Schedule II - Valuation and Qualifying Accounts and Reserves (Detail) - Allowance for Credit Losses - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 7	$ 2	$ 2
Charged to Income		8	9	5
Other Charges		0	0	0
Payments & Deductions	[1]	8	4	5
Balance at End of Period		$ 7	$ 7	$ 2

[1] Write-off of individual bad debt accounts