Equity Activity - Reclassifications and Taxes (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Cost of sales	$ 1,684		$ 1,582	$ 3,234	$ 2,960
Cost of services	8,523		8,691	17,076	17,074
SG&A expense	5,160		5,349	10,312	11,361
Other (income) and expense	(76)		37	(104)	289
Interest expense	147		167	283	315
Provision for/(benefit from) income taxes	111	$ (329)	544	(218)	(439)
Net (income) loss	(2,331)		(2,504)	(4,082)	(4,518)
Other comprehensive income/(loss)				1,208	1,002
Accumulated Other Comprehensive Income/(Loss)
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Net of Tax Amount				486	135
Reclassification/amortization, Net of Tax Amount				723	867
Other comprehensive income/(loss), Before Tax Amount	432		617	1,211	1,023
Other comprehensive income/(loss), Tax (Expense)/Benefit	88		(223)	(3)	(21)
Other comprehensive income/(loss)	520		394	1,208	1,002
Foreign Currency Translation Adjustments
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Net of Tax Amount				510	351
Reclassification/amortization, Net of Tax Amount				0	0
Other comprehensive income/(loss), Before Tax Amount	(38)		(248)	124	(10)
Other comprehensive income/(loss), Tax (Expense)/Benefit	278		95	386	361
Other comprehensive income/(loss)	240		(154)	510	351
Net Unrealized Gains/(Losses) on Available-For-Sale Securities
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Before Tax Amount	4		1	3	(35)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	(1)		0	(1)	14
Unrealized gains/(losses) arising during the period, Net of Tax Amount	2		1	2	(22)
Reclassification/amortization, Net of Tax Amount				1	23
Other comprehensive income/(loss), Before Tax Amount	3		1	4	2
Other comprehensive income/(loss), Tax (Expense)/Benefit	(1)		0	(1)	(1)
Other comprehensive income/(loss)	2		1	2	1
Net Unrealized Gains/(Losses) on Available-For-Sale Securities | Reclassifications
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Other (income) and expense	0		0	1	37
Provision for/(benefit from) income taxes	0		0	0	(14)
Net (income) loss	0		0	1	23
Net Unrealized Gains/(Losses) on Cash Flow Hedges
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Before Tax Amount	(96)		9	(128)	(256)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	24		5	32	96
Unrealized gains/(losses) arising during the period, Net of Tax Amount	(71)		13	(96)	(160)
Reclassification/amortization, Net of Tax Amount				(175)	4
Other comprehensive income/(loss), Before Tax Amount	(272)		111	(402)	(245)
Other comprehensive income/(loss), Tax (Expense)/Benefit	90		(34)	131	90
Other comprehensive income/(loss)	(183)		76	(271)	(156)
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Cost of sales	(10)		8	(22)	(1)
Cost of services	(18)		5	(27)	11
SG&A expense	(8)		7	(29)	3
Other (income) and expense	(146)		75	(211)	(12)
Interest expense	7		7	14	9
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications | Cost of sales
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Provision for/(benefit from) income taxes	3		(3)	6	(1)
Net (income) loss	(8)		5	(16)	(2)
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications | Cost of services
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Provision for/(benefit from) income taxes	7		(2)	10	(5)
Net (income) loss	(11)		3	(17)	7
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications | SG&A expense
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Provision for/(benefit from) income taxes	2		(3)	7	(2)
Net (income) loss	(6)		4	(22)	1
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications | Other (income) and expense
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Provision for/(benefit from) income taxes	56		(29)	81	5
Net (income) loss	(90)		46	(130)	(7)
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications | Interest expense
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Provision for/(benefit from) income taxes	(3)		(3)	(6)	(4)
Net (income) loss	4		5	9	6
Net Change Retirement-Related Benefit Plans
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Net of Tax Amount				70	(34)
Reclassification/amortization, Net of Tax Amount				897	840
Other comprehensive income/(loss), Before Tax Amount	738		754	1,486	1,277
Other comprehensive income/(loss), Tax (Expense)/Benefit	(278)		(283)	(519)	(471)
Other comprehensive income/(loss)	461		471	967	806
Retirement-Related Benefit Plans, Prior Service Costs/(Credits)
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Before Tax Amount				0
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit				0
Unrealized gains/(losses) arising during the period, Net of Tax Amount				0
Reclassification/amortization, Before Tax Amount	(22)		(27)	(44)	(53)
Reclassification/amortization, Tax (Expense)/Benefit	8		10	15	19
Reclassification/amortization, Net of Tax Amount	(14)		(17)	(28)	(33)
Retirement-Related Benefit Plans, Net Gains/(Losses)
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Before Tax Amount	44		78	105	(68)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	(17)		(27)	(37)	25
Unrealized gains/(losses) arising during the period, Net of Tax Amount	27		51	69	(43)
Reclassification/amortization, Before Tax Amount	713		693	1,423	1,383
Reclassification/amortization, Tax (Expense)/Benefit	(268)		(263)	(497)	(510)
Reclassification/amortization, Net of Tax Amount	445		431	926	873
Retirement-Related Benefit Plans, Curtailments and Settlements
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Unrealized gains/(losses) arising during the period, Before Tax Amount	3		10	1	14
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	(1)		(4)	(1)	(5)
Unrealized gains/(losses) arising during the period, Net of Tax Amount	$ 2		$ 6	$ 1	$ 9