Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Ending balance as of December 31, 2013	$ 2,088	$ 1,851
Amounts recognized in consolidated balance sheets:
Non-current liabilities	(264)	(529)
Retirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Net benefit obligation at beginning of year	2,171	1,834
Service cost	10	24	67
Interest cost	91	93	99
Plan participant's contributions	0	1
Actuarial loss (gain)	(178)	287
Gross benefits paid	(77)	(71)
Foreign currency effect	8	11
Curtailment	(26)	0
Other adjustments	5	(8)
Net benefit obligation at end of year	2,004	2,171	1,834
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance as of December 31, 2012	1,851	1,505
Actual return on plan assets	281	212
Employer contributions	27	193
Plan participant's contributions	0	1
Gross benefits paid	(77)	(71)
Foreign currency effect	6	11
Ending balance as of December 31, 2013	2,088	1,851	1,505
Funded status	84	(320)
Amounts recognized in consolidated balance sheets:
Non-current assets	261	98
Current liabilities	(7)	(7)
Non-current liabilities	(170)	(411)
Amounts Recognized in Consolidated Balance Sheet, Total	84	(320)
Accumulated benefit obligation	2,004	2,093
Plans with accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	176	1,773
Accumulated benefit obligation	158	1,756
Fair value of plan assets	0	1,356
Amounts recognized in accumulated other comprehensive loss, net of tax:
Net actuarial loss	227	455
Prior service credit	1	(4)
Total recognized	228	451
Postretirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Net benefit obligation at beginning of year	129	129
Service cost	2	3	3
Interest cost	5	5	6
Plan participant's contributions	4	5
Actuarial loss (gain)	(13)	3
Gross benefits paid	(13)	(17)
Foreign currency effect	0	0
Curtailment	(11)	0
Other adjustments	0	1
Net benefit obligation at end of year	103	129	129
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance as of December 31, 2012	0	0
Actual return on plan assets	0	0
Employer contributions	9	12
Plan participant's contributions	4	5
Gross benefits paid	(13)	(17)
Foreign currency effect	0	0
Ending balance as of December 31, 2013	0	0	0
Funded status	(103)	(129)
Amounts recognized in consolidated balance sheets:
Non-current assets	0	0
Current liabilities	(9)	(11)
Non-current liabilities	(94)	(118)
Amounts Recognized in Consolidated Balance Sheet, Total	(103)	(129)
Amounts recognized in accumulated other comprehensive loss, net of tax:
Net actuarial loss	(11)	(3)
Prior service credit	(1)	(1)
Total recognized	$ (12)	$ (4)