Revenue Recognition Revenue Recognition (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jun. 30, 2018	Jan. 01, 2018	Jun. 30, 2017	Dec. 31, 2016
Inventory Costs in Excess of Average Cost Per Unit	$ 0		$ 0		$ 438,000,000
Capitalized Contract Cost, Gross							$ 700,000,000
Previously Recognized Customer Funding to Contract Liability							850,000,000
Revenues	16,510,000,000	$ 15,062,000,000	48,457,000,000	$ 44,157,000,000
Research and development	586,000,000	592,000,000	1,729,000,000	1,797,000,000
Selling, general and administrative	1,681,000,000	1,582,000,000	5,151,000,000	4,709,000,000
Total costs and expenses	14,803,000,000	13,280,000,000	43,118,000,000	38,912,000,000
Other income, net	131,000,000	250,000,000	1,303,000,000	1,095,000,000
Operating profit	1,838,000,000	2,032,000,000	6,642,000,000	6,340,000,000
Non-service pension cost (benefit)	(188,000,000)	(131,000,000)	(571,000,000)	(380,000,000)
Interest expense, net	258,000,000	223,000,000	721,000,000	662,000,000
Income from operations before income taxes	1,768,000,000	1,940,000,000	6,492,000,000	6,058,000,000
Income tax expense	419,000,000	506,000,000	1,636,000,000	1,624,000,000
Net Income from operations	1,349,000,000	1,434,000,000	4,856,000,000	4,434,000,000
Less: Noncontrolling interest in subsidiaries' earnings from operations	111,000,000	104,000,000	273,000,000	279,000,000
Net income attributable to common shareowners	1,238,000,000	1,330,000,000	4,583,000,000	4,155,000,000
Accounts receivable, net	12,550,000,000		12,550,000,000		12,595,000,000
Contract with Customer, Asset, Net, Current	3,450,000,000		3,450,000,000		0
Inventories and contracts in progress, net	9,068,000,000		9,068,000,000		9,881,000,000
Other assets, current	1,337,000,000		1,337,000,000		1,397,000,000
Future income tax benefits	1,701,000,000		1,701,000,000		1,723,000,000
Intangible assets, net	15,701,000,000		15,701,000,000		15,883,000,000
Other assets	7,070,000,000		7,070,000,000		5,983,000,000
Accrued liabilities	8,867,000,000		8,867,000,000		12,316,000,000
Contract with Customer, Liability, Current	5,460,000,000		5,460,000,000		0
Other long-term liabilities	13,373,000,000		13,373,000,000		12,952,000,000
Noncontrolling interest	2,144,000,000	1,810,000,000	2,144,000,000	1,810,000,000	1,811,000,000	$ 1,982,000,000		$ 1,713,000,000	$ 1,590,000,000
Retained earnings	57,706,000,000		57,706,000,000		55,242,000,000
Contract with Customer, Asset, Reclassified to Receivable	(21,093,000,000)
Revenue, Remaining Performance Obligation, Amount	$ 106,800,000,000		$ 106,800,000,000
Revenue, Remaining Performance Obligations, to be recognized within 24 months	42.00%		42.00%
Contract Asset and Liability [Abstract]
Contract with Customer, Asset, Net, Current	$ 3,450,000,000		$ 3,450,000,000		0
Contract with Customer, Asset, Net, Noncurrent	1,075,000,000		1,075,000,000
Contract with Customer, Asset, Net	4,525,000,000		4,525,000,000
Contract with Customer, Liability, Current	5,460,000,000		5,460,000,000		0
Contract with Customer, Liability, Noncurrent	5,044,000,000		5,044,000,000
Contract with Customer, Liability	10,504,000,000		10,504,000,000
Contract with Customer, Net	5,979,000,000		5,979,000,000				6,365,000,000
Contract with Customer, Liability, Revenue Recognized	19,499,000,000				$ 1,978,000,000
Product [Member]
Revenues	11,254,000,000	10,378,000,000	33,032,000,000	30,676,000,000
Cost of Goods and Services Sold	9,342,000,000	7,800,000,000	26,512,000,000	23,068,000,000
Service [Member]
Revenues	5,256,000,000	4,684,000,000	15,425,000,000	13,481,000,000
Cost of Goods and Services Sold	3,194,000,000	$ 3,306,000,000	9,726,000,000	$ 9,338,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Satisfied Portion of the Performance Obligation of CIP							220,000,000
Inventory Costs in Excess of Average Cost Per Unit							438,000,000
Revenues	49,000,000		455,000,000
Research and development	(28,000,000)		(65,000,000)
Selling, general and administrative	0		0
Total costs and expenses	(53,000,000)		355,000,000
Other income, net	(1,000,000)		(4,000,000)
Operating profit	101,000,000		96,000,000
Non-service pension cost (benefit)	0		0
Interest expense, net	0		0
Income from operations before income taxes	101,000,000		96,000,000
Income tax expense	25,000,000		24,000,000
Net Income from operations	76,000,000		72,000,000
Less: Noncontrolling interest in subsidiaries' earnings from operations	(2,000,000)		4,000,000
Net income attributable to common shareowners	78,000,000		68,000,000
Accounts receivable, net	(1,438,000,000)		(1,438,000,000)
Contract with Customer, Asset, Net, Current	3,450,000,000		3,450,000,000
Inventories and contracts in progress, net	(2,269,000,000)		(2,269,000,000)
Other assets, current	32,000,000		32,000,000
Future income tax benefits	32,000,000		32,000,000
Intangible assets, net	(70,000,000)		(70,000,000)
Other assets	1,083,000,000		1,083,000,000
Accrued liabilities	(5,286,000,000)		(5,286,000,000)
Contract with Customer, Liability, Current	5,460,000,000		5,460,000,000
Other long-term liabilities	1,016,000,000		1,016,000,000
Noncontrolling interest	6,000,000		6,000,000
Retained earnings	(412,000,000)		(412,000,000)				$ 480,000,000
Contract Asset and Liability [Abstract]
Contract with Customer, Asset, Net, Current	3,450,000,000		3,450,000,000
Contract with Customer, Liability, Current	5,460,000,000		5,460,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Product [Member]
Revenues	26,000,000		231,000,000
Cost of Goods and Services Sold	(47,000,000)		262,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Service [Member]
Revenues	23,000,000		224,000,000
Cost of Goods and Services Sold	22,000,000		158,000,000
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenues	16,461,000,000		48,002,000,000
Research and development	614,000,000		1,794,000,000
Selling, general and administrative	1,681,000,000		5,151,000,000
Total costs and expenses	14,856,000,000		42,763,000,000
Other income, net	132,000,000		1,307,000,000
Operating profit	1,737,000,000		6,546,000,000
Non-service pension cost (benefit)	(188,000,000)		(571,000,000)
Interest expense, net	258,000,000		721,000,000
Income from operations before income taxes	1,667,000,000		6,396,000,000
Income tax expense	394,000,000		1,612,000,000
Net Income from operations	1,273,000,000		4,784,000,000
Less: Noncontrolling interest in subsidiaries' earnings from operations	113,000,000		269,000,000
Net income attributable to common shareowners	1,160,000,000		4,515,000,000
Accounts receivable, net	13,988,000,000		13,988,000,000
Contract with Customer, Asset, Net, Current	0		0
Inventories and contracts in progress, net	11,337,000,000		11,337,000,000
Other assets, current	1,305,000,000		1,305,000,000
Future income tax benefits	1,669,000,000		1,669,000,000
Intangible assets, net	15,771,000,000		15,771,000,000
Other assets	5,987,000,000		5,987,000,000
Accrued liabilities	14,153,000,000		14,153,000,000
Contract with Customer, Liability, Current	0		0
Other long-term liabilities	12,357,000,000		12,357,000,000
Noncontrolling interest	2,138,000,000		2,138,000,000
Retained earnings	58,118,000,000		58,118,000,000
Contract Asset and Liability [Abstract]
Contract with Customer, Asset, Net, Current	0		0
Contract with Customer, Liability, Current	0		0
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Product [Member]
Revenues	11,228,000,000		32,801,000,000
Cost of Goods and Services Sold	9,389,000,000		26,250,000,000
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Service [Member]
Revenues	5,233,000,000		15,201,000,000
Cost of Goods and Services Sold	$ 3,172,000,000		$ 9,568,000,000