Pension and Other Benefit Programs - Change to US Operations SERP Benefit Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in benefit obligation:
Benefit obligation at beginning of year	$ 853	$ 861
Interest cost	27	27	$ 34
Actuarial loss	(44)	(14)
Benefit obligation at year end	875	853	861
Funded status	(6)	(172)
Defined Benefit Plan SERP Benefit Obligation Estimated Future Benefit Payments [Abstract]
2018	50
2019	50
2020	49
2021	49
2022	49
Next 5 years	247
Supplemental Employee Retirement Plan
Change in benefit obligation:
Benefit obligation at beginning of year	54	61
Interest cost	1	1
Actuarial loss	2	1
Benefits paid	(8)	(9)
Benefit obligation at year end	49	54	$ 61
Funded status	(49)	(54)
Amounts recognized in the accompanying consolidated balance sheets:
Other current liabilities	(7)	(8)
Accrued employee benefits	(42)	$ (46)
Defined Benefit Plan SERP Benefit Obligation Estimated Future Benefit Payments [Abstract]
2018	7
2019	5
2020	5
2021	5
2022	5
Next 5 years	$ 15