Income Taxes Deferred Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Income Tax Contingency [Line Items]
Deferred tax liabilities, Intangible assets	$ 8,404	$ 9,044
Deferred tax liabilities, Fixed assets	10,662	9,135
Total deferred tax liabilities	19,066	18,179
Deferred tax assets, Reserves and accruals	(58,786)	(77,746)
Deferred tax assets, Tax credits	(48,897)	(48,659)
Deferred tax assets, Tax loss carryforwards	(64,624)	(63,228)
Deferred tax assets, Derivative transactions	(10,775)	(12,760)
Deferred tax assets, Postretirement and other benefits	(32,361)	(29,786)
Deferred Tax Assets, Unrealized Currency Losses	(14,530)	0
Deferred tax assets, Other	(14,713)	(752)
Gross deferred tax assets	(244,686)	(232,931)
Valuation allowance	143,345	138,787
Total deferred tax assets	(101,341)	(94,144)
Net deferred tax asset	(82,275)	(75,965)
Current asset	(23,855)	(3,955)
Non-current asset	(73,378)	(82,707)
Non-current liability	9,494	3,816
Decrease in deferred taxes assets for certain adjustments	449
Deferred tax assets, operating loss carryforwards, foreign	66,662
Deferred tax assets, operating loss carryforwards, domestic	105,186
Deferred tax assets, operating loss carryforwards, state and local	250,381
Deferred tax assets, tax credit carryforwards, foreign	45,085
Foreign repatriated earnings	316,046	226,971
Non-U.S [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration Within Five Years	35,267
Deferred tax assets, operating loss carryforwards, subject to expiration	18,994
Operating loss carryforwards, expiration dates (in years)	P5Y
Deferred tax assets, operating loss carryforwards, not subject to expiration	12,401
U.S. [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration Within Five Years	41,336
Deferred tax assets, operating loss carryforwards, subject to expiration	209,045
Operating loss carryforwards, expiration dates (in years)	P5Y
Current Asset [Member]
Income Tax Contingency [Line Items]
Current asset	(23,855)	(3,955)
Current Liability [Member]
Income Tax Contingency [Line Items]
Current liability	5,464	6,881
Noncurrent Asset [Member]
Income Tax Contingency [Line Items]
Non-current asset	(73,378)	(82,707)
Noncurrent Liability [Member]
Income Tax Contingency [Line Items]
Non-current liability	$ 9,494	$ 3,816