Employee Benefit Plans - Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plans			$ 194	$ 127	$ 141
Net actuarial (gain) loss			52	(118)	(73)
Amortization of net actuarial loss	[1]		(236)	(160)	(186)
Amortization of net prior service credit	[1]		(10)	(10)	(38)
Total Recognized in Other Comprehensive Income			(169)	(141)	(212)
Interest Expense on Non-TRA Obligations			257	296	311
Interest Expense Allocated to TRA Participant Accounts			127	83	(25)
Expected Investment Income on Non-TRA Assets			321	356	388
Actual Investment Income on TRA Assets			127	83	(25)
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plans			194	127	141
Pension Plan [Member] | Benefit plans net actuarial loss [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year			(83)
Pension Plan [Member] | Benefit plans prior service credits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year			6
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost			5	6	7
Interest cost	[2]		28	32	34
Expected return on plan assets	[3]		0	0	0
Recognized net actuarial loss			1	2	1
Amortization of prior service credit			(4)	(5)	(18)
Recognized settlement loss			0	0	0
Recognized curtailment gain		$ 22	0	0	(22)
Defined Benefit Plans			30	35	2
Net Periodic Benefit Cost			30	35	2
Net actuarial (gain) loss			(16)	(75)	(4)
Prior service credit			0	0	(32)
Amortization of net actuarial loss			(1)	(2)	(1)
Amortization of net prior service credit			4	5	18
Curtailment gain			0	0	22
Total Recognized in Other Comprehensive Income			(13)	(72)	3
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income			17	(37)	5
Other Postretirement Benefits Plan [Member] | Benefit plans net actuarial loss [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year			0
Other Postretirement Benefits Plan [Member] | Benefit plans prior service credits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year			3
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost			2	4	4
Interest cost	[2]		226	184	80
Expected return on plan assets	[3]		(227)	(190)	(79)
Recognized net actuarial loss			21	26	24
Amortization of prior service credit			(2)	(2)	(2)
Recognized settlement loss			133	65	88
Recognized curtailment gain			0	0	0
Defined Benefit Plans			153	87	115
Defined contribution plans			25	30	33
Net Periodic Benefit Cost			178	117	148
Net actuarial (gain) loss			238	84	(74)
Prior service credit			0	0	0
Amortization of net actuarial loss			(154)	(92)	(112)
Amortization of net prior service credit			2	2	2
Curtailment gain			0	0	0
Total Recognized in Other Comprehensive Income			86	(6)	(184)
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income			264	111	(36)
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost			29	31	32
Interest cost	[2]		158	195	203
Expected return on plan assets	[3]		(221)	(249)	(284)
Recognized net actuarial loss			79	65	70
Amortization of prior service credit			(4)	(3)	4
Recognized settlement loss			2	1	1
Recognized curtailment gain			(2)	0	0
Defined Benefit Plans			41	40	26
Defined contribution plans			29	31	33
Net Periodic Benefit Cost			70	71	59
Net actuarial (gain) loss			(273)	76	204
Prior service credit			(1)	0	(16)
Amortization of net actuarial loss			(81)	(66)	(71)
Amortization of net prior service credit			4	3	(4)
Curtailment gain			0	0	0
Total Recognized in Other Comprehensive Income			(351)	13	113
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income			$ (281)	$ 84	$ 172

[1] Reclassified to Total Net Periodic Benefit Cost - refer to Note 17 - Employee Benefit Plans for additional information.

[2] Interest cost for Pension Benefits includes interest expense on non-TRA obligations of $257, $296 and $311 and interest expense (income) directly allocated to TRA participant accounts of $127, $83 and $(25) for the years ended December 31, 2017, 2016 and 2015, respectively.

[3] Expected return on plan assets includes expected investment income on non-TRA assets of $321, $356 and $388 and actual investment income (loss) on TRA assets of $127, $83 and $(25) for the years ended December 31, 2017, 2016 and 2015, respectively.