Employee Benefit Plans - Accumulated Benefit Obligation in Excess of Plan Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	$ 0		$ 0		$ 0
Pension Benefit Obligation	856		989		1,007
Net Funded Status	(856)	[1]	(989)	[1]
United States Pension Plans of US Entity, Defined Benefit [Member] | United States
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	2,900
Pension Benefit Obligation	3,900
Net Funded Status	(1,000)
United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	3,887		5,027
Fair Value of Pension Plan Assets	2,876		3,573		3,393
Pension Benefit Obligation	3,893		5,033		4,670
Net Funded Status	(1,017)	[1]	(1,460)	[1]
Foreign Pension Plans, Defined Benefit [Member] | Funded and Unfunded Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	8,700
Pension Benefit Obligation	10,600
Net Funded Status	(1,900)
Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	6,368		6,359
Fair Value of Pension Plan Assets	5,789		5,431		4,884
Pension Benefit Obligation	6,664		6,708		5,835
Net Funded Status	(875)	[1]	(1,277)	[1]
Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | UNITED KINGDOM
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	3,700
Pension Benefit Obligation	3,900
Net Funded Status	(200)
Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	700
Pension Benefit Obligation	900
Net Funded Status	(200)
Underfunded [Member] | United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	3,571		4,679
Accumulated Benefit Obligation	3,565		4,672
Fair value of plan assets	2,876		3,574
Underfunded [Member] | Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	5,350		5,997
Accumulated Benefit Obligation	5,104		5,686
Fair value of plan assets	4,964		5,213
Unfunded [Member] | United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	322		355
Accumulated Benefit Obligation	322		355
Fair value of plan assets	0		0
Unfunded [Member] | United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | United States
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	0
Pension Benefit Obligation	300
Net Funded Status	(300)
Unfunded [Member] | Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	540		527
Accumulated Benefit Obligation	526		520
Fair value of plan assets	0		0
Unfunded [Member] | Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | Pension Plans All Other Countries [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	0
Pension Benefit Obligation	500
Net Funded Status	(500)
Underfunded and unfunded pension benefit plans [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	9,783		11,558
Accumulated Benefit Obligation	9,517		11,233
Fair value of plan assets	7,840		8,787
Underfunded and unfunded pension benefit plans [Member] | United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	3,893		5,034
Accumulated Benefit Obligation	3,887		5,027
Fair value of plan assets	2,876		3,574
Underfunded and unfunded pension benefit plans [Member] | Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	5,890		6,524
Accumulated Benefit Obligation	5,630		6,206
Fair value of plan assets	4,964		5,213
Funded [Member] | United States Pension Plans of US Entity, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | United States
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	2,900
Pension Benefit Obligation	3,600
Net Funded Status	(700)
Funded [Member] | Foreign Pension Plans, Defined Benefit [Member] | Defined Benefit Pension Plans, Defined Benefit [Member] | Pension Plans All Other Countries [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Pension Plan Assets	1,400
Pension Benefit Obligation	1,400
Net Funded Status	$ 0

[1] (1)Includes under-funded and un-funded plans.