Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income taxes:
Current Federal Tax Expense (Benefit)		$ (635)	$ 959	$ 245
Current Foreign Tax Expense (Benefit)		(636)	(734)	(485)
Current State Tax Expense (Benefit)		51	(36)	(49)
Total current		(50)	1,729	779
Deferred income taxes:
Federal		(18)	83	4
Foreign		262	357	125
State		(20)	14	2
Total deferred		224	454	132
Income tax benefit (provision)		274	(1,275)	(648)
The United States and foreign components of income from continuing operations before income taxes [Abstract]
United States		(1,560)	3,020	1,070
Foreign		624	1,692	1,694
Income (loss) from continuing operations before income taxes		$ (936)	$ 4,712	$ 2,764
Reconciliations between the actual provision for income taxes on continuing operations [Abstract]
United States statutory rate		35.00%	35.00%	35.00%
Impact of foreign income taxed at different rates		(15.60%)	(5.70%)	(9.30%)
Effective Income Tax Reconciliation, Foreign Exchange Loss, Percent		4.30%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent		3.50%	(3.60%)	(0.10%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges, Percent		(3.00%)	(0.00%)	(0.00%)
Effective Income Tax Reconciliation, Nondeductible Expense, Acquisition Costs, Percent		2.60%	0.00%	0.00%
Domestic manufacturing deduction		(0.00%)	(1.90%)	(2.00%)
State income taxes		0.30%	0.80%	1.70%
Adjustments of prior year taxes		(0.70%)	0.30%	(0.60%)
Other impact of foreign operations		(0.50%)	(0.10%)	(0.70%)
Other items, net		3.40%	2.30%	(0.50%)
Total effective tax rate on continuing operations		29.30%	27.10%	23.50%
Restructuring Charges		$ 2,177	$ 129	$ 0
Foreign Currency Transaction Gain (Loss), Realized	$ 199
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		201
Increase (Decrease) in Prepaid Taxes		150
Gross deferred tax assets:
Net operating loss carryforwards		540	462
Accrued Liabilities		392	494
Employee compensation and benefits		403	395
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		365	79
Other		354	236
Total gross deferred tax assets		2,054	1,666
Gross deferred tax liabilities:
Depreciation and amortization		1,334	1,005
Other		109	111
Total gross deferred tax liabilities		1,443	1,116
Valuation allowances		213	184
Net deferred income tax asset		398	366
Unrecognized Tax Benefits
Beginning Balance	314	314	175	228
Change in prior year tax positions		(33)	(83)	(53)
Change in current year tax positions		62	84	30
Cash settlements with taxing authorities		(16)	(27)	(21)
Lapse of statute of limitations		(5)	(1)	(9)
Ending balance		322	314	175
Interest and Penalties
Beginning balance	56	56	34	68
Change in prior year tax positions		(7)	(24)	(9)
Change in current year tax positions		1	0	1
Cash settlements with taxing authorities		(15)	(1)	(17)
Lapse of statute of limitations		(2)	(1)	(9)
Ending balance		47	56	$ 34
Deferred tax liability not recognized, cumulative amount of temporary difference		6,900
Remaining balance if resolved in our favor would positively impact the effective tax rate		176	$ 194
Unrecognized tax benefit related to an indemnification asset		10
Portion of unrecognized tax benefits that could be resolved within the next 12 months		37
Foreign Country
Interest and Penalties
Operating loss carryforwards that will expire		2,000
Years 2025-2035 [Domain]
Interest and Penalties
Operating loss carryforwards that will expire		285
Years 2020-2024 [Domain]
Interest and Penalties
Operating loss carryforwards that will expire		367
Years 2016-2019 [Domain]
Interest and Penalties
Operating loss carryforwards that will expire		375
VENEZUELA
Reconciliations between the actual provision for income taxes on continuing operations [Abstract]
Effective Income Tax Reconciliation, Foreign Exchange Loss, Percent			0.00%	0.00%
Foreign Currency Transaction Gain (Loss), Realized	$ (199)	(199)	$ 0
All Other Countries [Domain]
Interest and Penalties
Remaining balance if resolved in our favor would positively impact the effective tax rate		$ 67	$ 46