Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
United States Pension Plans of US Entity, Defined Benefit [Member]
Change in benefit obligations:
Balance at January 1,	$ 8,327	$ 7,043
Service costs	224	187	172
Interest costs	406	404	393
Plan participants' contributions	0	0
Net actuarial (gains) losses	999	1,072
Acquisition, divestitures and curtailments	0	0
Change in benefits	0	17
Benefits paid	(476)	(396)
Transfers	0	0
Effect of foreign currency translation and other	0	0
Balance at December 31,	9,480	8,327	7,043
Change in plan assets:
Fair value of plan assets at beginning of year	7,108	6,310
Actual return on plan assets	740	944
Acquisition and divestitures	0	0
Employer contributions	507	250
Benefits paid	(476)	(396)
Transfers	0	0
Effect of foreign currency translation	0	0
Fair value of plan assets at end of year	7,879	7,108	6,310
Over (under) funded status at end of year	(1,601)	(1,219)
Amounts recognized in the consolidated balance sheets consist of:
Other assets	0	0
Other liabilities	(1,601)	(1,219)
Net amount recognized	(1,601)	(1,219)
Accumulated other comprehensive (income) loss:
Net actuarial (gains) losses	3,047	2,498
Prior service costs (credit)	24	30
Accumulated other comprehensive (income) loss, before income tax	3,071	2,528
Accumulated benefit obligation	8,866	7,849
Foreign Pension Plans, Defined Benefit [Member]
Change in benefit obligations:
Balance at January 1,	773	676
Service costs	75	64	8
Interest costs	17	16	6
Plan participants' contributions	0	0
Net actuarial (gains) losses	32	24
Acquisition, divestitures and curtailments	(12)	(5)
Change in benefits	(1)	0
Benefits paid	(41)	(30)
Transfers	0	(13)
Effect of foreign currency translation and other	(20)	41
Balance at December 31,	823	773	676
Change in plan assets:
Fair value of plan assets at beginning of year	185	178
Actual return on plan assets	20	(4)
Acquisition and divestitures	(11)	(4)
Employer contributions	74	55
Benefits paid	(41)	(30)
Transfers	0	(13)
Effect of foreign currency translation	(3)	3
Fair value of plan assets at end of year	224	185	178
Over (under) funded status at end of year	(599)	(588)
Amounts recognized in the consolidated balance sheets consist of:
Other assets	6	3
Other liabilities	(605)	(591)
Net amount recognized	(599)	(588)
Accumulated other comprehensive (income) loss:
Net actuarial (gains) losses	27	10
Prior service costs (credit)	2	2
Accumulated other comprehensive (income) loss, before income tax	29	12
Accumulated benefit obligation	724	658
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Change in benefit obligations:
Balance at January 1,	2,093	1,808
Service costs	21	16	16
Interest costs	103	106	111
Plan participants' contributions	29	28
Net actuarial (gains) losses	261	267
Acquisition, divestitures and curtailments	0	0
Change in benefits	0	0
Benefits paid	(132)	(132)
Transfers	0	0
Effect of foreign currency translation and other	0	0
Balance at December 31,	2,375	2,093	1,808
Change in plan assets:
Fair value of plan assets at beginning of year	1,240	1,185
Actual return on plan assets	105	80
Acquisition and divestitures	0	0
Employer contributions	78	79
Benefits paid	(132)	(132)
Transfers	0	0
Effect of foreign currency translation	0	0
Fair value of plan assets at end of year	1,320	1,240	1,185
Over (under) funded status at end of year	(1,055)	(853)
Amounts recognized in the consolidated balance sheets consist of:
Other assets	0	0
Other liabilities	(1,055)	(853)
Net amount recognized	(1,055)	(853)
Accumulated other comprehensive (income) loss:
Net actuarial (gains) losses	799	623
Prior service costs (credit)	(74)	(179)
Accumulated other comprehensive (income) loss, before income tax	725	444
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Change in benefit obligations:
Balance at January 1,	39	37
Service costs	1	1	1
Interest costs	2	2	2
Plan participants' contributions	0	0
Net actuarial (gains) losses	4	2
Acquisition, divestitures and curtailments	(3)	1
Change in benefits	0	0
Benefits paid	(2)	(4)
Transfers	0	0
Effect of foreign currency translation and other	2	0
Balance at December 31,	43	39	37
Change in plan assets:
Fair value of plan assets at beginning of year	13	15
Actual return on plan assets	2	(1)
Acquisition and divestitures	(3)	0
Employer contributions	4	1
Benefits paid	(2)	(2)
Transfers	0	0
Effect of foreign currency translation	1	0
Fair value of plan assets at end of year	15	13	15
Over (under) funded status at end of year	(28)	(26)
Amounts recognized in the consolidated balance sheets consist of:
Other assets	0	0
Other liabilities	(28)	(26)
Net amount recognized	(28)	(26)
Accumulated other comprehensive (income) loss:
Net actuarial (gains) losses	3	2
Prior service costs (credit)	1	1
Accumulated other comprehensive (income) loss, before income tax	$ 4	$ 3