Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
	Feb. 29, 2012	Mar. 31, 2013	Mar. 31, 2012
Defined Benefit Plan Disclosure
Net loss (gain) due to facility closure	$ (6)
Pension contributions
Contributions to pension plans		142	174
Expected full year contributions pension plans during the year		480
U.S. Pension Benefits
Components of net periodic benefit cost
Service cost		49	46
Interest cost		145	154
Expected return on plan assets		(208)	(203)
Amortization of:
Transition obligation / (asset)		0	0
Prior service cost / (credit)		4	5
Net actuarial loss / (gain)		136	124
Net periodic benefit cost, excluding curtailments, settlements and special termination benefits		126	126
Curtailments, settlements and special termination benefits		0	0
Total cost included in operating profit		126	126
Weighted-average assumptions used to determine net cost:
Discount rate (as a percent)		3.70%	4.30%
Expected return on plan assets (as a percent)		7.80%	8.00%
Rate of compensation increase (as a percent)		4.50%	4.50%
Non-U.S. Pension Benefits
Components of net periodic benefit cost
Service cost		31	28
Interest cost		43	45
Expected return on plan assets		(59)	(54)
Amortization of:
Transition obligation / (asset)		0	0
Prior service cost / (credit)		0	0
Net actuarial loss / (gain)		33	24
Net periodic benefit cost, excluding curtailments, settlements and special termination benefits		48	43
Curtailments, settlements and special termination benefits	10	0	10
Total cost included in operating profit		48	53
Weighted-average assumptions used to determine net cost:
Discount rate (as a percent)		3.70%	4.30%
Expected return on plan assets (as a percent)		6.70%	7.10%
Rate of compensation increase (as a percent)		3.90%	3.90%
Other Postretirement Benefits
Defined Benefit Plan Disclosure
Defined benefit plan loss of third party receivable	21
Components of net periodic benefit cost
Service cost		24	24
Interest cost		49	55
Expected return on plan assets		(14)	(16)
Amortization of:
Transition obligation / (asset)		1	1
Prior service cost / (credit)		(18)	(17)
Net actuarial loss / (gain)		27	25
Net periodic benefit cost, excluding curtailments, settlements and special termination benefits		69	72
Curtailments, settlements and special termination benefits	(37)	0	(40)
Total cost included in operating profit		$ 69	$ 32
Weighted-average assumptions used to determine net cost:
Discount rate (as a percent)		3.70%	4.30%
Expected return on plan assets (as a percent)		7.80%	8.00%
Rate of compensation increase (as a percent)		4.40%	4.40%