Inventories (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Average or actual cost (which approximates current costs):
Finished products	$ 228.0	$ 220.8
In-process	2,507.0	2,360.6
Raw materials and supplies	798.2	753.7
Inventory, gross	3,533.2	3,335.1
Less:
Reserve to reduce certain inventories to LIFO basis	(54.6)	(54.2)
Progress payments and advances	(417.0)	(404.3)
Total	$ 3,061.6	$ 2,876.6