Condensed Consolidating Financial Information, (As Restated for fiscal 2014 and 2013) - Schedule of Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Nov. 30, 2012
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 211.1	$ 243.3	$ 253.5	$ 215.7	$ 265.9	$ 154.9	$ 120.7	$ 144.1	$ 197.6	$ 162.1
Accounts receivable	171.5	189.3	175.6	190.0	170.5	200.5	177.3	186.1
Inventories	157.5	147.9	150.1	161.5	138.0	131.8	131.7	136.2
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	30.0				25.4
Other current assets, net	61.5	63.3	49.0	43.7	38.6	30.1	24.5	28.6
Income taxes	2.9			2.3	2.1	13.7	11.8	11.8
Deferred income taxes	28.1	14.0	19.3	18.7	19.9	10.7	18.6	19.2
Total Current Assets	662.6	687.0	677.2	661.4	660.4	567.8	511.6	554.4
Property, plant and equipment, net	365.8	351.8	356.3	357.2	366.5	369.3	369.6	372.4
Recoverable from the U.S. government and other third parties for environmental remediation costs	210.4	123.2	76.8	79.3	87.2	89.6	87.5	92.5
Deferred income taxes	286.7	254.6	247.3	256.0	261.4	182.5	180.2	185.6
Goodwill	158.1	158.1	158.1	158.1	158.1	158.1	158.1	153.1
Intercompany receivable	0.0				0.0
Investments in subsidiaries	0.0				0.0
Other noncurrent assets and intangibles, net	351.3				385.0
Total Assets	2,034.9	1,957.6	1,899.3	1,895.7	1,918.6	1,742.3	1,673.2	1,717.8
Short-term borrowings and current portion of long-term debt	5.3	5.3	5.3	5.3	5.3	5.5	4.2	3.0
Accounts payable	105.2	88.7	88.1	85.0	104.0	115.4	94.4	97.1
Reserves for environmental remediation costs	32.6	37.6	38.7	38.3	31.9	35.0	36.0	38.0
Postretirement medical and life insurance benefits	6.0	6.4	6.4	6.4	6.4	7.2	7.2	7.2
Other current liabilities and advance payments on contracts	405.0				418.8
Total Current Liabilities	554.1	593.4	536.7	555.5	566.4	497.2	428.9	457.2
Long-term debt	646.7				776.9
Reserves for environmental remediation costs	273.5	198.5	122.8	124.3	134.1	133.6	127.7	132.4
Pension benefits	566.2	471.9	475.5	479.1	482.8	257.7	262.1	266.5
Intercompany payable	0.0				0.0
Postretirement medical and life insurance benefits	45.5	49.4	50.1	50.6	51.7	57.1	57.5	58.5
Other noncurrent liabilities	94.4				80.6
Total Liabilities	$ 2,180.4	2,066.9	1,997.4	2,024.5	$ 2,092.5	1,802.9	1,733.3	1,682.2
Commitments and contingencies
Redeemable common stock	$ 0.9				$ 1.6
Total stockholders’ (deficit) equity	(146.4)	(109.4)	(98.2)	(128.9)	(175.5)	(60.8)	(60.2)	35.5	37.3	(394.3)
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity	2,034.9	1,957.6	1,899.3	1,895.7	1,918.6	1,742.3	1,673.2	1,717.8
As Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents		243.3	253.5	215.7	265.9	154.9	120.7	144.1	197.6	162.1
Accounts receivable		186.7	173.7	206.1	172.9	214.7	191.7	199.2
Inventories		148.7	150.3	161.4	139.0	132.3	131.9	139.2
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs					25.4
Other current assets, net		60.0	45.4	42.5	35.9	26.7	19.6	22.5
Income taxes				1.9	2.1	13.4	10.7	5.8
Deferred income taxes		19.4	24.8	22.5	25.3	4.0	16.2	18.6
Total Current Assets		687.3	677.4	679.6	666.5	572.1	517.8	557.8
Property, plant and equipment, net		351.8	356.3	358.8	367.5	370.6	370.6	372.7
Recoverable from the U.S. government and other third parties for environmental remediation costs		123.2	76.8	79.3	81.2	83.6	81.5	86.5
Deferred income taxes		253.6	245.3	254.5	259.0	180.0	170.2	175.9
Goodwill		164.4	164.4	164.4	164.4	164.4	164.4	159.4
Intercompany receivable					0.0
Investments in subsidiaries					0.0
Other noncurrent assets and intangibles, net					383.0
Total Assets		1,957.4	1,898.1	1,911.7	1,921.6	1,749.7	1,675.6	1,714.6
Short-term borrowings and current portion of long-term debt		5.3	5.3	5.3	5.3	5.5	4.2	3.0
Accounts payable		88.7	87.6	84.5	103.5	115.4	94.5	98.0
Reserves for environmental remediation costs		37.6	38.7	38.3	31.9	35.0	36.0	38.0
Postretirement medical and life insurance benefits		6.4	6.4	6.4	6.4	7.2	7.2	7.2
Other current liabilities and advance payments on contracts					420.2
Total Current Liabilities		591.0	533.8	569.8	567.3	501.9	431.1	453.5
Long-term debt					776.9
Reserves for environmental remediation costs		198.5	122.8	124.3	134.1	133.6	127.7	132.4
Pension benefits		471.7	475.4	479.1	482.8	248.3	252.7	257.2
Intercompany payable					0.0
Postretirement medical and life insurance benefits		49.4	50.1	50.6	51.7	57.1	57.5	58.5
Other noncurrent liabilities					79.7
Total Liabilities		2,064.6	1,993.7	2,038.1	$ 2,092.5	1,798.2	1,724.6	1,666.8
Commitments and contingencies
Redeemable common stock					$ 1.6
Total stockholders’ (deficit) equity		(107.3)	(95.7)	(126.5)	(172.5)	(48.7)	(49.1)	47.7
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity		$ 1,957.4	$ 1,898.1	$ 1,911.7	1,921.6	$ 1,749.7	$ 1,675.6	$ 1,714.6
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	(10.8)				(5.7)				0.0	(10.3)
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				0.0
Income taxes	(41.6)				(30.7)
Deferred income taxes	0.0				0.0
Total Current Assets	(52.4)				(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	(227.4)				(126.9)
Investments in subsidiaries	(543.2)				(500.2)
Other noncurrent assets and intangibles, net	0.0				0.0
Total Assets	(823.0)				(663.5)
Short-term borrowings and current portion of long-term debt	0.0				0.0
Accounts payable	(10.8)				(5.7)
Reserves for environmental remediation costs	0.0				0.0
Postretirement medical and life insurance benefits	0.0				0.0
Other current liabilities and advance payments on contracts	(41.6)				(30.7)
Total Current Liabilities	(52.4)				(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	(227.4)				(126.9)
Postretirement medical and life insurance benefits	0.0				0.0
Other noncurrent liabilities	0.0				0.0
Total Liabilities	$ (279.8)				$ (163.3)
Commitments and contingencies
Redeemable common stock	$ 0.0				$ 0.0
Total stockholders’ (deficit) equity	(543.2)				(500.2)
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity	(823.0)				(663.5)
Eliminations [Member] | As Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents					(5.7)				0.0	(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 current assets, net					0.0
Income taxes					(30.7)
Deferred income taxes					0.0
Total Current Assets					(36.4)
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					(126.9)
Investments in subsidiaries					(503.0)
Other noncurrent assets and intangibles, net					0.0
Total Assets					(666.3)
Short-term borrowings and current portion of long-term debt					0.0
Accounts payable					(5.7)
Reserves for environmental remediation costs					0.0
Postretirement medical and life insurance benefits					0.0
Other current liabilities and advance payments on contracts					(30.7)
Total Current Liabilities					(36.4)
Long-term debt					0.0
Reserves for environmental remediation costs					0.0
Pension benefits					0.0
Intercompany payable					(126.9)
Postretirement medical and life insurance benefits					0.0
Other noncurrent liabilities					0.0
Total Liabilities					(163.3)
Redeemable common stock					0.0
Total stockholders’ (deficit) equity					(503.0)
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity					(666.3)
Parent [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	221.9				271.6				192.7	172.4
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				0.1
Other current assets, net	3.1				3.5
Income taxes	44.2				31.0
Deferred income taxes	6.5				5.6
Total Current Assets	275.7				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	66.2				57.4
Goodwill	0.0				0.0
Intercompany receivable	0.0				0.0
Investments in subsidiaries	543.2				500.2
Other noncurrent assets and intangibles, net	31.4				28.1
Total Assets	921.9				902.9
Short-term borrowings and current portion of long-term debt	5.0				5.0
Accounts payable	1.0				1.5
Reserves for environmental remediation costs	0.7				1.0
Postretirement medical and life insurance benefits	4.6				5.0
Other current liabilities and advance payments on contracts	26.8				32.1
Total Current Liabilities	38.1				44.6
Long-term debt	646.6				776.6
Reserves for environmental remediation costs	4.5				4.8
Pension benefits	98.8				67.0
Intercompany payable	227.4				126.9
Postretirement medical and life insurance benefits	32.9				37.7
Other noncurrent liabilities	19.1				19.2
Total Liabilities	$ 1,067.4				$ 1,076.8
Commitments and contingencies
Redeemable common stock	$ 0.9				$ 1.6
Total stockholders’ (deficit) equity	(146.4)				(175.5)
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity	921.9				902.9
Parent [Member] | As Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents					271.6				192.7	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
Other current assets, net					3.5
Income taxes					31.0
Deferred income taxes					5.6
Total Current Assets					311.8
Property, plant and equipment, net					4.7
Recoverable from the U.S. government and other third parties for environmental remediation costs					0.7
Deferred income taxes					57.7
Goodwill					0.0
Intercompany receivable					0.0
Investments in subsidiaries					503.0
Other noncurrent assets and intangibles, net					28.1
Total Assets					906.0
Short-term borrowings and current portion of long-term debt					5.0
Accounts payable					1.5
Reserves for environmental remediation costs					1.0
Postretirement medical and life insurance benefits					5.0
Other current liabilities and advance payments on contracts					31.5
Total Current Liabilities					44.0
Long-term debt					776.6
Reserves for environmental remediation costs					4.8
Pension benefits					67.0
Intercompany payable					126.9
Postretirement medical and life insurance benefits					37.7
Other noncurrent liabilities					19.9
Total Liabilities					1,076.9
Redeemable common stock					1.6
Total stockholders’ (deficit) equity					(172.5)
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity					906.0
Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0.0				0.0				4.9	0.0
Accounts receivable	167.4				168.0
Inventories	150.8				132.6
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs	30.0				25.3
Other current assets, net	57.5				34.3
Income taxes	0.3				1.8
Deferred income taxes	20.4				13.4
Total Current Assets	426.4				375.4
Property, plant and equipment, net	355.3				355.9
Recoverable from the U.S. government and other third parties for environmental remediation costs	209.7				86.5
Deferred income taxes	203.4				186.1
Goodwill	158.1				158.1
Intercompany receivable	192.9				97.7
Investments in subsidiaries	0.0				0.0
Other noncurrent assets and intangibles, net	258.6				300.9
Total Assets	1,804.4				1,560.6
Short-term borrowings and current portion of long-term debt	0.3				0.3
Accounts payable	112.9				103.6
Reserves for environmental remediation costs	31.9				30.9
Postretirement medical and life insurance benefits	1.4				1.4
Other current liabilities and advance payments on contracts	413.4				413.9
Total Current Liabilities	559.9				550.1
Long-term debt	0.1				0.3
Reserves for environmental remediation costs	269.0				129.3
Pension benefits	467.4				415.8
Intercompany payable	0.0				0.0
Postretirement medical and life insurance benefits	12.6				14.0
Other noncurrent liabilities	62.6				49.8
Total Liabilities	$ 1,371.6				$ 1,159.3
Commitments and contingencies
Redeemable common stock	$ 0.0				$ 0.0
Total stockholders’ (deficit) equity	432.8				401.3
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity	1,804.4				1,560.6
Guarantor Subsidiaries [Member] | As Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents					0.0				4.9	0.0
Accounts receivable					170.4
Inventories					133.6
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs					25.3
Other current assets, net					31.6
Income taxes					1.8
Deferred income taxes					18.8
Total Current Assets					381.5
Property, plant and equipment, net					356.9
Recoverable from the U.S. government and other third parties for environmental remediation costs					80.5
Deferred income taxes					183.4
Goodwill					164.4
Intercompany receivable					97.7
Investments in subsidiaries					0.0
Other noncurrent assets and intangibles, net					298.9
Total Assets					1,563.3
Short-term borrowings and current portion of long-term debt					0.3
Accounts payable					103.1
Reserves for environmental remediation costs					30.9
Postretirement medical and life insurance benefits					1.4
Other current liabilities and advance payments on contracts					415.9
Total Current Liabilities					551.6
Long-term debt					0.3
Reserves for environmental remediation costs					129.3
Pension benefits					415.8
Intercompany payable					0.0
Postretirement medical and life insurance benefits					14.0
Other noncurrent liabilities					48.2
Total Liabilities					1,159.2
Redeemable common stock					0.0
Total stockholders’ (deficit) equity					404.1
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity					1,563.3
Non-guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0.0				0.0				0.0	0.0
Accounts receivable	4.1				2.5
Inventories	6.7				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	0.9				0.8
Income taxes	0.0				0.0
Deferred income taxes	1.2				0.9
Total Current Assets	12.9				9.6
Property, plant and equipment, net	5.8				5.9
Recoverable from the U.S. government and other third parties for environmental remediation costs	0.0				0.0
Deferred income taxes	17.1				17.9
Goodwill	0.0				0.0
Intercompany receivable	34.5				29.2
Investments in subsidiaries	0.0				0.0
Other noncurrent assets and intangibles, net	61.3				56.0
Total Assets	131.6				118.6
Short-term borrowings and current portion of long-term debt	0.0				0.0
Accounts payable	2.1				4.6
Reserves for environmental remediation costs	0.0				0.0
Postretirement medical and life insurance benefits	0.0				0.0
Other current liabilities and advance payments on contracts	6.4				3.5
Total Current Liabilities	8.5				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	12.7				11.6
Total Liabilities	$ 21.2				$ 19.7
Commitments and contingencies
Redeemable common stock	$ 0.0				$ 0.0
Total stockholders’ (deficit) equity	110.4				98.9
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity	$ 131.6				118.6
Non-guarantor Subsidiaries [Member] | As Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents					0.0				$ 0.0	$ 0.0
Accounts receivable					2.5
Inventories					5.4
Recoverable from the U.S. government, Northrop, and other third parties for environmental remediation costs					0.0
Other current assets, net					0.8
Income taxes					0.0
Deferred income taxes					0.9
Total Current Assets					9.6
Property, plant and equipment, net					5.9
Recoverable from the U.S. government and other third parties for environmental remediation costs					0.0
Deferred income taxes					17.9
Goodwill					0.0
Intercompany receivable					29.2
Investments in subsidiaries					0.0
Other noncurrent assets and intangibles, net					56.0
Total Assets					118.6
Short-term borrowings and current portion of long-term debt					0.0
Accounts payable					4.6
Reserves for environmental remediation costs					0.0
Postretirement medical and life insurance benefits					0.0
Other current liabilities and advance payments on contracts					3.5
Total Current Liabilities					8.1
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					11.6
Total Liabilities					19.7
Redeemable common stock					0.0
Total stockholders’ (deficit) equity					98.9
Total liabilities, redeemable common stock, and stockholders’ (deficit) equity					$ 118.6