Employee Benefit Plans - Contributions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Post Retirement Benefit Plan, Future Employer Contribution in Next Fixcal Year		$ 71
2015		894
2016		595
2017		597
2018		602
2019		605
Years 2020-2023		3,220
Post employment benefit plan contributions by employer		102	89	61
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit pension plan contributions by employer		284
Defined Benefit Plans, Future Employer Contributions in Next Fiscal Year		340
United States Pension Plan of US Entity [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit pension plan contributions by employer		124
Defined Benefit Plans, Future Employer Contributions in Next Fiscal Year		180
2015		643
2016		343
2017		336
2018		333
2019		326
Years 2020-2023		1,681
Discount rate assumptions used to determine benefit obligations		3.90%	4.80%	3.70%
Rate of compensation increase assumptions used to determine benefit obligation		0.20%	0.20%	0.20%
Discount rate assumptions used to determine net periodic benefit costs		4.80%	3.70%	4.80%
Expected return on plan assets assumptions used to determine net periodic benefit cost		7.80%	7.80%	7.80%
Rate of compensation increase assumptions used to determine net periodic benefit cost		0.20%	0.20%	3.50%
Foreign Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit pension plan contributions by employer		160
Defined Benefit Plans, Future Employer Contributions in Next Fiscal Year		160
2015		251
2016		252
2017		261
2018		269
2019		279
Years 2020-2023		1,539
Discount rate assumptions used to determine benefit obligations		3.10%	4.20%	4.00%
Rate of compensation increase assumptions used to determine benefit obligation		2.60%	2.70%	2.60%
Discount rate assumptions used to determine net periodic benefit costs		4.20%	4.00%	4.60%
Expected return on plan assets assumptions used to determine net periodic benefit cost		6.10%	6.10%	6.20%
Rate of compensation increase assumptions used to determine net periodic benefit cost		2.70%	2.60%	2.70%
Postretirement Health Coverage [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2015		71
2016		70
2017		70
2018		69
2019		68
Years 2020-2023		323
Discount rate assumptions used to determine benefit obligations		3.80%	4.50%	3.60%
Discount rate assumptions used to determine net periodic benefit costs	3.80%	4.50%	3.60%	4.50%
Other Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit pension plan contributions by employer		70
Health care cost trend rate assumed for next year		0.070	0.072
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		0.049	0.049
Year that the rate reaches the ultimate trend rate		2023	2023
Effect on total service and interest cost components - 1% increase		1
Effect on total service and interest cost components - 1% decrease		(1)
Effect on post-retirement benefit obligation - 1% increase		46
Effect on post-retirement benefit obligation - 1% decrease		(39)
Scenario, Forecast [Member] | United States Pension Plan of US Entity [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate assumptions used to determine net periodic benefit costs	3.90%
Expected return on plan assets assumptions used to determine net periodic benefit cost	7.50%
Rate of compensation increase assumptions used to determine net periodic benefit cost	0.20%
Scenario, Forecast [Member] | Foreign Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate assumptions used to determine net periodic benefit costs	3.10%
Expected return on plan assets assumptions used to determine net periodic benefit cost	5.20%
Rate of compensation increase assumptions used to determine net periodic benefit cost	2.60%
ITO [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Post employment benefit plan contributions by employer		$ 8	7	2