Income Taxes - Provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income before income taxes:
United States	$ 226	$ 176	$ 109
Foreign	543	566	490
Income before income taxes	769	742	599
Current tax expense
US federal	(13)	95	26
State and local	4	8	3
Foreign	179	148	164
Total current tax expense	170	251	193
Deferred tax expense (benefit):
US federal	77	13	(8)
State and local	4	1	(1)
Foreign	(14)	(19)	3
Total deferred tax expense (benefit)	67	(5)	(6)
Total provision for income taxes	237	246	$ 187
Deferred tax assets attributable to:
Employee benefit accruals	20	39
Pension and postretirement plans	20	30
Derivative contracts	5	3
Net operating loss carryforwards	32	18
Foreign tax credit carryforwards		4
Other		24
Gross deferred tax assets	77	118
Valuation allowance	(34)	(21)
Net deferred tax assets	43	97
Deferred tax liabilities attributable to:
Property, plant and equipment	185	206
Identified intangibles	37	55
Other	11
Gross deferred tax liabilities	233	261
Net deferred tax liabilities	190	164
Valuation allowance on foreign subsidiaries net deferred tax assets	2	2
State and Local Jurisdiction
Deferred tax assets attributable to:
Net operating loss carryforwards	9	8
Deferred tax liabilities attributable to:
Loss carryforwards, valuation allowance	9	8
Credit carryforwards, valuation allowance	2	2
Foreign Tax Authority
Deferred tax assets attributable to:
Net operating loss carryforwards	23
Deferred tax liabilities attributable to:
Loss carryforwards, valuation allowance	$ 21	$ 9