Acquisitions and Divestitures - Summary of Final Allocation of Purchase Price by Major Asset Acquired and Liability Assumed, Amount of Goodwill Recognized and Net Present Value of Potential Earn-out (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Goodwill	$ 5,148	$ 5,249	$ 5,087
Total assets		2,003	3,515
Liabilities:
Total liabilities		$ 868	$ 345
Firth Rixson [Member]
Assets:
Receivables from customers	193
Inventories	227
Prepaid expenses and other current assets	22
Properties, plants, and equipment	493
Goodwill	1,801
Other noncurrent assets	758
Total assets	3,494
Liabilities:
Accounts payable	162
Other current liabilities	100
Contingent consideration	130
Other noncurrent liabilities	107
Total liabilities	$ 499