Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets
Accrued expenses	$ 377	$ 389
Retirement benefits	411	352
Tax credits and net operating losses	747	547
Valuation allowances	(150)	(135)
Total deferred tax assets	1,385	1,153
Deferred tax liabilities
Subsidiaries' unremitted earnings	145	147
Asset basis differences	704	847
Total deferred tax liabilities	849	994
Net deferred tax asset	$ 536	$ 159