Commitments and Contingencies (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Commercial Litigation - Cogent Inc. Delaware Court of Chancery
Loss contingencies
Number of Cogent, Inc. shares held by subsidiary shareholders that have asserted appraisal rights	5,800,000
Commercial Litigation - Ceradyne Inc.
Loss contingencies
Number of purported class actions filed	4
Number of Ceradyne shareholders who filed petition for appraisal rights under Delaware law	1
Number of purported shares held by Ceradyne shareholder who filed petition for appraisal rights	16,656
Commercial Litigation - Ceradyne Inc. California Superior Court
Loss contingencies
Number of purported class actions filed	2
Commercial Litigation - Ceradyne Inc. Delaware Chancery Court
Loss contingencies
Number of purported class actions filed	2
Commercial Litigation - Meda AB
Loss contingencies
The estimated minimum amount the lawsuit seeks to recover	300
Number of claims filed	3
Commercial Litigation - TransWeb Corporation
Loss contingencies
Number of counts jury did not rule in favor of Transweb	1