interests	Note 6—Shareholders’ Equity and Noncontrolling Interests Net income attributable to noncontrolling interests is classified below net income. Earnings per share is determined after the impact of the noncontrolling interests’ share in net income of the Company. In addition, the equity attributable to noncontrolling interests is presented as a separate caption within equity. A rollforward of consolidated changes in equity for the three months ended March 31, 2018 is as follows: Amphenol Corporation Shareholders Accumulated Common Stock Other Shares Additional Retained Comprehensive Treasury Noncontrolling Total (in millions) Amount Paid-In Capital Earnings Loss Stock Interests Equity Balance as of December 31, 2017 305.7 $ 0.3 $ 1,249.0 $ 2,941.5 $ (201.0) $ — $ 53.6 $ 4,043.4 Cumulative effect of adoption of revenue recognition standard (Note 2) 3.2 3.2 Net income 265.6 2.7 268.3 Other comprehensive income 61.3 1.5 62.8 Acquisitions resulting in noncontrolling interest 0.1 0.1 Distributions to shareholders of noncontrolling interests (3.9) (3.9) Purchase of treasury stock (382.0) (382.0) Retirement of treasury stock (4.2) (382.0) 382.0 — Stock options exercised 0.6 20.7 20.7 Dividends declared (57.4) (57.4) Stock-based compensation expense 12.7 12.7 Balance as of March 31, 2018 302.1 $ 0.3 $ 1,282.4 $ 2,770.9 $ (139.7) $ — $ 54.0 $ 3,967.9 A rollforward of consolidated changes in equity for the three months ended March 31, 2017 is as follows: Amphenol Corporation Shareholders Accumulated Common Stock Other Shares Additional Retained Comprehensive Treasury Noncontrolling Total (in millions) Amount Paid-In Capital Earnings Loss Stock Interests Equity Balance as of December 31, 2016 308.3 $ 0.3 $ 1,020.9 $ 3,122.7 $ (469.0) $ — $ 48.2 $ 3,723.1 Net income 224.9 2.4 227.3 Other comprehensive income 66.7 0.5 67.2 Distributions to shareholders of noncontrolling interests (4.2) (4.2) Purchase of treasury stock (249.2) (249.2) Retirement of treasury stock (3.7) (249.2) 249.2 — Stock options exercised 0.8 23.7 23.7 Dividends declared (48.9) (48.9) Stock-based compensation expense 12.1 12.1 Balance as of March 31, 2017 305.4 $ 0.3 $ 1,056.7 $ 3,049.5 $ (402.3) $ — $ 46.9 $ 3,751.1 On January 24, 2017, the Company’s Board of Directors authorized a stock repurchase program under which the Company could purchase up to $1,000.0 of the Company’s Common Stock during the two-year period ending January 24, 2019 in accordance with the requirements of Rule 10b-18 of the Exchange Act (the “2017 Stock Repurchase Program”). During the three months ended March 31, 2018, the Company repurchased 4.2 million shares of its common stock for $382.0. These treasury shares have been retired by the Company and common stock and retained earnings were reduced accordingly. As of March 31, 2018, the Company had repurchased approximately 12.6 million shares for $1,000.0 under the previously announced $1,000.0 2017 Stock Repurchase Program, thus completing the 2017 Stock Repurchase Program . On April 24, 2018, the Company’s Board of Directors authorized a new stock repurchase program under which the Company may purchase up to $2,000.0 of the Company’s Common Stock during the three-year period ending April 24, 2021 in accordance with the requirements of Rule 10b-18 of the Exchange Act (the “2018 Stock Repurchase Program”). As of April 30, 2018, the Company repurchased approximately 0.7 million shares of its common stock for $55.5 under the 2018 Stock Repurchase Program. The price and timing of any future purchases under the 2018 Stock Repurchase Program will depend on factors such as levels of cash generation from operations, the volume of stock option exercises by employees, cash requirements for acquisitions, dividends, economic and market conditions and stock price. Contingent upon declaration by the Board of Directors, the Company generally pays a quarterly dividend on shares of its Common Stock. The following table summarizes the declared quarterly dividends per share as well as the dividends declared and paid for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 2017 Dividends declared per share $ 0.19 $ 0.16 Dividends declared $ 57.4 $ 48.9 Dividends paid (including those declared in the prior year) 58.1 49.3 On April 24, 2018, the Company’s Board of Directors approved an increase to its quarterly dividend rate from $0.19 to $0.23 per share effective with dividends declared in the second quarter of 2018.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share
Earnings Per Share	Note 7—Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing net income attributable to Amphenol Corporation by the weighted average number of common shares outstanding. Diluted EPS is computed by dividing net income attributable to Amphenol Corporation by the weighted average number of common shares and dilutive common shares outstanding, which relates to stock options. A reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three months ended March 31, 2018 and 2017 is as follows: Three Months Ended March 31, (dollars and shares in millions, except per share data) 2018 2017 Net income attributable to Amphenol Corporation shareholders $ 265.6 $ 224.9 Basic weighted average common shares outstanding 303.7 Effect of dilutive stock options 12.3 Diluted weighted average common shares outstanding 316.0 Earnings per share attributable to Amphenol Corporation shareholders: Basic $ 0.87 $ 0.73 Diluted $ 0.84 $ 0.71 There were no anti-dilutive common shares excluded from the computations above for both the three months ended March 31, 2018 and 2017.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies
Commitments and Contingencies	Note 8—Commitments and Contingencies The Company has been named as a defendant in several legal actions arising from normal business activities. The Company records a loss contingency liability when a loss is considered probable and the amount can be reasonably estimated. Although the potential liability with respect to certain of such legal actions cannot be reasonably estimated, none of such matters is expected to have a material adverse effect on the Company’s financial condition, results of operations or cash flows. The Company’s legal costs associated with defending itself are recorded to expense as incurred. Certain operations of the Company are subject to environmental laws and regulations which govern the discharge of pollutants into the air and water, as well as the handling and disposal of solid and hazardous wastes. The Company believes that its operations are currently in substantial compliance with applicable environmental laws and regulations and that the costs of continuing compliance will not have a material adverse effect on the Company’s financial condition, results of operations or cash flows.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Stock-Based Compensation
Stock-Based Compensation	Note 9—Stock-Based Compensation For the three months ended March 31, 2018 and 2017, the Company’s income before income taxes was reduced for stock-based compensation expense of $12.7 and $12.1, respectively. In addition, for the three months ended March 31, 2018 and 2017, the Company recognized aggregate income tax benefits associated with stock-based compensation of $5.9 and $11.0, respectively, in the provision for income taxes in the accompanying Condensed Consolidated Statements of Income, which include the excess tax benefits from option exercises of $4.1 (or $0.01 per share) and $8.0 (or $0.02 per share), respectively. T he impact associated with recognizing excess tax benefits from option exercises in the provision for income taxes on our consolidated financial statements could result in significant fluctuations in our effective tax rate in the future, since the provision for income taxes will be impacted by the timing and intrinsic value of future stock-based compensation award exercises. Stock-based compensation expense includes the estimated effects of forfeitures, which are adjusted over the requisite service period to the extent actual forfeitures differ or are expected to differ from such estimates. Changes in estimated forfeitures are recognized in the period of change and impact the amount of expense to be recognized in future periods. The expense incurred for stock-based compensation plans is included in Selling, general and administrative expenses in the accompanying Condensed Consolidated Statements of Income. Stock Options In May 2017, the Company adopted the 2017 Stock Purchase and Option Plan for Key Employees of Amphenol and Subsidiaries (the “2017 Employee Option Plan”). The Company also continues to maintain the 2009 Stock Purchase and Option Plan for Key Employees of Amphenol and Subsidiaries, as amended (the “2009 Employee Option Plan”) and the 2000 Stock Purchase and Option Plan for Key Employees of Amphenol and Subsidiaries, as amended (the “2000 Employee Option Plan”). No additional stock options will be granted under the 2009 Employee Option Plan. The 2000 Employee Option Plan expired in May 2011, except that its terms continue with respect to outstanding options granted thereunder. A committee of the Company’s Board of Directors has been authorized to grant stock options pursuant to the 2017 Employee Option Plan. The number of shares of the Company’s Class A Common Stock (“Common Stock”) reserved for issuance under the 2017 Employee Option Plan is 30,000,000 shares. As of March 31, 2018, there were 23,016,700 shares of Common Stock available for the granting of additional stock options under the 2017 Employee Option Plan. Options granted under the 2017 Employee Option Plan and the 2009 Employee Option Plan generally vest ratably over a period of five years from the date of grant and are generally exercisable over a period of ten years from the date of grant. Options granted under the 2000 Employee Option Plan are fully vested and are generally exercisable over a period of ten years from the date of grant. In 2004, the Company adopted the 2004 Stock Option Plan for Directors of Amphenol Corporation (the “2004 Directors Option Plan”). The 2004 Directors Option Plan is administered by the Company’s Board of Directors. The 2004 Directors Option Plan expired in May 2014, except that its terms continue with respect to outstanding options granted thereunder. Options were last granted under the 2004 Directors Option Plan in May 2011. Options granted under the 2004 Directors Option Plan are fully vested and are generally exercisable over a period of ten years from the date of grant. Stock option activity for the three months ended March 31, 2018 was as follows: Weighted Average Aggregate Weighted Remaining Intrinsic Average Contractual Value Options Exercise Price Term (in years) (in millions) Options outstanding at January 1, 2018 33,222,364 $ 52.27 7.05 $ 1,180.3 Options granted — Options exercised (602,549) Options forfeited (32,240) Options outstanding at March 31, 2018 32,587,575 $ 52.58 6.84 $ 1,093.2 Vested and non-vested options expected to vest at March 31, 2018 30,726,902 $ 51.92 6.76 $ 1,051.0 Exercisable options at March 31, 2018 13,086,775 $ 39.76 5.20 $ 606.8 A summary of the status of the Company’s non-vested options as of March 31, 2018 and changes during the three months then ended is as follows: Weighted Average Fair Value at Options Grant Date Non-vested options at January 1, 2018 19,600,440 $ 8.29 Options granted — — Options vested (67,400) 8.13 Options forfeited (32,240) 8.56 Non-vested options at March 31, 2018 19,500,800 $ 8.29 During the three months ended March 31, 2018 and 2017, the following activity occurred under the Company’s option plans: Three Months Ended March 31, 2018 2017 Total intrinsic value of stock options exercised $ 34.3 $ 34.5 Total fair value of stock options vested 0.5 0.7 As of March 31, 2018, the total compensation cost related to non-vested options not yet recognized was approximately $108.5 with a weighted average expected amortization period of 3.14 years. The grant-date fair value of each option grant under the 2000 Employee Option Plan, the 2009 Employee Option Plan, the 2017 Employee Option Plan and the 2004 Directors Option Plan is estimated using the Black-Scholes option pricing model. The grant-date fair value of each share grant is determined based on the closing share price of the Company’s Common Stock on the date of the grant. The fair value is then amortized on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. Use of a valuation model for option grants requires management to make certain assumptions with respect to selected model inputs. Expected share price volatility is calculated based on the historical volatility of the Common Stock and implied volatility derived from related exchange traded options. The average expected life is based on the contractual term of the option and expected exercise and historical post-vesting termination experience. The risk-free interest rate is based on U.S. Treasury zero-coupon issuances with a remaining term equal to the expected life assumed at the date of grant. The expected annual dividend per share is based on the Company’s dividend rate. Restricted Shares In 2012, the Company adopted the 2012 Restricted Stock Plan for Directors of Amphenol Corporation (the “2012 Directors Restricted Stock Plan”). The 2012 Directors Restricted Stock Plan is administered by the Company’s Board of Directors. As of March 31, 2018, the number of restricted shares available for grant under the 2012 Directors Restricted Stock Plan was 124,164. Restricted shares granted under the 2012 Directors Restricted Stock Plan generally vest on the first anniversary of the grant date. Grants under the 2012 Directors Restricted Stock Plan entitle the holder to receive shares of the Company’s Common Stock without payment. Restricted share activity for the three months ended March 31, 2018 was as follows: Weighted Average Remaining Restricted Fair Value at Amortization Shares Grant Date Term (in years) Restricted shares outstanding at January 1, 2018 12,905 $ 73.25 0.37 Restricted shares granted — — Restricted shares outstanding at March 31, 2018 12,905 $ 73.25 0.13 As of March 31, 2018, the total compensation cost related to non-vested restricted shares not yet recognized was approximately $0.1 with a weighted average expected amortization period of 0.13 years.

Benefit Plans and Other Postret

Benefit Plans and Other Postretirement Benefits	3 Months Ended
	Mar. 31, 2018
Benefit Plans and Other Postretirement Benefits
Benefit Plans and Other Postretirement Benefits	Note 10—Benefit Plans and Other Postretirement Benefits The Company and certain of its domestic subsidiaries have defined benefit pension plans (the “U.S. Plans”), which cover certain U.S. employees and which represent the majority of the plan assets and benefit obligations of the aggregate defined benefit plans of the Company. The U.S. Plans’ benefits are generally based on years of service and compensation and are generally noncontributory. Certain U.S. employees not covered by the U.S. Plans are covered by defined contribution plans. Certain foreign subsidiaries have defined benefit plans covering their employees (the “International Plans” and, together with the U.S. Plans, the “Plans”). The following is a summary, based on the most recent actuarial valuations of the Company’s net cost for pension benefits, of the Plans and other postretirement benefits for the three months ended March 31, 2018 and 2017: Other Postretirement Pension Benefits Benefits Three Months Ended March 31: 2018 2017 2018 2017 Service cost $ 1.9 $ 2.4 $ — $ — Interest cost 4.9 5.0 0.1 0.1 Expected return on plan assets (9.7) (7.7) — — Amortization of prior service cost 0.6 0.7 — — Amortization of net actuarial losses 5.9 5.7 0.1 0.2 Net pension expense $ 3.6 $ 6.1 $ 0.2 $ 0.3 As a result of the adoption of ASU 2017‑07, the Company records service costs in the same line item as the respective employee compensation costs and within operating income, while all other pension-related costs including interest cost, expected return on plan assets, amortization of prior service cost and amortization of net actuarial losses are reported separately within Other income, net in the Condensed Consolidated Statements of Income. In January 2018, the Company made a voluntary cash contribution of approximately $81.0 to fully fund its U.S. Plans, and estimates that, based on current actuarial calculations, cash contributions to the Plans will aggregate approximately $90.0 in 2018. The timing and amount of cash contributions in subsequent years will depend on a number of factors, including the investment performance of the Plans’ assets. This voluntary cash contribution made in the first quarter of 2018 is reflected as cash used in operating activities within Net change in other long-term assets and liabilities in the Condensed Consolidated Statements of Cash Flow. The Company offers various defined contribution plans for certain U.S. and foreign employees. Participation in these plans is based on certain eligibility requirements. The Company matches the majority of employee contributions to the U.S. defined contribution plans with cash contributions up to a maximum of 5% of eligible compensation. During the three months ended March 31, 2018 and 2017, the Company provided matching contributions to the U.S. defined contribution plans of approximately $2.3 and $1.7, respectively.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2018
Acquisitions
Acquisitions	Note 11—Acquisitions In the past twelve months, the Company has completed several acquisitions, including one acquisition in the first quarter of 2018, and is in the process of completing its analyses of the fair value of the assets acquired and liabilities assumed. The Company anticipates that the final assessments of values will not differ materially from the preliminary assessments. These acquisitions were not significant to the Company either individually or in the aggregate.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Other Intangible Assets
Goodwill and Other Intangible Assets	Note 12—Goodwill and Other Intangible Assets The changes in the carrying amount of goodwill by segment were as follows: Interconnect Cable Products and Products and Assemblies Solutions Total Goodwill at December 31, 2017 $ 3,896.1 $ 146.5 $ 4,042.6 Acquisition-related 73.3 — 73.3 Foreign currency translation 30.6 — 30.6 Goodwill at March 31, 2018 $ 4,000.0 $ 146.5 $ 4,146.5 Other than goodwill noted above, the Company’s intangible assets as of March 31, 2018 and December 31, 2017 were as follows: March 31, 2018 December 31, 2017 Weighted Gross Net Gross Net Average Carrying Accumulated Carrying Carrying Accumulated Carrying Life (years) Amount Amortization Amount Amount Amortization Amount Customer relationships 10 $ 403.9 $ 210.9 $ 193.0 $ 398.1 $ 199.8 $ 198.3 Proprietary technology 11 107.6 53.1 54.5 107.5 50.7 56.8 Backlog and other 2 34.0 33.6 0.4 34.0 33.6 0.4 Total intangible assets (definite-lived) 10 545.5 297.6 247.9 539.6 284.1 255.5 Trade names (indefinite-lived) 186.1 — 186.1 186.1 — 186.1 $ 731.6 $ 297.6 $ 434.0 $ 725.7 $ 284.1 $ 441.6 Intangible assets are included in Intangibles, net and other long-term assets in the accompanying Condensed Consolidated Balance Sheets. The amortization expense for the three months ended March 31, 2018 and 2017 was approximately $11.9 and $12.0, respectively. As of March 31, 2018, amortization expense relating to the Company’s current intangible assets estimated for the remainder of 2018 is approximately $35.3 and for each of the next five fiscal years is approximately $43.2 in 2019, $37.4 in 2020, $32.4 in 2021, $24.7 in 2022 and $22.2 in 2023.

Debt

Debt	3 Months Ended
	Mar. 31, 2018
Debt
Debt	Note 13—Debt The Company’s debt (net of any unamortized discount) consists of the following: March 31, 2018 December 31, 2017 Carrying Approximate Carrying Approximate Amount Fair Value Amount Fair Value Revolving Credit Facility $ — $ — $ — $ — Commercial Paper Program 869.6 869.6 1,175.4 1,175.4 2.55% Senior Notes due January 2019 749.8 748.9 749.8 752.8 2.20% Senior Notes due April 2020 399.8 395.0 399.8 398.0 3.125% Senior Notes due September 2021 374.9 374.1 374.8 381.2 4.00% Senior Notes due February 2022 499.5 513.0 499.5 522.5 3.20% Senior Notes due April 2024 349.7 341.6 349.6 351.9 Notes payable to foreign banks and other debt 7.8 7.8 6.6 6.6 Less unamortized deferred debt issuance costs (11.8) — (12.9) — Total debt 3,239.3 3,250.0 3,542.6 3,588.4 Less current portion 749.9 749.0 1.1 1.1 Total long-term debt $ 2,489.4 $ 2,501.0 $ 3,541.5 $ 3,587.3 Revolving Credit Facility The Company has a $2,000.0 unsecured credit facility (the “Revolving Credit Facility”), which matures March 2021 and gives the Company the ability to borrow at a spread over LIBOR. The Company may utilize the Revolving Credit Facility for general corporate purposes. The carrying value of any borrowings under the Revolving Credit Facility would approximate their fair value due primarily to their market interest rates and would be classified as Level 2 in the fair value hierarchy (Note 15). At March 31, 2018, there were no borrowings under the Revolving Credit Facility. The Revolving Credit Facility requires payment of certain annual agency and commitment fees and requires that the Company satisfy certain financial covenants. At March 31, 2018, the Company was in compliance with the financial covenants under the Revolving Credit Facility. Commercial Paper Program The Company has a commercial paper program (the “Commercial Paper Program”) pursuant to which the Company issues short-term unsecured commercial paper notes (“Commercial Paper”) in one or more private placements. Amounts available under the Commercial Paper Program are borrowed, repaid and re-borrowed from time to time. The maturities of the Commercial Paper vary, but may not exceed 397 days from the date of issue. The Commercial Paper is sold under customary terms in the commercial paper market and may be issued at a discount from par, or, alternatively, may be sold at par, and bears varying interest rates on a fixed or floating basis. The Commercial Paper Program is rated A-2 by Standard & Poor’s and P-2 by Moody’s and is backstopped by the Revolving Credit Facility. The maximum aggregate principal amount of the Commercial Paper outstanding under the Commercial Paper Program at any time is $2,000.0. The Commercial Paper is classified as long-term debt in the accompanying Condensed Consolidated Balance Sheets since the Company has the intent and ability to refinance the Commercial Paper on a long-term basis using the Revolving Credit Facility. The Commercial Paper is actively traded and is therefore classified as Level 1 in the fair value hierarchy (Note 15). The carrying value of Commercial Paper borrowings approximated their fair value. The average interest rate on the Commercial Paper as of March 31, 2018 was 2.33%. Senior Notes All of the Company’s outstanding senior notes (“Senior Notes”), listed in the table above, are unsecured and rank equally in right of payment with the Company’s other unsecured senior indebtedness. Interest on each series of Senior Notes is payable semiannually. The Company may, at its option, redeem some or all of any series of senior notes at any time subject to certain terms and conditions, which include paying 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of repurchase and, with certain exceptions, a make-whole premium. The fair value of each series of Senior Notes is based on recent bid prices in an active market and is therefore classified as Level 1 in the fair value hierarchy (Note 15). The 2.55% Senior Notes are due in January 2019 and are therefore recorded, net of the related unamortized discount and debt issuance costs, within Current portion of long-term debt in the accompanying Condensed Consolidated Balance Sheets as of March 31, 2018.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Taxes
Income Taxes	Note 14—Income Taxes Three Months Ended March 31, 2018 2017 Provision for income taxes $ (86.4) $ (71.1) Effective tax rate % % For the three months ended March 31, 2018 and 2017, stock option exercise activity had the impact of lowering our Provision for income taxes by approximately $4.1 and $8.0, respectively, and lowering our effective tax rate by approximately 110 basis points and 270 basis points, respectively, due to the recognition of excess tax benefits within Provision for income taxes in the accompanying Condensed Consolidated Statements of Income. On December 22, 2017, the United States federal government enacted the Tax Cuts and Jobs Act (“Tax Act”), marking a change from a worldwide tax system to a modified territorial tax system in the United States. As part of this change, the Tax Act, among other changes, provides for a transition tax on the accumulated unremitted foreign earnings and profits of the Company’s foreign subsidiaries (“Transition Tax”) and a reduction of the U.S. federal corporate income tax rate from 35% to 21%. In the fourth quarter of 2017, the Company recorded an income tax charge of $398.5 (“Tax Act Charge”) that was comprised of (i) the Transition Tax of $259.4, (ii) a charge of $176.6 related to changes in the Company’s permanent reinvestment assertion with regards to prior accumulated unremitted earnings from certain foreign subsidiaries, partially offset by (iii) a tax benefit of $37.5 associated with the remeasurement of the Company’s U.S. net deferred tax liabilities due to the U.S. federal corporate tax rate reduction. These three components were provisional amounts recorded in accordance with Staff Accounting Bulletin No. 118 (“SAB 118”) (now codified in ASU 2018-05), which addresses the application of U.S. GAAP in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting for certain income tax effects of the Tax Act. Due to the timing of the Tax Act’s enactment and the complexity of its provisions, the Company has not completed its accounting for the impact of the Tax Act. We continue to analyze guidance and technical interpretations of the provisions of the Tax Act, as well as refine, analyze and update the underlying data, computations and assumptions used to prepare these provisional amounts. We did not make any adjustments to the Tax Act Charge in the first quarter of 2018. In accordance with ASU 2018-05, the Company will complete its accounting for the income tax effects of the Tax Act within the one-year measurement period in 2018 once the Company has obtained, prepared and fully analyzed all the necessary information related to all three components of the Tax Act Charge recorded in the fourth quarter of 2017. We will pay the Transition Tax, net of applicable tax credits and deductions, in annual installments until 2025, as permitted under the Tax Act. The Company operates in the U.S. and numerous foreign taxable jurisdictions, and at any point in time has numerous audits underway at various stages of completion. With few exceptions, the Company is subject to income tax examinations by tax authorities for the years 2013 and after. The Company is generally not able to precisely estimate the ultimate settlement amounts or timing until the close of an audit. The Company evaluates its tax positions and establishes liabilities for uncertain tax positions that may be challenged by tax authorities and may not be fully sustained, despite the Company’s belief that the underlying tax positions are fully supportable. As of March 31, 2018, the amount of the liability for unrecognized tax benefits, including penalties and interest, which if recognized would impact the effective tax rate, was approximately $164.4, which is included in Other long-term liabilities in the accompanying Condensed Consolidated Balance Sheets. Unrecognized tax benefits are reviewed on an ongoing basis and are adjusted for changing facts and circumstances, including progress of tax audits and the closing of statutes of limitation. Based on information currently available, management anticipates that over the next twelve-month period, audit activity could be completed and statutes of limitation may close relating to existing unrecognized tax benefits of approximately $18.3

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements
Fair Value Measurements	Note 15—Fair Value Measurements Fair value is determined based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. These requirements establish market or observable inputs as the preferred source of values. Assumptions based on hypothetical transactions are used in the absence of market inputs. The Company does not have any non-financial instruments accounted for at fair value on a recurring basis. The valuation techniques required are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs create the following fair value hierarchy: Level 1 Quoted prices for identical instruments in active markets. Level 2 Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3 Significant inputs to the valuation model are unobservable. The Company believes that the assets or liabilities subject to such standards with fair value disclosure requirements are short-term investments and derivative instruments. Substantially all of the Company’s short-term investments consist of certificates of deposit with original maturities of twelve months or less and as such, are considered as Level 1 in the fair value hierarchy as they are traded in active markets for identical assets. The carrying amounts of these instruments, the majority of which are in non-U.S. bank accounts, approximate their fair value. The Company’s derivative instruments represent foreign exchange rate forward contracts, which are valued using bank quotations based on market observable inputs such as forward and spot rates and are therefore classified as Level 2 in the fair value hierarchy. The impact of the credit risk related to these financial assets is immaterial. The fair values of the Company’s financial and non-financial assets and liabilities subject to such standards at March 31, 2018 and December 31, 2017 are as follows: Fair Value Measurements Quoted Prices in Significant Significant Active Markets Observable Unobservable for Identical Inputs Inputs Total Assets (Level 1) (Level 2) (Level 3) March 31, 2018: Short-term investments $ 24.1 $ 24.1 $ — $ — Forward contracts (8.1) — (8.1) — Total $ 16.0 $ 24.1 $ (8.1) $ — December 31, 2017: Short-term investments $ 34.6 $ 34.6 $ — $ — Forward contracts 2.3 — 2.3 — Total $ 36.9 $ 34.6 $ 2.3 $ — The Company does not have any significant financial or non-financial assets and liabilities that are measured at fair value on a non-recurring basis. The amounts recognized in Accumulated other comprehensive income (loss) associated with foreign exchange rate forward contracts and the amount reclassified from Accumulated other comprehensive income (loss) to foreign exchange gain (loss) in the accompanying Condensed Consolidated Statements of Income during the three months ended March 31, 2018 and 2017 were not material. The fair values of the forward contracts are recorded within Other current assets, Intangibles, net and other long-term assets, Other accrued expenses or Other long-term liabilities in the accompanying Condensed Consolidated Balance Sheets, depending on their value and remaining contractual period.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue Recognition
Schedule of disaggregation of net sales	Three months ended March 31, 2018 Interconnect Cable Products and Products and Total Reportable Assemblies Solutions Business Segments Net sales by: Sales channel: End customers and contract manufacturers $ 1,515.6 $ 70.0 $ 1,585.6 Distributors and resellers 254.4 26.9 281.3 $ 1,770.0 $ 96.9 $ 1,866.9 Geography: United States $ 479.2 $ 47.8 $ 527.0 China 527.2 0.8 528.0 Other international locations 763.6 48.3 811.9 $ 1,770.0 $ 96.9 $ 1,866.9

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventories
Schedule of Inventories	March 31, December 31, 2018 2017 Raw materials and supplies $ 432.2 $ 386.2 Work in process 381.6 358.0 Finished goods 353.0 362.7 $ 1,166.8 $ 1,106.9

Reportable Business Segments (T

Reportable Business Segments (Tables)	3 Months Ended
	Mar. 31, 2018
Reportable Business Segments
Schedule of segment reporting information by segment	Interconnect Products Cable Products Total Reportable and Assemblies and Solutions Business Segments Three Months Ended March 31: 2018 2017 2018 2017 2018 2017 Net sales: External $ 1,770.0 $ 1,463.5 $ 96.9 $ 96.6 $ 1,866.9 $ 1,560.1 Intersegment 2.6 2.3 8.9 10.2 11.5 12.5 Segment operating income 391.1 323.9 11.3 13.7 402.4 337.6
Schedule of the reconciliation of segment operating income to consolidated income before income taxes	Three Months Ended March 31, 2018 2017 Segment operating income $ 402.4 $ 337.6 Interest expense (24.5) (19.3) Other income, net 2.3 3.6 Stock-based compensation expense (12.7) (12.1) Other operating expenses (12.8) (11.4) Income before income taxes $ 354.7 $ 298.4

Shareholders' Equity and Nonc26

Shareholders' Equity and Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 2018
Shareholders' Equity and Noncontrolling Interests
Rollforward of consolidated changes in equity	A rollforward of consolidated changes in equity for the three months ended March 31, 2018 is as follows: Amphenol Corporation Shareholders Accumulated Common Stock Other Shares Additional Retained Comprehensive Treasury Noncontrolling Total (in millions) Amount Paid-In Capital Earnings Loss Stock Interests Equity Balance as of December 31, 2017 305.7 $ 0.3 $ 1,249.0 $ 2,941.5 $ (201.0) $ — $ 53.6 $ 4,043.4 Cumulative effect of adoption of revenue recognition standard (Note 2) 3.2 3.2 Net income 265.6 2.7 268.3 Other comprehensive income 61.3 1.5 62.8 Acquisitions resulting in noncontrolling interest 0.1 0.1 Distributions to shareholders of noncontrolling interests (3.9) (3.9) Purchase of treasury stock (382.0) (382.0) Retirement of treasury stock (4.2) (382.0) 382.0 — Stock options exercised 0.6 20.7 20.7 Dividends declared (57.4) (57.4) Stock-based compensation expense 12.7 12.7 Balance as of March 31, 2018 302.1 $ 0.3 $ 1,282.4 $ 2,770.9 $ (139.7) $ — $ 54.0 $ 3,967.9 A rollforward of consolidated changes in equity for the three months ended March 31, 2017 is as follows: Amphenol Corporation Shareholders Accumulated Common Stock Other Shares Additional Retained Comprehensive Treasury Noncontrolling Total (in millions) Amount Paid-In Capital Earnings Loss Stock Interests Equity Balance as of December 31, 2016 308.3 $ 0.3 $ 1,020.9 $ 3,122.7 $ (469.0) $ — $ 48.2 $ 3,723.1 Net income 224.9 2.4 227.3 Other comprehensive income 66.7 0.5 67.2 Distributions to shareholders of noncontrolling interests (4.2) (4.2) Purchase of treasury stock (249.2) (249.2) Retirement of treasury stock (3.7) (249.2) 249.2 — Stock options exercised 0.8 23.7 23.7 Dividends declared (48.9) (48.9) Stock-based compensation expense 12.1 12.1 Balance as of March 31, 2017 305.4 $ 0.3 $ 1,056.7 $ 3,049.5 $ (402.3) $ — $ 46.9 $ 3,751.1
Schedules of dividends	Three Months Ended March 31, 2018 2017 Dividends declared per share $ 0.19 $ 0.16 Dividends declared $ 57.4 $ 48.9 Dividends paid (including those declared in the prior year) 58.1 49.3

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share
Schedule of the reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding	Three Months Ended March 31, (dollars and shares in millions, except per share data) 2018 2017 Net income attributable to Amphenol Corporation shareholders $ 265.6 $ 224.9 Basic weighted average common shares outstanding 303.7 Effect of dilutive stock options 12.3 Diluted weighted average common shares outstanding 316.0 Earnings per share attributable to Amphenol Corporation shareholders: Basic $ 0.87 $ 0.73 Diluted $ 0.84 $ 0.71

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Stock-Based Compensation
Schedule of stock option activity	Weighted Average Aggregate Weighted Remaining Intrinsic Average Contractual Value Options Exercise Price Term (in years) (in millions) Options outstanding at January 1, 2018 33,222,364 $ 52.27 7.05 $ 1,180.3 Options granted — Options exercised (602,549) Options forfeited (32,240) Options outstanding at March 31, 2018 32,587,575 $ 52.58 6.84 $ 1,093.2 Vested and non-vested options expected to vest at March 31, 2018 30,726,902 $ 51.92 6.76 $ 1,051.0 Exercisable options at March 31, 2018 13,086,775 $ 39.76 5.20 $ 606.8
Summary of status of non-vested options and changes during the year	Weighted Average Fair Value at Options Grant Date Non-vested options at January 1, 2018 19,600,440 $ 8.29 Options granted — — Options vested (67,400) 8.13 Options forfeited (32,240) 8.56 Non-vested options at March 31, 2018 19,500,800 $ 8.29
Summary of activity in the option plans	Three Months Ended March 31, 2018 2017 Total intrinsic value of stock options exercised $ 34.3 $ 34.5 Total fair value of stock options vested 0.5 0.7
Schedule of restricted share activity	Weighted Average Remaining Restricted Fair Value at Amortization Shares Grant Date Term (in years) Restricted shares outstanding at January 1, 2018 12,905 $ 73.25 0.37 Restricted shares granted — — Restricted shares outstanding at March 31, 2018 12,905 $ 73.25 0.13

Benefit Plans and Other Postr29

Benefit Plans and Other Postretirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2018
Benefit Plans and Other Postretirement Benefits
Schedule of components of net pension expense	Other Postretirement Pension Benefits Benefits Three Months Ended March 31: 2018 2017 2018 2017 Service cost $ 1.9 $ 2.4 $ — $ — Interest cost 4.9 5.0 0.1 0.1 Expected return on plan assets (9.7) (7.7) — — Amortization of prior service cost 0.6 0.7 — — Amortization of net actuarial losses 5.9 5.7 0.1 0.2 Net pension expense $ 3.6 $ 6.1 $ 0.2 $ 0.3

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Other Intangible Assets
Schedule of changes in the carrying amount of goodwill by segment	Interconnect Cable Products and Products and Assemblies Solutions Total Goodwill at December 31, 2017 $ 3,896.1 $ 146.5 $ 4,042.6 Acquisition-related 73.3 — 73.3 Foreign currency translation 30.6 — 30.6 Goodwill at March 31, 2018 $ 4,000.0 $ 146.5 $ 4,146.5
Summary of the Company's intangible assets	March 31, 2018 December 31, 2017 Weighted Gross Net Gross Net Average Carrying Accumulated Carrying Carrying Accumulated Carrying Life (years) Amount Amortization Amount Amount Amortization Amount Customer relationships 10 $ 403.9 $ 210.9 $ 193.0 $ 398.1 $ 199.8 $ 198.3 Proprietary technology 11 107.6 53.1 54.5 107.5 50.7 56.8 Backlog and other 2 34.0 33.6 0.4 34.0 33.6 0.4 Total intangible assets (definite-lived) 10 545.5 297.6 247.9 539.6 284.1 255.5 Trade names (indefinite-lived) 186.1 — 186.1 186.1 — 186.1 $ 731.6 $ 297.6 $ 434.0 $ 725.7 $ 284.1 $ 441.6

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt
Schedule of debt	March 31, 2018 December 31, 2017 Carrying Approximate Carrying Approximate Amount Fair Value Amount Fair Value Revolving Credit Facility $ — $ — $ — $ — Commercial Paper Program 869.6 869.6 1,175.4 1,175.4 2.55% Senior Notes due January 2019 749.8 748.9 749.8 752.8 2.20% Senior Notes due April 2020 399.8 395.0 399.8 398.0 3.125% Senior Notes due September 2021 374.9 374.1 374.8 381.2 4.00% Senior Notes due February 2022 499.5 513.0 499.5 522.5 3.20% Senior Notes due April 2024 349.7 341.6 349.6 351.9 Notes payable to foreign banks and other debt 7.8 7.8 6.6 6.6 Less unamortized deferred debt issuance costs (11.8) — (12.9) — Total debt 3,239.3 3,250.0 3,542.6 3,588.4 Less current portion 749.9 749.0 1.1 1.1 Total long-term debt $ 2,489.4 $ 2,501.0 $ 3,541.5 $ 3,587.3

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2018
Income Taxes
Schedule of provision for income taxes and effective tax rate	Three Months Ended March 31, 2018 2017 Provision for income taxes $ (86.4) $ (71.1) Effective tax rate % %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements
Fair values of financial and non-financial assets and liabilities	Fair Value Measurements Quoted Prices in Significant Significant Active Markets Observable Unobservable for Identical Inputs Inputs Total Assets (Level 1) (Level 2) (Level 3) March 31, 2018: Short-term investments $ 24.1 $ 24.1 $ — $ — Forward contracts (8.1) — (8.1) — Total $ 16.0 $ 24.1 $ (8.1) $ — December 31, 2017: Short-term investments $ 34.6 $ 34.6 $ — $ — Forward contracts 2.3 — 2.3 — Total $ 36.9 $ 34.6 $ 2.3 $ —

New Accounting Pronouncements (

New Accounting Pronouncements (Details) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements
Retained earnings	$ 2,770.9		$ 2,941.5
Impact of ASU 2014-09 | Impact of ASU 2014-09 adoption - Increase (decrease) to beginning retained earnings
New Accounting Pronouncements
Retained earnings		$ 3.2

Revenue Recognition (Details)

Revenue Recognition (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)item
Revenue recognition
Payment terms	Our contracts do not have any significant financing components, as payment terms are generally due net 30 to 120 days after delivery.
Practical expedient, performance obligation	true
Practical expedient, incremental cost of obtaining contract	true
Net sales	$ 1,866.9
Minimum
Revenue recognition
Number of reporting periods that may be extended across for multiple delivery dates | item	1
Maximum
Revenue recognition
Percentage of net sales recognized over time	5.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01 | Minimum
Revenue recognition
Remaining performance obligation term	3 months
Interconnect Products and Assemblies
Revenue recognition
Net sales	$ 1,770
Cable Products and Solutions
Revenue recognition
Net sales	96.9
End customers and contract manufacturers
Revenue recognition
Net sales	1,585.6
End customers and contract manufacturers | Interconnect Products and Assemblies
Revenue recognition
Net sales	1,515.6
End customers and contract manufacturers | Cable Products and Solutions
Revenue recognition
Net sales	70
Distributors and resellers
Revenue recognition
Net sales	281.3
Distributors and resellers | Interconnect Products and Assemblies
Revenue recognition
Net sales	254.4
Distributors and resellers | Cable Products and Solutions
Revenue recognition
Net sales	26.9
United States
Revenue recognition
Net sales	527
United States | Interconnect Products and Assemblies
Revenue recognition
Net sales	479.2
United States | Cable Products and Solutions
Revenue recognition
Net sales	47.8
China
Revenue recognition
Net sales	528
China | Interconnect Products and Assemblies
Revenue recognition
Net sales	527.2
China | Cable Products and Solutions
Revenue recognition
Net sales	0.8
Other international locations
Revenue recognition
Net sales	811.9
Other international locations | Interconnect Products and Assemblies
Revenue recognition
Net sales	763.6
Other international locations | Cable Products and Solutions
Revenue recognition
Net sales	$ 48.3

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventories
Raw materials and supplies	$ 432.2	$ 386.2
Work in process	381.6	358
Finished goods	353	362.7
Inventories	$ 1,166.8	$ 1,106.9

Reportable Business Segments (D

Reportable Business Segments (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)segment	Mar. 31, 2017USD ($)
Segment reporting information
Number of reportable business segments | segment	2
Net sales	$ 1,866.9	$ 1,560.1
Segment operating income	376.9	314.1
Operating Segment
Segment reporting information
Segment operating income	402.4	337.6
Operating Segment | Interconnect Products and Assemblies
Segment reporting information
Net sales	1,770	1,463.5
Segment operating income	391.1	323.9
Operating Segment | Cable Products and Solutions
Segment reporting information
Net sales	96.9	96.6
Segment operating income	11.3	13.7
Inter-Segment
Segment reporting information
Net sales	11.5	12.5
Inter-Segment | Interconnect Products and Assemblies
Segment reporting information
Net sales	2.6	2.3
Inter-Segment | Cable Products and Solutions
Segment reporting information
Net sales	$ 8.9	$ 10.2

Reportable Business Segments, R

Reportable Business Segments, Reconciliation of Segment Operating Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 376.9	$ 314.1
Interest expense	(24.5)	(19.3)
Other income, net	2.3	3.6
Stock-based compensation expense	(12.7)	(12.1)
Other operating expenses	(12.8)	(11.4)
Income before income taxes	354.7	298.4
Operating Segment
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 402.4	$ 337.6

Shareholders' Equity and Nonc39

Shareholders' Equity and Noncontrolling Interests (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) In Shareholders' Equity
Balance at beginning of period	$ 4,043.4	$ 3,723.1
Net income	268.3	227.3
Other comprehensive income	62.8	67.2
Acquisition resulting in noncontrolling interest	0.1
Distributions to shareholders of noncontrolling interests	(3.9)	(4.2)
Purchase of treasury stock	(382)	(249.2)
Stock options exercised	20.7	23.7
Dividends declared	(57.4)	(48.9)
Stock-based compensation expense	12.7	12.1
Balance at end of period	$ 3,967.9	$ 3,751.1
Common Stock
Increase (Decrease) In Shareholders' Equity
Balance (in shares)	305.7	308.3
Balance at beginning of period	$ 0.3	$ 0.3
Retirement of treasury stock (in shares)	(4.2)	(3.7)
Stock options exercised (in shares)	0.6	0.8
Balance (in shares)	302.1	305.4
Balance at end of period	$ 0.3	$ 0.3
Additional Paid-In Capital
Increase (Decrease) In Shareholders' Equity
Balance at beginning of period	1,249	1,020.9
Stock options exercised	20.7	23.7
Stock-based compensation expense	12.7	12.1
Balance at end of period	1,282.4	1,056.7
Retained Earnings
Increase (Decrease) In Shareholders' Equity
Balance at beginning of period	2,941.5	3,122.7
Net income	265.6	224.9
Retirement of treasury stock	(382)	(249.2)
Dividends declared	(57.4)	(48.9)
Balance at end of period	2,770.9	3,049.5
Accumulated Other Comprehensive Loss
Increase (Decrease) In Shareholders' Equity
Balance at beginning of period	(201)	(469)
Other comprehensive income	61.3	66.7
Balance at end of period	(139.7)	(402.3)
Treasury Stock
Increase (Decrease) In Shareholders' Equity
Purchase of treasury stock	(382)	(249.2)
Retirement of treasury stock	382	249.2
Noncontrolling Interests
Increase (Decrease) In Shareholders' Equity
Balance at beginning of period	53.6	48.2
Net income	2.7	2.4
Other comprehensive income	1.5	0.5
Acquisition resulting in noncontrolling interest	0.1
Distributions to shareholders of noncontrolling interests	(3.9)	(4.2)
Balance at end of period	54	$ 46.9
Impact of ASU 2014-09
Increase (Decrease) In Shareholders' Equity
Cumulative effect of adoption of revenue recognition standard (Note 2)	3.2
Impact of ASU 2014-09 | Retained Earnings
Increase (Decrease) In Shareholders' Equity
Cumulative effect of adoption of revenue recognition standard (Note 2)	$ 3.2

Shareholders' Equity and Nonc40

Shareholders' Equity and Noncontrolling Interests, Stock Repurchase (Details) - USD ($) shares in Millions, $ in Millions	Apr. 30, 2018	Apr. 24, 2018	Jan. 24, 2017	Mar. 31, 2018	Mar. 31, 2018
2017 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased			$ 1,000
Repurchase of stock program, period			2 years
Number of shares repurchased and retired				4.2	12.6
Payments for shares repurchased and retired (in dollars)				$ 382	$ 1,000
2018 Stock Repurchase Program
Shareholders' Equity
Value of shares authorized to be repurchased		$ 2,000
Repurchase of stock program, period		3 years
Number of shares repurchased	0.7
Payments for shares repurchased (in dollars)	$ 55.5

Shareholders' Equity and Nonc41

Shareholders' Equity and Noncontrolling Interests, Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 24, 2018	Mar. 31, 2018	Mar. 31, 2017
Shareholders' Equity and Noncontrolling Interests
Dividends declared per share (in dollars per share)	$ 0.23	$ 0.19	$ 0.16
Dividends declared		$ 57.4	$ 48.9
Dividends paid		$ 58.1	$ 49.3

Earnings Per Share, Reconciliat

Earnings Per Share, Reconciliation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share
Net income attributable to Amphenol Corporation shareholders	$ 265.6	$ 224.9
Basic weighted average common shares outstanding (in shares)	303.7	306.6
Effect of dilutive stock options (in shares)	12.3	9.8
Diluted weighted average common shares outstanding (in shares)	316	316.4
Earnings per share attributable to Amphenol Corporation shareholders:
Basic (in dollars per share)	$ 0.87	$ 0.73
Diluted (in dollars per share)	$ 0.84	$ 0.71
Anti-dilutive common shares
Anti-dilutive stock options, excluded from the computations of earning per share (in shares)	0	0

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 12.7	$ 12.1
Recognized tax benefit related to stock-based compensation	5.9	11
Impact on provision for income taxes	$ 4.1	$ 8
Increase in net income per common share - Diluted (in dollars per share)	$ 0.01	$ 0.02

Stock-Based Compensation, Sto44

Stock-Based Compensation, Stock Option and Restricted Shares (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
2000 Employee Option Plan
Stock-Based Compensation
Options exercisable period	10 years
2009 Employee Option Plan
Stock-Based Compensation
Number of additional stock options that will be granted (in shares)	0
Options ratable vesting period	5 years
Options exercisable period	10 years
2017 Employee Option Plan
Stock-Based Compensation
Common Stock reserved for issuance	30,000,000
Shares available for the granting of additional stock options	23,016,700
Options ratable vesting period	5 years
Options exercisable period	10 years
2004 Directors Option Plan
Stock-Based Compensation
Options exercisable period	10 years
Stock Options
Stock option activity
Options outstanding at the beginning of the period (in shares)	33,222,364
Options exercised (in shares)	(602,549)
Options forfeited (in shares)	(32,240)
Options outstanding at the end of the period (in shares)	32,587,575		33,222,364
Vested and non-vested options expected to vest at the end of the period (in shares)	30,726,902
Exercisable at the end of the period (in shares)	13,086,775
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share)	$ 52.27
Weighted average exercise price, options outstanding at the end of the period (in dollars per share)	52.58		$ 52.27
Weighted average exercise price, vested and non-vested options expected to vest (in dollars per share)	51.92
Weighted average exercise price, exercisable (in dollars per share)	$ 39.76
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding	6 years 10 months 2 days		7 years 18 days
Weighted average remaining contractual term of options vested options and non-vested expected to vest	6 years 9 months 4 days
Weighted average remaining contractual term of options exercisable	5 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding	$ 1,093.2		$ 1,180.3
Aggregate intrinsic value of options, vested and non-vested options expected to vest	1,051
Aggregate intrinsic value of options exercisable	$ 606.8
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)	19,600,440
Non-vested options, options vested (in shares)	(67,400)
Non-vested options, options forfeited (in shares)	(32,240)
Non-vested options at the end of the period (in shares)	19,500,800		19,600,440
Weighted Average Fair Value at Grant Date
Weighted average fair value at the grant date, options outstanding at the beginning of the period (in dollars per share)	$ 8.29
Weighted average fair value at grant date, options vested (in dollars per share)	8.13
Weighted average fair value at grant date, options forfeited (in dollars per share)	8.56
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)	$ 8.29		$ 8.29
Fair Value at Grant Date
Total intrinsic value of stock options exercised (in dollars)	$ 34.3	$ 34.5
Total fair value of stock options vested (in dollars)	0.5	$ 0.7
Total compensation cost related to non-vested options not yet recognized (in dollars)	$ 108.5
Weighted average expected amortization period	3 years 1 month 21 days
Restricted Shares | 2012 Directors Restricted Stock Plan
Stock-Based Compensation
Shares available for the granting of additional stock options	124,164
Restricted share activity
Restricted shares outstanding at the beginning of the period (in shares)	12,905
Restricted shares outstanding at the end of the period (in shares)	12,905		12,905
Fair Value at Grant Date
Fair value at the grant date, restricted shares outstanding at the beginning of the period (in dollars per share)	$ 73.25
Fair value at the grant date, restricted shares outstanding at the end of the period (in dollars per share)	$ 73.25		$ 73.25
Weighted Average Remaining Amortization Term (in years)	1 month 17 days		4 months 13 days
Total compensation cost related to non-vested restricted shares not yet recognized (in dollars)	$ 0.1
Weighted average expected amortization period	1 month 17 days

Benefit Plans and Other Postr45

Benefit Plans and Other Postretirement Benefits, Net pension expense (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018	Mar. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure
Estimated future employer contribution in fiscal year		$ 90
Components of net pension expense:
Service cost		1.9	$ 2.4
Interest cost		4.9	5
Expected return on plan assets		(9.7)	(7.7)
Amortization of prior service cost		0.6	0.7
Amortization of net actuarial losses		5.9	5.7
Net pension expense		3.6	6.1
Pension Benefits | United States
Defined Benefit Plan Disclosure
Plan contributions by employer	$ 81
Other Postretirement Benefits
Components of net pension expense:
Interest cost		0.1	0.1
Amortization of net actuarial losses		0.1	0.2
Net pension expense		$ 0.2	$ 0.3

Benefit Plans and Other Postr46

Benefit Plans and Other Postretirement Benefits, Defined contribution plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Benefit Plans and Other Postretirement Benefits
Contributions to U.S. defined contribution plans by the Company, maximum percentage of eligible compensation	5.00%
Matching contributions to U.S. defined contribution plans by the Company	$ 2.3	$ 1.7

Acquisitions (Details)

Acquisitions (Details)	3 Months Ended
	Mar. 31, 2018item
Acquisitions
Number of acquisitions	1

Goodwill and Other Intangible48

Goodwill and Other Intangible Assets, Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Goodwill.
Goodwill, Beginning Balance	$ 4,042.6
Acquisition-related	73.3
Foreign currency translation	30.6
Goodwill, Ending Balance	4,146.5
Interconnect Products and Assemblies
Goodwill.
Goodwill, Beginning Balance	3,896.1
Acquisition-related	73.3
Foreign currency translation	30.6
Goodwill, Ending Balance	4,000
Cable Products and Solutions
Goodwill.
Goodwill, Beginning Balance	146.5
Goodwill, Ending Balance	$ 146.5

Goodwill and Other Intangible49

Goodwill and Other Intangible Assets, Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Intangible Assets
Weighted average useful lives of acquired amortizable intangible assets	10 years
Gross Carrying Amount (definite-lived)	$ 545.5	$ 539.6
Intangible assets, gross (excluding goodwill)	731.6	725.7
Accumulated Amortization	297.6	284.1
Net Carrying Amount, (definite-lived)	247.9	255.5
Indefinite-lived trade name intangible asset	186.1	186.1
Net Carrying Amount, intangible assets	$ 434	441.6
Customer relationships
Intangible Assets
Weighted average useful lives of acquired amortizable intangible assets	10 years
Gross Carrying Amount (definite-lived)	$ 403.9	398.1
Accumulated Amortization	210.9	199.8
Net Carrying Amount, (definite-lived)	$ 193	198.3
Proprietary technology
Intangible Assets
Weighted average useful lives of acquired amortizable intangible assets	11 years
Gross Carrying Amount (definite-lived)	$ 107.6	107.5
Accumulated Amortization	53.1	50.7
Net Carrying Amount, (definite-lived)	$ 54.5	56.8
Backlog and other
Intangible Assets
Weighted average useful lives of acquired amortizable intangible assets	2 years
Gross Carrying Amount (definite-lived)	$ 34	34
Accumulated Amortization	33.6	33.6
Net Carrying Amount, (definite-lived)	$ 0.4	$ 0.4

Goodwill and Other Intangible50

Goodwill and Other Intangible Assets, Amortization (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Other Intangible Assets
Amortization expense	$ 11.9	$ 12
Amortization expense estimated for each of the next five fiscal years
Remainder of 2018	35.3
2,019	43.2
2,020	37.4
2,021	32.4
2,022	24.7
2,023	$ 22.2

Debt, Schedule of Debt (Details

Debt, Schedule of Debt (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt
Less deferred debt issuance costs	$ (11.8)	$ (12.9)
Total debt	3,239.3	3,542.6
Less current portion	749.9	1.1
Total long-term debt	2,489.4	3,541.5
Total debt, Approximate Fair Value	3,250	3,588.4
Less short-term debt, Approximate Fair Value	749	1.1
Long-term debt, Approximate Fair Value	2,501	3,587.3
Commercial Paper Program
Debt
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	869.6	1,175.4
Total debt, Approximate Fair Value	$ 869.6	$ 1,175.4
2.55% Senior Notes due January 2019
Debt
Stated interest rate (as a percent)	2.55%	2.55%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	$ 749.8	$ 749.8
Total debt, Approximate Fair Value	$ 748.9	$ 752.8
2.20% Senior Notes due April 2020
Debt
Stated interest rate (as a percent)	2.20%	2.20%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	$ 399.8	$ 399.8
Total debt, Approximate Fair Value	$ 395	$ 398
3.125% Senior Notes due September 2021
Debt
Stated interest rate (as a percent)	3.125%	3.125%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	$ 374.9	$ 374.8
Total debt, Approximate Fair Value	$ 374.1	$ 381.2
4.00% Senior Notes due February 2022
Debt
Stated interest rate (as a percent)	4.00%	4.00%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	$ 499.5	$ 499.5
Total debt, Approximate Fair Value	$ 513	$ 522.5
3.20% Senior Notes due April 2024
Debt
Stated interest rate (as a percent)	3.20%	3.20%
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	$ 349.7	$ 349.6
Total debt, Approximate Fair Value	341.6	351.9
Notes payable to foreign banks and other debt
Debt
Debt carrying amount, net of unamortized discount before deferred debt issuance costs	7.8	6.6
Total debt, Approximate Fair Value	$ 7.8	$ 6.6

Debt, Other (Details)

Debt, Other (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
The “Revolving Credit Facility”
Debt
Maximum borrowing capacity	$ 2,000
Borrowings under the Revolving Credit Facility	0
Commercial Paper Program
Debt
Maximum borrowing capacity	$ 2,000
Maturity term	397 days
Average interest rate (as a percent)	2.33%
Senior Notes
Debt
Redemption price as a percentage of principal amount	100.00%
2.55% Senior Notes due January 2019
Debt
Stated interest rate (as a percent)	2.55%	2.55%

Income Taxes, Provision and Eff

Income Taxes, Provision and Effective tax rate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Taxes
Provision for income taxes	$ (86.4)	$ (71.1)
Effective tax rate (as a percent)	24.40%	23.80%
Impact on provision for income taxes	$ 4.1	$ 8
Impact of provision for income taxes (in basis points)	1.10%	2.70%

Income Taxes, 2017 Tax Cuts and

Income Taxes, 2017 Tax Cuts and Jobs Act (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017USD ($)item	Dec. 31, 2017
Income Taxes
U.S. statutory federal tax rate (as a percent)	21.00%		35.00%
Estimated Tax Act Charge		$ 398.5
Estimated Transition Tax		259.4
Provisional charge on unremitted foreign earnings		176.6
Income tax expense (benefit) associated with the remeasurement of net deferred tax liabilities		$ (37.5)
Number of components | item		3

Income Taxes, Unrecognized tax

Income Taxes, Unrecognized tax benefits (Details) $ in Millions	Mar. 31, 2018USD ($)
Reconciliation of the gross amounts of unrecognized tax benefits including interest and penalties
Liability for unrecognized tax benefits, including penalties and interest, which if recognized would impact the effective tax rate	$ 164.4
Unrecognized tax benefits, anticipated adjustment for changing facts and circumstances, over the next twelve month period	$ 18.3

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Recurring basis - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Fair value of assets and liabilities measured on recurring basis
Short-term investments	$ 24.1	$ 34.6
Forward contracts		2.3
Forward contracts	(8.1)
Total	16	36.9
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair value of assets and liabilities measured on recurring basis
Short-term investments	24.1	34.6
Total	24.1	34.6
Significant Observable Inputs (Level 2)
Fair value of assets and liabilities measured on recurring basis
Forward contracts		2.3
Forward contracts	(8.1)
Total	$ (8.1)	$ 2.3