Accumulated Other Comprehensive Income - Summary of Changes in Balances for Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 1,370	$ (818)	$ (1,027)	$ (818)	$ (1,027)
Other comprehensive income (loss)	1	(2)	(1)
Ending balance	1,484	1,370	(999)	1,484	(910)
Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance as of beginning of period	(8)	(6)	(7)	(6)	(7)
Currency translation adjustments	1			(1)
Other comprehensive income (loss)	1			(1)
Balance as of end of period	(7)	(8)	(7)	(7)	(7)
Employee Benefit Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance as of beginning of period	11	11	14	11	14
Adoption of new accounting principle					3
Amortization of actuarial gain					(1)
Other comprehensive income (loss)					(1)
Balance as of end of period	11	11	16	11	16
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	3	5	7	5	7
Adoption of new accounting principle			3		3
Other comprehensive income (loss)	1	(2)	(1)	(1)	(1)
Ending balance	$ 4	$ 3	$ 9	$ 4	$ 9