RECENT ACCOUNTING PRONOUNCEMENTS - Effect of Topic 606 and ASU 2017-07 Adoption on Balance Sheets (Details) - USD ($)	Mar. 25, 2018	Dec. 31, 2017	Mar. 26, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 2,393,000,000	$ 2,861,000,000	$ 2,216,000,000	$ 1,837,000,000
Receivables, net	2,373,000,000	2,265,000,000
Contract assets	9,405,000,000	7,992,000,000
Inventories	3,196,000,000	2,878,000,000
Other current assets	449,000,000	1,509,000,000
Total current assets	17,816,000,000	17,505,000,000
Property, plant and equipment, net	5,749,000,000	5,775,000,000
Goodwill	10,806,000,000	10,807,000,000
Intangible assets, net	3,730,000,000	3,797,000,000
Deferred income taxes	3,084,000,000	3,156,000,000
Other noncurrent assets	5,449,000,000	5,580,000,000
Total assets	46,634,000,000	46,620,000,000
Current liabilities
Accounts payable	2,715,000,000	1,467,000,000
Contract liabilities	6,550,000,000	7,028,000,000
Salaries, benefits and payroll taxes	1,771,000,000	1,785,000,000
Current maturities of long-term debt	750,000,000	750,000,000
Other current liabilities	2,188,000,000	1,883,000,000
Total current liabilities	13,974,000,000	12,913,000,000
Long-term debt, net	13,473,000,000	13,513,000,000
Accrued pension liabilities	14,199,000,000	15,703,000,000
Other postretirement benefit liabilities	713,000,000	719,000,000
Other noncurrent liabilities	4,386,000,000	4,548,000,000
Total liabilities	46,745,000,000	47,396,000,000
Stockholders’ equity
Common stock, $1 par value per share	284,000,000	284,000,000
Additional paid-in capital	0	0
Retained earnings	14,123,000,000	11,405,000,000			$ 0
Accumulated other comprehensive loss	(14,589,000,000)	(12,539,000,000)
Total stockholders’ deficit	(182,000,000)	(850,000,000)
Noncontrolling interests in subsidiary	71,000,000	74,000,000
Total deficit	(111,000,000)	(776,000,000)	$ 1,482,000,000	$ 1,477,000,000
Total liabilities and equity	$ 46,634,000,000	$ 46,620,000,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Historical
Current assets
Cash and cash equivalents		$ 2,861,000,000
Receivables, net		8,603,000,000
Contract assets		0
Inventories		4,487,000,000
Other current assets		1,510,000,000
Total current assets		17,461,000,000
Property, plant and equipment, net		5,775,000,000
Goodwill		10,807,000,000
Intangible assets, net		3,797,000,000
Deferred income taxes		3,111,000,000
Other noncurrent assets		5,570,000,000
Total assets		46,521,000,000
Current liabilities
Accounts payable		1,467,000,000
Contract liabilities		6,752,000,000
Salaries, benefits and payroll taxes		1,785,000,000
Current maturities of long-term debt		750,000,000
Other current liabilities		1,883,000,000
Total current liabilities		12,637,000,000
Long-term debt, net		13,513,000,000
Accrued pension liabilities		15,703,000,000
Other postretirement benefit liabilities		719,000,000
Other noncurrent liabilities		4,558,000,000
Total liabilities		47,130,000,000
Stockholders’ equity
Common stock, $1 par value per share		284,000,000
Additional paid-in capital		0
Retained earnings		11,573,000,000
Accumulated other comprehensive loss		(12,540,000,000)
Total stockholders’ deficit		(683,000,000)
Noncontrolling interests in subsidiary		74,000,000
Total deficit		(609,000,000)
Total liabilities and equity		46,521,000,000
Adjustments for | ASC 606
Current assets
Cash and cash equivalents		0
Receivables, net		(6,338,000,000)
Contract assets		7,992,000,000
Inventories		(1,609,000,000)
Other current assets		(1,000,000)
Total current assets		44,000,000
Property, plant and equipment, net		0
Goodwill		0
Intangible assets, net		0
Deferred income taxes		45,000,000
Other noncurrent assets		10,000,000
Total assets		99,000,000
Current liabilities
Accounts payable		0
Contract liabilities		276,000,000
Salaries, benefits and payroll taxes		0
Current maturities of long-term debt		0
Other current liabilities		0
Total current liabilities		276,000,000
Long-term debt, net		0
Accrued pension liabilities		0
Other postretirement benefit liabilities		0
Other noncurrent liabilities		(10,000,000)
Total liabilities		266,000,000
Stockholders’ equity
Common stock, $1 par value per share		0
Additional paid-in capital		0
Retained earnings		(168,000,000)
Accumulated other comprehensive loss		1,000,000
Total stockholders’ deficit		(167,000,000)
Noncontrolling interests in subsidiary		0
Total deficit		(167,000,000)
Total liabilities and equity		$ 99,000,000