Employee Benefits (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Maximum annual increase percentage to company contribution for retiree medical coverage	4.00%
Contribution to employee pension plan	$ 238
Contribution to other post retirement plans	51
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan estimated future employer contributions in next fiscal year	1,000
Contribution to other post retirement plans	177
U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to employee pension plan	196
U.S. [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan estimated future employer contributions in next fiscal year	650
International [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan estimated future employer contributions in next fiscal year	$ 350