American Axle & Manufacturing (AXL) 10-Q 4 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Entity Registrant Name	AMERICAN AXLE & MANUFACTURING HOLDINGS INC
Entity Central Index Key	1,062,231
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Document Type	10-Q
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		111,658,423
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net sales	$ 1,858.4	$ 1,049.9
Cost of goods sold	1,542.1	839.2
Gross profit	316.3	210.7
Selling, general and administrative expenses	97.3	81.2
Amortization of intangible assets	24.9	1.6
Restructuring and acquisition-related costs	18.3	16
Operating income	175.8	111.9
Interest expense	(53.2)	(25.5)
Investment income	0.5	0.6
Debt refinancing and redemption costs	(10.3)	0
Other expense, net	(5.4)	(1.1)
Income before income taxes	107.4	85.9
Income tax expense	17.9	7.5
Net income	89.5	78.4
Net income attributable to noncontrolling interests	(0.1)	0
Net income attributable to AAM	$ 89.4	$ 78.4
Basic earnings per share	$ 0.78	$ 1
Diluted earnings per share	$ 0.78	$ 0.99

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income	$ 89.5	$ 78.4
Other comprehensive income (loss)
Defined benefit plans, net of tax (a)	1.3	(0.3)
Foreign currency translation adjustments	37.9	11.9
Changes in cash flow hedges, net of tax (b)	15.1	15.5
Other comprehensive income	54.3	27.1
Comprehensive income	143.8	105.5
Net income attributable to noncontrolling interests	(0.1)	0
Comprehensive income attributable to AAM	$ 143.7	$ 105.5

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other comprehensive income (loss), pension and other postretirement benefit plans, tax	$ (0.4)	$ 0.2
Other comprehensive income (loss), derivatives qualifying as hedges, tax	$ (1.1)	$ 0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 340.7	$ 376.8
Accounts receivable, net	1,238.2	1,035.9
Inventories, net	403.3	392
Prepaid expenses and other	172.9	140.3
Total current assets	2,155.1	1,945
Property, plant and equipment, net	2,491.9	2,402.9
Deferred income taxes	38.1	37.1
Goodwill	1,669.1	1,654.3
Intangible assets, net	1,188.8	1,212.5
GM postretirement cost sharing asset	250.3	252.2
Other assets and deferred charges	379	378.8
Total assets	8,172.3	7,882.8
Current liabilities
Current portion of long-term debt	31.8	5.9
Accounts payable	924.5	799
Accrued compensation and benefits	158.9	200
Deferred revenue	34	34.1
Accrued expenses and other	200.7	177.4
Total current liabilities	1,349.9	1,216.4
Long-term debt, net	3,986.2	3,969.3
Deferred revenue	77.6	78.8
Deferred income taxes	119.2	101.7
Postretirement benefits and other long-term liabilities	953.4	976.6
Total liabilities	6,486.3	6,342.8
Stockholders' equity
Common stock, par value $0.01 per share; 150.0 million shares authorized; 118.8 million shares issued as of March 31, 2018 and 118.2 million shares issued as of December 31, 2017	1.2	1.2
Paid-in capital	1,271.2	1,264.6
Retained earnings	850.4	761
Treasury stock at cost, 7.1 million shares as of March 31, 2018 and 6.9 million shares as of December 31, 2017	(201.6)	(198.1)
Accumulated other comprehensive income (loss)
Defined benefit plans, net of tax	(250.7)	(252)
Foreign currency translation adjustments	3.8	(34.1)
Unrecognized income (loss) on cash flow hedges, net of tax	8.5	(6.6)
Total AAM stockholders' equity	1,682.8	1,536
Noncontrolling interests in subsidiaries	3.2	4
Total stockholders' equity	1,686	1,540
Total liabilities and stockholders' equity	$ 8,172.3	$ 7,882.8

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Millions	Mar. 31, 2018	Dec. 31, 2017
Common stock, par or stated value per share	$ 0.01	$ 0.01
Common stock, shares authorized	150	150
Treasury stock, shares	7.1	6.9
Common stock, shares, issued	118.8	118.2

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income	$ 89.5	$ 78.4
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	127.8	56.2
Deferred income taxes	13.4	(5.4)
Stock-based compensation	6.7	5.5
Pensions and other postretirement benefits, net of contributions	1.6	(1.7)
Loss on disposal of property, plant and equipment, net	0.4	0.5
Debt refinancing and redemption costs	10.3	0
Changes in operating assets and liabilities, net of amounts acquired
Accounts receivable	(191)	(137.6)
Inventories	(8.7)	3
Accounts payable and accrued expenses	60.8	91.8
Deferred revenue	(2.1)	1.8
Other assets and liabilities	(41.8)	(30.2)
Net cash provided by operating activities	66.9	62.3
Investing activities
Purchases of property, plant and equipment	(130.8)	(34.9)
Proceeds from sale of property, plant and equipment	0.4	0.8
Purchase buyouts of leased equipment	(0.5)	(2.3)
Proceeds from sale of business, net	0	5.9
Acquisition of business, net of cash acquired	(1.3)	(144.1)
Net cash used in investing activities	(132.2)	(174.6)
Financing activities
Payments of long-term debt and capital lease obligations	(396.9)	(10.2)
Proceeds from issuance of long-term debt	431.4	1,209.4
Debt issuance costs	(6.8)	(21.2)
Purchase of noncontrolling interest	(0.9)	0
Purchase of treasury stock	(3.5)	(5.2)
Net cash provided by financing activities	23.3	1,172.8
Effect of exchange rate changes on cash	5.9	1.7
Net increase (decrease) in cash and cash equivalents	(36.1)	1,062.2
Cash and cash equivalents at beginning of period	376.8	481.2
Cash and cash equivalents at end of period	340.7	1,543.4
Supplemental cash flow information
Interest paid	27.2	17.9
Income taxes paid, net of refunds	$ 11.2	$ 4.7

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. ORGANIZATION AND BASIS OF PRESENTATION Organization We are a global Tier I supplier to the automotive, commercial and industrial markets. We design, engineer, validate and manufacture driveline, metal forming, powertrain and casting products, employing over 25,000 associates, operating at more than 90 facilities in 17 countries, to support our customers on global and regional platforms with a continued focus on delivering operational excellence, technology leadership and quality. Basis of Presentation We have prepared the accompanying interim condensed consolidated financial statements in accordance with the instructions to Form 10-Q under the Securities Exchange Act of 1934. These condensed consolidated financial statements are unaudited but include all normal recurring adjustments, which we consider necessary for a fair presentation of the information set forth herein. Results of operations for the periods presented are not necessarily indicative of the results for the full fiscal year. The balance sheet at December 31, 2017 presented herein has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America (GAAP) for complete consolidated financial statements. In order to prepare the accompanying interim condensed consolidated financial statements, we are required to make estimates and assumptions that affect the reported amounts and disclosures in our interim condensed consolidated financial statements. Actual results could differ from those estimates. For further information, refer to the audited consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2017 . Effect of New Accounting Standards Accounting Standards Update 2018-02 On February 14, 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220). ASU 2018-02 allows companies the option to reclassify disproportionate tax effects in accumulated other comprehensive income (AOCI) caused by the 2017 Tax Cuts and Jobs Act, also known as stranded tax effects, to retained earnings. ASU 2018-02 also requires expanded disclosures related to disproportionate income tax effects from AOCI, some of which are applicable to all companies regardless of whether the option to reclassify the stranded tax effects is exercised. This guidance becomes effective at the beginning of our 2019 fiscal year, however early adoption is permitted for financial statements which have not yet been issued. We are currently assessing the impact that this standard will have on our consolidated financial statements. Accounting Standards Update 2017-04 On January 26, 2017, the FASB issued ASU 2017-04 - Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment . The amendments in this update modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. An entity no longer will determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination, or what is referred to under existing guidance as "Step 2." Instead, under the amendments in this update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. This guidance becomes effective at the beginning of our 2020 fiscal year and early adoption is permitted. The guidance requires a prospective transition method. We do not expect the adoption of this guidance to have a material effect on our consolidated financial statements, however, goodwill could be more susceptible to impairment in periods subsequent to adoption. Accounting Standards Update 2016-02 On February 25, 2016, the FASB issued ASU 2016-02 - Leases (Topic 842) , which supersedes the existing lease accounting guidance and establishes new criteria for recognizing lease assets and liabilities. The most significant impact of the update, to AAM, is that a lessee will be required to recognize a "right-of-use" asset and lease liability for operating lease agreements that were not previously included on the balance sheet under the existing lease guidance. A lessee will be permitted to make a policy election, excluding recognition of the right-of-use asset and associated liability for lease terms of 12 months or less. Expense recognition in the statement of income along with cash flow statement classification for both financing (capital) and operating leases under the new standard will not be significantly changed from existing lease guidance. This guidance becomes effective for AAM at the beginning of our 2019 fiscal year and requires transition under a modified retrospective method. We are currently assessing the impact that this standard will have on our consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers Revenue from Contracts with Customers (Notes)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	2. REVENUE FROM CONTRACTS WITH CUSTOMERS On January 1, 2018, we adopted new accounting guidance under Accounting Standards Codification Topic 606 (ASC 606) Revenue from Contracts with Customers . ASC 606 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most existing revenue recognition guidance, including industry-specific guidance. The guidance is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We have elected to adopt this guidance utilizing the modified retrospective transition method, which requires a one-time adjustment to opening retained earnings for the cumulative impact of adopting the new guidance. No adjustment to retained earnings was required as of January 1, 2018 as there was no impact to previously reported revenue or expenses associated with adopting ASC 606. We are obligated under our contracts with customers to manufacture and supply products for use in our customers’ operations. We satisfy these performance obligations at the point in time that the customer obtains control of the products, which is the point in time that the customer is able to direct the use of, and obtain substantially all of the remaining benefits from, the products. This typically occurs upon shipment to the customer in accordance with purchase orders and delivery releases issued by our customers. There is significant judgment involved in determining when the customer obtains control of the products and we have utilized the following indicators of control in our assessment: • We have the present right to payment for the asset; • The customer has legal title to the asset; • We have transferred physical possession of the asset; • The customer has the significant risks and rewards of ownership of the asset; and • The customer has accepted the asset. Our product offerings by segment are as follows: • Driveline products consist primarily of axles, driveshafts, power transfer units, rear drive modules, transfer cases, and electric and hybrid driveline products and systems for light trucks, SUVs, crossover vehicles, passenger cars and commercial vehicles; • Metal Forming products consist primarily of axle and transmission shafts, ring and pinion gears, differential gears, transmission gears, and suspension components for Original Equipment Manufacturers and Tier 1 automotive suppliers; • The Powertrain segment products consist primarily of transmission module and differential assemblies, transmission valve bodies, connecting rod forging and assemblies, torsional vibration dampers, and variable valve timing products for Original Equipment Manufacturers and Tier I automotive suppliers; and • The Casting segment produces both thin wall castings and high strength ductile iron castings, as well as differential cases, steering knuckles, control arms, brackets, and turbo charger housings for the global light vehicle, commercial and industrial markets. Our contracts with customers generally state the terms of the sale, including the quantity and price of each product purchased. Trade accounts receivable from our customers are generally due approximately 50 days from the date our customers receive our product. Our contracts typically do not contain variable consideration as the contracts include stated prices. We provide our customers with assurance type warranties, which are not separate performance obligations and are outside the scope of ASC 606. Refer to Note 11 - Product Warranties for further information. Disaggregation of Net Sales Net sales recognized from contracts with customers, disaggregated by segment and geographical location, are presented in the following table for the three months ended March 31, 2018 and 2017. Net sales are attributed to regions based on the location of production. Intersegment sales have been excluded from the table. Three Months Ended March 31, 2018 Driveline Metal Forming Powertrain Casting Total North America $ 885.3 $ 216.3 $ 199.2 $ 209.8 $ 1,510.6 Asia 122.8 1.4 31.1 — 155.3 Europe 29.0 73.4 55.9 — 158.3 South America 33.3 — 0.9 — 34.2 Total $ 1,070.4 $ 291.1 $ 287.1 $ 209.8 $ 1,858.4 Three Months Ended March 31, 2017 Driveline Metal Forming Powertrain Casting Total North America $ 865.2 $ 51.1 $ — $ — $ 916.3 Asia 85.5 — — — 85.5 Europe 20.7 — — — 20.7 South America 27.4 — — — 27.4 Total $ 998.8 $ 51.1 $ — $ — $ 1,049.9 Contract Assets and Liabilities The following table summarizes our beginning and ending balances for accounts receivable and contract liabilities associated with our contracts with customers: Accounts Receivable, Net Contract Liabilities (Current) Contract Liabilities (Long-term) December 31, 2017 $ 1,035.9 $ 34.1 $ 78.8 March 31, 2018 1,238.2 34.0 77.6 Increase/(decrease) $ 202.3 $ (0.1 ) $ (1.2 ) Contract liabilities relate to deferred revenue associated with cash receipts from our customers for various settlements and commercial agreements for which we have a future performance obligation to the customer. We recognize this deferred revenue into revenue over the life of the associated program as we satisfy our performance obligations to the customer. We do not have contract assets as defined in ASC 606. For the three months ended March 31, 2018, we recognized contract liabilities of $6.7 million , all of which have been recorded in our Condensed Consolidated Balance Sheet as long-term deferred revenue. During this period, we also amortized $8.0 million of previously recorded contract liabilities into revenue as we satisfied performance obligations with our customers. Sales and Other Taxes ASC 606 provides a practical expedient that allows companies to exclude from the transaction price any amounts collected from customers for all sales (and other similar) taxes. We do not include sales and other taxes in our transaction price and thus do not recognize these amounts as revenue.

Restructuring and Acquisition-R

Restructuring and Acquisition-Related Costs	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Business Acquisition, Integration, Restructuring and Other Related Costs [Text Block]	3. RESTRUCTURING AND ACQUISITION-RELATED COSTS In 2016, AAM initiated actions under a global restructuring program focused on creating a more streamlined organization in addition to reducing our cost structure and preparing for acquisition integration activities. A summary of this activity for the first three months of 2018 and 2017 is shown below: Severance Charges Implementation Costs Total (in millions) Accrual as of December 31, 2016 $ 0.6 $ 9.2 $ 9.8 Charges 1.2 5.6 6.8 Cash utilization (1.1 ) (1.5 ) (2.6 ) Accrual as of March 31, 2017 $ 0.7 $ 13.3 $ 14.0 Accrual as of December 31, 2017 $ 0.3 $ — $ 0.3 Charges 0.2 3.9 4.1 Cash utilization (0.4 ) (0.5 ) (0.9 ) Accrual as of March 31, 2018 $ 0.1 $ 3.4 $ 3.5 As part of our restructuring actions, we incurred severance charges of approximately $0.2 million and $1.2 million , as well as implementation costs, including professional expenses, of approximately $3.9 million and $5.6 million , during the three months ended March 31, 2018 and 2017 , respectively. Since the inception of our global restructuring program, we have incurred severance charges totaling $2.8 million and implementation costs totaling $28.0 million . We expect to incur $10 to $20 million of additional charges under our global restructuring program in 2018 . In 2017, we completed the acquisitions of Metaldyne Performance Group, Inc. (MPG) and USM Mexico Manufacturing LLC (USM Mexico). During the three months ended March 31, 2018 , we incurred the following charges related to these acquisitions: Acquisition-Related Costs Integration Expenses Total (in millions) Charges $ 1.1 $ 13.1 $ 14.2 Total restructuring and acquisition-related charges $ 18.3 Acquisition-related costs primarily consist of advisory, legal, accounting, valuation and certain other professional or consulting fees incurred. Integration expenses reflect costs incurred for information technology systems, ongoing operational activities, and consulting fees incurred in conjunction with the acquisitions. Total charges associated with our global restructuring program and acquisition-related charges of $18.3 million are shown on a separate line item titled "Restructuring and Acquisition-Related Costs" in our Condensed Consolidated Statement of Income for the three months ended March 31, 2018 .

Business Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	4. BUSINESS COMBINATIONS Acquisition of MPG On April 6, 2017, AAM completed its acquisition of 100% of the equity interests of MPG for a total purchase price of approximately $1.5 billion plus the assumption of approximately $1.7 billion in net debt (comprised of approximately $1.9 billion in debt less approximately $0.2 billion of MPG cash and cash equivalents). Under the terms of the agreement and plan of merger (Merger Agreement), each share of MPG common stock (other than MPG excluded shares as defined in the Merger Agreement) was converted into the right to receive (a) $13.50 in cash, without interest, and (b) 0.5 of a share of AAM common stock (Merger Consideration). Further, MPG stock options outstanding immediately prior to the effective time of the merger were accelerated and holders of the stock options received the Merger Consideration less the per share exercise price of the MPG stock options. All MPG restricted shares and restricted stock unit awards outstanding under an MPG equity plan were also accelerated and each holder thereof received the Merger Consideration for each restricted share or restricted stock unit award of MPG common stock. MPG provides highly-engineered components for use in powertrain and safety-critical platforms for the global light, commercial and industrial markets. MPG produces these components using complex metal-forming manufacturing technologies and processes for a global customer base of OEMs and Tier I suppliers, which help their customers meet fuel economy, performance and safety standards. Our acquisition of MPG contributes significantly to diversifying our global customer base and end markets, while also allowing us to expand our presence as a global Tier I supplier to the commercial and industrial markets, in addition to our existing presence as a global Tier I supplier to the automotive industry. The aggregate cash consideration for the acquisition of MPG was financed using (i) net proceeds from the issuance in March 2017 by AAM of $1.2 billion of new senior notes consisting of $700.0 million aggregate principal amount of 6.25% senior notes due 2025, and $500.0 million aggregate principal amount of 6.50% senior notes due 2027, and on April 6, 2017: (ii) borrowings by AAM of $100.0 million under a term loan that matures in 2022, (iii) borrowings by AAM of $1.55 billion under a term loan that matures in 2024, and (iv) cash on hand. The acquisition of MPG was accounted for under the acquisition method under ASC 805 with the purchase price allocated to the identifiable assets and liabilities of the acquired company based on the respective fair values of the assets and liabilities. The following represents the fair values of the assets acquired and liabilities assumed resulting from the acquisition, as well as the calculation of goodwill: (in millions) April 6, 2017 Cash consideration $ 953.5 Share consideration 576.7 Total consideration transferred $ 1,530.2 Fair value of MPG noncontrolling interests 3.6 Total fair value of MPG $ 1,533.8 Cash and cash equivalents $ 202.1 Accounts receivable 403.1 Inventories 199.0 Prepaid expenses and other long-term assets 119.9 Property, plant and equipment 971.8 Intangible assets 1,223.1 Total assets acquired $ 3,119.0 Accounts payable 287.8 Accrued expenses and other 137.7 Deferred income tax liabilities 580.2 Debt 1,918.7 Postretirement benefits and other long-term liabilities 54.1 Net assets acquired $ 140.5 Goodwill $ 1,393.3 Under the guidance in ASC 805, estimated amounts that are designated as provisional may be adjusted during a period referred to as the "measurement period." The measurement period is a period not to exceed one year from the acquisition date during which we may adjust estimated or provisional amounts recorded during purchase accounting if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in revised estimated values of those assets or liabilities as of that date. Measurement period adjustments are recorded in the period identified with an offsetting entry to goodwill. Any adjustments to amounts recorded in purchase accounting that do not qualify as measurement period adjustments are included in earnings in the period identified. We finalized the valuation of the assets and liabilities of MPG in the first quarter of 2018. In doing so, we made measurement period adjustments to reflect changes to facts and circumstances that existed as of the acquisition date, which resulted in a net increase in Goodwill of $0.9 million . These adjustments related to Property, plant and equipment, as well as the corresponding impact on Deferred income tax liabilities, as a result of customary post-closing reviews. Goodwill resulting from the acquisition is primarily attributable to anticipated synergies and economies of scale from which we expect to benefit as a combined entity. None of the goodwill is deductible for tax purposes. We recognized $1,223.1 million of amortizable intangible assets for customer platforms, customer relationships, developed technology and licensing agreements as a result of the acquisition of MPG. These intangible assets will be amortized over a period ranging from five to 17 years. The intangible assets were valued using primarily the relief from royalty method or the multi-period excess earnings method, both of which utilize significant unobservable inputs. These inputs are defined in the fair value hierarchy as Level 3 inputs, which require management to make estimates and assumptions regarding certain financial measures using forecasted or projected information. AAM had an existing accounts payable balance of $12.4 million with MPG as of the date of acquisition. As a result of the acquisition, this pre-existing accounts payable balance was settled and AAM accounted for this settlement separately from the acquisition. This resulted in a $12.4 million reduction in the purchase price. Included in net sales and net income attributable to AAM for the period January 1, 2018 through March 31, 2018 was approximately $738 million and $40 million , respectively, attributable to MPG. Unaudited Pro Forma Financial Information Unaudited pro forma net sales for AAM, on a combined basis with MPG for the three months ended March 31, 2017 were approximately $1.8 billion , excluding MPG sales to AAM during this period. Unaudited pro forma net income for the three months ended March 31, 2017 was approximately $95 million . Unaudited pro forma earnings per share for the three months ended March 31, 2017 were approximately $0.83 per share. The pro forma net income amount for the three months ended March 31, 2017 has been adjusted by approximately $20 million , net of tax, for acquisition-related costs reclassified from 2017 to 2016 as we are required to disclose the pro forma amounts as if our acquisition of MPG had been completed on January 1, 2016. The disclosure of unaudited pro forma net sales and earnings is for informational purposes only and does not purport to indicate the results that would actually have been obtained had the merger been completed on the assumed date for the periods presented, or which may be realized in the future. Acquisition of USM Mexico On March 1, 2017, AAM completed the acquisition of 100% of USM Mexico, a former subsidiary of U.S. Manufacturing Corporation (USM). The purchase price was funded with available cash and the acquisition was accounted for under the acquisition method. USM Mexico includes USM's operations in Guanajuato, Mexico, which has historically been one of the largest suppliers to AAM's Guanajuato Manufacturing Complex. This acquisition allows AAM to vertically integrate the supply chain and helps ensure continuity of supply for certain parts to our largest manufacturing facility. The following represents the fair value of the assets acquired and liabilities assumed resulting from the acquisition, as well as the calculation of goodwill: (in millions) March 1, 2017 Contractual purchase price $ 162.5 Adjustment to contractual purchase price for working capital settlement 2.5 Adjustment to contractual purchase price for capital equipment 4.9 Adjustment to contractual purchase price for settlement of existing accounts payable balance (22.8 ) Cash acquired (0.5 ) Adjusted purchase price, net of cash acquired $ 146.6 Accounts receivable 1.1 Inventories 4.8 Prepaid expenses and other 3.6 Property, plant and equipment 38.4 Intangible assets 31.7 Total assets acquired $ 79.6 Accounts payable 10.8 Accrued expenses and other 2.7 Deferred income tax liabilities 1.2 Net assets acquired $ 64.9 Goodwill $ 81.7 The purchase agreement specified a period of time subsequent to the acquisition date for calculating the final working capital amount of USM Mexico as of the acquisition date, which was finalized in the first quarter of 2018. None of the goodwill is deductible for tax purposes. AAM had an existing accounts payable balance of $22.8 million with USM Mexico as of the date of acquisition. As a result of the acquisition, this pre-existing accounts payable balance was settled and AAM accounted for this settlement separately from the acquisition. This resulted in a $22.8 million reduction in the purchase price. The operating results of USM Mexico were insignificant to AAM's Condensed Consolidated Statement of Income for the three months ended March 31, 2018. Further, we have not included pro forma revenue and earnings for the three months ended March 31, 2017 as the inclusion of USM Mexico would be insignificant to AAM's consolidated results for this period.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets Disclosure [Text Block]	5. GOODWILL AND INTANGIBLE ASSETS Goodwill The following table provides a reconciliation of changes in goodwill for the three months ended March 31, 2018 : Driveline Metal Forming Powertrain Casting Consolidated (in millions) Balance as of December 31, 2017 $ 211.1 $ 558.9 $ 478.8 $ 405.5 $ 1,654.3 Acquisition of MPG — 0.9 — — 0.9 Acquisition of USM Mexico 1.3 — — — 1.3 Foreign currency translation (0.2 ) 4.7 8.1 — 12.6 Balance as of March 31, 2018 $ 212.2 $ 564.5 $ 486.9 $ 405.5 $ 1,669.1 Intangible Assets The following table provides a reconciliation of the gross carrying amount and associated accumulated amortization for AAM's total intangible assets, which are all subject to amortization: March 31, December 31, 2018 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in millions) Capitalized computer software $ 36.8 $ (15.7 ) $ 21.1 $ 35.6 $ (14.3 ) $ 21.3 e-AAM in-process research and development 5.8 (0.2 ) 5.6 5.9 — 5.9 Customer platforms 952.2 (70.5 ) 881.7 952.2 (52.9 ) 899.3 Customer relationships 151.8 (9.9 ) 141.9 151.8 (7.3 ) 144.5 Technology and other 150.8 (12.3 ) 138.5 150.8 (9.3 ) 141.5 Total $ 1,297.4 $ (108.6 ) $ 1,188.8 $ 1,296.3 $ (83.8 ) $ 1,212.5 Amortization expense for these intangible assets was $24.9 million for the three months ended March 31, 2018 , and $1.6 million for the three months ended March 31, 2017 . Estimated amortization expense for each of the years 2018 through 2022 is approximately $100 million .

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventory Disclosure [Text Block]	6. INVENTORIES We state our inventories at the lower of cost or net realizable value. The cost of our inventories is determined using the first-in first-out method. When we determine that our gross inventories exceed usage requirements, or if inventories become obsolete or otherwise not saleable, we record a provision for such loss as a component of our inventory accounts. Inventories consist of the following: March 31, 2018 December 31, 2017 (in millions) Raw materials and work-in-progress $ 337.0 $ 319.7 Finished goods 84.6 89.6 Gross inventories 421.6 409.3 Inventory valuation reserves (18.3 ) (17.3 ) Inventories, net $ 403.3 $ 392.0

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Long-term Debt [Text Block]	7. LONG-TERM DEBT Long-term debt consists of the following: March 31, 2018 December 31, 2017 (in millions) Revolving Credit Facility $ — $ — Term Loan A Facility 92.5 92.5 Term Loan B Facility 1,526.8 1,526.8 7.75% Notes due 2019 200.0 200.0 6.625% Notes due 2022 550.0 550.0 6.50% Notes due 2027 500.0 500.0 6.25% Notes due 2026 400.0 — 6.25% Notes due 2025 700.0 700.0 6.25% Notes due 2021 16.9 400.0 Foreign credit facilities 81.2 53.2 Capital lease obligations 27.5 28.3 Total debt 4,094.9 4,050.8 Less: Current portion of long-term debt 31.8 5.9 Long-term debt 4,063.1 4,044.9 Less: Debt issuance costs 76.9 75.6 Long-term debt, net $ 3,986.2 $ 3,969.3 Senior Secured Credit Facilities In 2017 , Holdings and American Axle & Manufacturing, Inc. (AAM, Inc.) entered into a credit agreement (the Credit Agreement). In connection with the Credit Agreement, Holdings, AAM, Inc. and certain of their restricted subsidiaries entered into a Collateral Agreement and Guarantee Agreement with the financial institutions party thereto as collateral agent and administrative agent. Pursuant to the Credit Agreement, the lenders agreed to provide a $100.0 million term loan A facility (the Term Loan A Facility), a $1.55 billion term loan B facility (the Term Loan B Facility) and a $900 million multi-currency revolving credit facility (the Revolving Credit Facility, and together with the Term Loan A Facility and the Term Loan B Facility, the Senior Secured Credit Facilities). The proceeds of the Revolving Credit Facility are used for general corporate purposes. As of March 31, 2018 we have prepaid $3.8 million of the outstanding principal on our Term Loan A Facility and $11.6 million of the outstanding principal on our Term Loan B Facility. These payments satisfy our obligation for principal payments under the Term Loan A Facility and Term Loan B Facility for the next three quarters. As a result, approximately $5 million related to the Term Loan A Facility and Term Loan B Facility is presented in the Current portion of long-term debt line item in our Condensed Consolidated Balance Sheet as of March 31, 2018 . At March 31, 2018 , we had $865.3 million available under the Revolving Credit Facility. This availability reflects a reduction of $34.7 million for standby letters of credit issued against the facility. The Senior Secured Credit Facilities provide back-up liquidity for our foreign credit facilities. We intend to use the availability of long-term financing under the Senior Secured Credit Facilities to refinance any current maturities related to such debt agreements that are not otherwise refinanced on a long-term basis in their local markets, except where otherwise reclassified to Current portion of long-term debt on our Condensed Consolidated Balance Sheet. 6.25% Notes due 2026 In March 2018, we issued $400.0 million in aggregate principal amount of 6.25% senior notes due 2026 (the 6.25% Notes due 2026). Proceeds from the 6.25% Notes due 2026 were used primarily to fund the tender offer for the 6.25% senior notes due 2021 (the 6.25% Notes due 2021) described below. We paid debt issuance costs of $6.6 million in the first three months of 2018 related to the 6.25% Notes due 2026. Tender Offer of 6.25% Notes due 2021 Also in March 2018, we made a tender offer for our 6.25% Notes due 2021. Under this tender offer, we retired $383.1 million of the 6.25% Notes due 2021. During the first quarter of 2018 , we expensed $2.5 million for the write-off of the remaining unamortized debt issuance costs that we had been amortizing over the expected life of the borrowing and $7.8 million in tender premiums. We redeemed the remaining $16.9 million of the 6.25% Notes due 2021 in April 2018 . Foreign credit facilities We utilize local currency credit facilities to finance the operations of certain foreign subsidiaries. At March 31, 2018 , $81.2 million was outstanding under our foreign credit facilities and an additional $135.8 million was available. The weighted-average interest rate of our long-term debt outstanding was 5.8% at March 31, 2018 and 5.7% at December 31, 2017 .

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	8. FAIR VALUE Accounting Standards Codification 820 - Fair Value Measurement defines fair value as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” The definition is based on an exit price rather than an entry price, regardless of whether the entity plans to hold or sell the asset. This guidance also establishes a fair value hierarchy to prioritize inputs used in measuring fair value as follows: • Level 1: Observable inputs such as quoted prices in active markets; • Level 2: Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and • Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial instruments The estimated fair value of our financial assets and liabilities that are recognized at fair value on a recurring basis, using available market information and other observable data, are as follows: March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Input (in millions) Balance Sheet Classification Cash equivalents $ 88.0 $ 88.0 $ 72.8 $ 72.8 Level 1 Prepaid expenses and other Cash flow hedges - currency forward contracts 2.7 2.7 0.1 0.1 Level 2 Cash flow hedges - variable-to-fixed interest rate swap 1.5 1.5 1.3 1.3 Level 2 Nondesignated - currency forward contracts 1.6 1.6 — — Level 2 Other assets and deferred charges Cash flow hedges - currency forward contracts 2.2 2.2 0.2 0.2 Level 2 Cash flow hedges - variable-to-fixed interest rate swap 4.5 4.5 0.9 0.9 Level 2 Accrued expenses and other Cash flow hedges - currency forward contracts 1.2 1.2 6.0 6.0 Level 2 Nondesignated - currency forward contracts — — 2.8 2.8 Level 2 Postretirement benefits and other long-term liabilities Cash flow hedges - currency forward contracts — — 2.6 2.6 Level 2 Cash flow hedges - variable-to-fixed interest rate swap — — 0.3 0.3 Level 2 The carrying values of our cash, accounts receivable, accounts payable and accrued liabilities approximate their fair values due to the short-term maturities of these instruments. The carrying values of our borrowings under the foreign credit facilities approximate their fair value due to the frequent resetting of the interest rates. We estimated the fair value of the amounts outstanding on our debt using available market information and other observable data, to be as follows: March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Input (in millions) Revolving Credit Facility $ — $ — $ — $ — Level 2 Term Loan A Facility 92.5 92.8 92.5 92.5 Level 2 Term Loan B Facility 1,526.8 1,533.0 1,526.8 1,528.7 Level 2 7.75% Notes due 2019 200.0 211.5 200.0 217.5 Level 2 6.625% Notes due 2022 550.0 567.9 550.0 570.2 Level 2 6.50% Notes due 2027 500.0 499.8 500.0 527.5 Level 2 6.25% Notes due 2026 400.0 397.4 — — Level 2 6.25% Notes due 2025 700.0 697.3 700.0 736.8 Level 2 6.25% Notes due 2021 16.9 17.2 400.0 410.0 Level 2

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	9. DERIVATIVES Our business and financial results are affected by fluctuations in world financial markets, including interest rates and currency exchange rates. Our hedging policy has been developed to manage these risks to an acceptable level based on management’s judgment of the appropriate trade-off between risk, opportunity and cost. We do not hold financial instruments for trading or speculative purposes. On January 1, 2018, we early adopted new accounting guidance under Accounting Standards Update (ASU) 2017-12 - Targeted Improvements for Hedging Activities (Topic 815). ASU 2017-12 is intended to better align the risk management activities of a company with the company's financial reporting for hedging relationships. This guidance expands and refines several aspects of hedge accounting. The most applicable changes to AAM as a result of the new guidance are as follows: 1) the concept of risk component hedging is introduced in ASU 2017-12, which could allow us to hedge contractually specified components in a contract; 2) the guidance now allows entities to utilize a 31-day period in assessing whether the critical terms of a forecasted transaction match the maturity of the hedging derivative, which could allow for expanded use of hedging instruments for certain sales and purchases; and 3) we may now qualitatively assess hedge effectiveness on a quarterly basis when the facts and circumstances related to the hedging relationship have not changed significantly. The early adoption of this guidance did not have any impact on the measurement of our existing hedging relationships. Currency derivative contracts From time to time, we use foreign currency forward and option contracts to reduce the effects of fluctuations in exchange rates relating to the Mexican Peso, Euro, Brazilian Real, British Pound Sterling, Thai Baht, Swedish Krona, Chinese Yuan, Polish Zloty and Indian Rupee. As of March 31, 2018 , we have currency forward and option contracts outstanding with a notional amount of $192.1 million that hedge our exposure to changes in foreign currency exchange rates for certain payroll expenses into the fourth quarter of 2020 and other items into the fourth quarter of 2018. Variable-to-fixed interest rate swap In the second quarter of 2017, we entered into a variable-to-fixed interest rate swap to reduce the variability of cash flows associated with interest payments on our variable rate debt. We have the following notional amounts hedged in relation to our variable-to-fixed interest rate swap: $750.0 million through May 2018, $600.0 million through May 2019, $450.0 million through May 2020 and $200.0 million through May 2021. The following table summarizes the reclassification of derivative gains and losses into net income from accumulated other comprehensive income (loss) for those derivative instruments designated as cash flow hedges under ASC 815 - Derivatives and Hedging : Location Gain (Loss) Reclassified Total of Financial Gain Expected of Gain (Loss) During Three Months Ended Statement to be Reclassified Reclassified into March 31, Line Item During the Net Income 2018 2017 2018 Next 12 Months (in millions) Currency forward contracts Cost of Goods Sold $ (2.0 ) $ (2.8 ) $ 1,542.1 $ 1.6 Variable-to-fixed interest rate swap Interest Expense 0.4 — 53.2 2.3 See Note 14 - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (AOCI) for amounts recognized in other comprehensive income (loss) during the three months ended March 31, 2018 and 2017. The following table summarizes the amount and location of gains recognized in the Condensed Consolidated Statements of Income for those derivative instruments not designated as hedging instruments under ASC 815: Gain Recognized During Total of Financial Location of Gain Three Months Ended Statement Line Recognized in March 31, Item Net Income 2018 2017 2018 (in millions) Currency forward contracts Cost of Goods Sold $ 4.0 $ 3.5 $ 1,542.1

Employee Benefit Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	10. EMPLOYEE BENEFIT PLANS In 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 . The amendments in this update require that an employer disaggregate the service cost component from the other components of defined benefit pension cost and postretirement benefit cost (net benefit cost). The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This guidance became effective January 1, 2018 and requires a retrospective transition method for the income statement classification of the net benefit cost components and a prospective transition method for the capitalization of the service cost component in assets. Upon adoption of this guidance, we now include the components of net benefit cost other than service cost in Other income (expense) in our Condensed Consolidated Statements of Income. We have not retrospectively restated the Condensed Consolidated Statement of Income for the three months ended March 31, 2017 as the total of the components of net benefit cost other than service cost were immaterial for this period. For the three months ended March 31, 2018, the total of the components of net benefit cost other than service cost included in Other income (expense) was expense of $0.2 million , which excludes the curtailment shown in the table below. This curtailment was associated with a recent restructuring of certain benefit plans as a result of our integration of MPG and has been presented in the Restructuring and acquisition-related costs line item in our Condensed Consolidated Statement of Income for the three months ended March 31, 2018. The components of net periodic benefit cost (credit) are as follows: Pension Benefits Three Months Ended March 31, 2018 2017 (in millions) Service cost $ 1.1 $ 0.8 Interest cost 6.9 6.8 Expected asset return (11.5 ) (10.5 ) Amortized loss 2.2 1.7 Curtailment 3.2 — Net periodic benefit cost (credit) $ 1.9 $ (1.2 ) Other Postretirement Benefits Three Months Ended March 31, 2018 2017 (in millions) Service cost $ 0.1 $ 0.1 Interest cost 3.1 3.3 Amortized loss 0.2 0.2 Amortized prior service credit (0.7 ) (0.7 ) Net periodic benefit cost $ 2.7 $ 2.9 The noncurrent liabilities associated with our pension and other postretirement benefit plans are classified as postretirement benefits and other long-term liabilities on our Condensed Consolidated Balance Sheets. As of March 31, 2018 and December 31, 2017 , we have a noncurrent pension liability of $132.4 million and $134.7 million , respectively. As of March 31, 2018 and December 31, 2017 , we have a noncurrent other postretirement benefits liability of $582.2 million and $583.0 million , respectively. Due to the availability of our pre-funded pension balances (previous contributions in excess of prior required pension contributions) related to certain of our U.S. pension plans, we expect our regulatory pension funding requirements in 2018 to be approximately $2 million . We expect our cash payments for other postretirement benefit obligations in 2018 , net of GM cost sharing, to be approximately $17 million .

Product Warranties

Product Warranties	3 Months Ended
	Mar. 31, 2018
Product Warranties Disclosures [Abstract]
Product Warranty Disclosure [Text Block]	11. PRODUCT WARRANTIES We record a liability for estimated warranty obligations at the dates our products are sold. These estimates are established using sales volumes and internal and external warranty data where there is no payment history and historical information about the average cost of warranty claims for customers with prior claims. We estimate our costs based on the contractual arrangements with our customers, existing customer warranty terms and internal and external warranty data, which includes a determination of our warranty claims and actions taken to improve product quality and minimize warranty claims. We continuously evaluate these estimates and our customers' administration of their warranty programs. We closely monitor actual warranty claim data and adjust the liability, as necessary, on a quarterly basis. The following table provides a reconciliation of changes in the product warranty liability: Three Months Ended March 31, 2018 2017 (in millions) Beginning balance $ 49.5 $ 42.9 Accruals 4.3 5.5 Payments (0.5 ) (0.9 ) Adjustment to prior period accruals — (0.2 ) Foreign currency translation 0.3 0.2 Ending balance $ 53.6 $ 47.5

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	12. INCOME TAXES Tax Provision for the Three Months Ended March 31, 2018 and 2017 We are required to adjust our effective tax rate each quarter based on our estimated annual effective tax rate. We must also record the tax impact of certain discrete, unusual or infrequently occurring items, including changes in judgment about valuation allowances and effects of changes in tax laws or rates, in the interim period in which they occur. In addition, jurisdictions with a projected loss for the year or a year-to-date loss where no tax benefit can be recognized are excluded from the estimated annual effective tax rate. The impact of such an exclusion could result in a higher or lower effective tax rate during a particular quarter, based upon the mix and timing of actual earnings versus annual projections. Income tax expense was $17.9 million for the three months ended March 31, 2018 as compared to $7.5 million for the three months ended March 31, 2017 . Our effective income tax rate was 16.7% in the first quarter of 2018 as compared to 8.7% in the first quarter of 2017 . The changes in income tax expense and effective income tax rate for the three months ended March 31, 2018 , as compared to the three months ended March 31, 2017 , were the result of 1) a benefit recognized in the first quarter of 2017 in the U.S. as a result of an increase in forecasted annual interest expense attributable to the first quarter of 2017 resulting from the issuance of certain notes; and 2) a decrease in the proportionate share of income attributable to lower tax rate jurisdictions due primarily to the decrease in the U.S. statutory tax rate. These factors were partially offset by 1) the reduction in U.S. statutory tax rate as a result of the enactment of the 2017 Act; and 2) a benefit related to additional U.S. tax credits. In comparison to the U.S. statutory rate, our income tax expense and effective income tax rate for the three months ended March 31, 2018 reflect the benefit associated with the additional U.S. tax credits, as well as the impact of favorable foreign tax rates. Based on the protocol of finalizing audits and advance pricing agreements with the relevant tax authorities, it is not possible to estimate the timing or impact of changes, if any, to previously recorded uncertain tax positions. As of March 31, 2018 and December 31, 2017, we have recorded a liability for unrecognized income tax benefits and related interest and penalties of $55.4 million and $55.2 million , respectively. In 2018, we may finalize advance pricing agreements in a foreign jurisdiction, which could result in cash payments to the relevant tax authorities and a reduction of our liability for unrecognized tax benefits and related interest and penalties. We do not expect the settlements will be materially different from what we have recorded in unrecognized tax benefits. We will continue to monitor the progress and conclusions of current and future audits and other communications with tax authorities and will adjust our estimated liability as necessary. Tax Cuts and Jobs Act On December 22, 2017, the Tax Cuts and Jobs Act (the 2017 Act) was enacted in the United States. The following is a summary of the key provisions of the 2017 Act: • Reduces the U.S. federal statutory income tax rate for corporations from 35% to 21% • Requires companies to pay a one-time transition tax (Transition Tax) on certain foreign earnings for which U.S. income tax was previously deferred • Generally eliminates U.S. federal income taxes on dividends from foreign subsidiaries • Requires a current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations (GILTI) • Eliminates the corporate alternative minimum tax (AMT) and changes how existing AMT credits can be realized • Creates a new limitation on deductible net interest expense incurred by U.S. corporations • Allows for immediate expensing of certain capital investments in the U.S. for the period September 27, 2017 through December 31, 2022 • Creates a new base erosion anti-abuse minimum tax (BEAT) • Allows for a current deduction for a portion of foreign derived intangible income (FDII) Following the enactment of the 2017 Act, the Securities and Exchange Commission issued Staff Accounting Bulletin (SAB) 118 to provide guidance on the accounting and reporting impacts of the 2017 Act. For the impact of changes resulting from the 2017 Act, under the guidance in SAB 118, we either 1) recorded an estimated provisional amount when the impact of the change could be reasonably estimated; or 2) continued to apply the accounting guidance that was in effect immediately prior to the 2017 Act when the impact of the change could not be reasonably estimated. For estimated provisional amounts recorded, there is a measurement period of no longer than one year during which we should adjust those amounts as additional information becomes available. In connection with our preliminary analysis of the impacts of the 2017 Act, we recorded estimates in 2017 related to the remeasurement of our net deferred tax liabilities as a result of the change in tax rate, a reduction of a previously recorded deferred tax liability on certain foreign earnings, and estimated expense related to the Transition Tax. These estimates were based on information available at the time and, in accordance with the guidance in SAB 118, we designated these amounts as provisional. As such, these amounts are subject to adjustment as we obtain additional information and complete our analysis. The additional information required is as follows: Reduction of U.S. federal corporate tax rate: While we were able to make a reasonable estimate in 2017 of the impact of the reduction in the corporate tax rate, the final impact may be affected by other elements related to the 2017 Act including, but not limited to, our calculation of deemed repatriation of deferred foreign income and the state tax effect of adjustments made to federal temporary differences. Transition Tax: In order to finalize the impact of the Transition Tax, we must determine, in addition to other factors, the amount of earnings of certain foreign subsidiaries, as well as the amount of non-U.S. income taxes paid on these earnings. In 2017, we were able to make a reasonable estimate, however, we are continuing to gather information to more precisely calculate the Transition Tax. For the three months ended March 31, 2018, we did not record any adjustments to these provisional amounts as we did not obtain sufficient information to adjust the estimates previously recorded.

Earnings Per Share (EPS)

Earnings Per Share (EPS)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	13. EARNINGS PER SHARE (EPS) We present earnings per share using the two-class method. This method allocates undistributed earnings between common shares and non-vested share based payment awards that entitle the holder to non-forfeitable dividend rights. Our participating securities include non-vested restricted stock units. The following table sets forth the computation of our basic and diluted EPS available to shareholders of common stock (excluding participating securities): Three Months Ended March 31, 2018 2017 (in millions, except per share data) Numerator Net income attributable to AAM $ 89.4 $ 78.4 Less: Net income attributable to participating securities (2.2 ) (1.9 ) Net income attributable to common shareholders - Basic and Dilutive $ 87.2 $ 76.5 Denominators Basic common shares outstanding - Weighted-average shares outstanding 114.2 78.5 Less: Participating securities (2.8 ) (1.9 ) Weighted-average common shares outstanding 111.4 76.6 Effect of dilutive securities - Dilutive stock-based compensation 0.5 0.4 Diluted shares outstanding - Adjusted weighted-average shares after assumed conversions 111.9 77.0 Basic EPS $ 0.78 $ 1.00 Diluted EPS $ 0.78 $ 0.99

Reclassifications out of Accumu

Reclassifications out of Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Reclassifications out of Accumulated Other Comprehensive Income (Loss) [Abstract]
Disclosure of Reclassification Amount [Text Block]	14. RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (AOCI) Reclassification adjustments and other activity impacting accumulated other comprehensive income (loss) during the three months ended March 31, 2018 and March 31, 2017 are as follows (in millions) : Defined Benefit Plans Foreign Currency Translation Adjustments Unrecognized Gain (Loss) on Cash Flow Hedges Total Balance at December 31, 2017 $ (252.0 ) $ (34.1 ) $ (6.6 ) $ (292.7 ) Other comprehensive income before reclassifications — 37.9 14.6 52.5 Income tax effect of other comprehensive income before reclassifications — — (1.1 ) (1.1 ) Amounts reclassified from accumulated other comprehensive loss 1.7 (a) — 1.6 (b) 3.3 Income taxes reclassified into net income (0.4 ) — — (0.4 ) Net current period other comprehensive income 1.3 37.9 15.1 54.3 Balance at March 31, 2018 $ (250.7 ) $ 3.8 $ 8.5 $ (238.4 ) Defined Benefit Plans Foreign Currency Translation Adjustments Unrecognized Gain (Loss) on Cash Flow Hedges Total Balance at December 31, 2016 $ (243.5 ) $ (122.4 ) $ (23.7 ) $ (389.6 ) Other comprehensive income (loss) before reclassifications (1.7 ) 11.9 12.7 22.9 Income tax effect of other comprehensive loss before reclassifications 0.6 — — 0.6 Amounts reclassified from accumulated other comprehensive loss 1.2 (a) — 2.8 (b) 4.0 Income taxes reclassified into net income (0.4 ) — — (0.4 ) Net current period other comprehensive income (loss) (0.3 ) 11.9 15.5 27.1 Balance at March 31, 2017 $ (243.8 ) $ (110.5 ) $ (8.2 ) $ (362.5 ) (a) The amount reclassified from AOCI included $1.5 million in cost of goods sold (COGS) and $0.3 million in selling, general & administrative expenses (SG&A) for the three months ended March 31, 2018 and $1.4 million in COGS and $(0.2) million in SG&A for the three months ended March 31, 2017. (b) The amounts reclassified from AOCI included $2.0 million in COGS and $(0.4) million in interest expense for the three months ended March 31, 2018 and $2.8 million in COGS for the three months ended March 31, 2017.

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	15. SEGMENT REPORTING Our business is organized into four business units, each representing a reportable segment under ASC 280 Segment Reporting . The four segments are Driveline, Metal Forming, Powertrain and Casting. The results of each segment are regularly reviewed by the chief operating decision maker to assess the performance of the segment and make decisions regarding the allocation of resources to the segments. Refer to Note 2 - Revenue from Contracts with Customers for a description of our product offerings by segment. We use Segment Adjusted EBITDA as the measure of earnings to assess the performance of each segment and determine the resources to be allocated to the segments. Segment Adjusted EBITDA is defined as earnings before interest expense, income taxes, depreciation and amortization for our reportable segments, excluding the impact of restructuring and acquisition-related costs and debt refinancing and redemption costs. The following tables represent information by reportable segment for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 Driveline Metal Forming Powertrain Casting Total Sales $ 1,070.6 $ 397.0 $ 291.9 $ 239.0 $ 1,998.5 Less: intersegment sales 0.2 105.9 4.8 29.2 140.1 Net external sales $ 1,070.4 $ 291.1 $ 287.1 $ 209.8 $ 1,858.4 Segment Adjusted EBITDA $ 170.0 $ 75.3 $ 50.1 $ 21.6 $ 317.0 Three Months Ended March 31, 2017 Driveline Metal Forming Powertrain Casting Total Sales $ 999.3 $ 150.0 $ — $ — $ 1,149.3 Less: intersegment sales 0.5 98.9 — — 99.4 Net external sales $ 998.8 $ 51.1 $ — $ — $ 1,049.9 Segment Adjusted EBITDA $ 153.2 $ 30.4 $ — $ — $ 183.6 The following table represents a reconciliation of Total Segment Adjusted EBITDA to consolidated income before income taxes for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 Total Segment Adjusted EBITDA $ 317.0 $ 183.6 Interest expense (53.2 ) (25.5 ) Depreciation and amortization (127.8 ) (56.2 ) Restructuring and acquisition-related costs (18.3 ) (16.0 ) Debt refinancing and redemption costs (10.3 ) — Income before income taxes $ 107.4 $ 85.9

Supplemental Guarantor Condense

Supplemental Guarantor Condensed Consolidating Financial Statements	3 Months Ended
	Mar. 31, 2018
Supplemental Guarantor Condensed Consolidating Financial Statements [Abstract]
Supplemental Guarantor Disclosure [Text Block]	16. SUPPLEMENTAL GUARANTOR CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Holdings has no significant assets other than its 100% ownership in AAM, Inc. and Metaldyne Performance Group, Inc. (MPG Inc.), and no direct subsidiaries other than AAM, Inc. and MPG Inc. The 7.75% Notes, 6.625% Notes, 6.50% Notes, 6.25% Notes (due 2026), 6.25% Notes (due 2025), and 6.25% Notes (due 2021) are senior unsecured obligations of AAM, Inc.; all of which are fully and unconditionally guaranteed, on a joint and several basis, by Holdings and substantially all domestic subsidiaries of AAM, Inc. and MPG Inc. These Condensed Consolidating Financial Statements are prepared under the equity method of accounting whereby the investments in subsidiaries are recorded at cost and adjusted for the parent’s share of the subsidiaries’ cumulative results of operations, capital contributions and distributions, and other equity changes. Condensed Consolidating Statements of Income Three Months Ended March 31, (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2018 Net sales External $ — $ 301.5 $ 582.3 $ 974.6 $ — $ 1,858.4 Intercompany — 1.0 78.0 9.5 (88.5 ) — Total net sales — 302.5 660.3 984.1 (88.5 ) 1,858.4 Cost of goods sold — 278.2 576.8 775.6 (88.5 ) 1,542.1 Gross profit — 24.3 83.5 208.5 — 316.3 Selling, general and administrative expenses — 59.8 21.9 15.6 — 97.3 Amortization of intangible assets — 1.5 22.6 0.8 — 24.9 Restructuring and acquisition-related costs — 16.3 1.1 0.9 — 18.3 Operating income (loss) — (53.3 ) 37.9 191.2 — 175.8 Non-operating income (expense), net — (70.5 ) 5.0 (2.9 ) — (68.4 ) Income (loss) before income taxes — (123.8 ) 42.9 188.3 — 107.4 Income tax expense — 1.1 0.4 16.4 — 17.9 Earnings from equity in subsidiaries 89.4 67.2 40.5 — (197.1 ) — Net income (loss) before royalties 89.4 (57.7 ) 83.0 171.9 (197.1 ) 89.5 Royalties — 84.2 1.0 (85.2 ) — — Net income after royalties 89.4 26.5 84.0 86.7 (197.1 ) 89.5 Net income attributable to noncontrolling interests — — — (0.1 ) — (0.1 ) Net income attributable to AAM $ 89.4 $ 26.5 $ 84.0 $ 86.6 $ (197.1 ) $ 89.4 Other comprehensive income, net of tax 54.3 25.6 35.1 43.7 (104.4 ) 54.3 Comprehensive income attributable to AAM $ 143.7 $ 52.1 $ 119.1 $ 130.3 $ (301.5 ) $ 143.7 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2017 Net sales External $ — $ 296.6 $ 50.1 $ 703.2 $ — $ 1,049.9 Intercompany — 0.3 66.7 4.9 (71.9 ) — Total net sales — 296.9 116.8 708.1 (71.9 ) 1,049.9 Cost of goods sold — 277.2 94.9 539.0 (71.9 ) 839.2 Gross profit — 19.7 21.9 169.1 — 210.7 Selling, general and administrative expenses — 72.5 — 8.7 — 81.2 Amortization of intangible assets — 1.3 — 0.3 — 1.6 Restructuring and acquisition-related costs — 15.3 — 0.7 — 16.0 Operating income (loss) — (69.4 ) 21.9 159.4 — 111.9 Non-operating income (expense), net — (26.2 ) 2.4 (2.2 ) — (26.0 ) Income (loss) before income taxes — (95.6 ) 24.3 157.2 — 85.9 Income tax expense (benefit) — (2.8 ) 0.1 10.2 — 7.5 Earnings (loss) from equity in subsidiaries 78.4 91.6 (0.6 ) — (169.4 ) — Net income (loss) before royalties 78.4 (1.2 ) 23.6 147.0 (169.4 ) 78.4 Royalties — 79.6 — (79.6 ) — — Net income after royalties 78.4 78.4 23.6 67.4 (169.4 ) 78.4 Net income attributable to noncontrolling interests — — — — — — Net income attributable to AAM $ 78.4 $ 78.4 $ 23.6 $ 67.4 $ (169.4 ) $ 78.4 Other comprehensive income, net of tax 27.1 27.1 10.5 26.4 (64.0 ) 27.1 Comprehensive income attributable to AAM $ 105.5 $ 105.5 $ 34.1 $ 93.8 $ (233.4 ) $ 105.5 Condensed Consolidating Balance Sheets (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated March 31, 2018 Assets Current assets Cash and cash equivalents $ — $ 115.4 $ 0.3 $ 225.0 $ — $ 340.7 Accounts receivable, net — 184.1 360.2 693.9 — 1,238.2 Intercompany receivables — 3,718.1 717.3 74.7 (4,510.1 ) — Inventories, net — 36.0 146.5 220.8 — 403.3 Prepaid expenses and other — 40.4 28.2 104.3 — 172.9 Total current assets — 4,094.0 1,252.5 1,318.7 (4,510.1 ) 2,155.1 Property, plant and equipment, net — 274.1 774.4 1,443.4 — 2,491.9 Goodwill — — 1,219.3 449.8 — 1,669.1 Intangible assets, net — 20.8 1,133.1 34.9 — 1,188.8 Intercompany notes and accounts receivable 11.7 — 224.6 — (236.3 ) — Other assets and deferred charges — 347.7 108.9 210.8 — 667.4 Investment in subsidiaries 2,990.9 2,065.7 1,336.5 — (6,393.1 ) — Total assets $ 3,002.6 $ 6,802.3 $ 6,049.3 $ 3,457.6 $ (11,139.5 ) $ 8,172.3 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ 22.0 $ — $ 9.8 $ — $ 31.8 Accounts payable — 170.1 243.9 510.5 — 924.5 Intercompany payables 1,316.6 902.2 2,190.3 101.0 (4,510.1 ) — Accrued expenses and other — 164.7 40.9 188.0 — 393.6 Total current liabilities 1,316.6 1,259.0 2,475.1 809.3 (4,510.1 ) 1,349.9 Intercompany notes and accounts payable — 9.9 — 226.4 (236.3 ) — Long-term debt, net — 3,888.0 3.7 94.5 — 3,986.2 Other long-term liabilities — 634.1 332.0 184.1 — 1,150.2 Total liabilities 1,316.6 5,791.0 2,810.8 1,314.3 (4,746.4 ) 6,486.3 Total AAM Stockholders’ equity 1,682.8 1,011.3 3,238.5 2,140.1 (6,389.9 ) 1,682.8 Noncontrolling interests in subsidiaries 3.2 — — 3.2 (3.2 ) 3.2 Total stockholders’ equity 1,686.0 1,011.3 3,238.5 2,143.3 (6,393.1 ) 1,686.0 Total liabilities and stockholders’ equity $ 3,002.6 $ 6,802.3 $ 6,049.3 $ 3,457.6 $ (11,139.5 ) $ 8,172.3 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated December 31, 2017 Assets Current assets Cash and cash equivalents $ — $ 91.9 $ 0.1 $ 284.8 $ — $ 376.8 Accounts receivable, net — 138.9 287.9 609.1 — 1,035.9 Intercompany receivables — 3,475.2 479.9 7.5 (3,962.6 ) — Inventories, net — 37.2 147.4 207.4 — 392.0 Prepaid expenses and other — 40.4 9.9 90.0 — 140.3 Total current assets — 3,783.6 925.2 1,198.8 (3,962.6 ) 1,945.0 Property, plant and equipment, net — 250.9 786.8 1,365.2 — 2,402.9 Goodwill — — 1,218.4 435.9 — 1,654.3 Intangible assets, net — 21.0 1,155.6 35.9 — 1,212.5 Intercompany notes and accounts receivable 11.7 — 243.5 — (255.2 ) — Other assets and deferred charges — 349.1 122.8 196.2 — 668.1 Investment in subsidiaries 2,841.3 1,955.2 1,280.1 — (6,076.6 ) — Total assets $ 2,853.0 $ 6,359.8 $ 5,732.4 $ 3,232.0 $ (10,294.4 ) $ 7,882.8 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ — $ — $ 5.9 $ — $ 5.9 Accounts payable — 139.0 204.6 455.4 — 799.0 Intercompany payables 1,313.0 563.7 2,017.7 68.2 (3,962.6 ) — Accrued expenses and other — 181.6 52.4 177.5 — 411.5 Total current liabilities 1,313.0 884.3 2,274.7 707.0 (3,962.6 ) 1,216.4 Intercompany notes and accounts payable — 11.7 — 243.5 (255.2 ) — Long-term debt, net — 3,894.6 4.4 70.3 — 3,969.3 Other long-term liabilities — 639.1 333.2 184.8 — 1,157.1 Total liabilities 1,313.0 5,429.7 2,612.3 1,205.6 (4,217.8 ) 6,342.8 Total AAM Stockholders’ equity 1,536.0 930.1 3,120.1 2,022.4 (6,072.6 ) 1,536.0 Noncontrolling interests in subsidiaries 4.0 — — 4.0 (4.0 ) 4.0 Total stockholders’ equity 1,540.0 930.1 3,120.1 2,026.4 (6,076.6 ) 1,540.0 Total liabilities and stockholders’ equity $ 2,853.0 $ 6,359.8 $ 5,732.4 $ 3,232.0 $ (10,294.4 ) $ 7,882.8 Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2018 Net cash provided by (used in) operating activities $ — $ 46.5 $ 39.0 $ (18.6 ) $ — $ 66.9 Investing activities Purchases of property, plant and equipment — (21.5 ) (37.6 ) (71.7 ) — (130.8 ) Proceeds from sale of property, plant and equipment — — 0.3 0.1 — 0.4 Purchase buyouts of leased equipment — — (0.5 ) — — (0.5 ) Acquisition of business, net of cash acquired — — — (1.3 ) — (1.3 ) Intercompany activity — (0.1 ) 0.1 — — — Net cash used in investing activities — (21.6 ) (37.7 ) (72.9 ) — (132.2 ) Financing activities Net debt activity — 8.9 (0.2 ) 25.8 — 34.5 Debt issuance costs — (6.8 ) — — — (6.8 ) Purchase of treasury stock (3.5 ) — — — — (3.5 ) Purchase of noncontrolling interest — — (0.9 ) — — (0.9 ) Intercompany activity 3.5 (3.5 ) — — — — Net cash provided by (used in) financing activities — (1.4 ) (1.1 ) 25.8 — 23.3 Effect of exchange rate changes on cash — — — 5.9 — 5.9 Net increase (decrease) in cash and cash equivalents — 23.5 0.2 (59.8 ) — (36.1 ) Cash and cash equivalents at beginning of period — 91.9 0.1 284.8 — 376.8 Cash and cash equivalents at end of period $ — $ 115.4 $ 0.3 $ 225.0 $ — $ 340.7 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2017 Net cash provided by (used in) operating activities $ — $ 161.8 $ 5.3 $ (104.8 ) — $ 62.3 Investing activities Purchases of property, plant and equipment — (11.6 ) (5.2 ) (18.1 ) — (34.9 ) Proceeds from sale of property, plant and equipment — 0.2 — 0.6 — 0.8 Purchase buyouts of leased equipment — (2.3 ) — — — (2.3 ) Proceeds from sale of business, net — 7.5 (1.6 ) — — 5.9 Acquisition of business, net of cash acquired — — — (144.1 ) — (144.1 ) Net cash used in investing activities — (6.2 ) (6.8 ) (161.6 ) — (174.6 ) Financing activities Net debt activity — 1,199.8 (0.1 ) (0.5 ) — 1,199.2 Debt issuance costs — (21.2 ) — — — (21.2 ) Purchase of treasury stock (5.2 ) — — — — (5.2 ) Intercompany activity 5.2 (5.2 ) — — — — Net cash provided by (used in) financing activities — 1,173.4 (0.1 ) (0.5 ) — 1,172.8 Effect of exchange rate changes on cash — — — 1.7 — 1.7 Net increase (decrease) in cash and cash equivalents — 1,329.0 (1.6 ) (265.2 ) — 1,062.2 Cash and cash equivalents at beginning of period — 84.3 1.6 395.3 — 481.2 Cash and cash equivalents at end of period $ — $ 1,413.3 $ — $ 130.1 $ — $ 1,543.4

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2018
Subsequent Event [Line Items]
Subsequent Events [Text Block]	17. SUBSEQUENT EVENT In April 2018, we completed the sale of the aftermarket business associated with our Powertrain segment for approximately $50 million , of which we received net proceeds of approximately $47 million . We expect to record a pre-tax gain of $15 to $20 million for this transaction during the second quarter of 2018. The impact to our Condensed Consolidated Balance Sheet is immaterial.

Organization and Basis of Pre25

Organization and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation We have prepared the accompanying interim condensed consolidated financial statements in accordance with the instructions to Form 10-Q under the Securities Exchange Act of 1934. These condensed consolidated financial statements are unaudited but include all normal recurring adjustments, which we consider necessary for a fair presentation of the information set forth herein. Results of operations for the periods presented are not necessarily indicative of the results for the full fiscal year. The balance sheet at December 31, 2017 presented herein has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America (GAAP) for complete consolidated financial statements. In order to prepare the accompanying interim condensed consolidated financial statements, we are required to make estimates and assumptions that affect the reported amounts and disclosures in our interim condensed consolidated financial statements. Actual results could differ from those estimates. For further information, refer to the audited consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2017 .
New Accounting Pronouncements, Policy [Policy Text Block]	Effect of New Accounting Standards Accounting Standards Update 2018-02 On February 14, 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220). ASU 2018-02 allows companies the option to reclassify disproportionate tax effects in accumulated other comprehensive income (AOCI) caused by the 2017 Tax Cuts and Jobs Act, also known as stranded tax effects, to retained earnings. ASU 2018-02 also requires expanded disclosures related to disproportionate income tax effects from AOCI, some of which are applicable to all companies regardless of whether the option to reclassify the stranded tax effects is exercised. This guidance becomes effective at the beginning of our 2019 fiscal year, however early adoption is permitted for financial statements which have not yet been issued. We are currently assessing the impact that this standard will have on our consolidated financial statements. Accounting Standards Update 2017-04 On January 26, 2017, the FASB issued ASU 2017-04 - Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment . The amendments in this update modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. An entity no longer will determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination, or what is referred to under existing guidance as "Step 2." Instead, under the amendments in this update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. This guidance becomes effective at the beginning of our 2020 fiscal year and early adoption is permitted. The guidance requires a prospective transition method. We do not expect the adoption of this guidance to have a material effect on our consolidated financial statements, however, goodwill could be more susceptible to impairment in periods subsequent to adoption. Accounting Standards Update 2016-02 On February 25, 2016, the FASB issued ASU 2016-02 - Leases (Topic 842) , which supersedes the existing lease accounting guidance and establishes new criteria for recognizing lease assets and liabilities. The most significant impact of the update, to AAM, is that a lessee will be required to recognize a "right-of-use" asset and lease liability for operating lease agreements that were not previously included on the balance sheet under the existing lease guidance. A lessee will be permitted to make a policy election, excluding recognition of the right-of-use asset and associated liability for lease terms of 12 months or less. Expense recognition in the statement of income along with cash flow statement classification for both financing (capital) and operating leases under the new standard will not be significantly changed from existing lease guidance. This guidance becomes effective for AAM at the beginning of our 2019 fiscal year and requires transition under a modified retrospective method. We are currently assessing the impact that this standard will have on our consolidated financial statements.

Revenue from Contracts with C26

Revenue from Contracts with Customers Disaggregation of Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Table Text Block]	Disaggregation of Net Sales Net sales recognized from contracts with customers, disaggregated by segment and geographical location, are presented in the following table for the three months ended March 31, 2018 and 2017. Net sales are attributed to regions based on the location of production. Intersegment sales have been excluded from the table. Three Months Ended March 31, 2018 Driveline Metal Forming Powertrain Casting Total North America $ 885.3 $ 216.3 $ 199.2 $ 209.8 $ 1,510.6 Asia 122.8 1.4 31.1 — 155.3 Europe 29.0 73.4 55.9 — 158.3 South America 33.3 — 0.9 — 34.2 Total $ 1,070.4 $ 291.1 $ 287.1 $ 209.8 $ 1,858.4 Three Months Ended March 31, 2017 Driveline Metal Forming Powertrain Casting Total North America $ 865.2 $ 51.1 $ — $ — $ 916.3 Asia 85.5 — — — 85.5 Europe 20.7 — — — 20.7 South America 27.4 — — — 27.4 Total $ 998.8 $ 51.1 $ — $ — $ 1,049.9

Revenue from Contracts with C27

Revenue from Contracts with Customers Contract Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Contract with Customer, Asset and Liability [Abstract]
Contract with Customer, Asset and Liability [Table Text Block]	Contract Assets and Liabilities The following table summarizes our beginning and ending balances for accounts receivable and contract liabilities associated with our contracts with customers: Accounts Receivable, Net Contract Liabilities (Current) Contract Liabilities (Long-term) December 31, 2017 $ 1,035.9 $ 34.1 $ 78.8 March 31, 2018 1,238.2 34.0 77.6 Increase/(decrease) $ 202.3 $ (0.1 ) $ (1.2 )

Restructuring and Acquisition28

Restructuring and Acquisition-Related Costs (Tables)	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs [Table Text Block]	In 2016, AAM initiated actions under a global restructuring program focused on creating a more streamlined organization in addition to reducing our cost structure and preparing for acquisition integration activities. A summary of this activity for the first three months of 2018 and 2017 is shown below: Severance Charges Implementation Costs Total (in millions) Accrual as of December 31, 2016 $ 0.6 $ 9.2 $ 9.8 Charges 1.2 5.6 6.8 Cash utilization (1.1 ) (1.5 ) (2.6 ) Accrual as of March 31, 2017 $ 0.7 $ 13.3 $ 14.0 Accrual as of December 31, 2017 $ 0.3 $ — $ 0.3 Charges 0.2 3.9 4.1 Cash utilization (0.4 ) (0.5 ) (0.9 ) Accrual as of March 31, 2018 $ 0.1 $ 3.4 $ 3.5
Business Combination, Separately Recognized Transactions [Table Text Block]	2017, we completed the acquisitions of Metaldyne Performance Group, Inc. (MPG) and USM Mexico Manufacturing LLC (USM Mexico). During the three months ended March 31, 2018 , we incurred the following charges related to these acquisitions: Acquisition-Related Costs Integration Expenses Total (in millions) Charges $ 1.1 $ 13.1 $ 14.2 Total restructuring and acquisition-related charges $ 18.3

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Mar. 31, 2018
Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The acquisition of MPG was accounted for under the acquisition method under ASC 805 with the purchase price allocated to the identifiable assets and liabilities of the acquired company based on the respective fair values of the assets and liabilities. The following represents the fair values of the assets acquired and liabilities assumed resulting from the acquisition, as well as the calculation of goodwill: (in millions) April 6, 2017 Cash consideration $ 953.5 Share consideration 576.7 Total consideration transferred $ 1,530.2 Fair value of MPG noncontrolling interests 3.6 Total fair value of MPG $ 1,533.8 Cash and cash equivalents $ 202.1 Accounts receivable 403.1 Inventories 199.0 Prepaid expenses and other long-term assets 119.9 Property, plant and equipment 971.8 Intangible assets 1,223.1 Total assets acquired $ 3,119.0 Accounts payable 287.8 Accrued expenses and other 137.7 Deferred income tax liabilities 580.2 Debt 1,918.7 Postretirement benefits and other long-term liabilities 54.1 Net assets acquired $ 140.5 Goodwill $ 1,393.3
USM Mexico Manufacturing LLC [Member]
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	On March 1, 2017, AAM completed the acquisition of 100% of USM Mexico, a former subsidiary of U.S. Manufacturing Corporation (USM). The purchase price was funded with available cash and the acquisition was accounted for under the acquisition method. USM Mexico includes USM's operations in Guanajuato, Mexico, which has historically been one of the largest suppliers to AAM's Guanajuato Manufacturing Complex. This acquisition allows AAM to vertically integrate the supply chain and helps ensure continuity of supply for certain parts to our largest manufacturing facility. The following represents the fair value of the assets acquired and liabilities assumed resulting from the acquisition, as well as the calculation of goodwill: (in millions) March 1, 2017 Contractual purchase price $ 162.5 Adjustment to contractual purchase price for working capital settlement 2.5 Adjustment to contractual purchase price for capital equipment 4.9 Adjustment to contractual purchase price for settlement of existing accounts payable balance (22.8 ) Cash acquired (0.5 ) Adjusted purchase price, net of cash acquired $ 146.6 Accounts receivable 1.1 Inventories 4.8 Prepaid expenses and other 3.6 Property, plant and equipment 38.4 Intangible assets 31.7 Total assets acquired $ 79.6 Accounts payable 10.8 Accrued expenses and other 2.7 Deferred income tax liabilities 1.2 Net assets acquired $ 64.9 Goodwill $ 81.7

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	Goodwill The following table provides a reconciliation of changes in goodwill for the three months ended March 31, 2018 : Driveline Metal Forming Powertrain Casting Consolidated (in millions) Balance as of December 31, 2017 $ 211.1 $ 558.9 $ 478.8 $ 405.5 $ 1,654.3 Acquisition of MPG — 0.9 — — 0.9 Acquisition of USM Mexico 1.3 — — — 1.3 Foreign currency translation (0.2 ) 4.7 8.1 — 12.6 Balance as of March 31, 2018 $ 212.2 $ 564.5 $ 486.9 $ 405.5 $ 1,669.1
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The following table provides a reconciliation of the gross carrying amount and associated accumulated amortization for AAM's total intangible assets, which are all subject to amortization: March 31, December 31, 2018 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in millions) Capitalized computer software $ 36.8 $ (15.7 ) $ 21.1 $ 35.6 $ (14.3 ) $ 21.3 e-AAM in-process research and development 5.8 (0.2 ) 5.6 5.9 — 5.9 Customer platforms 952.2 (70.5 ) 881.7 952.2 (52.9 ) 899.3 Customer relationships 151.8 (9.9 ) 141.9 151.8 (7.3 ) 144.5 Technology and other 150.8 (12.3 ) 138.5 150.8 (9.3 ) 141.5 Total $ 1,297.4 $ (108.6 ) $ 1,188.8 $ 1,296.3 $ (83.8 ) $ 1,212.5 Amortization expense for these intangible assets was $24.9 million for the three months ended March 31, 2018 , and $1.6 million for the three months ended March 31, 2017 . Estimated amortization expense for each of the years 2018 through 2022 is approximately $100 million .

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Schedule of Inventory, Current [Table Text Block]	Inventories consist of the following: March 31, 2018 December 31, 2017 (in millions) Raw materials and work-in-progress $ 337.0 $ 319.7 Finished goods 84.6 89.6 Gross inventories 421.6 409.3 Inventory valuation reserves (18.3 ) (17.3 ) Inventories, net $ 403.3 $ 392.0

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	Long-term debt consists of the following: March 31, 2018 December 31, 2017 (in millions) Revolving Credit Facility $ — $ — Term Loan A Facility 92.5 92.5 Term Loan B Facility 1,526.8 1,526.8 7.75% Notes due 2019 200.0 200.0 6.625% Notes due 2022 550.0 550.0 6.50% Notes due 2027 500.0 500.0 6.25% Notes due 2026 400.0 — 6.25% Notes due 2025 700.0 700.0 6.25% Notes due 2021 16.9 400.0 Foreign credit facilities 81.2 53.2 Capital lease obligations 27.5 28.3 Total debt 4,094.9 4,050.8 Less: Current portion of long-term debt 31.8 5.9 Long-term debt 4,063.1 4,044.9 Less: Debt issuance costs 76.9 75.6 Long-term debt, net $ 3,986.2 $ 3,969.3

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	The estimated fair value of our financial assets and liabilities that are recognized at fair value on a recurring basis, using available market information and other observable data, are as follows: March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Input (in millions) Balance Sheet Classification Cash equivalents $ 88.0 $ 88.0 $ 72.8 $ 72.8 Level 1 Prepaid expenses and other Cash flow hedges - currency forward contracts 2.7 2.7 0.1 0.1 Level 2 Cash flow hedges - variable-to-fixed interest rate swap 1.5 1.5 1.3 1.3 Level 2 Nondesignated - currency forward contracts 1.6 1.6 — — Level 2 Other assets and deferred charges Cash flow hedges - currency forward contracts 2.2 2.2 0.2 0.2 Level 2 Cash flow hedges - variable-to-fixed interest rate swap 4.5 4.5 0.9 0.9 Level 2 Accrued expenses and other Cash flow hedges - currency forward contracts 1.2 1.2 6.0 6.0 Level 2 Nondesignated - currency forward contracts — — 2.8 2.8 Level 2 Postretirement benefits and other long-term liabilities Cash flow hedges - currency forward contracts — — 2.6 2.6 Level 2 Cash flow hedges - variable-to-fixed interest rate swap — — 0.3 0.3 Level 2
Fair Value, Financial Instruments not Carried at Fair Value [Table Text Block]	We estimated the fair value of the amounts outstanding on our debt using available market information and other observable data, to be as follows: March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Input (in millions) Revolving Credit Facility $ — $ — $ — $ — Level 2 Term Loan A Facility 92.5 92.8 92.5 92.5 Level 2 Term Loan B Facility 1,526.8 1,533.0 1,526.8 1,528.7 Level 2 7.75% Notes due 2019 200.0 211.5 200.0 217.5 Level 2 6.625% Notes due 2022 550.0 567.9 550.0 570.2 Level 2 6.50% Notes due 2027 500.0 499.8 500.0 527.5 Level 2 6.25% Notes due 2026 400.0 397.4 — — Level 2 6.25% Notes due 2025 700.0 697.3 700.0 736.8 Level 2 6.25% Notes due 2021 16.9 17.2 400.0 410.0 Level 2

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following table summarizes the reclassification of derivative gains and losses into net income from accumulated other comprehensive income (loss) for those derivative instruments designated as cash flow hedges under ASC 815 - Derivatives and Hedging : Location Gain (Loss) Reclassified Total of Financial Gain Expected of Gain (Loss) During Three Months Ended Statement to be Reclassified Reclassified into March 31, Line Item During the Net Income 2018 2017 2018 Next 12 Months (in millions) Currency forward contracts Cost of Goods Sold $ (2.0 ) $ (2.8 ) $ 1,542.1 $ 1.6 Variable-to-fixed interest rate swap Interest Expense 0.4 — 53.2 2.3 The following table summarizes the amount and location of gains recognized in the Condensed Consolidated Statements of Income for those derivative instruments not designated as hedging instruments under ASC 815: Gain Recognized During Total of Financial Location of Gain Three Months Ended Statement Line Recognized in March 31, Item Net Income 2018 2017 2018 (in millions) Currency forward contracts Cost of Goods Sold $ 4.0 $ 3.5 $ 1,542.1

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Schedule of Net Benefit (Credits) Costs [Table Text Block]	The components of net periodic benefit cost (credit) are as follows: Pension Benefits Three Months Ended March 31, 2018 2017 (in millions) Service cost $ 1.1 $ 0.8 Interest cost 6.9 6.8 Expected asset return (11.5 ) (10.5 ) Amortized loss 2.2 1.7 Curtailment 3.2 — Net periodic benefit cost (credit) $ 1.9 $ (1.2 ) Other Postretirement Benefits Three Months Ended March 31, 2018 2017 (in millions) Service cost $ 0.1 $ 0.1 Interest cost 3.1 3.3 Amortized loss 0.2 0.2 Amortized prior service credit (0.7 ) (0.7 ) Net periodic benefit cost $ 2.7 $ 2.9

Product Warranties (Tables)

Product Warranties (Tables)	3 Months Ended
	Mar. 31, 2018
Product Warranties Disclosures [Abstract]
Schedule of Product Warranty Liability [Table Text Block]	The following table provides a reconciliation of changes in the product warranty liability: Three Months Ended March 31, 2018 2017 (in millions) Beginning balance $ 49.5 $ 42.9 Accruals 4.3 5.5 Payments (0.5 ) (0.9 ) Adjustment to prior period accruals — (0.2 ) Foreign currency translation 0.3 0.2 Ending balance $ 53.6 $ 47.5

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the computation of our basic and diluted EPS available to shareholders of common stock (excluding participating securities): Three Months Ended March 31, 2018 2017 (in millions, except per share data) Numerator Net income attributable to AAM $ 89.4 $ 78.4 Less: Net income attributable to participating securities (2.2 ) (1.9 ) Net income attributable to common shareholders - Basic and Dilutive $ 87.2 $ 76.5 Denominators Basic common shares outstanding - Weighted-average shares outstanding 114.2 78.5 Less: Participating securities (2.8 ) (1.9 ) Weighted-average common shares outstanding 111.4 76.6 Effect of dilutive securities - Dilutive stock-based compensation 0.5 0.4 Diluted shares outstanding - Adjusted weighted-average shares after assumed conversions 111.9 77.0 Basic EPS $ 0.78 $ 1.00 Diluted EPS $ 0.78 $ 0.99

Reclassifications out of Accu38

Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Reclassifications out of Accumulated Other Comprehensive Income (Loss) [Abstract]
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	Reclassification adjustments and other activity impacting accumulated other comprehensive income (loss) during the three months ended March 31, 2018 and March 31, 2017 are as follows (in millions) : Defined Benefit Plans Foreign Currency Translation Adjustments Unrecognized Gain (Loss) on Cash Flow Hedges Total Balance at December 31, 2017 $ (252.0 ) $ (34.1 ) $ (6.6 ) $ (292.7 ) Other comprehensive income before reclassifications — 37.9 14.6 52.5 Income tax effect of other comprehensive income before reclassifications — — (1.1 ) (1.1 ) Amounts reclassified from accumulated other comprehensive loss 1.7 (a) — 1.6 (b) 3.3 Income taxes reclassified into net income (0.4 ) — — (0.4 ) Net current period other comprehensive income 1.3 37.9 15.1 54.3 Balance at March 31, 2018 $ (250.7 ) $ 3.8 $ 8.5 $ (238.4 ) Defined Benefit Plans Foreign Currency Translation Adjustments Unrecognized Gain (Loss) on Cash Flow Hedges Total Balance at December 31, 2016 $ (243.5 ) $ (122.4 ) $ (23.7 ) $ (389.6 ) Other comprehensive income (loss) before reclassifications (1.7 ) 11.9 12.7 22.9 Income tax effect of other comprehensive loss before reclassifications 0.6 — — 0.6 Amounts reclassified from accumulated other comprehensive loss 1.2 (a) — 2.8 (b) 4.0 Income taxes reclassified into net income (0.4 ) — — (0.4 ) Net current period other comprehensive income (loss) (0.3 ) 11.9 15.5 27.1 Balance at March 31, 2017 $ (243.8 ) $ (110.5 ) $ (8.2 ) $ (362.5 ) (a) The amount reclassified from AOCI included $1.5 million in cost of goods sold (COGS) and $0.3 million in selling, general & administrative expenses (SG&A) for the three months ended March 31, 2018 and $1.4 million in COGS and $(0.2) million in SG&A for the three months ended March 31, 2017. (b) The amounts reclassified from AOCI included $2.0 million in COGS and $(0.4) million in interest expense for the three months ended March 31, 2018 and $2.8 million in COGS for the three months ended March 31, 2017.

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	The following tables represent information by reportable segment for the three months ended March 31, 2018 and 2017 : Three Months Ended March 31, 2018 Driveline Metal Forming Powertrain Casting Total Sales $ 1,070.6 $ 397.0 $ 291.9 $ 239.0 $ 1,998.5 Less: intersegment sales 0.2 105.9 4.8 29.2 140.1 Net external sales $ 1,070.4 $ 291.1 $ 287.1 $ 209.8 $ 1,858.4 Segment Adjusted EBITDA $ 170.0 $ 75.3 $ 50.1 $ 21.6 $ 317.0 Three Months Ended March 31, 2017 Driveline Metal Forming Powertrain Casting Total Sales $ 999.3 $ 150.0 $ — $ — $ 1,149.3 Less: intersegment sales 0.5 98.9 — — 99.4 Net external sales $ 998.8 $ 51.1 $ — $ — $ 1,049.9 Segment Adjusted EBITDA $ 153.2 $ 30.4 $ — $ — $ 183.6
Reconciliation of Total Segment Adjusted EBITDA to Income Before Income Taxes [Table Text Block]	The following table represents a reconciliation of Total Segment Adjusted EBITDA to consolidated income before income taxes for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 Total Segment Adjusted EBITDA $ 317.0 $ 183.6 Interest expense (53.2 ) (25.5 ) Depreciation and amortization (127.8 ) (56.2 ) Restructuring and acquisition-related costs (18.3 ) (16.0 ) Debt refinancing and redemption costs (10.3 ) — Income before income taxes $ 107.4 $ 85.9

Supplemental Guarantor Conden40

Supplemental Guarantor Condensed Consolidating Financial Statements (Tables)	3 Months Ended
	Mar. 31, 2018
Supplemental Guarantor Condensed Consolidating Financial Statements [Abstract]
Supplemental Guarantor Consolidating Income Statement [Table Text Block]	Condensed Consolidating Statements of Income Three Months Ended March 31, (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2018 Net sales External $ — $ 301.5 $ 582.3 $ 974.6 $ — $ 1,858.4 Intercompany — 1.0 78.0 9.5 (88.5 ) — Total net sales — 302.5 660.3 984.1 (88.5 ) 1,858.4 Cost of goods sold — 278.2 576.8 775.6 (88.5 ) 1,542.1 Gross profit — 24.3 83.5 208.5 — 316.3 Selling, general and administrative expenses — 59.8 21.9 15.6 — 97.3 Amortization of intangible assets — 1.5 22.6 0.8 — 24.9 Restructuring and acquisition-related costs — 16.3 1.1 0.9 — 18.3 Operating income (loss) — (53.3 ) 37.9 191.2 — 175.8 Non-operating income (expense), net — (70.5 ) 5.0 (2.9 ) — (68.4 ) Income (loss) before income taxes — (123.8 ) 42.9 188.3 — 107.4 Income tax expense — 1.1 0.4 16.4 — 17.9 Earnings from equity in subsidiaries 89.4 67.2 40.5 — (197.1 ) — Net income (loss) before royalties 89.4 (57.7 ) 83.0 171.9 (197.1 ) 89.5 Royalties — 84.2 1.0 (85.2 ) — — Net income after royalties 89.4 26.5 84.0 86.7 (197.1 ) 89.5 Net income attributable to noncontrolling interests — — — (0.1 ) — (0.1 ) Net income attributable to AAM $ 89.4 $ 26.5 $ 84.0 $ 86.6 $ (197.1 ) $ 89.4 Other comprehensive income, net of tax 54.3 25.6 35.1 43.7 (104.4 ) 54.3 Comprehensive income attributable to AAM $ 143.7 $ 52.1 $ 119.1 $ 130.3 $ (301.5 ) $ 143.7 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2017 Net sales External $ — $ 296.6 $ 50.1 $ 703.2 $ — $ 1,049.9 Intercompany — 0.3 66.7 4.9 (71.9 ) — Total net sales — 296.9 116.8 708.1 (71.9 ) 1,049.9 Cost of goods sold — 277.2 94.9 539.0 (71.9 ) 839.2 Gross profit — 19.7 21.9 169.1 — 210.7 Selling, general and administrative expenses — 72.5 — 8.7 — 81.2 Amortization of intangible assets — 1.3 — 0.3 — 1.6 Restructuring and acquisition-related costs — 15.3 — 0.7 — 16.0 Operating income (loss) — (69.4 ) 21.9 159.4 — 111.9 Non-operating income (expense), net — (26.2 ) 2.4 (2.2 ) — (26.0 ) Income (loss) before income taxes — (95.6 ) 24.3 157.2 — 85.9 Income tax expense (benefit) — (2.8 ) 0.1 10.2 — 7.5 Earnings (loss) from equity in subsidiaries 78.4 91.6 (0.6 ) — (169.4 ) — Net income (loss) before royalties 78.4 (1.2 ) 23.6 147.0 (169.4 ) 78.4 Royalties — 79.6 — (79.6 ) — — Net income after royalties 78.4 78.4 23.6 67.4 (169.4 ) 78.4 Net income attributable to noncontrolling interests — — — — — — Net income attributable to AAM $ 78.4 $ 78.4 $ 23.6 $ 67.4 $ (169.4 ) $ 78.4 Other comprehensive income, net of tax 27.1 27.1 10.5 26.4 (64.0 ) 27.1 Comprehensive income attributable to AAM $ 105.5 $ 105.5 $ 34.1 $ 93.8 $ (233.4 ) $ 105.5
Supplemental Guarantor Consolidating Balance Sheet [Table Text Block]	Condensed Consolidating Balance Sheets (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated March 31, 2018 Assets Current assets Cash and cash equivalents $ — $ 115.4 $ 0.3 $ 225.0 $ — $ 340.7 Accounts receivable, net — 184.1 360.2 693.9 — 1,238.2 Intercompany receivables — 3,718.1 717.3 74.7 (4,510.1 ) — Inventories, net — 36.0 146.5 220.8 — 403.3 Prepaid expenses and other — 40.4 28.2 104.3 — 172.9 Total current assets — 4,094.0 1,252.5 1,318.7 (4,510.1 ) 2,155.1 Property, plant and equipment, net — 274.1 774.4 1,443.4 — 2,491.9 Goodwill — — 1,219.3 449.8 — 1,669.1 Intangible assets, net — 20.8 1,133.1 34.9 — 1,188.8 Intercompany notes and accounts receivable 11.7 — 224.6 — (236.3 ) — Other assets and deferred charges — 347.7 108.9 210.8 — 667.4 Investment in subsidiaries 2,990.9 2,065.7 1,336.5 — (6,393.1 ) — Total assets $ 3,002.6 $ 6,802.3 $ 6,049.3 $ 3,457.6 $ (11,139.5 ) $ 8,172.3 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ 22.0 $ — $ 9.8 $ — $ 31.8 Accounts payable — 170.1 243.9 510.5 — 924.5 Intercompany payables 1,316.6 902.2 2,190.3 101.0 (4,510.1 ) — Accrued expenses and other — 164.7 40.9 188.0 — 393.6 Total current liabilities 1,316.6 1,259.0 2,475.1 809.3 (4,510.1 ) 1,349.9 Intercompany notes and accounts payable — 9.9 — 226.4 (236.3 ) — Long-term debt, net — 3,888.0 3.7 94.5 — 3,986.2 Other long-term liabilities — 634.1 332.0 184.1 — 1,150.2 Total liabilities 1,316.6 5,791.0 2,810.8 1,314.3 (4,746.4 ) 6,486.3 Total AAM Stockholders’ equity 1,682.8 1,011.3 3,238.5 2,140.1 (6,389.9 ) 1,682.8 Noncontrolling interests in subsidiaries 3.2 — — 3.2 (3.2 ) 3.2 Total stockholders’ equity 1,686.0 1,011.3 3,238.5 2,143.3 (6,393.1 ) 1,686.0 Total liabilities and stockholders’ equity $ 3,002.6 $ 6,802.3 $ 6,049.3 $ 3,457.6 $ (11,139.5 ) $ 8,172.3 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated December 31, 2017 Assets Current assets Cash and cash equivalents $ — $ 91.9 $ 0.1 $ 284.8 $ — $ 376.8 Accounts receivable, net — 138.9 287.9 609.1 — 1,035.9 Intercompany receivables — 3,475.2 479.9 7.5 (3,962.6 ) — Inventories, net — 37.2 147.4 207.4 — 392.0 Prepaid expenses and other — 40.4 9.9 90.0 — 140.3 Total current assets — 3,783.6 925.2 1,198.8 (3,962.6 ) 1,945.0 Property, plant and equipment, net — 250.9 786.8 1,365.2 — 2,402.9 Goodwill — — 1,218.4 435.9 — 1,654.3 Intangible assets, net — 21.0 1,155.6 35.9 — 1,212.5 Intercompany notes and accounts receivable 11.7 — 243.5 — (255.2 ) — Other assets and deferred charges — 349.1 122.8 196.2 — 668.1 Investment in subsidiaries 2,841.3 1,955.2 1,280.1 — (6,076.6 ) — Total assets $ 2,853.0 $ 6,359.8 $ 5,732.4 $ 3,232.0 $ (10,294.4 ) $ 7,882.8 Liabilities and Stockholders’ Equity Current liabilities Current portion of long-term debt $ — $ — $ — $ 5.9 $ — $ 5.9 Accounts payable — 139.0 204.6 455.4 — 799.0 Intercompany payables 1,313.0 563.7 2,017.7 68.2 (3,962.6 ) — Accrued expenses and other — 181.6 52.4 177.5 — 411.5 Total current liabilities 1,313.0 884.3 2,274.7 707.0 (3,962.6 ) 1,216.4 Intercompany notes and accounts payable — 11.7 — 243.5 (255.2 ) — Long-term debt, net — 3,894.6 4.4 70.3 — 3,969.3 Other long-term liabilities — 639.1 333.2 184.8 — 1,157.1 Total liabilities 1,313.0 5,429.7 2,612.3 1,205.6 (4,217.8 ) 6,342.8 Total AAM Stockholders’ equity 1,536.0 930.1 3,120.1 2,022.4 (6,072.6 ) 1,536.0 Noncontrolling interests in subsidiaries 4.0 — — 4.0 (4.0 ) 4.0 Total stockholders’ equity 1,540.0 930.1 3,120.1 2,026.4 (6,076.6 ) 1,540.0 Total liabilities and stockholders’ equity $ 2,853.0 $ 6,359.8 $ 5,732.4 $ 3,232.0 $ (10,294.4 ) $ 7,882.8
Supplemental Guarantor Consolidating Statement of Cash Flows [Table Text Block]	Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, (in millions) Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2018 Net cash provided by (used in) operating activities $ — $ 46.5 $ 39.0 $ (18.6 ) $ — $ 66.9 Investing activities Purchases of property, plant and equipment — (21.5 ) (37.6 ) (71.7 ) — (130.8 ) Proceeds from sale of property, plant and equipment — — 0.3 0.1 — 0.4 Purchase buyouts of leased equipment — — (0.5 ) — — (0.5 ) Acquisition of business, net of cash acquired — — — (1.3 ) — (1.3 ) Intercompany activity — (0.1 ) 0.1 — — — Net cash used in investing activities — (21.6 ) (37.7 ) (72.9 ) — (132.2 ) Financing activities Net debt activity — 8.9 (0.2 ) 25.8 — 34.5 Debt issuance costs — (6.8 ) — — — (6.8 ) Purchase of treasury stock (3.5 ) — — — — (3.5 ) Purchase of noncontrolling interest — — (0.9 ) — — (0.9 ) Intercompany activity 3.5 (3.5 ) — — — — Net cash provided by (used in) financing activities — (1.4 ) (1.1 ) 25.8 — 23.3 Effect of exchange rate changes on cash — — — 5.9 — 5.9 Net increase (decrease) in cash and cash equivalents — 23.5 0.2 (59.8 ) — (36.1 ) Cash and cash equivalents at beginning of period — 91.9 0.1 284.8 — 376.8 Cash and cash equivalents at end of period $ — $ 115.4 $ 0.3 $ 225.0 $ — $ 340.7 Holdings AAM Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Elims Consolidated 2017 Net cash provided by (used in) operating activities $ — $ 161.8 $ 5.3 $ (104.8 ) — $ 62.3 Investing activities Purchases of property, plant and equipment — (11.6 ) (5.2 ) (18.1 ) — (34.9 ) Proceeds from sale of property, plant and equipment — 0.2 — 0.6 — 0.8 Purchase buyouts of leased equipment — (2.3 ) — — — (2.3 ) Proceeds from sale of business, net — 7.5 (1.6 ) — — 5.9 Acquisition of business, net of cash acquired — — — (144.1 ) — (144.1 ) Net cash used in investing activities — (6.2 ) (6.8 ) (161.6 ) — (174.6 ) Financing activities Net debt activity — 1,199.8 (0.1 ) (0.5 ) — 1,199.2 Debt issuance costs — (21.2 ) — — — (21.2 ) Purchase of treasury stock (5.2 ) — — — — (5.2 ) Intercompany activity 5.2 (5.2 ) — — — — Net cash provided by (used in) financing activities — 1,173.4 (0.1 ) (0.5 ) — 1,172.8 Effect of exchange rate changes on cash — — — 1.7 — 1.7 Net increase (decrease) in cash and cash equivalents — 1,329.0 (1.6 ) (265.2 ) — 1,062.2 Cash and cash equivalents at beginning of period — 84.3 1.6 395.3 — 481.2 Cash and cash equivalents at end of period $ — $ 1,413.3 $ — $ 130.1 $ — $ 1,543.4

Organization and Basis of Pre41

Organization and Basis of Presentation Company Information (Details)	Mar. 31, 2018EmployeesCountriesFacilities
Franchisor Disclosure [Line Items]
Entity Number of Employees | Employees	25,000
Number of Facilities | Facilities	90
Number of Countries in which Entity Operates | Countries	17

Revenue from Contracts with C42

Revenue from Contracts with Customers Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 1,858.4	$ 1,049.9
North America [Member]
Disaggregation of Revenue [Line Items]
Net sales	1,510.6	916.3
Asia [Member]
Disaggregation of Revenue [Line Items]
Net sales	155.3	85.5
Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales	158.3	20.7
South America [Member]
Disaggregation of Revenue [Line Items]
Net sales	34.2	27.4
Driveline [Member]
Disaggregation of Revenue [Line Items]
Net sales	1,070.4	998.8
Driveline [Member] | North America [Member]
Disaggregation of Revenue [Line Items]
Net sales	885.3	865.2
Driveline [Member] | Asia [Member]
Disaggregation of Revenue [Line Items]
Net sales	122.8	85.5
Driveline [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales	29	20.7
Driveline [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Net sales	33.3	27.4
Metal Forming [Member]
Disaggregation of Revenue [Line Items]
Net sales	291.1	51.1
Metal Forming [Member] | North America [Member]
Disaggregation of Revenue [Line Items]
Net sales	216.3	51.1
Metal Forming [Member] | Asia [Member]
Disaggregation of Revenue [Line Items]
Net sales	1.4	0
Metal Forming [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales	73.4	0
Metal Forming [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Net sales	0	0
Powertrain [Member]
Disaggregation of Revenue [Line Items]
Net sales	287.1	0
Powertrain [Member] | North America [Member]
Disaggregation of Revenue [Line Items]
Net sales	199.2	0
Powertrain [Member] | Asia [Member]
Disaggregation of Revenue [Line Items]
Net sales	31.1	0
Powertrain [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales	55.9	0
Powertrain [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Net sales	0.9	0
Casting [Member]
Disaggregation of Revenue [Line Items]
Net sales	209.8	0
Casting [Member] | North America [Member]
Disaggregation of Revenue [Line Items]
Net sales	209.8	0
Casting [Member] | Asia [Member]
Disaggregation of Revenue [Line Items]
Net sales	0	0
Casting [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales	0	0
Casting [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 0	$ 0

Revenue from Contracts with C43

Revenue from Contracts with Customers Contract Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Accounts receivable, net	$ 1,238.2	$ 1,035.9
Deferred revenue, current	34	34.1
Deferred revenue, noncurrent	77.6	$ 78.8
Increase (decrease) in accounts receivable	202.3
Contract liability, current, increase (decrease)	(0.1)
Contract liability, noncurrent, increase (decrease)	(1.2)
Contract liability, additions	6.7
Contract with customer, liability, revenue recognized	$ 8

Restructuring and Acquisition44

Restructuring and Acquisition-Related Costs (Details) - USD ($) $ in Millions	3 Months Ended		18 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Restructuring reserve	$ 0.3	$ 9.8
Charges	4.1	6.8
Cash utilization	(0.9)	(2.6)
Restructuring reserve	3.5	14	$ 3.5
Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve	0	9.2
Charges	3.9	5.6	28
Cash utilization	(0.5)	(1.5)
Restructuring reserve	3.4	13.3	3.4
Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve	0.3	0.6
Charges	0.2	1.2	2.8
Cash utilization	(0.4)	(1.1)
Restructuring reserve	$ 0.1	$ 0.7	$ 0.1

Restructuring Reserve Narrative

Restructuring Reserve Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and acquisition-related costs	$ 18.3	$ 16
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost Remaining	20
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost Remaining	$ 10

Business Combinations, Separate

Business Combinations, Separately Recognized Transactions Table (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring and Related Activities [Abstract]
Acquisition-related costs	$ 1.1
Integration expenses	13.1
Acquisition-related costs and integration expenses	14.2
Restructuring and acquisition-related costs	$ 18.3	$ 16

Acquisition of MPG Narrative (D

Acquisition of MPG Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 06, 2017	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017
Business Acquisition [Line Items]
Business acquisition, share price	$ 13.50
Business acquisition, equity interest issued or issuable, number of shares	0.5
Proceeds from Issuance of Long-term Debt		$ 431.4		$ 1,209.4
Business Acquisition, Pro Forma Earnings Per Share, Diluted				$ 0.83
Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Total consideration transferred			$ 1,530.2
Net debt acquired			$ 1,700
Debt acquired	$ 1,918.7
Cash acquired	(202.1)
Proceeds from Notes Payable				$ 1,200
Goodwill, purchase accounting adjustments		0.9
Intangible assets	1,223.1
Adjustment to contractual purchase price for settlement of existing accounts payable balance	(12.4)
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		738
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		$ 40
Business Acquisition, Pro Forma Revenue				1,800
Business Acquisition, Pro Forma Net Income (Loss)				95
MPG Pro Forma Net Income Adjustment				20
6.25% Notes due 2025 [Member] | Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Proceeds from Notes Payable				$ 700
Debt Instrument, Interest Rate, Stated Percentage				6.25%
6.50% Notes [Member] | Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Proceeds from Notes Payable				$ 500
Debt Instrument, Interest Rate, Stated Percentage				6.50%
Term Loan A [Member] | Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Proceeds from Issuance of Long-term Debt	100
Term Loan B [Member] | Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Proceeds from Issuance of Long-term Debt	$ 1,550

MPG Acquisition Table (Details)

MPG Acquisition Table (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017	Apr. 06, 2017
Business Acquisition [Line Items]
Goodwill		$ 1,669.1	$ 1,654.3
Metaldyne Performance Group, Inc. [Member]
Business Acquisition [Line Items]
Cash consideration	$ 953.5
Share consideration	576.7
Total consideration transferred	$ 1,530.2
Fair value of MPG noncontrolling interests				$ 3.6
Total fair value of MPG				1,533.8
Cash acquired				202.1
Accounts receivable				403.1
Inventories				199
Prepaid expenses and other				119.9
Property, plant and equipment				971.8
Intangible assets				1,223.1
Total assets acquired				3,119
Accounts payable				287.8
Accrued expenses and other				137.7
Deferred income tax liabilities				580.2
Debt acquired				1,918.7
Postretirement benefits and other long-term liabilities				54.1
Net assets acquired				140.5
Goodwill				$ 1,393.3

USM Acquisition Table (Details)

USM Acquisition Table (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Mar. 01, 2017
Business Acquisition [Line Items]
Adjusted purchase price, net of cash acquired	$ 1.3	$ 144.1
Goodwill	$ 1,669.1		$ 1,654.3
USM Mexico Manufacturing LLC [Member]
Business Acquisition [Line Items]
Contractual purchase price		162.5
Adjustment to contractual purchase price for working capital settlement				$ 2.5
Adjustment to contractual purchase price for capital equipment				4.9
Adjustment to contractual purchase price for settlement of existing accounts payable balance				(22.8)
Cash acquired				(0.5)
Adjusted purchase price, net of cash acquired		$ 146.6
Accounts receivable				1.1
Inventories				4.8
Prepaid expenses and other				3.6
Property, plant and equipment				38.4
Intangible assets				31.7
Total assets acquired				79.6
Accounts payable				10.8
Accrued expenses and other				2.7
Deferred income tax liabilities				1.2
Net assets acquired				64.9
Goodwill				$ 81.7

Goodwill Rollforward (Details)

Goodwill Rollforward (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Goodwill [Roll Forward]
Goodwill	$ 1,654.3
Goodwill, Foreign Currency Translation Gain (Loss)	12.6
Goodwill	1,669.1
Driveline [Member]
Goodwill [Roll Forward]
Goodwill	211.1
Goodwill, Foreign Currency Translation Gain (Loss)	(0.2)
Goodwill	212.2
Metal Forming [Member]
Goodwill [Roll Forward]
Goodwill	558.9
Goodwill, Foreign Currency Translation Gain (Loss)	4.7
Goodwill	564.5
Powertrain [Member]
Goodwill [Roll Forward]
Goodwill	478.8
Goodwill, Foreign Currency Translation Gain (Loss)	8.1
Goodwill	486.9
Casting [Member]
Goodwill [Roll Forward]
Goodwill	405.5
Goodwill, Foreign Currency Translation Gain (Loss)	0
Goodwill	405.5
Metaldyne Performance Group, Inc. [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0.9
Metaldyne Performance Group, Inc. [Member] | Driveline [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Metaldyne Performance Group, Inc. [Member] | Metal Forming [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0.9
Metaldyne Performance Group, Inc. [Member] | Powertrain [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Metaldyne Performance Group, Inc. [Member] | Casting [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
USM Mexico Manufacturing LLC [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	1.3
USM Mexico Manufacturing LLC [Member] | Driveline [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	1.3
USM Mexico Manufacturing LLC [Member] | Metal Forming [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
USM Mexico Manufacturing LLC [Member] | Powertrain [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
USM Mexico Manufacturing LLC [Member] | Casting [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	$ 0

Intangible Assets Table (Detail

Intangible Assets Table (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 1,297.4		$ 1,296.3
Finite-Lived Intangible Assets, Accumulated Amortization	(108.6)		(83.8)
Finite-Lived Intangible Assets, Net	1,188.8		1,212.5
Amortization of Intangible Assets	24.9	$ 1.6
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	100
Finite-Lived Intangible Assets, Amortization Expense, Year Two	100
Finite-Lived Intangible Assets, Amortization Expense, Year Three	100
Finite-Lived Intangible Assets, Amortization Expense, Year Four	100
Finite-Lived Intangible Assets, Amortization Expense, Year Five	100
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	36.8		35.6
Finite-Lived Intangible Assets, Accumulated Amortization	(15.7)		(14.3)
Finite-Lived Intangible Assets, Net	21.1		21.3
In Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	5.8		5.9
Finite-Lived Intangible Assets, Accumulated Amortization	(0.2)		0
Finite-Lived Intangible Assets, Net	5.6		5.9
Customer Platforms - Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	952.2		952.2
Finite-Lived Intangible Assets, Accumulated Amortization	(70.5)		(52.9)
Finite-Lived Intangible Assets, Net	881.7		899.3
Customer Relationships - Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	151.8		151.8
Finite-Lived Intangible Assets, Accumulated Amortization	(9.9)		(7.3)
Finite-Lived Intangible Assets, Net	141.9		144.5
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	150.8		150.8
Finite-Lived Intangible Assets, Accumulated Amortization	(12.3)		(9.3)
Finite-Lived Intangible Assets, Net	$ 138.5		$ 141.5

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Raw materials and work-in-progress	$ 337	$ 319.7
Finished goods	84.6	89.6
Gross inventories	421.6	409.3
Inventory valuation reserves	(18.3)	(17.3)
Inventories, net	$ 403.3	$ 392

Schedule of Long-Term Debt (Det

Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt, Long-term and Short-term, Combined Amount	$ 4,094.9	$ 4,050.8
Current portion of long-term debt	31.8	5.9
Long-term debt	4,063.1	4,044.9
Long-term debt, net	3,986.2	3,969.3
Total Debt Instruments excluding Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	76.9	75.6
Secured Debt [Member] | Term Loan A [Member]
Debt Instrument [Line Items]
Long-term Debt	92.5	92.5
Secured Debt [Member] | Term Loan B [Member]
Debt Instrument [Line Items]
Long-term Debt	1,526.8	1,526.8
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	0	0
Unsecured Debt [Member] | 7.75% Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	200	200
Unsecured Debt [Member] | 6.625% Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	550	550
Unsecured Debt [Member] | 6.50% Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	500	500
Unsecured Debt [Member] | 6.25% Notes Due 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt	400	0
Unsecured Debt [Member] | 6.25% Notes due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt	700	700
Unsecured Debt [Member] | 6.25% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt	16.9	400
Foreign Credit Facilities [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Amount Outstanding	81.2	53.2
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Capital lease obligations	$ 27.5	$ 28.3

New Senior Secured Credit Facil

New Senior Secured Credit Facilities Narrative (Details) - USD ($) $ in Millions	Apr. 06, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt		$ 431.4	$ 1,209.4
Secured Debt, Current		31.8		$ 5.9
Term Loan A [Member]
Debt Instrument [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost		3.8
Term Loan B [Member]
Debt Instrument [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost		11.6
Metaldyne Performance Group, Inc. [Member] | Term Loan A [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	$ 100
Metaldyne Performance Group, Inc. [Member] | Term Loan B [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	1,550
Metaldyne Performance Group, Inc. [Member] | New Multi-Currency Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 900
Secured Debt [Member] | Term Loan A & Term Loan B [Domain]
Debt Instrument [Line Items]
Secured Debt, Current		5
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Line of Credit		0		$ 0
Line of Credit Facility, Remaining Borrowing Capacity		865.3
Line of Credit Facility, Standby Letters of Credit Issued Against the Facility		$ 34.7

Issuance of New Notes Narrative

Issuance of New Notes Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Debt Instrument [Line Items]
Payments of Debt Issuance Costs	$ 6.8	$ 21.2
6.25% Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
6.25% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
6.25% Notes Due 2025 & 6.50% Notes Due 2027 [Member]
Debt Instrument [Line Items]
Payments of Debt Issuance Costs	$ 6.6
Metaldyne Performance Group, Inc. [Member] | 6.25% Notes due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.25%
Metaldyne Performance Group, Inc. [Member] | 6.50% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.50%

Other Debt Disclosures Narrativ

Other Debt Disclosures Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Apr. 12, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost	$ 10.3	$ 0
Long-term Debt, Weighted Average Interest Rate, at Point in Time	5.80%			5.70%
Foreign Credit Facilities [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 81.2			$ 53.2
Debt Instrument, Unused Borrowing Capacity, Amount	$ 135.8
6.25% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
6.25% Notes Due 2021 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Debt Instrument, Repurchase Amount	$ 383.1
Write off of Deferred Debt Issuance Cost	2.5
Debt Instrument, Tender Premiums	$ 7.8
Subsequent Event [Member] | 6.25% Notes Due 2021 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount			$ 16.9

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	$ 88	$ 72.8
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Fair Value	88	72.8
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	2.7	0.1
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	2.7	0.1
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	2.2	0.2
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	2.2	0.2
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Accrued expenses and other [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	1.2	6
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Accrued expenses and other [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	1.2	6
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Postretirement benefits and other long-term liabilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	0	2.6
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Postretirement benefits and other long-term liabilities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	0	2.6
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	1.6	0
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	1.6	0
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member] | Accrued expenses and other [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	0	2.8
Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member] | Accrued expenses and other [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Liabilities, Fair Value Disclosure	0	2.8
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Assets, at Fair Value	1.5	0
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Assets, at Fair Value	1.5	1.3
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Assets, at Fair Value	4.5	0.9
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Assets, at Fair Value	4.5	0.9
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Postretirement benefits and other long-term liabilities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	0	0.3
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Postretirement benefits and other long-term liabilities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	$ 0	$ 0.3

Fair Value of Debt (Details)

Fair Value of Debt (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Revolving Credit Facility [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit Facility, Amount Outstanding	$ 0	$ 0
Revolving Credit Facility [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit Facility, Amount Outstanding	0	0
Term Loan A [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	92.5	92.5
Term Loan A [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	92.8	92.5
Term Loan B [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	1,526.8	1,526.8
Term Loan B [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	1,533	1,528.7
7.75% Notes [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	200	200
7.75% Notes [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	211.5	217.5
6.625% Notes [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	550	550
6.625% Notes [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	567.9	570.2
6.50% Notes [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	500	500
6.50% Notes [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	499.8	527.5
6.25% Notes Due 2026 [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	400	0
6.25% Notes Due 2026 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	397.4	0
6.25% Notes due 2025 [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	700	0
6.25% Notes due 2025 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	697.3	0
6.25% Notes Due 2021 [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	16.9	400
6.25% Notes Due 2021 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 17.2	$ 410

Derivatives Narrative (Details)

Derivatives Narrative (Details) $ in Millions	Mar. 31, 2018USD ($)
Foreign Currency Forward & Foreign Currency Option Contracts [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 192.1
Debt [Member] | Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivate, Amount of Hedged Item, Through May 2018	750
Derivative, Amount of Hedged Item, Through May 2019	600
Derivative, Amount of Hedged Item, Through May 2020	450
Derivative, Amount of Hedged Item, Through May 2021	$ 200

Schedule of Derivatives (Detail

Schedule of Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Cost of goods sold	$ 1,542.1	$ 839.2
Interest expense	$ 53.2	25.5
Foreign Exchange Forward [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Description of Location of Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments in Financial Statements	Cost of Goods Sold
Derivative Instruments Not Designated as Hedging Instruments, Gain	$ 4	3.5
Foreign Exchange Forward [Member] | Cost of Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Income Statement Location Gain (Loss) Reclassified from Accumulated OCI	Cost of Goods Sold
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (2)	(2.8)
Foreign Exchange Forward [Member] | Cost of Sales [Member] | Cash Flow Hedging [Member] | Scenario, Forecast [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain to be reclassified within twelve months			$ 1.6
Interest Rate Swap [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Income Statement Location Gain (Loss) Reclassified from Accumulated OCI	Interest Expense
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0.4	$ 0
Interest Rate Swap [Member] | Interest Expense [Member] | Cash Flow Hedging [Member] | Scenario, Forecast [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain to be reclassified within twelve months			$ 2.3

Schedule of Employee Benefit Pl

Schedule of Employee Benefit Plans Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.1	$ 0.8
Interest cost	6.9	6.8
Expected asset return	(11.5)	(10.5)
Amortized loss	2.2	1.7
Curtailment	3.2	0
Net periodic benefit cost (credit)	1.9	(1.2)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.1	0.1
Interest cost	3.1	3.3
Amortized loss	0.2	0.2
Amortized prior service credit	(0.7)	(0.7)
Net periodic benefit cost	2.7	$ 2.9
Other Operating Income (Expense) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Components of net periodic benefit cost other than service cost	$ 0.2

Employee Benefit Plans and Othe

Employee Benefit Plans and Other Postretirement Benefit Plans Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent	$ 132.4	$ 134.7
Liability, Other Postretirement Defined Benefit Plan, Noncurrent	582.2	$ 583
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	2
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 17

Product Warranties (Details)

Product Warranties (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Product Warranty Rollforward
Beginning balance	$ 49.5	$ 42.9
Accruals	4.3	5.5
Payments	(0.5)	(0.9)
Adjustment to prior period accruals	0	(0.2)
Foreign currency translation	0.3	0.2
Ending balance	$ 53.6	$ 47.5

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income tax expense	$ 17.9	$ 7.5
Effective income tax rate, continuing operations	16.70%	8.70%
Unrecognized tax benefit liability, including penalties and accrued interest	$ 55.4		$ 55.2

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator
Net income attributable to AAM	$ 89.4	$ 78.4
Less: Net income attributable to participating securities	(2.2)	(1.9)
Net income attributable to common shareholders - Basic and Dilutive	$ 87.2	$ 76.5
Denominators
Basic - Weighted-average shares outstanding	114.2	78.5
Basic - Less: Participating securities	(2.8)	(1.9)
Basic - Weighted-average common shares outstanding	111.4	76.6
Effect of dilutive securities - dilutive stock-based compensation	0.5	0.4
Diluted - Adjusted weighted-average shares after assumed conversions	111.9	77
Basic EPS	$ 0.78	$ 1
Diluted EPS	$ 0.78	$ 0.99

Reclassifications out of Accu66

Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Defined benefit plans - Beginning balance	$ (252)
Defined benefit plans, net current period other comprehensive income (loss)	1.3	$ (0.3)
Defined benefit plans - Ending balance	(250.7)
Foreign currency translation adjustments - Beginning balance	(34.1)
Foreign currency translation adjustments, net current period other comprehensive income (loss)	37.9	11.9
Foreign currency translation adjustments - Ending balance	3.8
Unrecognized gain (loss) on cash flow hedges - Beginning balance	(6.6)
Other comprehensive income (loss), derivatives qualifying as hedges, tax	(1.1)	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	15.1	15.5
Unrecognized loss on cash flow hedges - Ending balance	8.5
Other comprehensive income	54.3	27.1
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Defined benefit plans - Beginning balance	(252)	(243.5)
Defined benefit plans, other comprehensive income (loss), before reclassifications	0	(1.7)
Income tax effect of other comprehensive income (loss) before reclassifications	0	0.6
Defined benefit plans, amounts reclassified from accumulated other comprehensive income (loss)	1.7	1.2
Income taxes reclassified into net income	(0.4)	(0.4)
Defined benefit plans, net current period other comprehensive income (loss)	1.3	(0.3)
Defined benefit plans - Ending balance	(250.7)	(243.8)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Foreign currency translation adjustments - Beginning balance	(34.1)	(122.4)
Foreign currency translation adjustments, other comprehensive income (loss) arising during period	37.9	11.9
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	0	0
Foreign currency translation adjustments, amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax	0	0
Foreign currency translation adjustments, net current period other comprehensive income (loss)	37.9	11.9
Foreign currency translation adjustments - Ending balance	3.8	(110.5)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
Unrecognized gain (loss) on cash flow hedges - Beginning balance	(6.6)	(23.7)
Unrecognized gain (loss) on cash flow hedges, other comprehensive income (loss) arising during period	14.6	12.7
Other comprehensive income (loss), derivatives qualifying as hedges, tax	1.1	0
Unrecognized gain (loss) on cash flow hedges, amounts reclassified from accumulated other comprehensive income (loss)	1.6	2.8
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	0	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	15.1	15.5
Unrecognized loss on cash flow hedges - Ending balance	8.5	(8.2)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated other comprehensive income (loss), net of tax - Beginning balance	(292.7)	(389.6)
Other comprehensive income (loss) arising during period, total	52.5	22.9
Other Comprehensive Income (Loss) before Reclassifications, Tax	(1.1)	0.6
Other comprehensive income (loss), reclassification before tax	3.3	4
Reclassification from AOCI, Current Period, Tax	(0.4)	(0.4)
Other comprehensive income	54.3	27.1
Accumulated other comprehensive income (loss), net of tax - Ending balance	$ (238.4)	$ (362.5)

Reclassifications out of Accu67

Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cost of Sales [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Defined benefit plans, amounts reclassified from accumulated other comprehensive income (loss)	$ 1.5	$ 1.4
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	2	2.8
Selling, General and Administrative Expenses [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Defined benefit plans, amounts reclassified from accumulated other comprehensive income (loss)	0.3	(0.2)
Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	$ (0.4)	$ 0

Segment Reporting Sales and Seg

Segment Reporting Sales and Segment Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net, Inclusive of Intersegment Sales	$ 1,998.5	$ 1,149.3
Sales Revenue, Goods, Net, Intersegment Sales	140.1	99.4
Net sales	1,858.4	1,049.9
Total Segment Adjusted EBITDA	317	183.6
Driveline [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net, Inclusive of Intersegment Sales	1,070.6	999.3
Sales Revenue, Goods, Net, Intersegment Sales	0.2	0.5
Net sales	1,070.4	998.8
Total Segment Adjusted EBITDA	170	153.2
Metal Forming [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net, Inclusive of Intersegment Sales	397	150
Sales Revenue, Goods, Net, Intersegment Sales	105.9	98.9
Net sales	291.1	51.1
Total Segment Adjusted EBITDA	75.3	30.4
Powertrain [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net, Inclusive of Intersegment Sales	291.9	0
Sales Revenue, Goods, Net, Intersegment Sales	4.8	0
Net sales	287.1	0
Total Segment Adjusted EBITDA	50.1	0
Casting [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net, Inclusive of Intersegment Sales	239	0
Sales Revenue, Goods, Net, Intersegment Sales	29.2	0
Net sales	209.8	0
Total Segment Adjusted EBITDA	$ 21.6	$ 0

Reconciliation of Total Segment

Reconciliation of Total Segment Adjusted EBITDA to Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Total Segment Adjusted EBITDA	$ 317	$ 183.6
Interest expense	(53.2)	(25.5)
Depreciation and amortization	(127.8)	(56.2)
Restructuring and acquisition-related costs	(18.3)	(16)
Debt refinancing and redemption costs	(10.3)	0
Income before income taxes	$ 107.4	$ 85.9

Supplemental Guarantor Conden70

Supplemental Guarantor Condensed Consolidating Financial Statements Narrative (Details)	Mar. 31, 2018
Debt Instrument [Line Items]
Ownership in Subsidiary, Percentage	100.00%
6.25% Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
6.25% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Unsecured Debt [Member] | 7.75% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Unsecured Debt [Member] | 6.625% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
Unsecured Debt [Member] | 6.50% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Unsecured Debt [Member] | 6.25% Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Unsecured Debt [Member] | 6.25% Notes due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Unsecured Debt [Member] | 6.25% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%

Supplemental Guarantor Conden71

Supplemental Guarantor Condensed Consolidating Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net sales
External	$ 1,858.4	$ 1,049.9
Intercompany	0	0
Net sales	1,858.4	1,049.9
Cost of goods sold	1,542.1	839.2
Gross profit	316.3	210.7
Selling, general and administrative expenses	97.3	81.2
Amortization of intangible assets	24.9	1.6
Restructuring and acquisition-related costs	18.3	16
Operating income	175.8	111.9
Nonoperating Income (Expense)	(68.4)	(26)
Income (loss) before income taxes	107.4	85.9
Income tax expense (benefit)	17.9	7.5
Earnings from equity in subsidiaries	0	0
Net income (loss) before royalties	89.5	78.4
Royalties	0	0
Net income after royalties	89.5	78.4
Net income attributable to noncontrolling interests	(0.1)	0
Net income attributable to AAM	89.4	78.4
Other comprehensive income, net of tax	54.3	27.1
Comprehensive income attributable to AAM	143.7	105.5
Holdings [Member]
Net sales
External	0	0
Intercompany	0	0
Net sales	0	0
Cost of goods sold	0	0
Gross profit	0	0
Selling, general and administrative expenses	0	0
Amortization of intangible assets	0	0
Restructuring and acquisition-related costs	0	0
Operating income	0	0
Nonoperating Income (Expense)	0	0
Income (loss) before income taxes	0	0
Income tax expense (benefit)	0	0
Earnings from equity in subsidiaries	89.4	78.4
Net income (loss) before royalties	89.4	78.4
Royalties	0	0
Net income after royalties	89.4	78.4
Net income attributable to noncontrolling interests	0	0
Net income attributable to AAM	89.4	78.4
Other comprehensive income, net of tax	54.3	27.1
Comprehensive income attributable to AAM	143.7	105.5
AAM Inc. [Member]
Net sales
External	301.5	296.6
Intercompany	1	0.3
Net sales	302.5	296.9
Cost of goods sold	278.2	277.2
Gross profit	24.3	19.7
Selling, general and administrative expenses	59.8	72.5
Amortization of intangible assets	1.5	1.3
Restructuring and acquisition-related costs	16.3	15.3
Operating income	(53.3)	(69.4)
Nonoperating Income (Expense)	(70.5)	(26.2)
Income (loss) before income taxes	(123.8)	(95.6)
Income tax expense (benefit)	1.1	(2.8)
Earnings from equity in subsidiaries	67.2	91.6
Net income (loss) before royalties	(57.7)	(1.2)
Royalties	84.2	79.6
Net income after royalties	26.5	78.4
Net income attributable to noncontrolling interests	0	0
Net income attributable to AAM	26.5	78.4
Other comprehensive income, net of tax	25.6	27.1
Comprehensive income attributable to AAM	52.1	105.5
Guarantor Subsidiaries [Member]
Net sales
External	582.3	50.1
Intercompany	78	66.7
Net sales	660.3	116.8
Cost of goods sold	576.8	94.9
Gross profit	83.5	21.9
Selling, general and administrative expenses	21.9	0
Amortization of intangible assets	22.6	0
Restructuring and acquisition-related costs	1.1	0
Operating income	37.9	21.9
Nonoperating Income (Expense)	5	2.4
Income (loss) before income taxes	42.9	24.3
Income tax expense (benefit)	0.4	0.1
Earnings from equity in subsidiaries	40.5	(0.6)
Net income (loss) before royalties	83	23.6
Royalties	1	0
Net income after royalties	84	23.6
Net income attributable to noncontrolling interests	0	0
Net income attributable to AAM	84	23.6
Other comprehensive income, net of tax	35.1	10.5
Comprehensive income attributable to AAM	119.1	34.1
Non-Guarantor Subsidiaries [Member]
Net sales
External	974.6	703.2
Intercompany	9.5	4.9
Net sales	984.1	708.1
Cost of goods sold	775.6	539
Gross profit	208.5	169.1
Selling, general and administrative expenses	15.6	8.7
Amortization of intangible assets	0.8	0.3
Restructuring and acquisition-related costs	0.9	0.7
Operating income	191.2	159.4
Nonoperating Income (Expense)	(2.9)	(2.2)
Income (loss) before income taxes	188.3	157.2
Income tax expense (benefit)	16.4	10.2
Earnings from equity in subsidiaries	0	0
Net income (loss) before royalties	171.9	147
Royalties	(85.2)	(79.6)
Net income after royalties	86.7	67.4
Net income attributable to noncontrolling interests	(0.1)	0
Net income attributable to AAM	86.6	67.4
Other comprehensive income, net of tax	43.7	26.4
Comprehensive income attributable to AAM	130.3	93.8
Consolidation, Eliminations [Member]
Net sales
External	0	0
Intercompany	(88.5)	(71.9)
Net sales	(88.5)	(71.9)
Cost of goods sold	(88.5)	(71.9)
Gross profit	0	0
Selling, general and administrative expenses	0	0
Amortization of intangible assets	0	0
Restructuring and acquisition-related costs	0	0
Operating income	0	0
Nonoperating Income (Expense)	0	0
Income (loss) before income taxes	0	0
Income tax expense (benefit)	0	0
Earnings from equity in subsidiaries	(197.1)	(169.4)
Net income (loss) before royalties	(197.1)	(169.4)
Royalties	0	0
Net income after royalties	(197.1)	(169.4)
Net income attributable to noncontrolling interests	0	0
Net income attributable to AAM	(197.1)	(169.4)
Other comprehensive income, net of tax	(104.4)	(64)
Comprehensive income attributable to AAM	$ (301.5)	$ (233.4)

Supplemental Guarantor Conden72

Supplemental Guarantor Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 340.7	$ 376.8	$ 1,543.4	$ 481.2
Accounts receivable, net	1,238.2	1,035.9
Intercompany receivables	0	0
Inventories, net	403.3	392
Prepaid expenses and other	172.9	140.3
Total current assets	2,155.1	1,945
Property, plant and equipment, net	2,491.9	2,402.9
Goodwill	1,669.1	1,654.3
Intangible assets, net	1,188.8	1,212.5
Intercompany notes and accounts receivable	0	0
Other assets and deferred charges	667.4	668.1
Investment in subsidiaries	0	0
Total assets	8,172.3	7,882.8
Current liabilities
Current portion of long-term debt	31.8	5.9
Accounts payable	924.5	799
Intercompany payables	0	0
Accrued expenses and other	393.6	411.5
Total current liabilities	1,349.9	1,216.4
Intercompany notes and accounts payable	0	0
Long-term debt, net	3,986.2	3,969.3
Other long-term liabilities	1,150.2	1,157.1
Total liabilities	6,486.3	6,342.8
Stockholders' Equity Attributable to Parent	1,682.8	1,536
Noncontrolling interests in subsidiaries	3.2	4
Total stockholders' equity	1,686	1,540
Total liabilities and stockholders' equity	8,172.3	7,882.8
Holdings [Member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivables	0	0
Inventories, net	0	0
Prepaid expenses and other	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Intercompany notes and accounts receivable	11.7	11.7
Other assets and deferred charges	0	0
Investment in subsidiaries	2,990.9	2,841.3
Total assets	3,002.6	2,853
Current liabilities
Current portion of long-term debt	0	0
Accounts payable	0	0
Intercompany payables	1,316.6	1,313
Accrued expenses and other	0	0
Total current liabilities	1,316.6	1,313
Intercompany notes and accounts payable	0	0
Long-term debt, net	0	0
Other long-term liabilities	0	0
Total liabilities	1,316.6	1,313
Stockholders' Equity Attributable to Parent	1,682.8	1,536
Noncontrolling interests in subsidiaries	3.2	4
Total stockholders' equity	1,686	1,540
Total liabilities and stockholders' equity	3,002.6	2,853
AAM Inc. [Member]
Current assets
Cash and cash equivalents	115.4	91.9	1,413.3	84.3
Accounts receivable, net	184.1	138.9
Intercompany receivables	3,718.1	3,475.2
Inventories, net	36	37.2
Prepaid expenses and other	40.4	40.4
Total current assets	4,094	3,783.6
Property, plant and equipment, net	274.1	250.9
Goodwill	0	0
Intangible assets, net	20.8	21
Intercompany notes and accounts receivable	0	0
Other assets and deferred charges	347.7	349.1
Investment in subsidiaries	2,065.7	1,955.2
Total assets	6,802.3	6,359.8
Current liabilities
Current portion of long-term debt	22	0
Accounts payable	170.1	139
Intercompany payables	902.2	563.7
Accrued expenses and other	164.7	181.6
Total current liabilities	1,259	884.3
Intercompany notes and accounts payable	9.9	11.7
Long-term debt, net	3,888	3,894.6
Other long-term liabilities	634.1	639.1
Total liabilities	5,791	5,429.7
Stockholders' Equity Attributable to Parent	1,011.3	930.1
Noncontrolling interests in subsidiaries	0	0
Total stockholders' equity	1,011.3	930.1
Total liabilities and stockholders' equity	6,802.3	6,359.8
Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	0.3	0.1	0	1.6
Accounts receivable, net	360.2	287.9
Intercompany receivables	717.3	479.9
Inventories, net	146.5	147.4
Prepaid expenses and other	28.2	9.9
Total current assets	1,252.5	925.2
Property, plant and equipment, net	774.4	786.8
Goodwill	1,219.3	1,218.4
Intangible assets, net	1,133.1	1,155.6
Intercompany notes and accounts receivable	224.6	243.5
Other assets and deferred charges	108.9	122.8
Investment in subsidiaries	1,336.5	1,280.1
Total assets	6,049.3	5,732.4
Current liabilities
Current portion of long-term debt	0	0
Accounts payable	243.9	204.6
Intercompany payables	2,190.3	2,017.7
Accrued expenses and other	40.9	52.4
Total current liabilities	2,475.1	2,274.7
Intercompany notes and accounts payable	0	0
Long-term debt, net	3.7	4.4
Other long-term liabilities	332	333.2
Total liabilities	2,810.8	2,612.3
Stockholders' Equity Attributable to Parent	3,238.5	3,120.1
Noncontrolling interests in subsidiaries	0	0
Total stockholders' equity	3,238.5	3,120.1
Total liabilities and stockholders' equity	6,049.3	5,732.4
Non-Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	225	284.8	130.1	395.3
Accounts receivable, net	693.9	609.1
Intercompany receivables	74.7	7.5
Inventories, net	220.8	207.4
Prepaid expenses and other	104.3	90
Total current assets	1,318.7	1,198.8
Property, plant and equipment, net	1,443.4	1,365.2
Goodwill	449.8	435.9
Intangible assets, net	34.9	35.9
Intercompany notes and accounts receivable	0	0
Other assets and deferred charges	210.8	196.2
Investment in subsidiaries	0	0
Total assets	3,457.6	3,232
Current liabilities
Current portion of long-term debt	9.8	5.9
Accounts payable	510.5	455.4
Intercompany payables	101	68.2
Accrued expenses and other	188	177.5
Total current liabilities	809.3	707
Intercompany notes and accounts payable	226.4	243.5
Long-term debt, net	94.5	70.3
Other long-term liabilities	184.1	184.8
Total liabilities	1,314.3	1,205.6
Stockholders' Equity Attributable to Parent	2,140.1	2,022.4
Noncontrolling interests in subsidiaries	3.2	4
Total stockholders' equity	2,143.3	2,026.4
Total liabilities and stockholders' equity	3,457.6	3,232
Consolidation, Eliminations [Member]
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Intercompany receivables	(4,510.1)	(3,962.6)
Inventories, net	0	0
Prepaid expenses and other	0	0
Total current assets	(4,510.1)	(3,962.6)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Intercompany notes and accounts receivable	(236.3)	(255.2)
Other assets and deferred charges	0	0
Investment in subsidiaries	(6,393.1)	(6,076.6)
Total assets	(11,139.5)	(10,294.4)
Current liabilities
Current portion of long-term debt	0	0
Accounts payable	0	0
Intercompany payables	(4,510.1)	(3,962.6)
Accrued expenses and other	0	0
Total current liabilities	(4,510.1)	(3,962.6)
Intercompany notes and accounts payable	(236.3)	(255.2)
Long-term debt, net	0	0
Other long-term liabilities	0	0
Total liabilities	(4,746.4)	(4,217.8)
Stockholders' Equity Attributable to Parent	(6,389.9)	(6,072.6)
Noncontrolling interests in subsidiaries	(3.2)	(4)
Total stockholders' equity	(6,393.1)	(6,076.6)
Total liabilities and stockholders' equity	$ (11,139.5)	$ (10,294.4)

Supplemental Guarantor Conden73

Supplemental Guarantor Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net cash provided by (used in) operating activities	$ 66.9	$ 62.3
Investing activities
Purchases of property, plant and equipment	(130.8)	(34.9)
Proceeds from sale of property, plant and equipment	0.4	0.8
Purchase buyouts of leased equipment	(0.5)	(2.3)
Acquisition of business, net of cash acquired	(1.3)	(144.1)
Intercompany Activity - Investing	0
Proceeds from sale of business, net	0	5.9
Net cash used in investing activities	(132.2)	(174.6)
Financing activities
Net debt activity	34.5	1,199.2
Debt issuance costs	(6.8)	(21.2)
Purchase of treasury stock	(3.5)	(5.2)
Purchase of noncontrolling interest	(0.9)	0
Intercompany Activity - Financing	0	0
Net cash provided by financing activities	23.3	1,172.8
Effect of exchange rate changes on cash	5.9	1.7
Net increase (decrease) in cash and cash equivalents	(36.1)	1,062.2
Cash and cash equivalents at beginning of period	376.8	481.2
Cash and cash equivalents at end of period	340.7	1,543.4
Holdings [Member]
Net cash provided by (used in) operating activities	0	0
Investing activities
Purchases of property, plant and equipment	0	0
Proceeds from sale of property, plant and equipment	0	0
Purchase buyouts of leased equipment	0	0
Acquisition of business, net of cash acquired	0	0
Intercompany Activity - Investing	0
Proceeds from sale of business, net		0
Net cash used in investing activities	0	0
Financing activities
Net debt activity	0	0
Debt issuance costs	0	0
Purchase of treasury stock	(3.5)	(5.2)
Purchase of noncontrolling interest	0
Intercompany Activity - Financing	3.5	5.2
Net cash provided by financing activities	0	0
Effect of exchange rate changes on cash	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
AAM Inc. [Member]
Net cash provided by (used in) operating activities	46.5	161.8
Investing activities
Purchases of property, plant and equipment	(21.5)	(11.6)
Proceeds from sale of property, plant and equipment	0	0.2
Purchase buyouts of leased equipment	0	(2.3)
Acquisition of business, net of cash acquired	0	0
Intercompany Activity - Investing	(0.1)
Proceeds from sale of business, net		7.5
Net cash used in investing activities	(21.6)	(6.2)
Financing activities
Net debt activity	8.9	1,199.8
Debt issuance costs	(6.8)	(21.2)
Purchase of treasury stock	0	0
Purchase of noncontrolling interest	0
Intercompany Activity - Financing	(3.5)	(5.2)
Net cash provided by financing activities	(1.4)	1,173.4
Effect of exchange rate changes on cash	0	0
Net increase (decrease) in cash and cash equivalents	23.5	1,329
Cash and cash equivalents at beginning of period	91.9	84.3
Cash and cash equivalents at end of period	115.4	1,413.3
Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	39	5.3
Investing activities
Purchases of property, plant and equipment	(37.6)	(5.2)
Proceeds from sale of property, plant and equipment	0.3	0
Purchase buyouts of leased equipment	(0.5)	0
Acquisition of business, net of cash acquired	0	0
Intercompany Activity - Investing	0.1
Proceeds from sale of business, net		(1.6)
Net cash used in investing activities	(37.7)	(6.8)
Financing activities
Net debt activity	(0.2)	(0.1)
Debt issuance costs	0	0
Purchase of treasury stock	0	0
Purchase of noncontrolling interest	(0.9)
Intercompany Activity - Financing	0	0
Net cash provided by financing activities	(1.1)	(0.1)
Effect of exchange rate changes on cash	0	0
Net increase (decrease) in cash and cash equivalents	0.2	(1.6)
Cash and cash equivalents at beginning of period	0.1	1.6
Cash and cash equivalents at end of period	0.3	0
Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	(18.6)	(104.8)
Investing activities
Purchases of property, plant and equipment	(71.7)	(18.1)
Proceeds from sale of property, plant and equipment	0.1	0.6
Purchase buyouts of leased equipment	0	0
Acquisition of business, net of cash acquired	(1.3)	(144.1)
Intercompany Activity - Investing	0
Proceeds from sale of business, net		0
Net cash used in investing activities	(72.9)	(161.6)
Financing activities
Net debt activity	25.8	(0.5)
Debt issuance costs	0	0
Purchase of treasury stock	0	0
Purchase of noncontrolling interest	0
Intercompany Activity - Financing	0	0
Net cash provided by financing activities	25.8	(0.5)
Effect of exchange rate changes on cash	5.9	1.7
Net increase (decrease) in cash and cash equivalents	(59.8)	(265.2)
Cash and cash equivalents at beginning of period	284.8	395.3
Cash and cash equivalents at end of period	225	130.1
Consolidation, Eliminations [Member]
Investing activities
Purchase buyouts of leased equipment		0
Acquisition of business, net of cash acquired		0
Proceeds from sale of business, net		0
Consolidation, Eliminations [Member]
Net cash provided by (used in) operating activities	0	0
Investing activities
Purchases of property, plant and equipment	0	0
Proceeds from sale of property, plant and equipment	0	0
Purchase buyouts of leased equipment	0
Acquisition of business, net of cash acquired	0
Intercompany Activity - Investing	0
Net cash used in investing activities	0	0
Financing activities
Net debt activity	0	0
Debt issuance costs	0	0
Purchase of treasury stock	0	0
Purchase of noncontrolling interest	0
Intercompany Activity - Financing	0	0
Net cash provided by financing activities	0	0
Effect of exchange rate changes on cash	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$ 0	$ 0

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event [Member] $ in Millions	3 Months Ended
	Jun. 30, 2018USD ($)
Subsequent Event [Line Items]
Divestiture of Business - Selling Price	$ 50
Proceeds from Divestiture of Businesses	47
Minimum [Member]
Subsequent Event [Line Items]
Gain (Loss) on Disposition of Business	15
Maximum [Member]
Subsequent Event [Line Items]
Gain (Loss) on Disposition of Business	$ 20