Pension and Other Postretirement Employee Benefit Plans - Net Periodic Benefit Costs (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined benefit pension plan, U.S. [Member]
Components of net periodic benefit cost [Abstract]
Benefits earned during the year	$ 314	$ 272	$ 249
Interest cost on benefit obligations	447	466	451
Expected return on plan assets	(956)	(861)	(791)
Amortization:
Net loss	271	289	165
Prior service cost (credit)	(41)	(41)	(43)
Net periodic defined benefit cost	35	125	31
Other defined benefit pension plans	15	15	19
Total defined benefit plans	50	140	50
Total defined contribution plans	447	409	370
Total pension and OPEB cost included in compensation expense	497	549	420
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net (gain)/loss arising during the year	(1,817)	434	1,207
Prior service credit arising during the year	0	0	0
Amortization of net loss	271	289	165
Amortization of prior service (cost)/credit	41	41	43
Foreign exchange impact and other	0	0	0
Total recognized in other comprehensive income	(2,047)	186	1,085
Total recognized in net periodic benefit cost and other comprehensive income	(2,012)	311	1,116
Defined benefit pension plan, Non-U.S. [Member]
Components of net periodic benefit cost [Abstract]
Benefits earned during the year	34	41	36
Interest cost on benefit obligations	125	126	133
Expected return on plan assets	(142)	(137)	(141)
Amortization:
Net loss	49	36	48
Prior service cost (credit)	(2)	0	(1)
Net periodic defined benefit cost	64	66	75
Other defined benefit pension plans	14	8	12
Total defined benefit plans	78	74	87
Total defined contribution plans	321	302	285
Total pension and OPEB cost included in compensation expense	399	376	372
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net (gain)/loss arising during the year	19	146	25
Prior service credit arising during the year	0	(6)	0
Amortization of net loss	49	36	48
Amortization of prior service (cost)/credit	2	0	1
Foreign exchange impact and other	14	22	1
Total recognized in other comprehensive income	(14)	126	(21)
Total recognized in net periodic benefit cost and other comprehensive income	50	192	54
OPEB Plans [Member]
Components of net periodic benefit cost [Abstract]
Benefits earned during the year	1	1	1
Interest cost on benefit obligations	35	44	51
Expected return on plan assets	(92)	(90)	(88)
Amortization:
Net loss	1	(1)	1
Prior service cost (credit)	0	0	(8)
Net periodic defined benefit cost	(55)	(46)	(43)
Total defined benefit plans	(55)	(46)	(43)
Total pension and OPEB cost included in compensation expense	(55)	(46)	(43)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net (gain)/loss arising during the year	(257)	(43)	58
Prior service credit arising during the year	0	0	0
Amortization of net loss	1	(1)	1
Amortization of prior service (cost)/credit	0	0	8
Foreign exchange impact and other	0	(1)	0
Total recognized in other comprehensive income	(258)	(43)	65
Total recognized in net periodic benefit cost and other comprehensive income	$ (313)	$ (89)	$ 22