Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net sales to external customers:
Total Net sales to external customers	$ 1,089.9	$ 1,421.0
Intersegment sales:
Total Intersegment sales	21.0	30.5
Segment EBIT:
Total EBIT, as adjusted, for reportable segments	138.2	267.7
Unallocated corporate expenses	(19.9)	(20.7)
Interest expense	(6.4)	(8.6)
Interest income	0.5	0.7
Intersegment adjustments	1.4	(1.6)
Income Before Income Taxes	113.8	237.5
Mobile Industries [Member]
Net sales to external customers:
Total Net sales to external customers	397.0	469.1
Intersegment sales:
Total Intersegment sales	0.1	0
Segment EBIT:
Total EBIT, as adjusted, for reportable segments	51.2	86.7
Process Industries [Member]
Net sales to external customers:
Total Net sales to external customers	283.9	354.1
Intersegment sales:
Total Intersegment sales	1.3	1.5
Segment EBIT:
Total EBIT, as adjusted, for reportable segments	42.6	82.3
Aerospace [Member]
Net sales to external customers:
Total Net sales to external customers	82.5	91.3
Segment EBIT:
Total EBIT, as adjusted, for reportable segments	8.6	10.7
Steel [Member]
Net sales to external customers:
Total Net sales to external customers	326.5	506.5
Intersegment sales:
Total Intersegment sales	19.6	29.0
Segment EBIT:
Total EBIT, as adjusted, for reportable segments	$ 35.8	$ 88.0