Pension and Other Benefit Programs - Change to US Operations SERP Benefit Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in benefit obligation:
Benefit obligation at beginning of year	$ 875	$ 853
Interest cost	26	27	$ 27
Actuarial (gain) loss	(61)	44
Benefit obligation at year end	791	875	853
Funded status	3	(6)
Defined Benefit Plan SERP Benefit Obligation Estimated Future Benefit Payments [Abstract]
2019	50
2020	49
2021	49
2022	49
2023	50
Next 5 years	244
Supplemental Employee Retirement Plan
Change in benefit obligation:
Benefit obligation at beginning of year	49	54
Interest cost	1	1
Actuarial (gain) loss	(2)	2
Benefits paid	(7)	(8)
Benefit obligation at year end	41	49	$ 54
Funded status	(41)	(49)
Amounts recognized in the accompanying consolidated balance sheets:
Other current liabilities	(5)	(7)
Accrued employee benefits	(36)	$ (42)
Defined Benefit Plan SERP Benefit Obligation Estimated Future Benefit Payments [Abstract]
2019	5
2020	5
2021	5
2022	4
2023	4
Next 5 years	$ 14