Pensions and Other Post-Retirement Benefits - Summary of Changes in Fair Value of Pension Plans Level 3 Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Actual return on plan assets:
Effect of foreign currency translation	$ 2	$ (59)
Level 3
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Balance, beginning of year	174	196
Actual return on plan assets:
(Sales)/investments	(2)	(12)
Settlements	(148)
Unrealized gains (losses)		(1)
Effect of foreign currency translation	(2)	(9)
Balance, end of year	22	174
Level 3 | Real estate
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Balance, beginning of year	42	47
Actual return on plan assets:
(Sales)/investments	(2)	(4)
Settlements	(18)
Effect of foreign currency translation		(1)
Balance, end of year	22	42
Level 3 | Other
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Balance, beginning of year	132	149
Actual return on plan assets:
(Sales)/investments		(8)
Settlements	(130)
Unrealized gains (losses)		(1)
Effect of foreign currency translation	$ (2)	(8)
Balance, end of year		$ 132