Severance Costs	12 Months Ended
	Dec. 31, 2021
Restructuring and Related Activities [Abstract]
Exit and Disposal Costs	13.  Severance CostsWe incurred employee termination costs of $27 million in 2020 related to cost reduction initiatives. All charges were based on amounts incurred under ongoing severance arrangements or other statutory requirements, plus amounts earned under enhanced benefit arrangements. Payments for termination costs were $7 million in 2021 (2020: $20 million; 2019: $4 million)