Amounts reclassified from AOCL (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	$ 321	$ 248
Total reclassifications, before tax	191	127
Total reclassifications, net of tax	151	83
Reclassified from AOCL | Prior service cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	3	1
Reclassified from AOCL | Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassifications, before tax	3	1
Total reclassifications, net of tax	$ 3	$ 1