Benefit Plans - Pension Obligation and Funded Status (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
US
Benefit obligation
Balance at the beginning of the period	$ 393	$ 367
Service cost	6	6	$ 6
Interest cost	13	13	14
Benefits paid	(26)	(23)
Actuarial (gain) loss	(27)	30
Curtailment / settlement / amendments	(2)
Balance at the end of the period	357	393	367
Fair value of plan assets
Balance at the beginning of the period	404	368
Actual return on plan assets	(25)	59
Cash contributions made in period	2
Benefits paid	(26)	(23)
Plan settlements	(2)
Balance at the end of the period	353	404	368
Funded status	(4)	11
Non-US
Benefit obligation
Balance at the beginning of the period	248	223
Service cost	3	3	3
Interest cost	10	11	10
Benefits paid	(12)	(12)
Actuarial (gain) loss	(8)	7
Foreign currency translation	(18)	16
Balance at the end of the period	223	248	223
Fair value of plan assets
Balance at the beginning of the period	235	211
Actual return on plan assets		17
Cash contributions made in period	4	5
Benefits paid	(12)	(12)
Foreign currency translation	(20)	14
Balance at the end of the period	207	235	$ 211
Funded status	$ (16)	$ (13)

The amount of increase or decrease due to a) an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services, b) an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement, c) change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

No definition available.