Employee Benefit Plans (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2017
Components of Net Periodic Benefit Costs:
Defined Benefit Plans		$ 37	$ 33	$ 99	$ 76
Other changes in plan assets and benefit obligations recognized in Other Comprehensive Income (Loss):
Net actuarial loss (gain)(1)		(1)	(100)	(9)	(223)
Amortization of prior service credit	[1]	(3)	(3)	(5)	(5)
Amortization of net actuarial loss	[1]	44	41	110	93
Pension Plan [Member]
Contributions [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer				46	68	$ 178
Pension Plan [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year							$ 350
Pension Plan [Member] | Domestic Plan [Member]
Components of Net Periodic Benefit Costs:
Service cost		1	1	2	2
Interest cost		32	34	66	71
Expected return on plan assets		(30)	(35)	(61)	(74)
Recognized net actuarial loss		6	7	11	12
Amortization of prior service credit		(1)	(1)	(1)	(1)
Recognized settlement loss		19	17	61	46
Defined Benefit Plans		27	23	78	56
Defined contribution plans		7	8	13	15
Net Periodic Benefit Cost		34	31	91	71
Other changes in plan assets and benefit obligations recognized in Other Comprehensive Income (Loss):
Net actuarial loss (gain)(1)	[2]	12	134	20	257
Amortization of prior service credit		1	1	1	1
Amortization of net actuarial loss		(25)	(24)	(72)	(58)
Total Recognized in Other Comprehensive Income (Loss)(2)	[3]	(12)	111	(51)	200
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Loss)		22	142	40	271
Contributions [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer				12	11	24
Pension Plan [Member] | Domestic Plan [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year							174
Pension Plan [Member] | Domestic Plan [Member] | Qualified Plan [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year							150
Pension Plan [Member] | Domestic Plan [Member] | Minimum Funding Requirement [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year							15
Pension Plan [Member] | Domestic Plan [Member] | Voluntary Contributions [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year							135
Pension Plan [Member] | Foreign Plan [Member]
Components of Net Periodic Benefit Costs:
Service cost		8	10	15	16
Interest cost		38	51	77	101
Expected return on plan assets		(54)	(67)	(107)	(129)
Recognized net actuarial loss		19	17	38	34
Amortization of prior service credit		(1)	(1)	(2)	(2)
Recognized settlement loss		0	0	0	0
Defined Benefit Plans		10	10	21	20
Defined contribution plans		7	7	14	16
Net Periodic Benefit Cost		17	17	35	36
Other changes in plan assets and benefit obligations recognized in Other Comprehensive Income (Loss):
Net actuarial loss (gain)(1)	[2]	0	0	0	0
Amortization of prior service credit		1	1	2	2
Amortization of net actuarial loss		(19)	(17)	(38)	(34)
Total Recognized in Other Comprehensive Income (Loss)(2)	[3]	(18)	(16)	(36)	(32)
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Loss)		(1)	1	(1)	4
Contributions [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer				34	57	154
Pension Plan [Member] | Foreign Plan [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year							176
Retiree Health [Member]
Components of Net Periodic Benefit Costs:
Service cost		1	2	2	3
Interest cost		7	8	14	16
Expected return on plan assets		0	0	0	0
Recognized net actuarial loss		0	0	0	1
Amortization of prior service credit		(1)	(1)	(2)	(2)
Recognized settlement loss		0	0	0	0
Defined Benefit Plans		7	9	14	18
Net Periodic Benefit Cost		7	9	14	18
Other changes in plan assets and benefit obligations recognized in Other Comprehensive Income (Loss):
Net actuarial loss (gain)(1)	[2]	(11)	(34)	(11)	(34)
Amortization of prior service credit		1	1	2	2
Amortization of net actuarial loss		0	0	0	(1)
Total Recognized in Other Comprehensive Income (Loss)(2)	[3]	(10)	(33)	(9)	(33)
Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Loss)		$ (3)	$ (24)	5	(15)
Contributions [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer				$ 32	$ 30	$ 61
Retiree Health [Member] | Forecast
Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year							$ 63

[1] Reclassified to Total Net Periodic Benefit Cost - refer to Note 14 - Employee Benefit Plans for additional information.

[2] The net actuarial loss (gain) for U.S. Plans primarily reflects (i) the remeasurement of our primary U.S. pension plans as a result of the payment of periodic settlements and (ii) adjustments for the actuarial valuation results based on January 1st plan census data.

[3] Amounts represent the pre-tax effect included within Other comprehensive income (loss). Refer to Note 16 - Other Comprehensive Income (Loss) for related tax effects and the after-tax amounts.