Acquisition and Disposition Transactions - Summary of Loss on APP Sale Included in Loss on Asset Disposals (Detail) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Jun. 27, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Liabilities
Sale proceeds (net of transaction costs of $2)			$ 83	$ 55
Loss on asset disposals		$ 1	$ 103	$ 2
Alloy Piping Products [Member]
Assets
Inventory	$ 69
Property and equipment	25
Goodwill	90
Other assets	11
Assets sold	195
Liabilities
Account payable	8
Other liabilities	3
Liabilities sold	11
Net assets sold	184
Sale proceeds (net of transaction costs of $2)	83
Loss on asset disposals	$ 101