Income Taxes - Components of Our Net Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
State	$ 18	$ 18
Foreign	559	404
Tax credits	179	159
Postretirement benefits other than pensions	20	21
Pensions	158	158
Payroll accruals	23	24
Book over tax depreciation	91	68
Research expense capitalized for tax	72	30
Other accruals	167	133
Valuation allowance	(762)	(554)
Total deferred tax assets	525	461
Deferred tax liabilities
Amortization of intangibles	24	82
Total deferred tax liabilities	24	82
Net deferred tax assets	$ 501	$ 379