Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 4,996	$ 5,253	$ 14,181
Total other comprehensive income (loss), net of tax	40	(7)	(87)
Ending balance	3,900	4,996	5,253
Cumulative Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(479)	(493)
Other comprehensive income (loss) before reclassifications	(2)	4
Amounts reclassified to earnings	0	10
Total other comprehensive income (loss), net of tax	(2)	14
Ending balance	(481)	(479)	(493)
Pension and Postretirement Cost
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(399)	(398)
Other comprehensive income (loss) before reclassifications	(4)	(8)
Amounts reclassified to earnings	47	7
Total other comprehensive income (loss), net of tax	43	(1)
Ending balance	(356)	(399)	(398)
Derivative Financial Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(42)	(22)
Other comprehensive income (loss) before reclassifications	3	(14)
Amounts reclassified to earnings	(4)	(6)
Total other comprehensive income (loss), net of tax	(1)	(20)
Ending balance	(43)	(42)	(22)
AOCL
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(920)	(913)	(763)
Other comprehensive income (loss) before reclassifications	(3)	(18)
Amounts reclassified to earnings	43	11
Total other comprehensive income (loss), net of tax	40	(7)
Ending balance	$ (880)	$ (920)	$ (913)