Employee Benefit Plans - Net Periodic Benefit (Income) Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic benefit cost	$ 464	$ 152	$ (78)
Postemployment Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net service cost	17	17	24
Interest cost	3	5	6
Prior service cost	(4)	(4)	(4)
Actuarial loss	0	(2)	5
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	(13)
Net benefit cost	16	16	18
Restructuring severance cost	1	73	0
Net periodic benefit cost	17	89	18
Postretirement Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net service cost	0	0	0
Interest cost	1	1	1
Prior service cost	(18)	(18)	(18)
Actuarial loss	2	2	2
Net periodic benefit cost	(15)	(15)	(15)
Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net service cost	12	12	14
Interest cost	129	211	203
Expected return on plan assets	(132)	(222)	(208)
Prior service cost	1	2	6
Actuarial loss	29	150	(119)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	(2)	0	0
Defined Benefit Plan, Cost of Providing Special or Contractual Termination Benefits Recognized During Period	0	0	26
Settlement charge	427	(1)	0
Net periodic benefit cost	464	152	(78)
Company contributions	33	87
Pension liability	425	(1)
U.S. Pension Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net service cost	0	0	0
Interest cost	87	130	124
Expected return on plan assets	(72)	(118)	(109)
Prior service cost	0	0	0
Actuarial loss	27	146	(43)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0
Defined Benefit Plan, Cost of Providing Special or Contractual Termination Benefits Recognized During Period	0	0	26
Settlement charge	0	0	0
Net periodic benefit cost	42	158	(2)
Company contributions	0	18
Pension liability	0	0
International Pension Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net service cost	12	12	14
Interest cost	42	81	79
Expected return on plan assets	(60)	(104)	(99)
Prior service cost	1	2	6
Actuarial loss	2	4	(76)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	(2)	0	0
Defined Benefit Plan, Cost of Providing Special or Contractual Termination Benefits Recognized During Period	0	0	0
Settlement charge	427	(1)	0
Net periodic benefit cost	422	(6)	$ (76)
Company contributions	33	69
Pension liability	425	$ (1)
U.S. non-qualified plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Actuarial loss	$ 15