Significant Accounting Policies - Schedule of Effect of Adoption of ASU 606 on Balance Sheets (Details) - USD ($)	Dec. 31, 2018	Sep. 27, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 772,000,000		$ 2,861,000,000	$ 1,837,000,000	$ 1,090,000,000
Receivables, net	2,444,000,000		2,265,000,000
Contract assets	9,472,000,000		7,992,000,000
Inventories	2,997,000,000		2,878,000,000
Other current assets	418,000,000		1,509,000,000
Total current assets	16,103,000,000		17,505,000,000
Property, plant and equipment, net	6,124,000,000		5,775,000,000
Goodwill	10,769,000,000		10,807,000,000	10,764,000,000
Intangible assets, net	3,494,000,000		3,797,000,000
Deferred income taxes	3,208,000,000		3,156,000,000
Other noncurrent assets	5,178,000,000		5,580,000,000
Total assets	44,876,000,000		46,620,000,000
Accounts payable	2,402,000,000		1,467,000,000
Contract liabilities	6,491,000,000		7,028,000,000
Salaries, benefits and payroll taxes	2,122,000,000		1,785,000,000
Current maturities of long-term debt	1,500,000,000		750,000,000
Other current liabilities	1,883,000,000		1,883,000,000
Total current liabilities	14,398,000,000		12,913,000,000
Long-term debt, net	12,604,000,000		13,513,000,000
Accrued pension liabilities	11,410,000,000		15,703,000,000
Other postretirement benefit liabilities	704,000,000		719,000,000
Other noncurrent liabilities	4,311,000,000		4,548,000,000
Total liabilities	43,427,000,000		47,396,000,000
Common stock, $1 par value per share	$ 281,000,000		$ 284,000,000
Common stock, par value (in USD per share)	$ 1		$ 1
Additional paid-in capital	$ 0	$ 0	$ 0
Retained earnings	15,434,000,000		11,405,000,000
Accumulated other comprehensive loss	(14,321,000,000)		(12,539,000,000)
Total stockholders’ equity (deficit)	1,394,000,000		(850,000,000)
Noncontrolling interests in subsidiary	55,000,000		74,000,000
Total equity (deficit)	1,449,000,000		(776,000,000)	$ 1,477,000,000	$ 3,097,000,000
Total liabilities and equity	$ 44,876,000,000		46,620,000,000
Historical
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
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
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
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’ equity (deficit)			(683,000,000)
Noncontrolling interests in subsidiary			74,000,000
Total equity (deficit)			(609,000,000)
Total liabilities and equity			46,521,000,000
ASC 606 | Adjustments for
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
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
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
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’ equity (deficit)			(167,000,000)
Noncontrolling interests in subsidiary			0
Total equity (deficit)			(167,000,000)
Total liabilities and equity			$ 99,000,000