Employee Postretirement Benefits (Summarized Financial Information about Postretirement plans, Excluding Defined Contribution Retirement Plans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Noncurrent liability - Accrued benefit cost	$ (1,992,000,000)	$ (1,460,000,000)
Defined Benefit Pension [Member]
Benefit obligation at beginning of year	5,920,000,000	5,658,000,000
Service cost	45,000,000	57,000,000	56,000,000
Interest cost	279,000,000	307,000,000	309,000,000
Actuarial loss (gain)	854,000,000	374,000,000
Currency and other	79,000,000	(103,000,000)
Benefit payments from plans	(478,000,000)	(359,000,000)
Direct benefit payments	(14,000,000)	(14,000,000)
Defined Benefit Plan, Settlements, Benefit Obligation	(95,000,000)	0
Benefit obligation at end of year	6,590,000,000	5,920,000,000	5,658,000,000
Fair value of plan assets at beginning of year	5,214,000,000	4,600,000,000
Actual gain on plan assets	556,000,000	309,000,000
Employer contributions	110,000,000	679,000,000
Currency and other	60,000,000	(15,000,000)
Benefit payments from plans	(478,000,000)	(359,000,000)
Defined Benefit Plan, Settlements, Plan Assets	(87,000,000)	0
Fair value of plan assets at end of year	5,375,000,000	5,214,000,000	4,600,000,000
Funded Status	(1,215,000,000)	(706,000,000)
Noncurrent asset - Prepaid benefit cost	8,000,000	20,000,000
Current liability - Accrued benefit cost	(12,000,000)	(13,000,000)
Noncurrent liability - Accrued benefit cost	(1,211,000,000)	(713,000,000)
Net amount recognized	(1,215,000,000)	(706,000,000)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Benefit obligation at beginning of year	788,000,000	796,000,000
Service cost	15,000,000	14,000,000	14,000,000
Interest cost	36,000,000	41,000,000	44,000,000
Actuarial loss (gain)	37,000,000	33,000,000
Currency and other	3,000,000	(22,000,000)
Benefit payments from plans	0	0
Direct benefit payments	(55,000,000)	(74,000,000)
Defined Benefit Plan, Settlements, Benefit Obligation	0	0
Benefit obligation at end of year	824,000,000	788,000,000	796,000,000
Fair value of plan assets at beginning of year	0	0
Actual gain on plan assets	0	0
Employer contributions	0	0
Currency and other	0	0
Benefit payments from plans	0	0
Defined Benefit Plan, Settlements, Plan Assets	0	0
Fair value of plan assets at end of year	0	0	0
Funded Status	(824,000,000)	(788,000,000)
Noncurrent asset - Prepaid benefit cost	0	0
Current liability - Accrued benefit cost	(56,000,000)	(59,000,000)
Noncurrent liability - Accrued benefit cost	(768,000,000)	(729,000,000)
Net amount recognized	$ (824,000,000)	$ (788,000,000)