Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	$ 4,996	$ 5,253
Net current period other comprehensive income (loss)	(135)	(24)
Ending balance	3,479	4,983
Cumulative Translation Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	(479)
Other comprehensive income (loss) before reclassifications	(156)
Amounts reclassified to earnings	0
Net current period other comprehensive income (loss)	(156)
Ending balance	(635)
Pension and  Postretirement Costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	(399)
Other comprehensive income (loss) before reclassifications	(9)
Amounts reclassified to earnings	4
Net current period other comprehensive income (loss)	(5)
Ending balance	(404)
Derivative Financial Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	(42)
Other comprehensive income (loss) before reclassifications	25
Amounts reclassified to earnings	1
Net current period other comprehensive income (loss)	26
Ending balance	(16)
AOCL
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	(920)	(913)
Other comprehensive income (loss) before reclassifications	(140)
Amounts reclassified to earnings	5
Net current period other comprehensive income (loss)	(135)
Ending balance	$ (1,055)	$ (937)