Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018	Apr. 01, 2018	Dec. 31, 2017
Current assets:
Cash and equivalents		$ 673	$ 963	$ 4,332	$ 2,983
Accounts receivable		3,718	3,759
Unbilled receivables		7,367	6,576
Inventories		6,185	5,977
Other current assets		924	914
Total current assets		18,867	18,189
Noncurrent assets:
Property, plant and equipment (PP&E)		9,145	8,972
Accumulated depreciation of PP&E		(5,091)	(4,994)
Intangible assets, net		2,518	2,585
Goodwill	[1]	19,668	19,594
Other assets		2,359	1,062
Net investment in subsidiaries		0	0
Total noncurrent assets		28,599	27,219
Total assets		47,466	45,408
Current liabilities:
Short-term debt and current portion of long-term debt		2,097	973
Customer advances and deposits		6,695	7,270
Other current liabilities		6,590	6,496
Total current liabilities		15,382	14,739
Noncurrent liabilities:
Long-term debt		11,451	11,444
Other liabilities		8,399	7,493
Total noncurrent liabilities		19,850	18,937
Total shareholders’ equity		12,234	11,732	11,774	11,435
Total liabilities and shareholders’ equity		47,466	45,408
Consolidating Adjustments
Current assets:
Cash and equivalents		0	0	0	0
Accounts receivable		0	0
Unbilled receivables		0	0
Inventories		0	0
Other current assets		0	0
Total current assets		0	0
Noncurrent assets:
Property, plant and equipment (PP&E)		0	0
Accumulated depreciation of PP&E		0	0
Intangible assets, net		0	0
Goodwill		0	0
Other assets		0	0
Net investment in subsidiaries		(27,050)	(25,313)
Total noncurrent assets		(27,050)	(25,313)
Total assets		(27,050)	(25,313)
Current liabilities:
Short-term debt and current portion of long-term debt		0	0
Customer advances and deposits		0	0
Other current liabilities		0	0
Total current liabilities		0	0
Noncurrent liabilities:
Long-term debt		0	0
Other liabilities		0	0
Total noncurrent liabilities		0	0
Total shareholders’ equity		(27,050)	(25,313)
Total liabilities and shareholders’ equity		(27,050)	(25,313)
Parent Company
Current assets:
Cash and equivalents		329	460	3,787	1,930
Accounts receivable		0	0
Unbilled receivables		0	0
Inventories		0	0
Other current assets		(43)	(45)
Total current assets		286	415
Noncurrent assets:
Property, plant and equipment (PP&E)		288	273
Accumulated depreciation of PP&E		(85)	(83)
Intangible assets, net		0	0
Goodwill		0	0
Other assets		207	195
Net investment in subsidiaries		27,050	25,313
Total noncurrent assets		27,460	25,698
Total assets		27,746	26,113
Current liabilities:
Short-term debt and current portion of long-term debt		1,863	850
Customer advances and deposits		0	0
Other current liabilities		691	552
Total current liabilities		2,554	1,402
Noncurrent liabilities:
Long-term debt		11,405	11,398
Other liabilities		1,553	1,581
Total noncurrent liabilities		12,958	12,979
Total shareholders’ equity		12,234	11,732
Total liabilities and shareholders’ equity		27,746	26,113
Guarantor Subsidiaries
Current assets:
Cash and equivalents		0	0	0	0
Accounts receivable		1,253	1,171
Unbilled receivables		2,985	2,758
Inventories		6,067	5,855
Other current assets		445	441
Total current assets		10,750	10,225
Noncurrent assets:
Property, plant and equipment (PP&E)		7,263	7,177
Accumulated depreciation of PP&E		(4,138)	(4,071)
Intangible assets, net		241	251
Goodwill		8,036	8,031
Other assets		1,052	274
Net investment in subsidiaries		0	0
Total noncurrent assets		12,454	11,662
Total assets		23,204	21,887
Current liabilities:
Short-term debt and current portion of long-term debt		0	0
Customer advances and deposits		4,245	4,541
Other current liabilities		4,000	3,944
Total current liabilities		8,245	8,485
Noncurrent liabilities:
Long-term debt		39	39
Other liabilities		4,656	4,073
Total noncurrent liabilities		4,695	4,112
Total shareholders’ equity		10,264	9,290
Total liabilities and shareholders’ equity		23,204	21,887
Non-Guarantor Subsidiaries
Current assets:
Cash and equivalents		344	503	$ 545	$ 1,053
Accounts receivable		2,465	2,588
Unbilled receivables		4,382	3,818
Inventories		118	122
Other current assets		522	518
Total current assets		7,831	7,549
Noncurrent assets:
Property, plant and equipment (PP&E)		1,594	1,522
Accumulated depreciation of PP&E		(868)	(840)
Intangible assets, net		2,277	2,334
Goodwill		11,632	11,563
Other assets		1,100	593
Net investment in subsidiaries		0	0
Total noncurrent assets		15,735	15,172
Total assets		23,566	22,721
Current liabilities:
Short-term debt and current portion of long-term debt		234	123
Customer advances and deposits		2,450	2,729
Other current liabilities		1,899	2,000
Total current liabilities		4,583	4,852
Noncurrent liabilities:
Long-term debt		7	7
Other liabilities		2,190	1,839
Total noncurrent liabilities		2,197	1,846
Total shareholders’ equity		16,786	16,023
Total liabilities and shareholders’ equity		$ 23,566	$ 22,721

[1] Goodwill in the Information Technology and Mission Systems reporting units is net of $536 and $1.3 billion of accumulated impairment losses, respectively.