Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 532.0	$ 476.4
Accounts receivable, net	815.4	966.5
Inventories, net	373.6	459.7
Prepaid expenses and other	136.8	127.2
Total current assets	1,857.8	2,029.8
Property, plant and equipment, net	2,358.4	2,514.4
Deferred income taxes	64.1	45.5
Goodwill	699.1	1,141.8
Other intangible assets, net	864.5	1,111.1
GM postretirement cost sharing asset	223.3	219.4
Other assets and deferred charges	577.4	448.7
Total assets	6,644.6	7,510.7
Current liabilities
Current portion of long-term debt	28.7	121.6
Accounts payable	623.5	840.2
Accrued compensation and benefits	154.4	179.0
Deferred revenue	18.9	44.3
Accrued expenses and other	200.9	171.7
Total current liabilities	1,026.4	1,356.8
Long-term debt, net	3,612.3	3,686.8
Deferred revenue	83.7	77.6
Deferred income taxes	19.6	92.6
Postretirement benefits and other long-term liabilities	922.2	810.6
Total liabilities	5,664.2	6,024.4
Stockholders' equity
Series A junior participating preferred stock, par value $0.01 per share; 0.1 million shares authorized; no shares outstanding in 2019 or 2018	0.0	0.0
Preferred stock, par value $0.01 per share; 10.0 million shares authorized; no shares outstanding in 2019 or 2018	0.0	0.0
Series common stock, par value $0.01 per share; 40.0 million shares authorized; no shares outstanding in 2019 or 2018	0.0	0.0
Common stock, par value $0.01 per share; 150.0 million shares authorized; 120.2 million and 118.9 million shares issued as of December 31, 2019 and December 31, 2018, respectively	1.2	1.2
Paid-in capital	1,313.9	1,292.6
Retained earnings	248.6	703.5
Treasury stock at cost, 7.6 million shares in 2019 and 7.2 million shares in 2018	(209.3)	(201.8)
Accumulated other comprehensive loss
Defined benefit plans, net of tax	(259.9)	(213.9)
Foreign currency translation adjustments	(101.2)	(96.6)
Unrecognized loss on cash flow hedges, net of tax	(15.7)	(1.1)
Total AAM stockholders' equity	977.6	1,483.9
Noncontrolling interests in subsidiaries	2.8	2.4
Total stockholders' equity	980.4	1,486.3
Total liabilities and stockholders' equity	$ 6,644.6	$ 7,510.7