Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 154.0	$ 62.4
Accounts receivable, net	458.5	463.4
Inventories, net	261.8	224.3
Deferred income taxes	36.4	34.9
Prepaid expenses and other	87.1	87.1
Total current assets	997.8	872.1
Property, plant and equipment, net	1,058.5	1,009.7
Deferred income taxes	341.8	366.1
Goodwill	156.4	156.4
GM postretirement cost sharing asset	242.0	259.7
Other assets and deferred charges	232.5	202.0
Total assets	3,029.0	2,866.0
Current Liabilities
Accounts payable	445.8	396.1
Accrued compensation and benefits	110.1	84.9
Deferred revenue	17.0	17.2
Deferred income taxes	0.1	1.4
Other accrued expenses	94.1	101.2
Total current liabilities	667.1	600.8
Long-term debt	1,559.1	1,454.1
Deferred income taxes	9.8	9.5
Deferred revenue	76.4	82.2
Postretirement benefits and other long-term liabilities	683.0	840.2
Total liabilities	2,995.4	2,986.8
Stockholders' equity (deficit)
Series A junior participating preferred stock, par value $0.01 per share; 0.1 million shares authorized; no shares outstanding in 2013 or 2012	0	0
Preferred stock, par value $0.01 per share; 10.0 million shares authorized; no shares outstanding in 2013 or 2012	0	0
Common stock, par value $0.01 per share; 150.0 million shares authorized; 81.6 million and 80.9 million shares issued and outstanding in 2013 and 2012, respectively	0.8	0.8
Series common stock, par value $0.01 per share; 40.0 million shares authorized; no shares outstanding in 2013 or 2012	0	0
Paid-in capital	612.8	600.9
Accumulated deficit	(181.3)	(275.8)
Treasury stock at cost, 6.0 million shares in 2013 and 2012	(182.5)	(182.1)
Accumulated other comprehensive income (loss), net of tax
Defined benefit plans	(197.9)	(274.5)
Foreign currency translation adjustments	(18.6)	7.6
Unrecognized gain on derivatives	0.3	2.3
Total AAM stockholders' equity (deficit)	33.6	(120.8)
Noncontrolling interest in subsidiaries	0	0
Total stockholders’ equity (deficit)	33.6	(120.8)
Total liabilities and stockholders' equity (deficit)	$ 3,029.0	$ 2,866.0