Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 1,346	$ 1,423
Operating Income (Loss)	(301)	(39)
Depreciation and Amortization	123	147
Corporate General and Administrative	32	36
Goodwill, Impairment Loss	(229)	0	$ 0
Restructuring Charges	(20)	(25)
Western Hemisphere
Segment Reporting Information [Line Items]
Goodwill, Impairment Loss	(229)
Eastern Hemisphere
Segment Reporting Information [Line Items]
Goodwill, Impairment Loss	0
Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,346	1,423
Operating Income (Loss)	29	40
Depreciation and Amortization	120	146
Operating Segments | Western Hemisphere
Segment Reporting Information [Line Items]
Revenues	726	756
Operating Income (Loss)	9	24
Depreciation and Amortization	48	60
Operating Segments | Eastern Hemisphere
Segment Reporting Information [Line Items]
Revenues	620	667
Operating Income (Loss)	20	16
Depreciation and Amortization	72	86
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Depreciation and Amortization	3	1
Corporate General and Administrative	32	36
Segment Reconciling Items
Segment Reporting Information [Line Items]
Restructuring Charges	(20)	(25)
Impairment of Long-Lived Assets and Other Related Charges	$ (49)	$ (18)