Pension and Postretirement Benefit Plans - Amounts Recognized in the Balance Sheet and Amounts Recognized in AOCI (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in the balance sheet:
Noncurrent assets	$ 3	$ 2
Noncurrent liabilities	(607)	(565)
Pension Plan [Member] | UNITED STATES
Amounts recognized in the balance sheet:
Current liabilities
Noncurrent liabilities	(217)	(228)
Net amount recognized	(217)	(228)
Amounts recognized in AOCI:
Net actuarial loss (gain)	559	560
AOCI before tax	559	560
Deferred taxes	(10)	(17)
Net	549	543
Pension Plan [Member] | Foreign Plan [Member]
Amounts recognized in the balance sheet:
Noncurrent assets	3	2
Current liabilities	(13)	(9)
Noncurrent liabilities	(296)	(251)
Net amount recognized	(306)	(258)
Amounts recognized in AOCI:
Net actuarial loss (gain)	88	92
AOCI before tax	88	92
Deferred taxes	(22)	(24)
Net	66	68
Other Postretirement Benefits Plan [Member] | Foreign Plan [Member]
Amounts recognized in the balance sheet:
Current liabilities	(5)	(5)
Noncurrent liabilities	(94)	(86)
Net amount recognized	(99)	(91)
Amounts recognized in AOCI:
Net actuarial loss (gain)	(8)	(10)
AOCI before tax	(8)	(10)
Deferred taxes	3	3
Net	$ (5)	$ (7)