Condensed Consolidating Financial Statements (Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2019		Dec. 31, 2018	Apr. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and equivalents	$ 902		$ 963
Accounts receivable	3,544		3,759
Unbilled receivables	7,857		6,576
Inventories	6,306		5,977
Other current assets	1,171		914
Total current assets	19,780		18,189
Noncurrent assets:
PP&E	9,761		8,972
Accumulated depreciation of PP&E	(5,286)		(4,994)
Intangible assets, net	2,315		2,585
Goodwill	19,677		19,594	$ 11,955	$ 11,914
Other assets	2,594		1,062
Net investment in subsidiaries	0		0
Total noncurrent assets	29,061		27,219
Total assets	48,841		45,408		35,046
Current liabilities:
Short-term debt and current portion of long-term debt	2,920		973
Customer advances and deposits	7,148		7,270
Other current liabilities	6,733		6,496
Total current liabilities	16,801		14,739
Noncurrent liabilities:
Long-term debt	9,010		11,444
Other liabilities	9,453		7,493
Total noncurrent liabilities	18,463		18,937
Total shareholders’ equity	13,577		11,732		$ 11,435	$ 10,301
Total liabilities and shareholders’ equity	48,841		45,408
Consolidating Adjustments
Current assets:
Cash and equivalents	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:
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	(29,693)		(27,887)
Total noncurrent assets	(29,693)		(27,887)
Total assets	(29,693)		(27,887)
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	(29,693)		(27,887)
Total liabilities and shareholders’ equity	(29,693)		(27,887)
Parent
Current assets:
Cash and equivalents	601	[1]	460
Accounts receivable	0	[1]	0
Unbilled receivables	0	[1]	0
Inventories	0	[1]	0
Other current assets	(300)	[1]	(251)
Total current assets	301	[1]	209
Noncurrent assets:
PP&E	346	[1]	273
Accumulated depreciation of PP&E	(91)	[1]	(83)
Intangible assets, net	0	[1]	0
Goodwill	0	[1]	0
Other assets	203	[1]	195
Net investment in subsidiaries	29,693	[1]	27,887
Total noncurrent assets	30,151	[1]	28,272
Total assets	30,452	[1]	28,481
Current liabilities:
Short-term debt and current portion of long-term debt	2,497	[1]	850
Customer advances and deposits	0	[1]	0
Other current liabilities	487	[1]	552
Total current liabilities	2,984	[1]	1,402
Noncurrent liabilities:
Long-term debt	8,928	[1]	11,398
Other liabilities	4,963	[1]	3,949
Total noncurrent liabilities	13,891	[1]	15,347
Total shareholders’ equity	13,577	[1]	11,732
Total liabilities and shareholders’ equity	30,452	[1]	28,481
Guarantors on a Combined Basis
Current assets:
Cash and equivalents	0		0
Accounts receivable	1,188		1,171
Unbilled receivables	2,826		2,758
Inventories	6,191		5,855
Other current assets	989		647
Total current assets	11,194		10,431
Noncurrent assets:
PP&E	7,741		7,177
Accumulated depreciation of PP&E	(4,260)		(4,071)
Intangible assets, net	210		251
Goodwill	7,960		8,031
Other assets	1,278		274
Net investment in subsidiaries	0		0
Total noncurrent assets	12,929		11,662
Total assets	24,123		22,093
Current liabilities:
Short-term debt and current portion of long-term debt	2		0
Customer advances and deposits	4,174		4,541
Other current liabilities	4,391		3,944
Total current liabilities	8,567		8,485
Noncurrent liabilities:
Long-term debt	67		39
Other liabilities	2,995		2,115
Total noncurrent liabilities	3,062		2,154
Total shareholders’ equity	12,494		11,454
Total liabilities and shareholders’ equity	24,123		22,093
Other Subsidiaries on a Combined Basis
Current assets:
Cash and equivalents	301		503
Accounts receivable	2,356		2,588
Unbilled receivables	5,031		3,818
Inventories	115		122
Other current assets	482		518
Total current assets	8,285		7,549
Noncurrent assets:
PP&E	1,674		1,522
Accumulated depreciation of PP&E	(935)		(840)
Intangible assets, net	2,105		2,334
Goodwill	11,717		11,563
Other assets	1,113		593
Net investment in subsidiaries	0		0
Total noncurrent assets	15,674		15,172
Total assets	23,959		22,721
Current liabilities:
Short-term debt and current portion of long-term debt	421		123
Customer advances and deposits	2,974		2,729
Other current liabilities	1,855		2,000
Total current liabilities	5,250		4,852
Noncurrent liabilities:
Long-term debt	15		7
Other liabilities	1,495		1,429
Total noncurrent liabilities	1,510		1,436
Total shareholders’ equity	17,199		16,433
Total liabilities and shareholders’ equity	$ 23,959		$ 22,721

[1] Includes the funded status of the company’s primary domestic qualified defined-benefit pension plans as the Parent has the ultimate obligation for the plans.