Postretirement Benefit Plans - The Weighted Average Assumptions Used to Determine Net Periodic Benefit Costs (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	2.60%	3.30%	4.30%
Expected long-term return on plan assets	6.75%	6.75%	6.75%
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	1.40%	2.10%	2.80%
Expected long-term return on plan assets	1.13%	2.30%	3.82%