Retirement and Employee Benefit Plans Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost	$ 8	$ 38	$ 9
Projected benefit obligation	173	198
Accumulated benefit obligation for defined benefit pension plans	21	35
Employer contributions	5	23
Estimated future employer contributions in next fiscal year, cash	5
Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	123	133
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution expenses related to the defined contribution plans which cover certain employees	$ 37	$ 24	$ 30