Condensed Consolidating Financial Information - Schedule of Unaudited Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	May. 31, 2015	Nov. 30, 2014	May. 31, 2014	Nov. 30, 2013
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 253.5	$ 265.9	$ 120.7	$ 197.6
Accounts receivable	173.7	172.9
Inventories	150.3	139.0
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	29.7	25.4
Other current assets, net		35.9
Other current assets, net	45.4	38.0
Income taxes	1.4	2.1
Deferred income taxes	24.8	25.3
Total Current Assets	677.4	666.5
Property, plant and equipment, net	356.3	367.5
Recoverable from the U.S. government and other third parties for environmental remediation costs	76.8	81.2
Deferred income taxes	245.3	259.0
Goodwill	164.4	164.4
Intercompany receivable	0.0	0.0
Investments in subsidiaries	0.0	0.0
Other noncurrent assets and intangibles, net	377.9	383.0
Total Assets	1,898.1	1,921.6
Short-term borrowings and current portion of long-term debt	5.3	5.3
Accounts payable	87.6	103.5
Reserves for environmental remediation costs	38.7	31.9
Other current liabilities and advance payments on contracts	395.8	420.2
Postretirement medical and life insurance benefits	6.4	6.4
Total Current Liabilities	533.8	567.3
Long-term debt	712.6	776.9
Reserves for environmental remediation costs	122.8	134.1
Pension benefits	475.4	482.8
Intercompany payable	0.0	0.0
Postretirement medical and life insurance benefits	50.1	51.7
Other noncurrent liabilities	99.0	79.7
Total Liabilities	$ 1,993.7	$ 2,092.5
Commitments and contingencies (Note 7)
Redeemable common stock	$ 0.1	$ 1.6
Total stockholders’ (deficit) equity	(95.7)	(172.5)
Total Liabilities, Redeemable Common Stock and Stockholders’ Deficit	1,898.1	1,921.6
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	(3.0)	(5.7)	(4.6)	0.0
Accounts receivable	0.0	0.0
Inventories	0.0	0.0
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0.0	0.0
Other current assets, net		0.0
Other current assets, net	(16.9)
Income taxes		(30.7)
Deferred income taxes	0.0	0.0
Total Current Assets	(19.9)	(36.4)
Property, plant and equipment, net	0.0	0.0
Recoverable from the U.S. government and other third parties for environmental remediation costs	0.0	0.0
Deferred income taxes	0.0	0.0
Goodwill	0.0	0.0
Intercompany receivable	(148.3)	(126.9)
Investments in subsidiaries	(568.2)	(503.0)
Other noncurrent assets and intangibles, net	0.0	0.0
Total Assets	(736.4)	(666.3)
Short-term borrowings and current portion of long-term debt	0.0	0.0
Accounts payable	(3.0)	(5.7)
Reserves for environmental remediation costs	0.0	0.0
Other current liabilities and advance payments on contracts	(16.9)	(30.7)
Postretirement medical and life insurance benefits	0.0	0.0
Total Current Liabilities	(19.9)	(36.4)
Long-term debt	0.0	0.0
Reserves for environmental remediation costs	0.0	0.0
Pension benefits	0.0	0.0
Intercompany payable	(148.3)	(126.9)
Postretirement medical and life insurance benefits	0.0	0.0
Other noncurrent liabilities	0.0	0.0
Total Liabilities	$ (168.2)	$ (163.3)
Commitments and contingencies (Note 7)
Redeemable common stock	$ 0.0	$ 0.0
Total stockholders’ (deficit) equity	(568.2)	(503.0)
Total Liabilities, Redeemable Common Stock and Stockholders’ Deficit	(736.4)	(666.3)
Parent [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	255.8	271.6	125.0	192.7
Accounts receivable	0.0	0.0
Inventories	0.0	0.0
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0.1	0.1
Other current assets, net		3.5
Other current assets, net	20.7
Income taxes		31.0
Deferred income taxes	5.6	5.6
Total Current Assets	282.2	311.8
Property, plant and equipment, net	4.7	4.7
Recoverable from the U.S. government and other third parties for environmental remediation costs	0.7	0.7
Deferred income taxes	59.5	57.7
Goodwill	0.0	0.0
Intercompany receivable	0.0	0.0
Investments in subsidiaries	568.2	503.0
Other noncurrent assets and intangibles, net	26.8	28.1
Total Assets	942.1	906.0
Short-term borrowings and current portion of long-term debt	5.0	5.0
Accounts payable	1.6	1.5
Reserves for environmental remediation costs	1.2	1.0
Other current liabilities and advance payments on contracts	32.6	31.5
Postretirement medical and life insurance benefits	5.0	5.0
Total Current Liabilities	45.4	44.0
Long-term debt	712.4	776.6
Reserves for environmental remediation costs	4.3	4.8
Pension benefits	69.7	67.0
Intercompany payable	148.3	126.9
Postretirement medical and life insurance benefits	36.3	37.7
Other noncurrent liabilities	21.3	19.9
Total Liabilities	$ 1,037.7	$ 1,076.9
Commitments and contingencies (Note 7)
Redeemable common stock	$ 0.1	$ 1.6
Total stockholders’ (deficit) equity	(95.7)	(172.5)
Total Liabilities, Redeemable Common Stock and Stockholders’ Deficit	942.1	906.0
Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0.0	0.0	0.0	4.9
Accounts receivable	169.8	170.4
Inventories	144.0	133.6
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	29.6	25.3
Other current assets, net		31.6
Other current assets, net	40.4
Income taxes		1.8
Deferred income taxes	18.4	18.8
Total Current Assets	402.2	381.5
Property, plant and equipment, net	346.0	356.9
Recoverable from the U.S. government and other third parties for environmental remediation costs	76.1	80.5
Deferred income taxes	169.1	183.4
Goodwill	164.4	164.4
Intercompany receivable	115.7	97.7
Investments in subsidiaries	0.0	0.0
Other noncurrent assets and intangibles, net	294.0	298.9
Total Assets	1,567.5	1,563.3
Short-term borrowings and current portion of long-term debt	0.3	0.3
Accounts payable	85.0	103.1
Reserves for environmental remediation costs	37.5	30.9
Other current liabilities and advance payments on contracts	373.8	415.9
Postretirement medical and life insurance benefits	1.4	1.4
Total Current Liabilities	498.0	551.6
Long-term debt	0.2	0.3
Reserves for environmental remediation costs	118.5	129.3
Pension benefits	405.7	415.8
Intercompany payable	0.0	0.0
Postretirement medical and life insurance benefits	13.8	14.0
Other noncurrent liabilities	66.0	48.2
Total Liabilities	$ 1,102.2	$ 1,159.2
Commitments and contingencies (Note 7)
Redeemable common stock	$ 0.0	$ 0.0
Total stockholders’ (deficit) equity	465.3	404.1
Total Liabilities, Redeemable Common Stock and Stockholders’ Deficit	1,567.5	1,563.3
Non-guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0.7	0.0	$ 0.3	$ 0.0
Accounts receivable	3.9	2.5
Inventories	6.3	5.4
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0.0	0.0
Other current assets, net		0.8
Other current assets, net	1.2
Income taxes		0.0
Deferred income taxes	0.8	0.9
Total Current Assets	12.9	9.6
Property, plant and equipment, net	5.6	5.9
Recoverable from the U.S. government and other third parties for environmental remediation costs	0.0	0.0
Deferred income taxes	16.7	17.9
Goodwill	0.0	0.0
Intercompany receivable	32.6	29.2
Investments in subsidiaries	0.0	0.0
Other noncurrent assets and intangibles, net	57.1	56.0
Total Assets	124.9	118.6
Short-term borrowings and current portion of long-term debt	0.0	0.0
Accounts payable	4.0	4.6
Reserves for environmental remediation costs	0.0	0.0
Other current liabilities and advance payments on contracts	6.3	3.5
Postretirement medical and life insurance benefits	0.0	0.0
Total Current Liabilities	10.3	8.1
Long-term debt	0.0	0.0
Reserves for environmental remediation costs	0.0	0.0
Pension benefits	0.0	0.0
Intercompany payable	0.0	0.0
Postretirement medical and life insurance benefits	0.0	0.0
Other noncurrent liabilities	11.7	11.6
Total Liabilities	$ 22.0	$ 19.7
Commitments and contingencies (Note 7)
Redeemable common stock	$ 0.0	$ 0.0
Total stockholders’ (deficit) equity	102.9	98.9
Total Liabilities, Redeemable Common Stock and Stockholders’ Deficit	$ 124.9	$ 118.6