Goodwill and Deferred Charges and Other Non-Current Assets (Details) (USD $) In Thousands, unless otherwise specified	Jan. 01, 2012	Mar. 31, 2011
Goodwill
Balance at the end of the period	$ 1,251,536	$ 1,251,536
Deferred charges and other non-current assets
Gross debt issuance costs	27,613	34,823
Less accumulated amortization	(8,591)	(12,047)
Net debt issuance costs	19,022	22,776
Other intangible assets	123,494	131,850
Long term receivables	285,614	188,935
Long-term inventory	13,743	11,061
Environmental remediation receivable	29,465	26,761
Commodity forward contracts	1,824	12,619
Other non-current assets	53,841	50,806
Total deferred charges and other non-current assets	527,003	444,808
Aerospace Systems
Goodwill
Balance at the end of the period	676,516
Accumulated impairment losses	108,500
Armament Systems
Goodwill
Balance at the end of the period	124,558
Missile Products
Goodwill
Balance at the end of the period	242,389
Security and Sporting
Goodwill
Balance at the end of the period	$ 208,073