Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Aug. 31, 2014	Nov. 30, 2013	Aug. 31, 2013	Nov. 30, 2012
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 154.9	$ 197.6	$ 181.9	$ 162.1
Accounts receivable	214.7	214.1
Inventories	132.3	105.9
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	26.1	26.4
Other receivables, prepaid expenses and other	26.7	22.4
Income taxes	13.4	12.6
Deferred income taxes	4.0	17.0
Total Current Assets	572.1	596.0
Property, plant and equipment, net	370.6	374.7
Recoverable from the U.S. government and other third parties for environmental remediation costs	83.6	88.7
Deferred income taxes	180.0	175.7
Goodwill	164.4	159.6
Intercompany receivable	0	0
Investments in subsidiaries	0	0
Other noncurrent assets and intangibles, net	379.0	360.6
Total Assets	1,749.7	1,755.3
Short-term borrowings and current portion of long-term debt	5.5	2.9
Accounts payable	115.4	122.5
Reserves for environmental remediation costs	35.0	36.6
Income taxes payable	0	0
Other current liabilities and advance payments on contracts	338.8	310.4
Postretirement medical and life insurance benefits	7.2	7.3
Total Current Liabilities	501.9	479.7
Long-term debt	778.0	696.3
Reserves for environmental remediation costs	133.6	134.7
Pension benefits	248.3	261.7
Intercompany payable	0	0
Postretirement medical and life insurance benefits	57.1	59.3
Other noncurrent liabilities	79.3	73.8
Total Liabilities	1,798.2	1,705.5
Commitments and contingencies (Note 8)
Redeemable common stock	0.2	0.2
Total shareholders’ (deficit) equity	(48.7)	49.6
Total Liabilities, Redeemable Common Stock and Shareholders’ (Deficit) Equity	1,749.7	1,755.3
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	(0.2)	0	(0.7)	(10.3)
Accounts receivable	0	0
Inventories	0	0
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0	0
Other receivables, prepaid expenses and other	0	0
Income taxes	(12.1)	(17.5)
Deferred income taxes	(5.1)	0
Total Current Assets	(17.4)	(17.5)
Property, plant and equipment, net	0	0
Recoverable from the U.S. government and other third parties for environmental remediation costs	0	0
Deferred income taxes	0	0
Goodwill	0	0
Intercompany receivable	(41.0)	(65.7)
Investments in subsidiaries	(577.8)	(534.5)
Other noncurrent assets and intangibles, net	0	0
Total Assets	(636.2)	(617.7)
Short-term borrowings and current portion of long-term debt	0	0
Accounts payable	(0.2)	0
Reserves for environmental remediation costs	0	0
Income taxes payable	(12.1)	(17.5)
Other current liabilities and advance payments on contracts	(5.1)	0
Postretirement medical and life insurance benefits	0	0
Total Current Liabilities	(17.4)	(17.5)
Long-term debt	0	0
Reserves for environmental remediation costs	0	0
Pension benefits	0	0
Intercompany payable	(41.0)	(65.7)
Postretirement medical and life insurance benefits	0	0
Other noncurrent liabilities	0	0
Total Liabilities	(58.4)	(83.2)
Commitments and contingencies (Note 8)
Redeemable common stock	0	0
Total shareholders’ (deficit) equity	(577.8)	(534.5)
Total Liabilities, Redeemable Common Stock and Shareholders’ (Deficit) Equity	(636.2)	(617.7)
Parent [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	154.9	192.7	182.6	172.4
Accounts receivable	0	0
Inventories	0	0
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0.1	0.4
Other receivables, prepaid expenses and other	3.7	2.6
Income taxes	25.1	30.1
Deferred income taxes	9.1	10.9
Total Current Assets	192.9	236.7
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	0.4
Deferred income taxes	52.5	48.8
Goodwill	0	0
Intercompany receivable	10.6	33.5
Investments in subsidiaries	577.8	534.5
Other noncurrent assets and intangibles, net	29.3	27.7
Total Assets	868.5	886.3
Short-term borrowings and current portion of long-term debt	5.2	2.7
Accounts payable	1.8	2.2
Reserves for environmental remediation costs	2.0	3.8
Income taxes payable	0	0
Other current liabilities and advance payments on contracts	41.9	41.7
Postretirement medical and life insurance benefits	5.5	5.5
Total Current Liabilities	56.4	55.9
Long-term debt	777.6	695.7
Reserves for environmental remediation costs	4.5	4.3
Pension benefits	21.3	23.6
Intercompany payable	0	0
Postretirement medical and life insurance benefits	37.8	39.8
Other noncurrent liabilities	19.4	17.2
Total Liabilities	917.0	836.5
Commitments and contingencies (Note 8)
Redeemable common stock	0.2	0.2
Total shareholders’ (deficit) equity	(48.7)	49.6
Total Liabilities, Redeemable Common Stock and Shareholders’ (Deficit) Equity	868.5	886.3
Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	4.9	0	0
Accounts receivable	213.1	211.4
Inventories	126.4	100.5
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	26.0	26.0
Other receivables, prepaid expenses and other	22.1	18.8
Income taxes	0	0
Deferred income taxes	0	4.9
Total Current Assets	387.6	366.5
Property, plant and equipment, net	360.1	364.4
Recoverable from the U.S. government and other third parties for environmental remediation costs	82.9	88.3
Deferred income taxes	108.4	107.2
Goodwill	164.4	159.6
Intercompany receivable	0	0
Investments in subsidiaries	0	0
Other noncurrent assets and intangibles, net	300.1	289.0
Total Assets	1,403.5	1,375.0
Short-term borrowings and current portion of long-term debt	0.3	0.2
Accounts payable	112.6	119.1
Reserves for environmental remediation costs	33.0	32.8
Income taxes payable	12.1	16.9
Other current liabilities and advance payments on contracts	298.7	265.9
Postretirement medical and life insurance benefits	1.7	1.8
Total Current Liabilities	458.4	436.7
Long-term debt	0.4	0.6
Reserves for environmental remediation costs	129.1	130.4
Pension benefits	227.0	238.1
Intercompany payable	41.0	65.7
Postretirement medical and life insurance benefits	19.3	19.5
Other noncurrent liabilities	47.7	45.1
Total Liabilities	922.9	936.1
Commitments and contingencies (Note 8)
Redeemable common stock	0	0
Total shareholders’ (deficit) equity	480.6	438.9
Total Liabilities, Redeemable Common Stock and Shareholders’ (Deficit) Equity	1,403.5	1,375.0
Non-guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0.2	0	0	0
Accounts receivable	1.6	2.7
Inventories	5.9	5.4
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	0	0
Other receivables, prepaid expenses and other	0.9	1.0
Income taxes	0.4	0
Deferred income taxes	0	1.2
Total Current Assets	9.0	10.3
Property, plant and equipment, net	5.8	5.6
Recoverable from the U.S. government and other third parties for environmental remediation costs	0	0
Deferred income taxes	19.1	19.7
Goodwill	0	0
Intercompany receivable	30.4	32.2
Investments in subsidiaries	0	0
Other noncurrent assets and intangibles, net	49.6	43.9
Total Assets	113.9	111.7
Short-term borrowings and current portion of long-term debt	0	0
Accounts payable	1.2	1.2
Reserves for environmental remediation costs	0	0
Income taxes payable	0	0.6
Other current liabilities and advance payments on contracts	3.3	2.8
Postretirement medical and life insurance benefits	0	0
Total Current Liabilities	4.5	4.6
Long-term debt	0	0
Reserves for environmental remediation costs	0	0
Pension benefits	0	0
Intercompany payable	0	0
Postretirement medical and life insurance benefits	0	0
Other noncurrent liabilities	12.2	11.5
Total Liabilities	16.7	16.1
Commitments and contingencies (Note 8)
Redeemable common stock	0	0
Total shareholders’ (deficit) equity	97.2	95.6
Total Liabilities, Redeemable Common Stock and Shareholders’ (Deficit) Equity	$ 113.9	$ 111.7