Schedule of Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 2,865	$ 2,697	$ 2,420
Charged to costs and expenses	751	538	536
Deductions	1,571	370	259
Balance at end of period	2,045	2,865	2,697
Credit losses [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	437	384	405
Charged to costs and expenses	551	347	199
Deductions	421	294	220
Balance at end of period	567	437	384
Doubtful receivables [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	372	455	120
Charged to costs and expenses	24	(7)	374
Deductions	19	76	39
Balance at end of period	377	372	455
Inventories (primarily service part obsolescence) [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	225	254	262
Charged to costs and expenses	(33)	(29)	(8)
Deductions	0	0	0
Balance at end of period	192	225	254
Deferred tax assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	1,831	1,604	1,633
Charged to costs and expenses	209	227	(29)
Deductions	1,131	0	0
Balance at end of period	909	1,831	1,604
Valuation Allowance Of Deferred Tax Assets Recognized In Accumulated Other Comprehensive Income Loss [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Charged to costs and expenses	26	(142)	(428)
Valuation Allowance of Deferred Tax Assets Recognized in Income Statement [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Charged to costs and expenses	183	$ 369	$ 399
South America [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease)	$ (1,100)