Accumulated Other Comprehensive Income (Loss) -Reclassifications from AOCL to Results of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss before income taxes	$ 126	$ (1,483)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss before income taxes	5	6
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss before income taxes	$ 4	$ 1