Revenues - Disaggregation of revenues on geographic location of customers (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue
Revenues	$ 437	$ 436	$ 1,302	$ 1,256
U.S.
Revenue
Revenues	363	358	1,058	1,016
Asia
Revenue
Revenues	25	25	67	75
Australia
Revenue
Revenues	9	9	57	26
Europe
Revenue
Revenues	18	25	54	67
Middle East
Revenue
Revenues	13	12	40	38
South America
Revenue
Revenues	6	4	13	19
Other
Revenue
Revenues	$ 3	$ 3	$ 13	$ 15