Nature of Operations, Basis of Presentation and Change in Accounting Principle (Details 2) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Jun. 30, 2017	Jan. 01, 2017	Dec. 31, 2016
Statement of Results of Operations
Cost of Revenue		$ 9,022	$ 7,678	$ 27,010	$ 22,295
Selling, general and administrative expenses		1,299	1,254	4,015	3,619
Research and development expenses		479	461	1,384	1,344
Other operating (income) expenses		(390)	(348)	(1,028)	(1,751)
Total operating costs		11,375	9,904	33,970	29,493
Operating profit		2,135	1,509	6,410	3,073
Other income (expense)		102	132	350	260
Consolidated profit before taxes		2,135	1,523	6,455	2,971
Provision (benefit) for income taxes		415	470	1,377	921
Profit (loss) of consolidated companies		1,720	1,053	5,078	2,050
Profit of consolidated and affiliated companies		1,727	1,061	5,099	2,058
Profit	[1]	$ 1,727	$ 1,059	$ 5,099	$ 2,053
Profit per common share (in dollars per share)		$ 2.92	$ 1.79	$ 8.57	$ 3.48
Profit per common share - diluted (in dollars per share)	[2]	$ 2.88	$ 1.77	$ 8.45	$ 3.44
Statement of Comprehensive Income
Profit of consolidated and affiliated companies		$ 1,727	$ 1,061	$ 5,099	$ 2,058
Foreign currency translation, net of tax		(65)	248	(292)	719
Total other comprehensive income (loss), net of tax		(72)	238	(365)	806
Comprehensive income		1,655	1,299	4,734	2,864
Comprehensive income attributable to stockholders		1,655	1,297	4,734	2,859
Statement of Financial Position
Noncurrent deferred and refundable income taxes		1,288		1,288			$ 1,695	$ 1,693
Liability for postemployment benefits		7,046		7,046				8,365
Profit employed in the business		30,384		30,384			26,289	26,301
Accumulated other comprehensive income (loss)		(1,568)	(1,233)	(1,568)	(1,233)	$ (1,496)	(1,203)	(1,192)	$ (1,471)		$ (2,039)
Statement of Shareholders' Equity
Profit of consolidated and affiliated companies		1,727	1,061	5,099	2,058
Foreign currency translation, net of tax		(65)	248	(292)	719
Pension and other postretirement benefits, net of tax				(23)	(4)
Total stockholders' equity		15,890	15,697	15,890	15,697		$ 13,719	$ 13,766		$ 13,228	$ 13,213
Statement of Cash Flow
Profit of consolidated and affiliated companies		1,727	1,061	5,099	2,058
Adjustments for non-cash items: Other				630	596
Other assets - net				394	(137)
Other liabilities - net				(1,271)	(373)
Previous Accounting Guidance
Statement of Results of Operations
Cost of Revenue		8,997		27,020
Other operating (income) expenses				(1,034)
Operating profit		2,116		6,396
Consolidated profit before taxes		2,116		6,441
Provision (benefit) for income taxes		411		1,374
Profit (loss) of consolidated companies		1,705		5,067
Profit of consolidated and affiliated companies		1,712		5,088
Profit		1,712		5,088
Statement of Comprehensive Income
Profit of consolidated and affiliated companies		1,712		5,088
Statement of Financial Position
Noncurrent deferred and refundable income taxes		1,289		1,289
Profit employed in the business		30,385		30,385
Statement of Shareholders' Equity
Profit of consolidated and affiliated companies		1,712		5,088
Statement of Cash Flow
Profit of consolidated and affiliated companies		$ 1,712		$ 5,088
Previously Reported
Statement of Results of Operations
Cost of Revenue			7,633		22,160
Selling, general and administrative expenses			1,237		3,571
Research and development expenses			455		1,326
Other operating (income) expenses					(1,780)
Total operating costs			9,836		29,321
Operating profit			1,577		3,245
Other income (expense)			$ 64		$ 88

[1] 1 Profit attributable to common shareholders.

[2] 2 Diluted by assumed exercise of stock-based compensation awards using the treasury stock method.