Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current Assets
Cash and cash equivalents	$ 62.4	$ 169.2
Accounts receivable, net	463.4	333.3
Inventories, net	224.3	177.2
Deferred Tax Assets, Net of Valuation Allowance, Current	34.9	11.3
Prepaid expenses and other	87.1	72.1
Total current assets	872.1	763.1
Property, plant and equipment, net	1,009.7	971.2
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	366.1	20.1
Goodwill	156.4	155.9
GM postretirement cost sharing asset	259.7	260.2
Other assets and deferred charges	202.0	158.2
Total assets	2,866.0	2,328.7
Current Liabilities
Accounts payable	396.1	337.1
Accrued compensation and benefits	84.9	110.6
Deferred revenue	17.2	32.9
Deferred income taxes	1.4	9.9
Other accrued expenses	101.2	85.6
Total current liabilities	600.8	576.1
Long-term debt	1,454.1	1,180.2
Deferred Tax Liabilities, Property, Plant and Equipment	9.5	7.7
Deferred revenue	82.2	88.2
Postretirement benefits and other longterm liabilities	840.2	896.1
Total liabilities	2,986.8	2,748.3
Stockholders' Deficit
Series A junior participating preferred stock, par value $0.01 per share; 0.1 million shares authorized; no shares outstanding in 2012 or 2011	0	0
Preferred stock, par value $0.01 per share; 10.0 million shares authorized; no shares outstanding in 2012 or 2011	0	0
Common stock, par value $0.01 per share; 150.0 million shares authorized; 80.9 million and 79.3 million shares issued and outstanding in 2012 and 2011, respectively	0.8	0.8
Series common stock, par value $0.01 per share; 40.0 million shares authorized; no shares outstanding in 2012 or 2011	0	0
Paid-in capital	600.9	597.2
Accumulated deficit	(275.8)	(643.5)
Treasury stock at cost, 6.0 million shares in 2012 and 5.5 million shares in 2011	(182.1)	(176.2)
Accumulated other comprehensive income (loss), net of tax
Defined benefit plans	(274.5)	(215.6)
Foreign currency translation adjustments	7.6	17.3
Unrecognized gain (loss) on derivatives	2.3	(5.5)
Total AAM stockholders' deficit	(120.8)	(425.5)
Noncontrolling interest in subsidiaries	0	5.9
Total stockholders’ deficit	(120.8)	(419.6)
Total liabilities and stockholders' deficit	$ 2,866.0	$ 2,328.7