Equity Activity - Reclassifications and Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Cost of sales	$ 1,551	$ 1,378
Cost of services	8,553	8,382
SG&A expense	5,152	6,012
Other (income) and expense	(28)	253
Interest expense	135	147
Provision for/(benefit from) income taxes	(329)	(983)
Net (income) loss	(1,750)	(2,014)
Other comprehensive income/(loss)	688	608
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	284	218
Reclassification/amortization, Net of Tax Amount	404	391
Other comprehensive income/(loss), Before Tax Amount	779	406
Other comprehensive income/(loss), Tax (Expense)/Benefit	(92)	202
Other comprehensive income/(loss)	688	608
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	270	505
Reclassification/amortization, Net of Tax Amount	0	0
Other comprehensive income/(loss), Before Tax Amount	161	239
Other comprehensive income/(loss), Tax (Expense)/Benefit	108	266
Other comprehensive income/(loss)	270	505
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	(1)	(36)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	0	14
Unrealized gains/(losses) arising during the period, Net of Tax Amount	(1)	(22)
Reclassification/amortization, Net of Tax Amount	1	23
Other comprehensive income/(loss), Before Tax Amount	0	1
Other comprehensive income/(loss), Tax (Expense)/Benefit	0	0
Other comprehensive income/(loss)	0	0
Net Unrealized Gains/(Losses) on Available-For-Sale Securities | Reclassifications
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Other (income) and expense	1	37
Provision for/(benefit from) income taxes	0	(14)
Net (income) loss	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	(33)	(265)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	8	91
Unrealized gains/(losses) arising during the period, Net of Tax Amount	(25)	(174)
Reclassification/amortization, Net of Tax Amount	(64)	(58)
Other comprehensive income/(loss), Before Tax Amount	(130)	(356)
Other comprehensive income/(loss), Tax (Expense)/Benefit	41	124
Other comprehensive income/(loss)	(89)	(232)
Net Unrealized Gains/(Losses) on Cash Flow Hedges | Reclassifications
Reclassifications and Taxes Related to Items of Other Comprehensive Income
Cost of sales	(11)	(9)
Cost of services	(8)	6
SG&A expense	(20)	(3)
Other (income) and expense	(65)	(87)
Interest expense	7	2
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	2
Net (income) loss	(8)	(7)
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	3	(3)
Net (income) loss	(5)	4
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	5	0
Net (income) loss	(15)	(3)
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	25	33
Net (income) loss	(40)	(53)
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)	(1)
Net (income) loss	5	1
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	40	(91)
Reclassification/amortization, Net of Tax Amount	466	426
Other comprehensive income/(loss), Before Tax Amount	748	522
Other comprehensive income/(loss), Tax (Expense)/Benefit	(241)	(187)
Other comprehensive income/(loss)	507	335
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	(21)	(25)
Reclassification/amortization, Tax (Expense)/Benefit	7	9
Reclassification/amortization, Net of Tax Amount	(15)	(16)
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	61	(147)
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	(20)	53
Unrealized gains/(losses) arising during the period, Net of Tax Amount	41	(94)
Reclassification/amortization, Before Tax Amount	710	690
Reclassification/amortization, Tax (Expense)/Benefit	(229)	(248)
Reclassification/amortization, Net of Tax Amount	481	442
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	(1)	5
Unrealized gains/(losses) arising during the period, Tax (Expense)/Benefit	0	(2)
Unrealized gains/(losses) arising during the period, Net of Tax Amount	$ (1)	$ 3