Retirement Plans - Changes in Accumulated Other Comprehensive Income Before Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Roll Forward]
Net actuarial loss (gain)	$ 2	$ 0
Amortization of actuarial loss	1	0	$ 0
Pension Plans, Defined Benefit
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Roll Forward]
Total retirement benefit recognized in accumulated other comprehensive income at beginning of year	10	7
Net actuarial loss (gain)	2	3
Translation difference	0	(1)
Other	0	1
Total retirement benefit recognized in accumulated other comprehensive income at end of year	$ 13	$ 10	$ 7